Sample Exam 3

EXAM III FR 3218/5218 Semester II - 2004

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. Any number of multiple-choice options (including zero) may be correct responses to the question statement; circle all correct responses. Total points = 54.

(8) 1. Three (3) trees were tallied on a 30BAF variable-radius plot:

DBH (in.)	Height (logs)
10	1.5
14	3.5
12	2.0

Tree volumes (in board feet) can be found using the attached volume table. Find plot observations of:

a. basal area per acre

b. board foot volume per acre

(5) 2. Double (two-phase) sampling with variable-radius plots (20BAF) was used to cruise a stand to estimate volume per acre. A total of 25 plots were used. The total number of “in” trees on the 25 plots was 175. On five of the plots, trees were measured to compute tree volumes. A summary of results for those five plots is:

Plot	Number of trees tallied
1	9	1.5
2	8	1.2
3	4	0.6
4	7	1.0
5	8	1.0

The sum in the third column of the table is the sum of the volume:basal area ratios for the trees tallied on the plot.

Compute the double sampling ratio-of-means estimate of volume per acre using these results.

(3) 3. Why is there a dilemma regards conspicuously marking plots and trees when using permanent sample plots to monitor growth of forests?

(4) 4. 3P sampling, as described in the class lecture, combines the ideas of which two basic sampling techniques?

a. stratified random sampling

b. unequal probability sampling

c. two-phase sampling

d. ratio/regression sampling

(2) 5. Vertical line sampling is an efficient method of characterizing regeneration success expressed as:

a. trees per acre

b. basal area per acre

c. height per acre

d. spacing

(4) 6. What characteristic(s) of understory vegetation is (are) commonly measured in forestry?

a. diversity

b. density

c. spatial pattern

d. leaf area index

(3) 7. Draw height growth curves for a low quality site and a high quality site (two curves total) that illustrate the typical pattern of polymorphism in height growth (label the axes).

(6) 8. Develop a base age 40 anamorphic site index equation from the height growth equation:

ln (H) = 5.4 – 23.6 * (1/A)

where ln is natural logarithm, H is height of dominant trees, and A is total age. Predict the height of dominant trees at age 55 on site 70 land.

a. site index equation

b. height at age 55 for site index 70

(4) 9. Identify four different shortcomings of site index as a measure of site quality.

ii.

iii.

iv.

(4) 10. A 20 acre area where site index is known to be 65 feet was planted with red pine. Half the site was planted at 1000 stems per acre (Dens I) and half was planted at 600 stems per acre (Dens II). The forester in charge conducted no thinnings. It is likely that at age 35:

a. total volume per acre will be substantively greater in Dens I

b. trees per acre will be substantively greater in Dens I

c. volume per acre to a 4-inch top will be substantively greater in Dens II

d. dominant tree height will be substantively greater in Dens II

(7) 11. The density management diagram below displays a thin-from-below where quadratic mean diameter increases by ten (10) percent as a result of the thinning. The Reineke boundary line for the diagram is given by the equation:

N = 20000 * D^-1.6

where N is trees per acre and D is quadratic mean DBH. Compute basal area per acre before (point A) and after (point B) the thin using the appropriate equations (i.e. don’t just try to read the values off the chart).

(4) 12. An upland hardwood stand currently has 600 stems per acre and a basal area of 85 square feet per acre. On the chart below, diagram “cleaning” the stand to a residual basal area of 55 square feet per acre. What would trees per acre be after the cleaning?

“Equation sheet”