[BRACKPUB.HTM] Revision: 3/2004
Cris.Brack@anu.edu.au
|
[Theses] |
Publications by C.L. BrackSenior Lecturer in Forest Measurement, Modelling and Management.
E-mail: Cris.Brack@anu.edu.au |
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..
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
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 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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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
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.
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.
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.
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.
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.
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).
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.
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.
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™.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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. 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. (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., 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.
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. |
|
· 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) |
|
· 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://sres.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://sres.anu.edu.au/associated/mensuration/BrackandWood1998/MENSHOME.HTM |
|
|
|
|
[BRACKPUB.HTM] Revision: 3/2004 |