EXAM IV FR 3218/5218 Semester II - 2003
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. For multiple point questions, select the single best response. Total points = 48.
(4)
1. Sketch the typical sigmoidal (cumulative) growth curve on the top chart
below. On the lower chart, sketch the corresponding instantaneous growth curve.
Be sure the maximum of the instantaneous growth curve is properly aligned with
the corresponding point on the cumulative growth curve.
Age
(6) 2. Given the cumulative growth equation:
W = -600 + 40 A - 0.25 A2
where W is size and A is age, find:
1. current annual (instantaneous) increment at age 30
2. mean annual increment at age 30
3. periodic annual increment between ages 25 and 35
(2) 3. Name the two techniques discussed in your text for “measuring” past tree growth.
(4) 4. Define the four components of stand growth:
Survivor growth –
Ingrowth –
Mortality –
Outgrowth –
(4) 5. Sketch the form of the DBH distribution for an uneven-aged stand below. What role, if any, does the DBH distribution play in identifying a management strategy for an uneven-aged stand?
Role
(8) 6. Given the current number of trees in each DBH class and the 10-year DBH increments (inches) below, predict the future stand table in 10 years using stand table projection. Ignore stand ingrowth. Assume 5 percent of the trees in each class will die during the 10-year period. Assume no cutting.
|
DBH |
Increment |
Current Trees Per Acre |
|
12 |
2.2 |
50 |
|
14 |
1.8 |
70 |
|
16 |
1.6 |
60 |
|
18 |
1.2 |
30 |
(2) 7. Is TWIGS (the individual tree growth and yield model you used in your homework) a (circle one) distance independent or distance dependent model?
(2) 8. What advantages do individual tree growth and yield models have for application to forests of the Lake States region over competing model types (whole stand, diameter distribution)? I am looking for at least two advantages.
(3) 9. What two variables are used to predict yield in an empirical yield table (i.e. what defines a stand’s initial condition)? What assumption is made about a third important variable?
two variables used –
assumption regarding third variable –
(2) 10. The “Clutter” and “Buckman” approaches to developing whole stand, variable-density growth and yield models each consisted of two equations. What did those equations predict?
a. potential and realized growth
b. total yield and yield by size class
c. yield and density change
d. site index and trees per acre
(3) 11.You were able to change any of thinning {age, type, amount} when you used PCWTHIN to simulate size class diversity at age 35 for a loblolly pine stand, with diversity measured by Shannon’s Index. Explain what you found for your stand when you manipulated one or more of thinning {age, type, amount} in PCWTHIN. That is, how did one or more of thinning {age, type, amount} impact size class diversity in your model runs? I am not looking for exact results, just trends.
(2) 12. How do diameter distribution models compare to individual tree (IT) and whole stand (WS) models in terms of input requirement and output detail?
a. closer to IT in terms of input, closer to WS in terms of output
b. closer to IT in terms of input, closer to IT in terms of output
c. closer to WS in terms of input, closer to WS in terms of output
d. closer to WS in terms of input, closer to IT in terms of output
(2) 13. Both PnET and 3-PG directly model the carbon cycle. What additional cycle does PnET also model?
a. nitrogen
b. temperature
c. water
d. litterfall
(4) 14. List two pros and two cons when considering the practical application of ecosystem process models like PnET and 3-PG (only list two each).
Pros Cons