Forest Resource Measurement and Inventory Flashcards

The Chapman-Richards growth function is frequently used in forest mensuration to model:

Answer: Site index curves and individual tree or stand growth over time

The Chapman-Richards function is a flexible sigmoid growth model widely used for site index curves and tree/stand growth projections.

When measuring slope distance on a steep hillside, horizontal distance is calculated by multiplying slope distance by:

Answer: cos(slope angle)

Horizontal distance = slope distance × cosine of the slope angle, converting the hypotenuse to the horizontal leg of the right triangle.

Which inventory design is most efficient when the forest is highly heterogeneous and prior knowledge allows delineation of distinct strata?

Answer: Stratified random sampling

Stratified random sampling outperforms simple random when meaningful strata with lower within-group variance can be identified in advance.

The 'crown competition factor' (CCF) is used to describe:

Answer: The sum of individual tree maximum crown areas expressed as a percentage of stand area

CCF sums the theoretical maximum crown areas of all trees and expresses the total as a percentage of stand area, indicating stocking relative to open-grown tree standards.

A relascope angle of 1 in 33 (approximately 1.74°) corresponds to a basal area factor of:

Answer: 10 sq ft/acre

A 1-in-33 angle gauge (wedge prism) has a BAF of 10 sq ft per acre, one of the most common factors used in US timber cruising.

Which photogrammetric product derived from aerial imagery is most analogous to LiDAR's digital terrain model (DTM)?

Answer: Bare-earth DEM generated from stereo photogrammetry with vegetation removed

Stereo photogrammetry can produce a bare-earth DEM by filtering out vegetation-covered points, analogous to a LiDAR DTM.

In the three-P (probability proportional to prediction) sampling system, the probability of selecting a tree for measurement is proportional to:

Answer: A predicted value assigned before the tallier decides inclusion

In 3-P sampling, each tree is assigned a predicted volume; a random number drawn on site determines inclusion if the random number is less than the prediction, linking selection probability to predicted size.