Forest Mensuration

DSC08056hemlock“Forest mensuration is one of the most fundamental disciplines within forest and related sciences. It deals with the measurement of trees and stands and the analysis of the resultant information.” Another definition: [Forest mensuration is] “the art and science of providing the quantitative information about trees and forest stands necessary for forest management, planning and research.” Such measurements are the basis of sustainable harvest calculations for Nova Scotia.

The Science and Methodology

Scientists create a ‘video game of the forest’ to check the impact of climate change
By Carl Meyer in the National Observer Oct 5, 2018. “For decades, gathering data about the forest has been painstakingly done by hand, or in later years captured from above, from digital sensors on planes flying over the forest or from satellite data. Now, 3-D scanning technology can be put directly into scientists’ hands, allowing them to digitally map forests themselves more quickly and precisely, with more detail. “We can now map the distribution of trees” with LIDAR, explained Scott McPherson, planning forester and analyst for Nipissing Forest Resource Management Inc. The Contour device sends out a continuous signal and generates a field of points. The holder walks around to get different angles of trees. Eventually a 3D model of the forest is produced. Scientists manipulate the model to view different data points using software called CompuTree.”

CCC Forestry: Forest Mensuration
US Forestry Service. A good description of the techniques and instruments traditionally used in measurements. It is Ch VIII in CCC Forestry (1937). (CCC is Civilian Conservation Corps)

“Forest mensuration has undergone a number of important changes in recent years. Among the most notable are laser and ultrasound based measuring devices, and use of drones, terrestrial and airborne laserscanning, satellite imagery and other advanced remote sensing techniques that are being used to measure and monitor trees and forests. These devices have reduced considerably the time needed for field measurements and can be used to quickly obtain many tree characteristics including spatial positions. Additionally, new methods have been developed for conducting tree-ring analyses including techniques for assessing the physical, chemical, and anatomic properties of wood. Such measurements are being used for reconstructions of growth conditions and investigations of the impacts of environmental changes on forest growth.” – IURFO

Changing technologies: Leading Edge Geomatics
Based in new Brunswick. View also Fredericton’s Leading Edge Geomatics Ready for Takeoff With New Investment (Nov 20, 2017 in Huddle)

Tree and Stand Measurement
By Dr Mathias (Mat) Disney, University College London. “The simple techniques described in this paper have their limitations and are not suitable where a high degree of accuracy is required, however, they are suitable for most farm forestry situations and only require cheap equipment and basic mathematical skills.” Originally published in The Farmers Log 1999/

Lecture Notes for Forest Mensuration
Bechu K.V. Yadav, prepared 2009. Comprehensive, well laid out. 333 slides in PDF document.

Examples of Mensuration Tools
Basic Forest Measuring Tools Used by Foresters
Forestry Tools

Forest Mensuration: Measuring trees, stands and forests for effective forest management
Set of web pages pages on Fenner School of Environment and Society, Australian national University. Posted in 1997, some not maintained. probably most useful is the the Index page for Forest Mensuration. See also: Code of Forest Mensuration Practice and the Introduction Page, Forest Measurement and Modelling.

Forest Mensuration
Anthonie van Laar & Alparslan Akça. 2007. The entire Springer Volume is available online.

Assessing Trees and Woodlands (Videos)
University of Kentucky Forestry Extension videos showing woodlot owners how to measure or determine Tree Height, Growth Rates and Tree Ages, Size Classes & Management, Growing Stock, Tree Volume, Tree Diameter, Woodland Density, Crown Classes and how to set up a Sample Inventory Plot. See Forestry 101: Woodland Terms Part 1 and Part 2 for descriptive definitions of terms such as basal area, crown class, dbh, tree grade.

Pertaining to Nova Scotia

Forestry Field Handbook
NSDNR “This handbook includes site specific softwood and hardwood silviculture keys together with graphs and tables needed to estimate present and future stand characteristics… The growth projections and keys were developed by the Department of Natural Resources from research data and private and government experience. They are applicable to a wide variety of forest conditions, since decisions regarding the choice of silviculture treatments are based on specific site and stand characteristics.”

Growth of forests in Canada. Part 2: A Quantitative description of the land base and the mean annual increment. (1981).
Bickerstaff, A.; Wallace, W.L.; Evert, F. Environment Canada, Forestry Service, Petawawa National Forestry Institute, Chalk River, Ontario. Information Report PI-X-001. 136 p.

Ten Year Periodic Annual Increment For Nova Scotia Permanent Forest Inventory Plots 1990-95 to 2000-05.
NSDNR June 4, 2007

Land Capability and Site Index Curves for Nova Scotia Hardwoods
NSDNR 2011

Revised Normal Yield Tables for Nova Scotia Softwoods.
NSDNR 1990

FOREST SUSTAINABILITY A Grade 10 Science Program
A Program of the Natural Resources Education Center Middle Musquodoboit, Nova Scotia (no date)

Search page for “mean annual increment”.

Measurement of Tree Basal Area & Volume
FOR 1001 Fall 2012. Notes by Dr. Thom Erdle. See other Lecture Notes; 1) Measure of Tree Diameter & Height 2) Sample Plots 3) Measurement of Tree Basal Area & Volume 4) Tree Biomass & Carbon Price & Cost Information 5) Point Sampling 6) Snags and Coarse Woody Debris 7) Basic Data Concepts 8) Sampling Concepts Part 1

Assessing Tree Attributes
On measurements at “breast height” etc.

Variability in early height growth rate of forest trees: implications for retrospective studies of stand dynamics
Brian J. Palik and Kurt S. Pregitzer. Can. J. For. Res. 25:767-776 (1995). Data on years to reach breast height for diff species.

Field Technique Tips for Counting Whorls
In Forest Measurements: An Applied Approach by Joan DeYoung Open Oregon Educational Resources . No date

3. How to measure: Special techniques for trees

Ben Meadows 102336 Cruise Angle Gauge

Wedge Prism
Wikipedia ” the wedge prism is used to estimate basal area of a group of trees by counting trees which are “in” or “out” of a plot centered on a single point”

Low tech prism alternative by Medway Community Forest Co-op
Rainy day prism sweeps as we check on a contractor completing a partial harvest on a neighbouring woodlot in South Brookfield. The aim of this cut is to release existing regeneration and promote growth in shade-suppressed hemlock, pine and spruce. Angle gauges, versus the traditional prism are the fastest and easiest way to determine basal area (cross section area of stump).

Comparison of Combinations of Sighting Devices and Target Objects for Establishing Circular Plots in the Field
Sylvio Manne et al., USDA 2006

What is the “Cruiser’s CrutchTM“? Designed by Foresters For Foresters!

Woodland Management – University of Maryland Extension


Equipment Used to Cruise Timber and How to Use It

Simple Homemade Forestry Tools for Resource Inventories
By Donald P. Hanley, Extension Forestry Professor Emeritus, and J. Alan Wagar, Forestry Professor Emeritus,
University of Washington. Copyright 2011 Washington State University