# F 321 – Assignment #2

### Summarization of Forest Inventory Data

Objective: This assignment will ask you practice basic quantitative skills required for conducting forest field inventories. You will also start to show your mastery over the analytical skills need to summarize both fixed and variable radius forest inventory data.

Student Learning Outcomes: Upon completing this assignment you should be able to:

• Correct plots to eliminate bias when setting up a forest inventory.
• Summarize variable radius plot to determine basal area and trees per acre.
• Explain the statistical difference in how trees are selected for sampling in fixed and variable radius plots.

1. You are setting up a 1/10th acre circular plot on a 40° slope, what is the radius parallel and perpendicular to the slope to the nearest 1/10th foot?

2. You are setting up a 1/5th acre circular plot on a 30° slope, what is the radius parallel and perpendicular to the slope to the nearest 1/10th foot?

3. Calculate to the nearest 1/10th foot the radius of a 5th, 10th, and 100th acre circular plot.

4. Calculate to the nearest 1/10th meter the radius of a 7th, 12th, and 30th hectare circular plot.

5. Calculate to the nearest 1/10th foot the length of the side of a 5th, 10th, and 100th acre square plot.

6. Calculate to the nearest 1/10th meter the length of the side of a 7th, 12th, and 30th hectare square plot.

7. Using ten 1/10 acre plots within a 50 acre tract, the following measurements were made via simple random sampling (without replacement).

a) Calculate the mean, median, and mode for each of the measurements.

b) Calculate the standard error of the mean for each measurement.

c) Calculate the 95% confidence intervals for the mean of each measurement.

8. Calculate the limiting distance for an 18.2” DBH tree using both a 14 and 38 BAF instrument to the nearest 1/10th

9. Answer the following questions from the table summarizing a variable radius cruise.

a) Calculate the mean and standard deviation of basal area per acre assuming the cruise was done with a 30 BAF prism.

b) Calculate the mean and standard deviation of basal area per acre assuming the cruise was done with a 20 BAF prism.

10. Explain the difference in the statistical principals underlying the probability of a tree being selected using a fixed area vs Variable Plot sampling design.

11. Calculate how many trees per acre each tree would represent for the following 30 BAF plot data (e.g. how many of each size tree does it take to have 30 ft2 of basal area), and then calculate the average and standard deviation of trees per acre and the quadratic mean diameter to the nearest 1/10th Must show calculation steps for the first tree to receive credit.