FM FM Forest Measurements & Inventory

Question 1

Diameter at Breast Height (DBH) is the standard measurement of tree diameter taken at:

Accepted Answer

4.5 feet (1.37 meters) above ground on the uphill side of the tree

Answer

DBH is universally measured at 4.5 feet (1.37 m) above ground on the uphill side of sloped terrain, providing a standardized reference point for comparing tree sizes.

Question 2

What instrument is most commonly used to measure tree DBH in forest inventory?

Accepted Answer

Diameter tape or calipers

Answer

Diameter tapes (which convert circumference to diameter) and calipers are the standard field instruments for measuring tree diameter at breast height in forest inventory work.

Question 3

In a prism or wedge cruising system, a tree is counted in the plot when:

Accepted Answer

Its image in the prism appears to overlap with the actual tree trunk

Answer

In variable-radius (angle gauge) cruising, a tree is tallied when the displaced image seen through the prism overlaps the stem, selecting trees with a probability proportional to their basal area.

Question 4

The term 'basal area' in forest mensuration refers to:

Accepted Answer

The cross-sectional area of a tree stem or all stems per unit area, typically expressed in square feet per acre

Answer

Basal area is the cross-sectional area of a tree at DBH (or the sum for all trees per acre), serving as a key measure of stand density and growing stock used extensively in forest management.

Question 5

A 'site index' in forest management is used to:

Accepted Answer

Measure forest site productivity based on the height of dominant trees at a base age

Answer

Site index is a numerical measure of forest site quality based on the average height of dominant and co-dominant trees at a specified base age (commonly 25 or 50 years), predicting potential timber productivity.

(FM) Forest Management Certification Practice Test

(FM) Forest Management Certification Practice Test

FM FM Forest Measurements & Inventory