Forest Mensuration. Brack and Wood



Forest Mensuration
Measuring trees, stands and forests for effective forest management. ©
ISBN 0 7315 2413 6



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Picture of real and model stand of trees

Forest mensuration

Forest mensuration is about measuring the forest to help answer the three main questions and concepts involved in forest management:

  1. What is in the forest now ?
  2. How is the forest changing ?
  3. What can (and should) we do to manage the forest properly ?

Mensuration may be defined as:

the art and science of locating, measuring and calculating the length of lines, area of planes and volumes of solids.

Forest mensuration concentrates on trees and forests or potentially forested locations. Forest mensuration also includes measuring or calculating growth and change in trees and forests.

Forest mensuration then may be defined as:

the art and science of providing the quantitative information about trees and forest stands necessary for forest management, planning and research.

Why measure anything?

When you measure what you are speaking about and express it in numbers, you know something about it, but when you cannot (or do not) measure it, when you cannot (or do not) express it in numbers, your knowledge is of a meagre and unsatisfactory kind (Lord Kelvin).
When I use a word, it means exactly what I want it to mean, neither more or less (Humpty Dumpty).

To some extent, these remarks by Lord Kelvin and Humpty Dumpty highlight the essential difference between quantitative and qualitative assessment. Qualitative assessment (e.g. assessing a tree as tall or short) involves subjective judgment and is much more prone to personal bias and error.

Responsible use of forests and other natural resources associated with it (e.g. animals, plants, soil, water) is vital to the well being of a nation. Those entrusted with the planning and management of these resources are hamstrung unless reliable quantitative information on a multitude of topics relating to those resources is available to them. Such information derives from measurement.

We may define measurement as:

the determination of size in relation to some observed standard, e.g. metre, kilogram, second, ampere, degree Kelvin, candela, mole, or some unit derived from these seven basic units.

Tuesday, 30 June 1998