Trees, Timber, and Trade Fall 2001

These are due Monday, October 15^th at the beginning of class. Write your answers neatly and legibly on a separate piece of paper that you will turn in. You may need to access outside resources to completely answer the questions. Be prepared to discuss your answers with your study group.
 
 

1. Harvesting timber by clear cutting is a common practice here in the PNW. Early clearcuts grew back vigorously without replanting. As harvest levels increased, it became necessary to replant trees, and on sites harvested later, even replanting did not always guarantee regrowth of the trees. Explain this trend in terms of the topics covered in chapter 8. (hint: outline the stages and processes happening, this could end up being a book).


 

 

2. What role has plate tectonics had in the geologic history of the Pacific Northwest?


 

 

3. Draw graphs for the two components of species diversity, namely species richness and evenness, for the animals and plants on a small burn here in western Washington. Begin just prior to the fire and continue your graphs through a mature forest stage. Do one set of graphs for the animals and another for the plants. Explain your scenario and rationale.


 

 

4. What are some of the major forces that drive succession?


 

 

5. Why might a shelterwood harvest cut (leaving a percentage of the trees) regrow faster than a clear cut? Give specific examples of mechanisms.


 

 

6. Forest managers point out that clearcuts increase the forage areas for large mammals, thus increasing their abundance. Does this mean that the overall animal diversity is higher in the clearcut? Explain and support your answer.


 

 

7. What are the differences between primary and secondary succession? Give examples where you might find these processes occurring in local ecosystems.


 

 

8. Construct a dichotomous key for all the required trees from your species list. Use features that you will be able to readily observe.