Exam 3                                                 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. A good strategy would be to go through and answer/set up as much of each such question (especially the high point value questions) as you can and then go back to fill in details.

            The number preceding the question number is the point value of that particular question. Total points = 46.

 

(8) 1. Find trees per acre and basal area per acre observations for one, 30 BAF variable-radius plot where the trees tallied had DBHs:

            8, 9, 8, 10, 9

 

            trees per acre –

 

 

 

            basal area per acre –

 

 

 

(6) 2. Tally sheets from 15, 10 BAF variable-radius plots show that 25 red pine pole-sized trees were tallied. These 25 trees had a total of 60 pulpwood sticks in them. Given the individual tree volume equation:

            cords = 0.0003 D2H

(D=DBH and H=number of sticks) holds, estimate cords per acre and basal area per acre of red pine poles based on the data collected.

 

            cords per acre –

 

 

 

            basal area per acre –

 

 

 

(4) 3. Double sampling with variable-radius plots (with a ratio-of-means estimator) and Big BAF cruising share the following similarities:

a.       volume per acre =

b.      fewer trees are measured than are tallied

c.       both always employ tally by height only

d.      two different BAFs are used at all sample locations

 

 

 

(2) 4. Why do permanent sample plot timber inventory systems often include the use of high-end technologies like GPS, data recorders, and electronic tree measurement devices?

 

 

 

 

(4) 5. What role(s) does a volume table (equation) estimate of individual tree volume play in traditional 3P sampling applied to obtaining a timber sale volume estimate (as discussed in class)?

a.       none, volume table estimates aren’t ever used at all

b.      the pre-sampling guess of total sale volume () is the sum of volume table estimates for all the trees

c.       the random numbers are values from the volume table

d.      trees with large volume table estimates are sampled with greater probability

 

(3) 6. The regeneration sampling protocol for Company XYZ specifies 1/100-acre plots placed systematically (so location are known) in the tract. Tallies are kept separate by plot. A variance/standard error calculation is not called for. Why then are separate tallies kept by plot?

 

 

 

(6) 7. The following anamorphic site index equation is known to hold for a stand of interest:

           

(where S=site index, H=height of dominants, A=age, and Ai=base age, 50 here). Several dominant trees are observed with average height determined to be 55 feet and average age 40 years. How tall do you expect dominant trees in the stand to be at age 60 years?

 

 

 

 

 

 

(3) 8. Your Minnesota company decides to divest itself of all lands that are not suitable for growing aspen or red pine. “The boss” specifies that site index for one of the species must exceed 60 feet (base age 50) for the stand or the stand will be sold. The company’s inventory has aspen site index for all stands where aspen is currently the predominant species and red pine site index for all stands where red pine is currently the predominant species: there are many more stands where neither species is currently predominant or where only very recent regeneration is present. You are told to “go to the literature” and find the additional “tools” needed to complete an evaluation of all stands. What would you look for (what other tools are needed)?

 

 

(4) 9. Sketch Langsaeter’s hypothesis on the chart below, labeling the axes. Identify where on the chart you would manage stands if producing large, vigorously growing sawtimber trees is your objective.

 

 

 

 

 

 

 

 

 

 

 

 (6) 10. Your agency has just decided to begin using a density management diagram to determine thinning schedules. The upper and lower management lines for the density management diagram are given by:

            Nupper = 11500 D-1.6

 

            Nlower = 8500 D-1.6

 

You decide to “try it out” on a stand for which you determine N to be 650 trees per acre and D to be 7.0 inches. You decide to do a “thin from above” in the stand such that D decreases by six percent due to the thinning. What will basal area per acre be after thinning? Where is the stand now (above or below the upper management line)?

 

 

 

 

 

 

 

 

 

 

 

 

(3) Extra credit. You need a “quick and dirty” estimate of cords per acre for a stand. You take 10, 20 BAF variable-radius plots and tally 90 merchantable trees total (but take no measurements). Based on your walk through the stand you guess the average tree tallied would have been 9-inches DBH with three pulpwood sticks. What’s your “quick and dirty” estimate of cords per acre? (see attached volume table)

 

 

 

 

 

“Equation sheet”