[Papers, conferences]

[Theses]

[On-line textbooks]

[Other works]

Publications by C.L. Brack

Associate Professor in Forest Measurement, Modelling and Management.
Forestry program,
Fenner School of Environment and Society.
Australian National University.
Canberra 0200 Australia.

E-mail: Cris.Brack@anu.edu.au

Papers and
Conference Presentations

• Ford, A.J., Brack, C.L. and James, R.N. (2007) Site index prediction for Pinus radiata D.Don at local scale on the southern tablelands of New South Wales using a national forest productivity model. Australian Forestry 70(3): 152 - 157.

Productivity indices, developed by the Australian Greenhouse Office as part of the National Carbon Accounting System (NCAS) to aid spatial estimation of native forest productivity across Australia, were tested to estimate site quality for Pinus radata D.Don plantations at farm level in and around the tablelands in the south-eastern corner of New South Wales. This study found a significant (P < 0.01) relationship between site index and productivity indices generated by NCAS. 'Region', included as a categorical variable, was significant (P < 0.05) in the relationship between site index and these productivity indices. These results were consistent between indices that used long-term average data and those that used only data that coincided with the lifetime of the plantations. Various groupings of regions were tested to produce a logical and useful model to estimate site index. However, the causes of the significant differences between regions are not known and the classification of 'Region' is speculative for unplanted areas. The paper discusses differences in the models that use long-term or short-term productivity indices and the potential to transfer productivity estimates derived at national scale to local scale.

• Gilbert, M. and Brack, C.L. (2007) Changes in public requests to remove significant urban trees after severe bushfires in Canberra, Australia. Urban Forestry & Urban Greening 6: 41 - 48.

Trees on leased land provide an important contribution to Canberra's urban forest and consequently the Australian Capital Territory (ACT) Government introduced legislation to protect urban trees on leased land from unwarranted removal under the Tree Protection (Interim Scheme) Act 2001. This tree protection legislation applies to significant trees, classified using size-based criteria, on leased land for urban and other non-rural purposes. Responsibility resides with the ACT Government to preserve and protect significant trees on leased land in Canberra, until such time as removal is warranted and prudent. On Saturday 18 January 2003, 2 years after the introduction of the tree protection legislation, Canberra experienced a state of emergency when major bushfires swept through the bush-urban interface and penetrated into the western urban area subsequently destroying or damaging over 500 houses. There was a substantial increase in requests lodged under the Act immediately after the fires, but by February 2004 the number of requests returned to February 2002 levels which suggests leaseholder response to the fire declines relatively quickly. The percentage of requests approved (88%) remained relatively constant which indicates that the increased number of applications were for reasons that were considered valid under the Act although it is unlikely that these concerns only became valid during the month proceeding the fire. Dominant genera removed each February from 2002 to 2004 were similar; however, Eucalyptus species have shown a small but significant relative increase although there are insufficient data to conclude this increase indicates an increased aversion to this genus. Future management needs to consider the community perception of trees and temporal reaction to major events.

• Waterworth, R., Raison, J., Brack, C.L., Benson; M., Khanna; P. and Keryn P. (2007) Effects of irrigation and fertilisation on growth and structure of Pinus radiata stands between 10 and 29 years of age. Forest Ecology and Management 239: 169 - 181.

Temporal change in stem volume, basal area, diameter, and height are reported for stands of Pinus radiata growing near Canberra, ACT, Australia between the ages of 10 and 29 years. The stands were subjected to either a single fertilization (F) at age 10 years, irrigation (1), irrigation after a single fertilization at age 10 years (IF), irrigation with continuous liquid fertilization (IL), or no treatment (Control (Q). At age 15 years all the stands were thinned. At the same time, irrigation ceased in a duplicate IF stand, and irrigation and liquid fertilization ceased in a duplicate IL stand.

Stem growth responded markedly to irrigation, with a strong interactive effect when combined with N fertilization. Over a 19 year treatment period (ages 10-29 years) the percentage gross underbark volume responses, relative to the control which had an annual growth rate of 19.3 m 3 ha 1 year 1, were F (98%),1 (132%), IF (184%), and IL (229%). Standing stem volumes (m 3 ha- 1) at the end of the study were C (340), F (328), 1 (438), IF (624), and IL (776). The IF stand continued to grow at rates considerably greater than the 1 or F for the entire experiment, indicating efficient N cycling with increased water supply over a period of nearly 20 years. In non-irrigated stands, added N only increased growth during wet periods, and the response declined to be similar to the control within 5-8 years.

Irrigation increased growth in the larger trees proportionally more than the smaller trees, resulting in an increased diameter distribution compared with the non-irrigated stands. Cessation of irrigation in combination with thinning after 5 years of treatment immediately reduced annual basal area growth to levels similar to the control for at least 2 years, but did not lead to tree mortality. Thinning reduced stand basal area increment for 2-3 years in treatments without adequate N supply, even if they were irrigated. The study demonstrates the importance of monitoring long-term growth to understand the changing interactions between water and N availability. For example, initial responses to irrigation only were markedly attenuated over time because of increasing N limitations, while irrigated and fertilized stands showed little or no change in the response pattern. Understanding the temporal change in water-N interactions has implications for modelling long-term forest growth, and forest management..

• Waterworth, R.M., Richards, G.P., Brack, C.L. and Evans, D.M.W. (2007) A generalised hybrid process-empirical model for predicting plantation forest growth. Forest Ecology and Management 238: 231 - 243.

A generic model of plantation growth was developed for Australia's National Carbon Accounting System to allow spatial estimation of carbon stocks over time. Unlike the primary goal of most forest growth models, which is to predict log volume at harvest age, the international guidelines for carbon accounting require estimation of current annual increments of total (above and belowground) biomass. In contrast to most commercial forestry systems that are concerned with rotations of many years, capturing the effects of annual climate variability is important, a feature that would otherwise be largely ameliorated over a forest rotation.

While yield tables can provide the basis from which empirically based models can predict an 'averaged' performance over time, a process-based model can capture the effects of variability over short time periods. To utilise the valuable empirical data contained in yield tables, while also capturing the effects of process drivers, a hybrid model has been developed that integrates:

• a spatially and temporally explicit site class index based on a process model,
• a simple growth equation modified by the spatial and temporal site index,
• known empirical constraints on growth (as an average) sourced from yield tables,
• management effects.

Management effects may either increase overall site productivity, and hence biomass accumulation, or accelerate the rate of approach toward site carrying capacity. The effects of management are important and need to be captured in the model. Some 5000 forest management regimes, representing different species, regions, site qualities and variants in management in Australia have been described for application within the model. A national program of identifying both forest areas and forest age classes, using a 30-year archive of Landsat satellite data has been undertaken to provide inputs to the model.

• Brack, C.L. (2007) National forest inventories and biodiversity monitoring in Australia. Plant Biosystems 141: 104 - 112.

Forests currently cover over 20% of the Australian continent and are an important resource, subject to a wide range of economic and environmental pressures. These lands support substantial numbers of forest-dependent species with national forest inventories providing important information on biodiversity. National scale information on these forests has been collected or collated since 1988 under the National Forest Inventory (NFI) programme, but substantial problems with the 'snap shot' approach have been recognized, particularly with respect to monitoring change and a consequent move towards a permanent and sample-based continental forest monitoring framework (CFMF) has been proposed. CFMF is proposed to consist of three Tiers: (1) satellite imagery of the continent to identify forest and change in forest cover; (2) systematic highresolution remotely sensed data and (3) permanent ground points at 20620 km grid interception points. The CFMF approach is in line with the international trend of national forest inventories in developed countries although the Tier 2 approach offers a useful extension. An alternative inventory approach is provided by the National Carbon Accounting System (NCAS) which models the mass of carbon and nitrogen in seven separate living and dead biomass pools for any point under forest or agriculture land use since 1970. The NCAS approach allows fine spatial and temporal monitoring of changes in these carbon and nitrogen biomass pools, and predictions of changes that result from policy or management decisions. This paper briefly reviews NFI, NCAS and the proposed CFMF, with particular emphasis on issues of use and potential for monitoring biodiversity in this biologically very diverse country.

• Brack, C.L., Richards, G and Waterworth, R. (2006) Integrated and comprehensive estimation of greenhouse gas emissions from land systems. Sustainability Science 1: 91 - 106.

Exchanges of carbon and nitrogen between the atmosphere and terrestrial ecosystems involve a complex set of interactions affected by both natural and management processes. Understanding these processes is important for managing ecosystem productivity and sustainability. Management processes also affect the net outcome of exchanges of greenhouse gases between terrestrial ecosystems and the atmosphere. In developing a national carbon accounting system (NCAS) for Australia to account for emissions and removal of greenhouse gases to and from the atmosphere, a carbon:nitrogen mass balance ecosystem model (FullCAM) was developed. The FullCAM model is a hybrid of empirical and process modelling. The approach enables application to a wide range of natural resource management issues, because it is at land-management-relevant spatial and temporal resolution and captures the main process and management drivers. The scenario-prediction capability can be used to determine the emissions consequences of different management activities. Because, in Australia, emissions of greenhouse gases are closely related to the retention of dead organic matter and the availability of nitrogen for plant growth, the carbon and nitrogen cycling as modelled are good indicators of ecosystem productivity and condition. The NCAS also emphasizes the advantages of a comprehensive and integrated approach to developing a continental scale ecosystem-modelling system that has relevance both to estimation of greenhouse gas emissions and sustainable management of natural resources.

• Brack, C.L. (2006) Updating urban forest inventories: An example of the DISMUT model. Urban Forestry & Urban Greening 5:189 - 194.

Canberra is a unique city in Australia where the trees on public land that dominate the urban forest were planned for at the city's inception. In the mid-1990s, a 100% census of street and park trees was completed, and together with simple health, growth and yield models, this database formed the basis of a decision information system to support the management of the urban trees - DISMUT. The accuracy of the models was evaluated in a study in 2005 where models to predict total tree height were found to be unbiased and precise, tree crown dimension were under-estimated for small trees, and tree health was over-estimated. The over-estimate of health may be due to the relatively poor rainfall conditions over the past 10 years while the biases in crown dimension predictions are more likely due to a too simple model form. However, the existence of DISMUT predictions over all streets and parks in Canberra means that statistically efficient two-phase sampling approaches can be used to correct for any bias in the mean estimates of tree numbers and size, and also to predict the mean value of other environmental, economic or social parameters of interest that are correlated to tree size.

• Brookhouse, M. and Brack, C.L. (2006) Crossdating and analysis of eucalypt tree rings exhibiting terminal and reverse latewood. Trees DOI: 10.1007/s00468-006-0092-0

We investigated crossdating and climate sensitivity in tree-ring series from Eucalyptus delegatensis Baker, R.T. and E. obliqua L'Herit.We first visually crossdated the measured ring width series and then independently verified this crossdating using Xmatch and cross-correlation significance tests. Crossdating was verified in 28 of the 32 study trees. Crossdating success differed between E. delegatensis and E. obliqua. In E. delegatensis crossdating success appears to be related to tree dominance and elevation. In E. obliqua radial azimuth appears to affect crossdating success. We developed two chronologies for each of the species studied. The first of these chronologies was based on all visually crossdated radii and the other on radii for which crossdating had been independently verified. Signal strength was higher in the verified chronologies. Correlation analysis between the verified chronologies and climate data revealed no significant correlation between precipitation and ring width for either species. E. obliqua ring width was significantly correlated with mean minimum and maximum air temperature and vapour pressure deficit during summer of the growing season. The E. delegatensis chronology was significantly correlated with air temperature and frequency of frost during the preceding winter. Ring width in both species was significantly correlated with air temperature during the preceding summer. Potential physiological explanations for these results are discussed. Further study is required to verify the results of climatological analysis and to explore the causes of variation in signal strength within and between trees.

• McElhinny, C., Gibbons, P., Brack, C.L. and Bauhus, J. (2006) Fauna-habitat relationships: a basis for identifying key stand structural attributes in temperate Australian eucalypt forests and woodlands. Pacific Conservation Biology 12: 89 - 110.

We review a representative sample of the literature concerning fauna-habitat relationships in temperate Australian eucalypt forests and woodlands as a basis for identifying some key stand structural attributes in these ecosystems. Our review identifies 56 studies in southeast and southwest Australia in which the presence or abundance of different fauna were significantly associated with vegetation structural attributes at the scale of a stand. The majority of these studies concern bird, arboreal mammal, and ground mammal habitat requirements, with relatively few studies addressing the habitat requirements of reptiles, invertebrates, bats or amphibians. We identify 34 key structural attributes from these 56 studies, by grouping similar attributes, and then representing each group with a single generic attribute. Relatively few of these attributes are incorporated into indices used to quantify fauna habitat. We highlight the need for a quantitative method for selecting which key attributes should form the basis for an index of structural complexity or other surrogate measure of faunal diversity..

• McElhinny, C., Gibbons, P., Brack, C.L. and Bauhus, J. (2005) Forest and woodland stand structural complexity: Its definition and measurement. Forest Ecology and Management 218: 1 - 24.

This paper reviews the literature concerning forest and woodland structure at the scale of an individual stand. Stand structure is defined in terms of structural attributes and stand structural complexity. Stand structural complexity is considered to be a measure of the number of different attributes present and the relative abundance of each of these attributes. The review indicates there is no definitive suite of structural attributes; different authors emphasise subsets of different attributes, and relatively few studies provide quantitative evidence linking attributes to the provision of faunal habitat or other measures of biodiversity, although a number of studies identify attributes that distinguish between successional stages. A summary of key structural attributes identified in the literature is presented under the following stand elements: foliage arrangement, canopy cover, tree diameter, tree height, tree spacing, tree species, stand biomass, understorey vegetation, and deadwood. Indices of structural complexity are also reviewed. Three types of index framework are identified: indices based on the cumulative score of attributes; indices based on the average score of groups of attributes; and indices based on the interaction of attributes. The review identifies a variety of different indices under each of these frameworks with no single index preferred over the others. The most prominent of these indices are discussed in detail and the following guidelines suggested for the development of an index of structural
complexity: (1) Start with a comprehensive set of structural attributes, in which there is a demonstrated association between attributes and the elements of biodiversity that are of interest. (2) Use a simple mathematical system to construct the index; this facilitates the use of multiple attributes and interpretation of the index in terms of real stand conditions. (3) Score attributes relative to the range of values occurring in stands of a comparable vegetation community. (4) Try different weightings of attributes in the index, adopting those weightings which most clearly distinguish between stands.

• Brack, C.L. (2005) Environmental, amenity and Habitat Values of an Urban Forest: How to determine and manage for them in Canberra. Proceedings of the 9th Annual ISAAC National Conference. Launceston, Tasmania. September 30th - October 5th, 2005. P 19.

Individual trees provide a range of environmental and habitat values in an urban environment. While these values will be related to the size and structure of the canopy and the types of leaves / fruits / buds, a diversity of these attributes and even tree health within an urban environment will enhance the overall value. However, the diversity of many urban forests is a consequence of decisions that did not account for the long term or biological / physiological nature of the trees established and an optimal diversity is difficult to determine and manage. Management for diversity related to optimal habitat value, in particular, may directly oppose management for other values.

This presentation will use the urban forests planted on public land in Canberra as a case study to determine the value of a range of benefits, including:

• Amenity
• Pollution mitigation
• Amelioration of climatic extremes
• Storm water control
• Biodiversity and vegetation condition

A range of techniques adapted from traditional forestry mensuration, inventory and planning are used in the study. Values are based on a combination of extensive inventory and modelling of the current and potential structure of street- and park-scapes, then relating these structures to money or other indices of value where possible.

The management implications of the structure, age and species distribution of trees in Canberra on the environmental and habitat values are examined.

• Brack, C.L. (2005) Inventory systems in Australia using remotely sensed data to improve precision and scale of estimation. The International Forestry Review 7(5): 285.

• Brack, C.L. (2005) Teaching technology and individual feedback in forestry education. The International Forestry Review 7(5): 353.

• Lorenz, M., Varjo, J. and Bahamondez (2005) Forest Assessment for changing information needs. Contributing authors: C.L. Brack, M. Clarke, M. Gillis, H. Hironen, C. Kleinn, A. Riebau, H. Sase and T. Totsuka. In Forests in the Global Balance - Changing paradigms. G. Mery, R. Alfaro, M. Kanninen and M. Loboviko (eds). IUFRO World Series Volume 17: 139 - 150.

Forest assessment aims to meet the information needs of forestry for management decisions. It was introduced more than 500 years ago, when an increasing demand for continuous wood supply led to the idea of sustainable forest management. Since then, along with the evolution of planning from timber maximisation to holistic ecological management, several changes in paradigms have occurred in the evolution of forest assessment. Today, forest assessment has been implemented worldwide with different intensities and at different scales, ranging from stand level to the national, multinational and global scale. Paradigms are changing to different extents in most of these forestry systems. Multinational systems based on collations of national results, as well as harmonised transnational monitoring grids, assess indicators of forest health, climate change, carbon sequestration, biodiversity and sustainable forest management. However, even basic quantitative information on forests of many developing countries and nations with large territories is founded on estimations. Remote sensing can contribute to closing gaps in knowledge, especially when combined with terrestrial assessments. Harmonisation of assessment methods, standards and reporting systems among different countries enhances the comparibility of results. This is a precondition for multinational assessments, utilizing synergies and avoiding duplications. Any forest assessment system must have clearly defined objectives, must rely upon a statistically sound survey design and must be subjected to strict procedures of data quality assurance.

• Brack, C.L. (2004) Use of Instructional Technology in a B.Sc. (Forestry) Degree. In Proceedings of the IUFRO 6.15-00 conference "Modern Forestry Curricula - Response to changes in the field of profession". 8 - 12 March 1998, Freiburg Germany. S. Lewark and P. Schmidt (Eds). IUFRO 6.14-00 Education Group Publication No 1: 43 - 54. ISBN 3-933548-29-2.

• Lee, A., Lucas, R. and Brack, C.L. (2004) Quantifying vertical forest stand structure using small footprint LIDAR to assess potential stand dynamics. Proceedings of the ISPRS working group VIII/2 Laser-Scanners for Forest and Landscape Assessment conference. Freiburg, Germany 03-06 October 2004. Editors: M. Thies, B. Koch, H. Spiecker, H. Weinacker. International Archives of Photogrammetry, Remote Sensing and Spatial Information Sciences (ISSN 1682-1750) XXXVI, PART 8/W2: 213 - 217 (URL: http://www.isprs.org/commission8/wg2/workshop_laser_forest/LEE.pdf)

The vertical distribution of plant elements (e.g., foliage and wood) within a forest can yield important information on stand structure, dynamics and growth stage but such information is often difficult to acquire across landscapes using traditional methods of field survey and aerial photograph interpretation. Recent advances in airborne laser scanning (ALS), however, have facilitated rapid assessment of stand height and cover to levels of accuracy considered acceptable for forest inventory and management. A few studies have extended this analysis to the descriptions of growth stage and retrieval of biomass, particularly in complex forest environments. However, current research has raised issues as to how well the vertical profile can be represented and whether the relative amounts of over and understorey can be quantified accurately. Focusing on subtropical open forests and woodlands, in central Queensland, Australia, this paper provides a better insight into how small footprint Light Detection and Ranging (LiDAR) sensor data can be used to create apparent vertical profiles to describe aspects of vertical stand structure (e.g., overstorey/understorey) and also infer broad successional or growth stages. Such profiles were integrated with field measurements within a common reference matrix (based on 1 m cubes), thereby providing spatially explicit tree/crown maps in three dimensions and allowing validation of those generated from LiDAR. Such interpretations, as well as enhancing forest information retrieval, were considered important in the interpretation of other forms of remote sensing data, including radar and optical data. The conceptual basis for this integration method is outlined with an example utilising one field plot, and the role this method might play in quantifying stand dynamics and carbon sequestration is discussed.

• Brack, C.L. (2004) Projecting native forest inventory estimates from public to private tenures. Australian Forestry 67(4): 230 - 235.

Inventory information on privately managed forest areas tends to be more variable and less available than for equivalent publicly managed forests. This paper reports on an examination of the timber volume on Tasmanian private and public native forests and demonstrates that the differences between tenures in terms of total (entire stem) volume (m3ha-1) are significant but relatively small. The paper also demonstrates that information from public forest inventories may be used to generate auxiliary information that can improve the efficiency of sampling on equivalent private forests. Regression and variable probability sampling using auxiliary information generated from public forest inventories can reduce the need for establishing sample points in private forests to only 25% of that required under simple random sampling for a given level of precision.

• Richards, G.P and Brack, C.L. (2004) A continental biomass stock and stock change estimation approach for Australia. Australian Forestry 67(4): 284 - 288.

To implement Australia's National Carbon Accounting System it is necessary to estimate biomass stock, continentally, and change in stock, at a sub-hectare spatial resolution. The approach developed to meet this requirement is a hybrid between GIS-based process modelling and empiricism.

Multi-temporal mapping of productivity was carried out using a variant of the 3PG (physiological principles predicting growth) model. Relationships were found between mapped productivity indices and measurements of biomass at maturity (i.e. long-term undisturbed stands). This information was then used to interpolate maps of biomass potential.

Simple growth formulae were used to plot biomass accumulation, with the ‘rate' of approach to mature biomass set by the age at which maximum current annual increment occurs and the predicted site plant productivity over time. The age of the forest stand was determined from disturbance events detected by twelve national coverages of Landsat MSS, TM and ETM+ remotely-sensed data collected between 1972 and 2002. Responses to thinning of existing forests are calculated using an adjustment of stand age concurrent with the intensity of the thinning event.

• Richards, G.P and Brack, C.L. (2004) A modelled carbon account for Australia's post-1990 plantation estate. Australian Forestry 67(4): 289 - 300.

Australia's national carbon account for afforestation and reforestation activities qualifying under Articles 3.3 of the Kyoto Protocol between 2008 and 2012 can be estimated using a carbon accounting model supported by a range of forest related data.  Using inventories of current plantation areas and projected expansion of the plantation estate it is possible to project carbon sequestration in 36 known plantation management regimes to give an annual national account of net (sequestration minus emissions) carbon stock change.

Data for the modelling were provided through a range of studies undertaken for the development of the National Carbon Accounting System (NCAS).  These included compendiums of available information on management regimes, plantation growth and yield, wood density, carbon contents and allocations to non-stem tree components.

Future refinements of the modelling will include the extraction of a 'mask' of relevant afforestation and reforestation activities from the continental multi-temporal Landsat satellite coverages of Australia developed for the NCAS.  Other improvements will include the use of the NCAS national annual 1km grid productivity mapping to determine variability in growth associated with variability in climate and soil characteristics.  Soil carbon modelling capability using the Roth C model will also be possible when the spatial mapping is complete and details of plantation areas can be merged with the relevant maps of soils and climate.

• J.L. Kesteven, J.L., Brack, C.L. and Furby, S.L. (2003) Using remote sensing and a spatial plant productivity model to assess biomass change. In: Advances in Forest Inventory for Sustainable Forest Management and Biodiversity Monitoring. P. Corona, Michael Köhl and Marco Marchetti (Eds). Kluwer Academic Publishers, Dordrecht. p 33 - 56. ISNB 1-4020-1715-4

Accounting for biomass and carbon change in forestry and agriculture under the Kyoto and other international protocols requires an assessment of the change in land cover, including afforestation, reforestation and deforestation events. Due to the time associated with soil carbon and biomass decay, the impact of an event associated with land cover change may continue over many years. Remote sensing was used to identify the location, area and time of an afforestation, reforestation or deforestation event. This time-based, activity-by-activity approach, covering all continental woody vegetation, provides a platform of land cover history. This land cover history is used in conjunction with calculations of Net Primary Productivity and estimates of pool turnover and decay to provide a first phase estimate of biomass and carbon on a spatially referenced basis. The Net Primary Productivity was calculated for Australia using a physiological model (3-PG (Spatial)) based on the relationship between the photosynthetically active radiation absorbed by plant canopies (APAR) and the (biomass) productivity of those canopies at a monthly time step. The factor converting APAR to biomass was reduced from the selected optimum value by modifiers dependent on soil fertility; atmospheric vapour pressure deficits, soil water content and temperature. Leaf Area Index, essential for the calculation of APAR, was estimated from 10-year mean values of Normalized Difference Vegetation Indices. Incoming short-wave radiation - and hence APAR - was corrected for slope and aspect using a Digital Elevation Map. The ESOCLIM package was used to generate climate surfaces for the country. Soil fertility and water holding capacity values were obtained from the (digital) soil atlas of Australia The correlation between the first phase estimate of biomass and sites across Australia that ranged from arid shrublands to tall wet sclerophyll (2 - 450 t/ha biomass) was examined. This correlation is significant and is useful for improving the efficiency of estimating biomass and carbon totals and change.

• Croke, B., Merrit, W., Brack, C., and Jakeman, A (2003) Forests, catchment hydrology and catchment management. Paper presented to the Modelling Forests from leaves to landscapes Workshop. 1 - 3 December, 2003. University of Melbourne, Australia. PP 11.

Forests affect the quantity and quality of water delivered by catchments. Examples include impacts on water balance, as well as sediment, salt and carbon fluxes. Therefore, there is a need to integrate the knowledge from both forestry and hydrology disciplines in order to advance our understanding of the role of forests in the broader context. A decadal initiative on Prediction in Ungauged Basins (PUB) has been recently implemented by the International Association of Hydrological Sciences - a key component of this will be furthering our understanding of the influence of land use (particularly forests) on catchment response. This will require improved understanding of plant characteristics, and how these influence the catchment scale response. Examples of the modelling approaches that have been used to simulate the impact of forests (and more generally, trees) on hydrological response will be discussed. These include (a) modelling the influence of land use change on catchment response, (b) estimation of hydrologic the response at ungauged sites, (c) simulating the effects of agroforestry mosaics on streamflow and sediment transport, (d) modelling land use impacts on salt mobilisation, including estimation of recharge and subsurface flows, and (f) simulating the influence of riparian zone vegetation on sediment exports through bank stabilisation and trapping of surface eroded material. While detailed, spatially explicit models can be constructed for these purposes, at the catchment scale much of the influence represented in such models is not observed. This is the result of the averaging effect of the catchment. Instead, lumped conceptual models with limited spatial detail are used (the appropriate scale at which the spatial detail needs to be considered is an important field of investigation itself). This is particularly true for integrated assessment of catchment management options where the individual models used must not be complex in order to be able to calibrate and characterise the response of the integrated model. Catchment scale models can also help bridge the gap between the regional decision-making scale and the operational scale for forest management by simulating possible changes in water quantity and quality in response to forest management regimes. Examples of integrated assessment will also be presented, where the social and economic impacts of land use and policy changes are studied.

• Lee, A. and Brack, C.L., (2003) Forest stand structural descriptions using LIDAR - integrated methods to assess growth stage and linkages between mapping baselines and monitoring frameworks. Paper presented to the Modelling Forests from leaves to landscapes Workshop. 1 - 3 December, 2003. University of Melbourne, Australia. PP 12.

Airborne laser scanners (ALS) or LIDAR have traditionally been used to estimate stand height and crown canopy cover from first and last return data. These two parameters are positively correlated with stand volume (R2>0.6, P less than 0.01) and other useful forest parameters for native eucalypt forests in Queensland and Victoria. However, laser scanners provide significantly more data than just the first and last return details. Profiles of laser return data - cumulative percentage by height above ground - form approximate sigmoid curves. The shape and area under these curves is related to characteristics of the LIDAR and the structural properties of the stand, including understorey presence, dominance and closure of the overstorey, openness of tree canopy species, leaf and branching structure, height and density of foliage. Broad growth stages, biomass and volume of eucalypt forests, including relatively undisturbed and recently harvested, are determined from various aspects of the profile derived from LIDAR over a 220,000ha study area in the south central Queensland woodlands and part of a National Forest Inventory Continental Forest Monitoring Framework pilot project in North East Victoria. The methods investigated in this paper can provide insight into resolving issues with integrating existing baseline vegetation mapping with continental vegetation monitoring frameworks, for improved ecosystem management.

• Brack, C.L. (2003) Modern Forest Inventory: Is there a need to go to the field any more? Proceedings of the Joint Australian and New Zealand Institute of Forestry Conference " Australasian Forestry - A Stratefic Vision", 27 April - 1 May 2002. Queenstown, New Zealand. P 144 - 156.

Demands for quality information about the forest and its products have continued to increase. These demands include detailed information about wide range of resources - both wood and non-wood based - on small, nominated units of land. The Kyoto-type carbon credit schemes for example require the precise estimation of carbon pools in forests at specific sub-hectare locations. An increasing proportion of production forestry is also on privately managed lands that are disjoint and have a very heterogeneous management history, which makes accessibility and traditional sampling very difficult. Fortunately, there are increasingly powerful technologies that can be brought to bear to assist in meeting the information demands. These technologies include a range of powerful remote sensing and measuring devices, which have led some to ask whether direct or on-ground measurement is a thing of the past? The powerful technologies however appear to be applied in a relatively inefficient manner that hasn't changed since the first aerial photographs were used in forest inventory.

This presentation reviews the modern technologies now being applied to quantifying the forest for wood and non-wood values and examines the potential to optimise their usefulness. Particular emphasis is placed on sampling approaches that utilise available information more fully than traditional simple random sampling, stratified random sampling and other equal probability-based systems. When on-ground visits are required, these advanced sampling approaches can ensure that the maximum use is made from each expensive measurement.

• Banks, J.C.G. and Brack, C.L. (2003) Canberra's Urban Forest: Evolution and planning for future landscapes. Urban Forestry & Urban Greening 1(3): 151 - 160.

Canberra, Australia's national capital, is a planned city established on grazing lands in the southern tablelands of New South Wales. Over the past nine decades it has grown into a garden city of 300,000 people. Landscaping was an early priority as much of the chosen site for the city was a treeless plain. Major tree planting began in the 1920's and today the urban forest on public lands contains 400,000 trees from over 200 species in streets and parklands. The species used has changed over time with exotic deciduous trees and conifers dominating early plantings. By the 1970's native species, mostly eucalypts, were planted. Today fewer species comprising an equal mix of native and exotics are used. Trees in the earlier plantings are now mature and given the harshness of the local climate many will come to the end of their 'safe life' in the early decades of this century. This provides new challenges for urban tree managers as to how to effect tree replacement that is aesthetically pleasing, ecologically sound and socially acceptable. To assist in this planning a tree data base and modeling system has been assembled. This system - Decision Information System for Managing Urban Trees or DISMUT - facilitates the development of forest- level management programs by allowing the projection of change and work requirements that the result from historical and current plantings over the entire urban forest.

• Brack, C.L. (2002) Pollution mitigation and carbon sequestration by an urban forest. Environmental Pollution 116(1):195 - 200. (URL http://www.elsevier.com/locate/envpol)

At the beginning of the 1900s, the Canberra plain was largely treeless. Graziers had carried out extensive clearing of the original trees since the 1820s leaving only scattered remnants and some plantings near homesteads. With the selection of Canberra as the site for the new capital of Australia, extensive tree plantings began in 1911. These trees have delivered a number of benefits, including aesthetic values and the amelioration of climatic extremes. Recently, however, it was considered that the benefits might extend to pollution mitigation and the sequestration of carbon. This paper outlines a case study of the value of the Canberra urban forest with particular reference to pollution mitigation. This study uses a tree inventory, modelling and decision support system developed to collect and use data about trees for tree asset management. The decision support system (DISMUT) was developed to assist in the management of about 400,000 trees planted in Canberra. The size of trees during the 5-year Kyoto Commitment Period was estimated using DISMUT and multiplied by estimates of value per square meter of canopy derived from available literature. The planted trees are estimated to have a combined energy reduction, pollution mitigation and carbon sequestration value of US$20-67 million during the period 2008-2012.

• Brack, C.L. and Richards, G.P. (2002) Carbon accounting model for forests in Australia. Environmental Pollution 116 (1): 187 - 194. (URL http://www.elsevier.com/locate/envpol)

CAMFor (Carbon Accounting Model for Forests) is a sophisticated spreadsheet model developed to assist in carbon accounting and projection. This model can integrate information from a range of alternate sources including user input, default parameters and third party model outputs to calculate the carbon flows associated with a stand of trees and the wood products derived from harvests of that stand. Carbon is tracked in the following pools:

• Biomass (stemwood, branches, bark, fine and coarse roots, leaves and twigs)
• Soil (organic matter and inert charcoal)
• Debris (coarse and fine litter, slash, below ground dead material)
• Products (waste wood, sawn timber, paper, biofuel, reconstituted wood products)

These pools can be tracked following thinning, fires and over multiple rotations. A sensitivity module has been developed to assist examination of the important assumptions and inputs. This paper reviews the functionality of CAMFor and reports on its use in a case study to explore the precision of estimates of carbon sequestration in a eucalypt plantation. Information on variability in unbiased models, measurement accuracy and other sources of error are combined in a sensitivity analysis to estimate the overall precision of sequestration estimates.

• Brack, C.L. (2002) Comparing total tree volume and growth on similar stands of differing tenure. In Biomass Estimation: Approaches for Assessment of Stocks and Change. G.P. Richards (Ed). National Carbon Accounting System Technical Report no 27: 91 - 142. (URL: http://www.greenhouse.gov.au/ncas/publications/index.html)
• Brack, C.L. (2002) Forecasting Carbon Sequestration from Individual Eucalypt Plantations. In Biomass Estimation: Approaches for Assessment of Stocks and Change. G.P. Richards (Ed). National Carbon Accounting System Technical Report no 27: 105 - 116. (URL: http://www.greenhouse.gov.au/ncas/publications/index.html)
• Brack, C.L. and Richards, G. (2002) Development of a National Forest Model. In Biomass Estimation: Approaches for Assessment of Stocks and Change. G.P. Richards (Ed). National Carbon Accounting System Technical Report no 27: 133 - 139. (URL: http://www.greenhouse.gov.au/ncas/publications/index.html)
• Kesteven J. and Brack, C.L. (2001) Using remote sensing and a spatial plant productivity model to assess biomass change. Proceedings of the IUFRO 4.02.05 Conference "Collecting and Analysing Information for Sustainable Forest Management and Biodiversity Monitoring." 4th - 7th December, 2001. Palermo, Sicily. (URL: http://www.geolab.unifi.it/iufro_conference/Default.htm)

Accounting for biomass and carbon change in forestry and agriculture under the Kyoto and other international protocols requires an assessment of the change in land cover, including afforestation, reforestation and deforestation events. Due to the time associated with soil carbon and biomass decay, the impact of an event associated with land cover change may continue over many years. Remote sensing was used to identify the location, area and time of an afforestation, reforestation or deforestation event. This time-based, activity-by-activity approach, covering all continental woody vegetation, provides a platform of land cover history. This land cover history is used in conjunction with calculations of Net Primary Productivity and estimates of pool turnover and decay to provide a first phase estimate of biomass and carbon on a spatially referenced basis.

The Net Primary Productivity was calculated for Australia using a physiological model (3-PG (Spatial)) based on the relationship between the photosynthetically active radiation absorbed by plant canopies (APAR) and the (biomass) productivity of those canopies at a monthly time step. The factor converting APAR to biomass was reduced from the selected optimum value by modifiers dependent on soil fertility; atmospheric vapour pressure deficits, soil water content and temperature. Leaf Area Index, essential for the calculation of APAR, was estimated from 10-year mean values of Normalized Difference Vegetation Indices. Incoming short-wave radiation - and hence APAR - was corrected for slope and aspect using a Digital Elevation Map. The ESOCLIM package was used to generate climate surfaces for the country. Soil fertility and water holding capacity values were obtained from the (digital) soil atlas of Australia.

The correlation between the first phase estimate of biomass and sites across Australia that ranged from arid shrublands to tall wet sclerophyll (2 - 450 t/ha biomass) was examined. This correlation is significant and is useful for improving the efficiency of estimating biomass and carbon totals and change

• Brack, C.L. and Banks, J.C.G. (2001) Planning for future streetscapes. Proceedings of the International Society of Arboriculture (Australia) conference "Arboricultural Health". 11 - 12 October, 2001. Canberra, Australia.

Canberra's urban forest has undergone numerous changes in planting policies over the past 90 years. Today, the streetscape includes diverse tree species and is well appreciated by residents and tourists alike. In the new millennium many of these streetscapes will come up for tree maintenance and renewal. We have developed an urban forest decision support system that includes a database of the current streetscapes (including species, size and health of publicly planted trees), and models to predict tree growth, health and maintenance needs. This presentation briefly overviews this system - DISMUT - and demonstrates how it can be used by urban forest managers to plan for the renewal of streetscapes.

• Brack, C.L. and Richards, G. (2001) FullCAM: An integrated model for predicting carbon stocks at a landscape and national scales. Proceedings of the IUFRO Conference "Forest Modelling for Ecosystem Management, Forest Certification, and Sustainable Management". 12 - 17 August, 2001. Vancouver, BC Canada. [URL: http://www.forestry.ubc.ca/forestmodel/index.htm]

Estimation of national or regional stocks of carbon in forests, woodlands and grazing land requires integration of data about the stocks and changes in tree and agricultural biomass, soil carbon, litter and debris, and the decay of off-site material (wood products). The Australian Greenhouse Office is fulfilling its international obligations of national carbon reporting through an integration of the CAMFor forests carbon accounting model (Richards and Evans 2000) with process and hybrid models. These models include: 3PG forest growth model (Landsberg and Wareing, 1997; Landsberg et. al. 2000; Coops, et. al. 1998; Coops, et. al. 2000); the GENDEC litter decomposition model (Moorhead and Reynolds 1991; Moorhead et. al. 1999); and the Rothamsted soil carbon model (Roth C) (Jenkinson, et. al. 1987; Jenkinson et. al. 1991). A parallel version of the CAMFor model (CAMAg) developed for agricultural systems and is also integrated with GENDEC and the Roth C model.

The model developed, known as FullCAM, integrates the CAMFor and CAMAg based routines to a single C code model capable of accounting in transitional (afforestation, reforestation and deforestation) and mixed (e.g., agroforestry) systems.

The FullCAM model can be run in a spatial mode which will integrate information drawn from remotely sensed land cover change, productivity maps and other ancillary data to perform the various accounting routines described in the preceding sections. Although specifically developed for carbon accounting purposes, FullCAM has the potential to serve as a valuable model framework for a range of forest inventory and monitoring tasks.

• Brack, C.L. (2001) Risk and Uncertainty in a Forest Carbon Sequestration Project. Proceedings of the IEA Bioenergy Task 25/38 Conference "Carbon Accounting, emissions trading and COP6 negotiations related to bioenergy, wood products and carbon sequestration". 28 - 30 March, 2001. (URL: http://www.joanneum.ac.at/iea-bioenergy-task38)
• Brack, C.L. (2001) Information Technology in Forestry Education and its Role in Enhancing Flexible and Distance Education. Proceedings of the 7th Annual AusWeb - World Wide Web Conference. 21 - 25 April, 2001. Coffs Harbour, Australia. (In prep)

Computers and other Instructional or Information Technologies (IT) have been gaining importance in forestry education since the 1970's. The role of this IT has progressed from improving the efficiency of operations (eg automating common administrative procedures) through to changing the way things are taught and learnt and even what is taught and learnt.

Early examples of IT include word processor packages and databases that make it easier to update teaching materials and student records. IT that supports the reliable transfer of digital documents and other files - including file-servers and early examples of the Internet - allowed increased and more flexible access to traditional teaching resources during the 1980's. The 1990's saw the increasing use of presentation technology that allows academics and teachers to explore new ways of recording and showing information. This presentation IT includes digital slide shows, animations, digitised sound and movies, etc. In the 1990's another major emphasis was IT designed to enhance communication between individuals and within groups. This technology includes e-mail, bulletin boards and chat rooms and is being incorporated into many examples of flexible teaching to enhance the communication between students, teachers and other stakeholders. The world-wide-web (www) networks now allows the integration of many of these technologies by imposing a consistent protocol and standard of communication and digital information transfer. Currently there is an increasing interest in organisations who are integrating the administrative and teaching functions of these ITs into holistic packages.

The IT is being used to support teaching in different ways. These different ways may allow students to learn more effectively and in more flexible styles. This flexibility may also allow forest education and further learning to be available to stakeholders who are not able to attend traditional teaching campuses, ie distance education and open learning students. The IT is also used to increase the efficiency in teaching, where efficiency may be measured as increased output (more graduates) for less input (less time spent by academics, etc.).

This Report will review some of the reasons that IT has been introduced into forestry education. The review will include examples of IT that has been introduced and how the curriculum and student learning changed as a consequence. Some examples of quantitative feedback from students to IT and its role in teaching and learning is included from case studies at the Australian National University. The Report will also cover examples and the reported strengths and weaknesses of flexible teaching and learning, including distance education, that utilises this IT.

• Good, N. M., M. Paterson, Brack, C and Mengersen, K. (2001). Estimating Tree Component Biomass using Variable Probability Sampling Methods. Journal of Agricultural, Biological and Environmental Sciences 6(2): 241-250.

As a signatory to the Kyoto Protocol, Australia is obliged to stabilise greenhouse gas emissions at 8 % above 1990 levels by 2008-2012. To demonstrate achievement of this goal, Australia requires national annual estimates of changes in vegetation biomass as greenhouse gas emissions from land use change. These emission estimates are, however, uncertain due largely to the scarcity of existing allometric equations for calculating biomass. The large investment of time and funding required for harvesting, particularly using traditional techniques such as double regression and ratio sampling, also precludes the generation of new equations. Alternative techniques for rapid, cost-effective and reliable estimation of biomass therefore require investigation.

This study, conducted in central Queensland, compared estimates of component biomass that were generated, for seven trees of the woodland species Eucalyptus populnea (Poplar Box), using ratio sampling and variable probability sampling techniques, namely randomised branch sampling (RBS) and RBS with importance sampling (IS). Application of randomised branch sampling consistently underestimated the biomass of leaf and small branches (less than 1cm diameter) and produced weak prediction equations. In contrast, results suggest that RBS with IS is particularly useful in predicting woody (trunk and branches more than 1cm diameter) biomass, and prediction equations agreed with existing equations for this species. However, this method tended to overestimate individual tree woody biomass. The study concluded that RBS with IS was a viable alternative to current methods.

• Ozolins, A., Brack, C.L. and Freudenberger, D. (2001) Abundance and Decline of Isolated Trees in the Agricultural Landscape of Central West New South Wales, Australia. Pacific Conservation Biology 7(3): 195 - 203. [URL: http://wwwscience.murdoch.edu.au/centres/others/pcb/]

Prior to this study, isolated trees were largely isolated from research. This study has provided a methodology, rigorous assessment of isolated tree density and distribution, and identified the potential ecological, social and economic importance of isolated trees, in a relatively small, but probably typical area of the wheat-sheep zone of eastern Australia. The abundance and decline of isolated native trees was measured by line-intersect sampling in the highly fragmented agricultural landscapes of the mid-Lachlan Valley of central New South Wales, Australia. A total of 7 000 trees were sampled along 5 678 km of transect on 441 aerial photographs.

• Penny, R., Brack, C, von Gadow, K. and Lund, G. (2001) Inventory and Forecasting Productive Capacity for Natural Forests. Criteria and indicators for sustainable forest management John Raison, Alan Brown and David Flinn (Eds). CABI International Publishing, New York. pp 165 - 182.

The productive capacity of natural forests can be monitored against three common indicators: area of forest available for timber production; extent to which harvested areas are regenerated; and level of harvesting for wood and non-wood products compared to the sustainable level. These indicators have been derived from an analysis of five internationally representative approaches to sustainable forest management (SFM).

Although our knowledge of the productive capacity of forests is long established and considerable, there are many opportunities to enhance this knowledge base. This chapter considers these indicators in the context of natural forest inventory and forecasting, and recommends enhancements of and extensions to the existing productive capacity knowledge base.

• Brack, C.L. (2000) State of Knowledge Report for IUFRO Unit 6.15.00 Improving education and further education in forestry. IUFRO World Conference, Malaysia, 2000. P 15. (URL: http://iufro.boku.ac.at/iufro/iufronet/d6/wu61500/skr61500.htm)
  
• Brack, C.L. (2000) Biomass and Carbon Sequestration in an Urban Forest. Proceedings of the "Advances in Terrestrial Ecosystem Carbon Inventory, measurements and modelling". 3 - 5 October, 2000. Raleigh, North Carolina USA. (Abstract only)
  
• Brack, C.L. (2000) Carbon Assessment Model for Forests (CAMFor). Presentation made to Task 25: Greenhouse Gas Balances of Bioenergy Systems Modelling Workshop: "Bioenergy, Greenhouse Gases and Carbon Sequestration". 22 - 26 May 2000 Zagreb, Croatia. URL: http://www.joanneum.ac.at/iea-bioenergy-task38/workshop/fwrkshp.htm
  
• Brack, C.L. and Richards, G. (2000) Carbon Account Modelling for Forests in Australia. Proceedings of the "Advances in Terrestrial Ecosystem Carbon Inventory, measurements and modelling". 3 - 5 October, 2000. Raleigh, North Carolina USA. (Abstract only)

• Brack, C.L. (2000) Audit of changes to the modelling systems used for land evaluation by Forestry Tasmania. Consultancy Report to Forestry Tasmania. P 16.

• Brack, C.L., Banks, J.G. and James, R.N. (1999) Forestry out of the forests. Proceedings of the IFA Biennial Conference "Practising Forestry Today". Hobart, Tasmania 3-8 October, 1999. P 100-107.

Foresters are increasingly required to apply their skills outside the confines of the traditional natural or plantation production-oriented forest. One new area of application is the urban forest. The authors have been involved in urban forestry for a few years through the design of an inventory and management system for urban forests in Canberra. The system is based on the street (or park) and includes a count of individual trees by species and health-category. The application of predictive models for tree size and health indicators allows the requirements for future maintenance to be estimated, along with an estimation of associated work requirements and costs. We have also developed a system for the spatial planning of treed precincts. The treatment of urban trees is usually based on enhancing the value of each tree in the streetscape where aesthetic values are the predominant reason for tree establishment. Other values such as amelioration of climate and pollution, environmental engineering and augmentation of city architecture are also important. The techniques of tending individual trees in the urban forest differ from those applied to trees in forest stands and foresters can learn much from urban forest managers about this. On the other hand, the skills foresters possess about stand management and the integration of multiple uses could make a positive contribution to urban forest management.

• Brack, C.L., James, R.N. and Banks, J.G. (1999) Data collection and management for tree assets in urban environments. Proceedings of the 21st Urban Data Management Symposium "UDMS'99". Venice, Italy. 21-23 April, 1999. Published on CD-ROM.

Trees are important and valuable assets in an urban environment. The presence of well developed and healthy trees can add thousands of dollars to the value of adjoining land as well as enhancing the environment. However, unhealthy and poorly maintained trees can cause major health and safety problems that may lead to accidents and expensive litigation. Trees are also living organisms that pass through a sequence of life and habit stages with corresponding values and costs.

Data collected on urban trees must reflect the unique values of trees in an urban environment. These values are different from traditional forest or farm tree values. The management of the urban tree assets must also account for the growth of trees and their changing maintenance needs. The data may also need to be made available to a wide range of stake-holders.

This paper presents two case studies of decision support systems developed to collect and use data about trees for tree asset management. The first study describes a decision support system (DISMUT) that has been developed to assist in the management of about 500,000 trees in Canberra (the National Capital of Australia). The second case study focuses on a precinct-scale tree management system that uses a notebook computer, laser survey equipment and a pen-based Geographic Information System to help manage about 7,000 trees on a 150 ha campus within the city.

• Banks, J.C., Brack, C.L. and James, R.N. (1999) Modelling Changes in Dimensions, Health Status and Arboricultural Implications for Urban Trees. Urban Ecosystems 1(3): 1 - 7.

Canberra, the capital of Australia since 1911, has been developed into a modern city from its original site on a near treeless plain. Today the city has about 300 000 inhabitants and 500 000 trees. The authors were requested by the managers of the urban public tree resource to survey their asset and to develop a computer based system which would aid them in anticipating future maintenance requirements and its costs. This paper reports on our response. We have surveyed 3 000 streets and parks in the city noting the species, number and condition of every public space tree. We have also obtained the dimensions of sample trees noting their: total height, maximum crown width, height of maximum crown width, diameter at maximum crown width and height at crown break. A management system has been developed using Microsoft Access™.

Using standard regression techniques available on the package JMP™, we found that total tree height was related to age for all species and that all other parameters of interest were related to height or transformed values of height. We assumed a sigmoidal growth curve and calibrated 114 height/ age curves to cover the 165 000 trees of the 340 species we have in our database. As well we used the data on tree condition to determine the rate at which populations change from healthy to stressed.

By interviewing foremen and supervisors we were able to determine the maintenance treatments carried out in Canberra, the equipment used and the number of trees which can be treated in a day, for each type of operation.

The management system can be used to display the current inventory for each street or park, by suburb, in the database. It can also be used to model future increases in size or crown condition, predict the operations that will be required as a consequence of tree growth or crown deterioration and finally, by applying multipliers to equipment and personnel, estimate the future costs of tree maintenance. Managers can use the system to anticipate problems such as uneven expenditure requirements in future years.

• Hamilton, F. and Brack, C.L. (1999) Stand volume estimates from modelling inventory data. Australian Forestry 62(4): 360 - 367.

Model-based sampling capitalised on relationships between the parameter of interest and other available data. In this inventory of the forests of North East Victoria, a model-based approach was used to sample an area of 227,000 ha, using 271 plots. Significant relationships were found between sawlog volume and several stand descriptors, including elevation, crown cover, stand height and species. A stratified random sampling approach would have required considerable more plots to ahcieve estimates of similar precision.

• Research Working Group #2 (1999) Code of Forest Mensuration Practice: A guide to good tree measurement practice in Australia and New Zealand. Wood, Turner and Brack (eds). URL: http://www.anu.edu.au/Forestry/mensuration/rwg2/code. ISBN:0-7315-3310-0
• Tidemann, C.R., Vardon, M.J. and Brack, C.L. (1999) Flying-foxes in Australian Cities: Management Problems and Solutions. Proceedings of the 4th International Symposium on Urban Wildlife Conservation. Tuscon, Arizona. 1 - 5 May, 1999.
• Turner, B., Wells, K., Bauhus, J., Cary, G., Brack, C. and Kanowski, P. (1999) Biomass and accumulation project under the National Carbon Accounting System. Technical Report 13. Consultancy Report to Australian Greenhouse Office. P 38.
• Banks, J.C.G., Brack, C.L. and James, R.N. (1998) Canberra Urban Tree Management Survey of Urban Tree Assets: Volumes I to IV. Report for Canberra Urban Parks.
• Brack, C., Ferguson, I., Howell, C., Leech, J., Tickle, P. and Wild, I. (1998) The Development of an Effective Methodology to Capture Forest Type, Condition and Volume Data for Privately Managed Forests. Report for the Forest and Wood Products Research and Development Corporation. P 33.
• Brack, C.L. and P. Marshall (1998) Sequential sampling with systematic selection for estimating mean dominant height. Australian Forestry 61(4): 253 - 257.

Sequential sampling theory relies on the random selection of observations. Systematically selecting observations for sequential sampling from populations that are not themselves randomly ordered can cause a disproportionate number of incorrect decisions and/or sample sizes to be larger than what would be expected for randomly selected observations. However, if the customary precautions for systematic forest surveys are taken (e.g., random starting point, running sampling lines across topography), sequential sampling for mean dominant height should not produce estimates with unacceptable levels of bias. Sample sizes will be less than the standard sample size of 25 if the model prediction adequately represents the population mean.

• IUFRO (1998) Guidelines for Designing Multipurpose Resource Inventories. H. Gyde Lund (ed.) Vienna: IUFRO World Series Vol 8. P 216. (Contributing author)
• Brack, C.L. (1997) Forest Inventory in the 21st Century. Proceedings of the Australian and New Zealand Institute of Foresters Conference "Preparing for the 21st Century". 21 - 24 April, 1997. Canberra, ACT. p 329 - 335.
• Brack, C.L. (1997) Measuring Stand Basal Area. Technical Note: IFA Newsletter 38(5): 16 - 17.
• James, R., Brack, C. and Banks, J. (1997) DISMUT: Decision Information System for Managing Urban Trees. Paper presented to the Third National Urban Tree Seminar "Proactive Processes: from turf to trees". 3 - 5 August, 1997. Coolum Queensland.
• Trevitt, A.C.F., Åkerlind, G.S., Brack, C. and Pettigrove, M. (1997) The Role of Student Assessment: to Gauge Students' Performance, to Enhance Learning and Professional Skills, or to Inform Program Evolution?, Chapter 3 in G. Ryan (ed), " Learner Assessment and Program Evaluation in Problem Based Learning: A. Monograph", Australian Problem Based Learning Network, The University of Newcastle.
• Brack, C.L. (1996) Linking the data to develop knowledge: A neglected part of developing WEB-based university resources. Procdings from AusWeb96: The second Australian World Wide Wb Conference. Gold Coast, Queensland, 7-9 July, 1996. Southern Cross University Press. p 219 - 224.

The hypertext nature of World Wide Web materials allows the development of structural and knowledge-based links between pieces of information. The development of structural links has been acknowledged as important to ensure users are not lost in the web of information to the WEB. However, there is little published material on the potential for knowledge-based links to promote problem-based learning skills.

This presentation discusses the creation of WEB-based resources for a senior undergraduate unit in Forestry at the Australian National University. Emphasis is directed towards the development and use of knowledge-based links.

• Brack, C.L. and P. Marshall (1996) Test of Knowledge-based Forest Operations Scheduling Systems. Canadian Journal of Forest Research 26: 1193 - 1202.

Five knowledge-based approaches (three search routines and two expert systems) to forest operations scheduling were compared to mathematical programming (linear programming and mixed integer programming) and simulation approaches for two plantation forests in New South Wales, Australia. Strategies produced using these approaches were compared on the basis of scores for timber volume flow, scenic beauty, stand health, and water quality. Timber flow scores were highest for the linear programming strategies, but some of the strategies produced by the knowledge-based approaches scored almost as high. The timber flow scores for the mixed integer programming strategies were exceeded by some of the knowledge-based strategies, because of the approximations required to achieve mixed integer programming solutions for larger problems. The knowledge-based approaches could produce higher scoring strategies for the other criteria than the mathematical programming or simulation approaches. The multiple strategies produced by two of the search procedures, and the goal hierarchy incorporated into the expert systems, allow the user to make explicit tradeoffs among strategies in terms of performance for the various criteria.

• Brack, C.L. (1996) Using best guesses to improve forest inventory. Australian Forestry 59(2): 108- 113..

The experience and best guesses of personnel in the Inverell District of NSW. were used as the basis for estimating a list of commercial sawlog volumes in each compartment of a large Management Area. The list was stored in a standard format in the newly developed Forested Area Management Information System (FAMIS) and then manipulated for use in a regression sample that correlated the guesses with inventory based estimates. Resulting correlations allowed estimates of compartment sawlog volumes with confidence limits of about 10% for a total cost of less than $0:50 / ha. Maps of compartments with volumes and other parameters could also be developed from the correlations and FAMIS database.

• Brack, C.L. (1995) Lets play the game: an artificial intelligence approach to forest management. Proceedings from IFA Conference Applications of New Technologies in Forestry. Ballarat, Victoria, 18-21 April 1995, Bren and Greenwood (eds) . IFA Inc, Canberra, Australia. p 107 - 116.

Forest managers know a lot about their forests. Unfortunately much of this knowledge is not easily incorporated into traditional decision-making systems. Nor can the solutions and outcomes produced by the traditional management analysis systems (eg. linear programming) be easily understood or explained to an interested society.

Artificial intelligence tools can be incorporate many forms of knowledge and information. These tools are readily used if forest management is viewed as a puzzle or a game. If an appropriate game form is adopted, the management process can become much more transparent and easily explained or defended. This paper suggests an appropriate way of visualising forest management as a game that suggests good management alternatives to meet a wide range of goals while simultaneously improving an understanding of the management situation.

• Brack, C.L. and A.C.F. Trevitt (1995) Accessing the data to create the knowledge: a case study from forestry. IPCT 3(1): 9 - 16.

Data is just an accumulation of observations and numbers. It is only when it is accessible and can be ordered and summarised that patterns can be found and used in the creation of knowledge. Unfortunately, the quantity of data relevant to researchers and managers keeps expanding while the ability to keep abreast is decreasing. Relevant data include the publication of new methods of practice, guidelines for management, public perceptions of activities and newspaper articles as well as scientifically refereed journal papers.

Recent undergraduate curriculum changes in the Department of Forestry, Australian National University, introduced several computer based materials that promote improved access, summary and understanding of data. These changes have proven to be an effective way of updating and integrating diverse pieces of literature, documented experience and other sources of information (weather maps, case studies, guidelines, operational manuals) and have served as the basis for a new problem based learning approach in the Fire Science and Management unit. The newly restructured Forest Mensuration unit is also taking advantage of computer based storage and presentation facilities to integrate and present data using a variety of multi-media techniques that improve the chances of students understanding the complex mathematical and geometrical concepts involved in mensuration. The Forestry Department is currently studying the potential for developing these approaches further as an ongoing Professional development program which will be readily available to students, modellers and managers and which can quickly respond to new data and deliver it as knowledge.

• Brack, C.L. and J. Edwards (1995) Efficient Data Capture Using Pen-based Recording Devices. Proceedings of the AUC Academic conference Technology '95, 3 - 6 July, 1995. Perth. W.A.

Natural resource data are expensive to collect and traditional ways of recording these data tend to introduce errors. Pen-based digital data recording devices have significant advantages over paper based recording systems and keyboard-based recording devices. These advantages include easier visual error detection, effective collection and storage of graphical and text data and a more intuitive user interface. This paper discusses the development of the Newton MessagePad as an efficient pen-based data recording device for forest management.

• Trevitt, C, C.L. Brack, M. Ryan, C. Hilliker and S. Hedenstroem (1995) Forestry education and information technology at ANU: tools, toys or a turn-up for the books? Proceedings from IFA Conference Applications of New Technologies in Forestry. Ballarat, Victoria, 18-21 April 1995, Bren and Greenwood (eds) . IFA Inc, Canberra, Australia. p 169 - 178.

Academia, like the forestry profession, is subject to pressures to change and adapt. Technological developments are one force at work, changing social values and concerns are another. This paper looks at some of the new ways in which information technology permits the use of alternative approaches to forestry education, including a problem-based learning approach. Examples are drawn from teaching areas such as fire science and management, and mensuration. Applications for information technology in forestry education include: novel presentation and visualisation techniques; linking relevant material via hypertext pointers, thereby permitting users to choose the most personally relevant way through "webbed" information; and, new computer-based communications networks such as FireNet. Some future possibilities for using emerging networks like FireNet include: improving public education, bringing up-to-date field-based material into the classroom, and promoting in-service professional development.

• Trevitt, C., G. Akerlind, C. Brack and M. Pettigrove (1995) The role of student assessment: to gauge students' performance, to enhance learning and professional skills, or to informa program evolution?. Proceedings of the PBL Conference '95.

Assessment is a multifaceted activity with the potential for different and varied goals. This paper traces a transition in assessment practices inspired by a shift to a problem-based learning focus in an otherwise traditional forestry professional curriculum. This transition harnesses the powerful motivational forces attached to student assessment, designed to encourage life-long learning habits and professional skills such as self- and co-assessment within a real-world context. We argue that it is only in this way that students can be appropriately prepared for professional careers, and have found that students appreciate these motivations and are strongly supportive of our innovations.

• Brack, C.L. and P. Marshall (1992) Solving a 'puzzling' problem: Knowledge-based approaches to forest operations scheduling. A.I. App. in Nat. Res. Man. 6(4): 39 - 47

Viewing forest operations scheduling problems as puzzles or games allows an expanded range of knowledge to be used in finding an acceptable solution comparable to those derived from methematical programming and simulation procedures. Artifical Intelligence tools can be used to incorporate silvicultural, economic, and management heuristics and knowledge into a knowledge-based decision support system (expert system) based on this paradigm. Five decision support systems (three search models and two expert systems) developed for radiata pine (Pinus radiata D.Don) plantations in Australia are described. A combination of random and well-disciplined search components are used in the search models StratSearch-1 and -2. A well disciplined, best first procedure without backtracking is used in the third search model (StratSearch-3). The expert systems were developed to improve existing solutions, either by modifying the regime for a single stand at a time (ES-1) or by selecting a group of target stands and then modifying the regimes for the stands within that group (ES-2). Systems similar to those described can produce feasible solutions to many practical operations scheduling problems, and can help the forest manager understand and explain the solutions.

• Brack, C.L. and P. Marshall (1992) Using artificial intelligence to integrate forest management information. Proceedings from IUFRO Conference Integrating Forest Information over Space and Time. January 1992, Wood and Turner (eds), ANUTECH Pty Ltd, Canberra, Australia. pp 207 - 218

Forest management support systems of the 1990's need to permit foresters to visualise the multi-resource tradeoffs associated with management decisions. Foresters need systems which integrate knowledge about the forest and management objectives to help provide plans that are realistic, sound and defensible. Traditional methematical programming tools cannot realistically help the manager to integrate spatial and temporal information over the whole forest.

This presentation will discuss an approach to decision support that makes use of artificial intelligence tools. The approach attempts to duplicate the way in which human forest managers schedule forestry operations. This allows great flexibility and a wide range of quantitative and qualitative objectives to be considered

A heuristically controlled search model for plantation management is developed and discussed. This model integrates silvicultural knowledge, and spatial and temporal management objectives to produce a series of plans that consider wood and non-wood values. The interaction between the objectives can be seen and plans redirected to consider this interaction. Plans developed by this model in a small plantation estate in south-eastern New South Wales were able to balance wood flow commitments while maintaining scenic beauty standards and forest health. The wood flows were within 8% of the theoretical optimal projected by linear programming, and superior to integer solutions. The manager is more able to make an informed decision using this consultant-like decision support system.

• Brack, C.L. (1992) Knowledge-based approaches to forest operations scheduling problems. Unpublished Ph.D. dissertation, University of British Columbia, B.C. Canada.

Operation scheduling in fast growing, intensively managed forest plantations is characterized by diverse qualitative and quantitative goals and constraints. These goals and constraints may be temporal or spatial, and may interact in complex ways. Traditional linear programming approaches to forest operations scheduling generally require significant simplifications to the problem statement before they can be solved and do not provide managers with easily understandable solutions except in simple cases.

A series of knowledge-based models was developed to assist forest managers in operations scheduling problems. These knowledge-based models included random and heuristic search models using different knowledge amounts, and expert systems. The models used silvicultural knowledge derived from plantation management plans of the Forestry Commission of New South Wales to construct practical and feasible thinning and harvesting regimes for each stand in a plantation. Other knowledge was derived from game and puzzle solving domains and human experts in operations scheduling to help construct forest operations schedules that simultaneously considered some stand and forest management and environmental considerations.

Operations schedules produced for two intensively managed and rapidly growing plantation forests by the knowledge-based models were evaluated for timber flow, stand health, scenic beauty, and water quality. Schedules were found that were within 5% of the optimal timber flow found by (integer) linear programming approaches. The knowledge-based model solutions were superior to the linear programming solutions for at least one of the health, beauty or water quality considerations, and were at least as good as solutions produced by human operations scheduling experts.

The knowledge-based models were used to explore the relationships between the various goals and objectives. The knowledge-based approach was also used to develop robust strategies in the presence of uncertainty in the growth models. Important stand / regime combinations were isolated to allow management to reduce the impact of uncertainty.

The quality of the knowledge-based model solutions depended upon the specific knowledge included, and the forest structure. However, more knowledge did not necessarily lead to a better solution. In the larger plantation forest examined, additional knowledge did not lead to a better solution relative to the solution generated by a model using little knowledge. This was because the additional knowledge lacked key information about the forest age class distribution and problem size. Without this information, the additional knowledge was incomplete and directed the model solution inappropriately.

The knowledge-based models developed are simple and easy to understand. They can be used to integrate silvicultural knowledge with other forestry domain knowledge to produce plans that can be understood and defended. They can also serve to integrate future knowledge development and show the potential advantages of research.

• Brack, C.L. (1991) Knowledge-based operations scheduling support systems for forestry. Agric. Sys. Info. Tech. N. 3(3): 61 - 64.

·         Brack, C.L. and P. Marshall (1990) Sequential sampling and modelling for mean dominant height estimation. Aust. For. 53(1): 41 - 46.

A method of checking the validity of model predictions of the mean dominant height (MDH) for a cutting unit using sequential sampling is presented. Inventory data provided by the Forestry Commission of New South Wales were used to test the impact of decision criteria and acceptable type 1 and type 2 error levels on average sample size. Using sequential sampling to check model predictions of cutting unit MDH lowered the standard error of the prediction and reduced the maximum error by over half that of using the model predictions alone. The average sample size for the model with sequential sampling varied with the decision criteria and acceptable error levels. Using sequential sampling to check the validity of model predictions can reduce the number of heights that need to be measured during an inventory without greatly increasing the error in estimating MDH for a cutting unit.

• Brack, C.L., A. Kozak, P.L. Marshall and V.M. LeMay (1990) A front end package for a taper equation. Proceedings of the conference Canada's Timber Resources. June 3 - 6, Victoria, B.C. Canada.

·         Brack, C.L. (1988) Management Information Systems for plantations of the New South Wales Forestry Commission. Proceedings from the URPIS conference Management Information Systems in Action. Sydney, NSW Australia. pp 65 - 74.

·         Brack, C.L. (1988) The RADHOP System. In Modelling Trees, Stands and Forests, Bulletin No 5 of the School of Forestry, University of Melbourne. pp 509 - 526.

The yield scheduling system, RADHOP, used by the Forestry Commission of New South Wales, is reviewed. This system couples a computer based stand simulation model with a linear programming package. The system structure and model components are discussed.

• Brack, C.L. (1988) Plantation Technical Manaual. Forestry Commission of New South Wales. 100 pages.

Brack, C.L., M. Gill and M. Dawson (1985) Bark, Leaf and Sapwood Dimensions in Eucalyptus. Aust. For. Res. 15: 1 - 7.

Bark thickness, sapwood thickness, leaf area, bole diameter and crown condition were estimated and their relationships studied in each of three species of Eucalyptus with barks known as 'gum', 'peppermint' and 'stringybark'. Interest focused on bark dimensions because of their importance to fire resistance. Bark thickness was not as well correlated with other variables as was bark cross-sectional area, which was closely correlated with some or all surrogates for physiological variables, viz. leaf area, sapwood cross-sectional area and crown condition. From non-destructive measurements such as bole diameter, bark area and crown condition, leaf area could be estimated for trees of different age and health.

• Gill, M., C.L. Brack and M. Dawson (1982) Bark Probe - an instrument for measuring bark thickness of eucalypts. Aust. For. 45(3): 206 - 208.

The instrument consists of a modified solid brass cylinder through which moves a plunger tipped with a blunt needle. The needle is pushed through the bark to the wood surface and the depth of penetration is read from a scale on the barrel. The instrument enables fast and accurate measurements of bark thickness to be made on gum, peppermint and stringybark eucalypts. The measuring technique is virtually non-destructive and is simpler and more accurate and precise that other commonly used techniques, including the Swedish bark guage.

Theses from Research Students

Golman, M. 2007. Resource planning for Samsai Niksek tribal forest of Papua New Guinea - recognising land, people and the forests (PhD)

Roberts, S. 2007. Projecting Farm Scale Product Volumes and Values. (Honours - First Class)

Musk, R. 2006. Estimating stem profile using canopy metrics (PhD)

Gowae, G. 2005. A Cohort Model for Pometia genus in the lowland tropical rainforests of Papua New Guinea (PhD).

McElhinny, C. 2005. Quantifying stand structural complexity in woodland and dry sclerophyll forest, south-eastern Australia. (PhD).

Kemmerer, E. 2005. Optimising sawlog production in even-aged eucalypt stands. (PhD)

Gilbert, M. 2004. Trends in Urban Tree Removal on Leased Land across Canberra, ACT. (Honours - First Class)

Soraya, E. 2004. Management models for rattan gardens of Kedang Pahu West Kutai, East Kalimantan, Indonesia. (Masters by research)

Andriyana, W. 2004. Testing the feasibility of centroid and importance sampling for estimating volume of standing trees in a tropical forest context. (Masters by research)

Agombe, S. 2004. Site Form and improving volume estimation of uneven-aged forest stands in northern Namibia (Masters by research).

Kyle, J. 2003. Investigating land cover change and vegetation growth in Turner as a way of quantifying the changes in Canberra as a Garden City. (Honours - 2A Class)

Ho, A. 2002. Particulate pollution capture and retention by Eucalyptus elata (Dehnh) in the A.C.T. (Honours - First Class)

Titheradge, S. 2002. Tree crown dieback of Fraxinus oxycarpa cv Raywood in Canberra's urban forest. (Honours - 2A Class)

Ellis, P. 2001. The aerodynamic and combustion characteristics of Eucalypt bark - a firebrand study. (PhD)

Payne, D. 2001. Modelling the effect of forest management on the carbon pools in a Eucalyptus pilularis (blackbutt) regrowth forest. (Honours - 2A Class)

Garner, M. 1999. Determining an Appropriate Protocol for Amenity Tree Valuation in Australia. (Honours - First Class)

Ozolins, A. 1999. Abundance and Decline of Isolated Trees in the Agricultural Landscape of Central West NSW. (Honours - First Class)

Wee, M.L. 1999. Predicting Urban Tree Benefits and Costs using Growth Models (Honours - First Class)

Pokharel, B. 1998. Use of GIS and modelling to determine the site productivity of an uneven-aged forest. (Honours - First Class)

Frankcombe, M. 1997. Determination of site productivity in native regrowth forests using permanent growth plot data. (Honours - First Class)

Brookhouse, M. 1997. Identification and analysis of growth rings in Eucalyptus obliqua and E. cypellocarpa. (Honours - First Class)

Dekaris, D. 1997. Incorporating point density, tree dominance, soil type and altitude into taper models for Eucalyptus pilularis. (Honours - 2A Class)

Crook, D. 1997. A comparison of the importance and centroid sampling methods in the valuation of Pinus radiata trees. (Honours 2A Class)

Croft, A. 1996. Comparison and verification of basal area growth models for Pinus radiata plantations. (Honours - First Class)

Rivers, G. 1996. Evaluating MARVL inventory system volume and value estimates. (Honours - 2A Class)

On-line Textbooks and Resources

Brack, C.L. (1999, 2000, 2001) Forest Measurement and Modeling - Measuring trees, stands and forests for effective forest management. Computer-based course resources for Forest Measurement and Modeling (FSTY2009) at the Australian National University http://fennerschool.anu.edu.au/associated/mensuration/home.htm

Brack, C.L. (2000, 2001) Forest Inventory - Measuring a Forest. Computer-based course resources for Forest Inventory (FSTY2010) at the Australian National University http://www.anu.edu.au/Forestry/mensuration/forest.htm

Research Working Group #2 (1999) Code of Forest Mensuration Practice: A guide to good tree measurement practice in Australia and New Zealand Wood, Turner and Brack (eds). URL: http://fennerschool.anu.edu.au/associated/mensuration/rwg2/code. ISBN:0-7315-3310-0

Brack, C.L. and Wood, G.B. (1995, 1996, 1997, 1998) Forest Mensuration - Measuring trees, stands and forests for effective forest management. ISBN 0 7315 2413 6. Computer-based course resources for Forest Mensuration (FSTY2101) at the Australian National University. http://fennerschool.anu.edu.au/associated/mensuration/BrackandWood1998/MENSHOME.HTM

Other works

• Book Review. Forestry in a Global Context By Rodger Sands Australian Forestry 69(4): 313.
• Book Review: Tree and Forest Measurement By Phil West. Australian Forestry 68(1): 73.
• Encyclopedia Of Forest Sciences (2004) Timber and Tree Measurements. Elsevier Ltd ISBN: 0121451607 P 566 - 573.
• Commonwealth of Australia (2002). Tree measurement manual for farm foresters - Practical guidelines for farm foresters undertaking basic inventory in forest plantation stands. National Forest Inventory, Bureau of Rural Sciences. ISBN 0 642 47568 7 P 88.
• Book Review: How much wood has your woodlot got? By J. Piers Maclaren. Australian Forestry 64(1):69.
• Book Review: Decision methods for forest resource management. By Buongiorno and Gilless. Australian Forestry 67(1):73.
• Commonwealth of Australia (2001). Field measurement procedures for carbon accounting. Bush for Greenhouse Report 2, February 2002. Australian Greenhouse Office. ISBN 1 876536 62 4.
• Timing of carbon credits and debits a matter of politics. ANU Reporter Volume 32 No.7, Friday 11 May 2001. http://www.anu.edu.au/pad/reporter/V32/7/timing.html

[BRACKPUB.HTM] Revision: 3/2004
Cris.Brack@anu.edu.au