Forestry Measurement and Mensuration

Introduction

• In forestry, especially for entry-level jobs, you will engage in forest measurement or mensuration.
• Also known as timber inventory or timber cruising.

Purpose of Timber Measurement

• Reasons for conducting timber measurements include:
  • Inventory of forest stand
    • Assessing volume, basal area, and condition of the stand
  • Pre-thinning or pre-timber sale assessments
  • Scientific research and ecological objectives

Key Measurements

Basal Area

• Definition: Cross-sectional surface area of a tree at breast height.
• Importance:
  • Typically reported in square meters per hectare.
  • Essential to know total basal area and the proportion by species (e.g., Douglas fir, Western hemlock).

Volume

• Definition: Measurement of the amount of wood in a tree.
• Calculating Volume:
  • Use an estimate approach by treating the tree trunk as a cone.
  • Volume estimate formula:
    • Volume = (Basal Area × Height) / 3
• Importance of Volume Measurement:
  • Can be calculated for individual trees or scaled to stand level (cubic meters per hectare).
  • Important for management and timber purposes by species.

Summary

• Basal area and volume are critical statistics in forestry mensuration.
• Both must be measured at both the individual tree and stand levels, often categorized by tree species for effective management.