Growth and Yield Flashcards
What is the difference between Gross and Net yield?
Gross yield is absolute possible volume that can be produced whereas net yield is the volume available at rotation. The difference is Mortality and growth loss.
What successional stage does gross and net yield begin to differentiate?
Stem exclusion (crown closure): competition results in growth loss as well as individual tree mortality.
How can you increase net yield?
commercial thinning can help to recover stems that would otherwise be naturally thinned. This allows for the release of remaining trees. Thinning can be performed multiple times over a rotation.
What are some measures of yield?
M3/ha, BA/ha, SPH, FBM
What is the policy for pruning in BC?
leave at least 3 whorls of branches.
What are the factors that effect yield?
- Site Index
- Growing space
What defines growing space?
The area covered by the crown of a tree is its “growing space” required for optimum growth.
What is the optimum crown length for even aged stands?
1/2 - 1/3 of tree length.
What can result in the loss of crown length in even aged stands?
If the density is exceeded, there will not be enough light to maintain crown.
Why do we use the quadratic mean when calculating average DBH of a stand?
The quadratic mean reduces the impact of small diameter trees and focuses more on larger DBH trees, giving a much more accurate representation of targets.
What is the formula for quadratic mean
Square root of the sum of diameters^2 divided by number of trees sampled.
What is the stand density index?
Generates the optimum number of SPH that you should have to generate the optimum MAI at any time during the stands life.
If you don’t have enough or too much trees / hectare, what results?
You don’t maximize yield.
What stands does Reinekes Stand Density Index work best with?
Single species stands. (Normal Forests)
What was Yoda’s hypotheses?
Biomass will decrease by a factor -3/2 as density increases.
