EXAM IV FR 3218/5218 Semester II - 2005
If it is not clear what a question is asking, request clarification from the instructor. Misreading a question is not grounds for partial credit. To receive partial credit for the calculation problems, formulas and intermediate calculations must be legibly shown.
The number preceding the question number is the point value of that particular question. Total points = 42.
(3) 1. Given the cumulative increment equation:
W = -500 + 50 A - 0.25 A2
where W is size and A is age, find:
i. current annual (instantaneous) increment at age 40
ii. mean annual increment at age 40
iii. periodic annual increment between ages 35 and 45
Typical
DBH increment curve
(2) 2. Why does a DBH cumulative increment curve typically
exhibit no clear youth phase of growth?
(2) 3. What does a “stem analysis” (as defined in your text) involve in terms of work in the field?
(3) 4. Compute the four components of growth and compute net growth, all in terms of basal area per acre) using the following data from a 1/30-acre permanent sample plot. BA1 is the basal area of the tree at time 1 and BA2 is the basal area of the tree at time 2; -- means the tree isn’t present.
Tree BA1 BA2 Tree BA1 BA2
1 .16 Dead 5 -- .15
2 .38 .51 6 .22 Dead
3 .22 .36 7 .28 .42
4 .32 Cut
Survivor growth –
Ingrowth –
Outgrowth –
Mortality –
Net growth –
(3) 5. Draw the DBH distribution of an unthinned, even-aged stand i. before crown closure and ii. near the time when the stand reaches its biological rotation age.
What stand development process contributes to the distribution shape change when moving from i. to ii.?
(2) 6. Describe how you would mark an uneven-aged stand for a partial harvest if its actual and target DBH distributions looked like the following:
(6) 7. Given the number of trees in each DBH class, the 10-year DBH increments (inches), and the mortality percents below, predict the future stand table in 10 years using stand table projection. Assume no stand ingrowth or cutting.
|
DBH |
DBH Increment |
Mortality Percent |
Current Trees Per Acre |
|
12 |
1.2 |
4 |
60 |
|
13 |
1.1 |
2 |
40 |
|
14 |
0.9 |
2 |
30 |
|
15 |
0.8 |
0 |
20 |
(3) 8. What basic equations (what do they predict) constitute (make up) any individual tree growth and yield model?
(3) 9. What primary factor driving stand dynamics do distance dependent and distance independent individual tree growth and yield models account for differently? How do they each account for the factor?
i. Factor –
ii. How the factor is accounted for:
a. distance dependent model
b. distance independent model
(3) 10. Using the whole stand growth and yield model defined by the following equations (directly from your textbook), predict yield at age 50 for a stand that is currently 40 years old growing on site index 100 land with a basal area (currently) of 100 square feet per acre.
where Y = yield (ft3 per acre), S=site index, A=age, G=basal area (ft2) per acre, ln=natural logarithm, and the subscripts 1 and 2 refer to time.
Yield at age 50 –
(2) 11. What is the primary disadvantage of variable-density, whole stand growth and yield models versus the alternative growth and yield models that we discussed in class?
(3) 12. Describe (in words; no equations necessary) how one would go about computing the volume per acre of a certain product class of trees (defined by DBH limits) in a stand given an estimate of the probability distribution function for the stand’s DBH distribution.
(3) 13. You compared at least three thinning alternatives (one alternative may have been no thinning at all) for your loblolly pine stand in question 3. on the last homework. Based on what you did, what characteristics of a thinning treatment lead to greater size class diversity as measured by Shannon’s Index?
(2) 14. List two primary reasons for adopting complex, ecosystem process models (such as 3-PG) in a “management for forest production” environment.
(2) 15. List two environmental modifiers used to lower maximum rate of photosynthesis in the light-use efficiency models 3-PG and/or PnET.