Exam 3 FR 3218/5218 Semester II, 2006

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. A good strategy would be to go through and answer/set up as much of each calculation question as you can and then go back to fill in details. Time could be an issue.

The number preceding the question number is the point value of that particular question. Total points = 71.

(12) 1. The following trees were tallied on one 30BAF variable-radius plot:

Tree	DBH	# Bolts
1	6	2
2	8	4
3	10	5
4	8	3

The attached Table 6 was determined to be appropriate for computing tree volumes. Find observations of (be sure to state units in your answer):

a. trees per acre

b. basal area per acre

c. cordwood volume per acre

(6) 2. A total of 25, 14-inch DBH sugar maple trees (or loblolly pine trees if your initials are RKB) were tallied on 10, 20BAF variable-radius plots. The total volume of the 25 trees was determined to be 3500 board feet. Provide the stand table (only) entry for 14-inch DBH sugar maple.

(6) 3. The BigBAF method was used to cruise an aspen pulpwood stand. A total of 10 plots were taken. A 20BAF was used to tally trees. A total of 80 trees were tallied with the 20BAF. A 200BAF was used to select measure trees. A total of 7 trees were measured across the 10 plots. The volume:basal area ratios for these 7 trees were:

.09 .10 .14 .09 .25 .15 .20

From this cruise, what is your estimate of volume per acre for this aspen pulpwood stand?

(4) 4. Why is use of permanent sample plots (plots that are remeasured over time) preferred, from a statistical perspective, over use of temporary sample plots when interest lies in forest growth/change?

(4) 5. In traditional 3P sampling (application in small area, high value timber sales) we select trees for measurement with probability proportional to predicted volume. We briefly discussed an extension of this idea (and the text lays the extension out further) to a larger area where variable-radius plots are used as a first stage tree selection criterion, with first stage trees then sub-sampled based on a second criterion (tree dimension).

a. What is a reasonable second criterion, given interest lies in volume?

b. Why is it a reasonable criterion?

(6) 6. Briefly compare and contrast the a. objectives and b. methods of the two inventory systems presented on by Sarah McCourtney (Potlatch) and Mark Hansen (USDA Forest Service). Write legibly.

a.

b.

(8) 7. In the literature you find the following anamorphic site index equation that appears to be applicable for the stand whose site quality you wish to assess:

(where S=site index, H=height of dominants, A=age, and A_i=base age, 50 here). On a sample of four dominant trees in the stand you measure height and core the trees for age and find:

Tree	Total Height	Age
1	65	48
2	63	54
3	59	52
4	63	46

a. Compute site index for the stand.

b. How tall do you predict the average dominant tree to be in 10 years?

(6) 8. List three different situations where it is not possible to use traditional site index as a measure of site quality and identify what approach you would use instead to assess site quality.

Case	Describe Case	Alternative to Site Index
1
2
3

(4) 9. When we are assessing stand density we are attempting to characterize the competition among trees for site resources. For what stand structure will the stand-level measures of density we discussed in class be good indicators of resource competition?

The text presents several tree-level measures of competition that get at the issue more directly. Identify one of those measures or the generic characteristics of such a measure.

(9) 10. The Reineke stand density boundary line for species X is given by (also see attached chart):

Currently species X is planted at 500 stems per acre. The existing initial thinning prescription for species X in you company management guide is to thin to 100 square feet per acre when the stand reaches 150 square feet per acre. (note – you can answer b. and c. without having answered a.!!!)

a. What percent of maximum stocking will such stands be at when the first thin is initiated based on the company management guide?

The new company vice president suggests that the current company management guide prescription involves waiting too long for the first thin. He suggests the first thin should occur when the stand reaches 55% of maximum stocking.

b. Based on the vice president’s prescription, what will basal area per acre be when the first thin is initiated (again, 500 stems per acre planted)?

The vice president further suggests using an intense thin-from-below (for the first thin) with D_{after thin}/D_{before thin} = 1.1, thinning back to the 40% of maximum stocking line.

c. What post thinning basal area per acre does the vice president’s prescription result in?

(6) 11. A young upland oak stand currently has 600 stems per acre and 90 square feet per acre of basal area. Based on a stand exam it is determined you need to remove 200 stems per acre, with those 200 stems having an average DBH of 4.8-inches.

a. On the attached chart, identify where the stand is now (X) and where it will be after (Y) “cleaning” (removing the recommended 200 stems per acre).

b. If you intend to clean the stand again (a second time) when it’s 100 percent stocked, how much will the stand have grown (after the first cleaning) in terms of basal area per acre.

“Equation sheet”