FE Ch 17. These are due Monday, Feb 25^th at the beginning of class. Write your answers neatly and legibly on a separate piece of paper that you will turn in. Be prepared to discuss your answers with your study group. You may need to access outside resources to completely answer these questions.

1. Refer to the definition of k on p 406. Given that k=0.18 for a Douglas fir forest and the annual litterfall is 1.3 kg/m²:

1. What is the amount of accumulated litter per square meter?
2. Assuming that the litter is 45% carbon and using the information in table 18-6 calculate the amount of carbon, nitrogen, and phophorus in the litter.
3. Assume that the forest litter is in steady state of production/ decomposition. The microbial population which breaks down the litter is 80% fungi and 20% bacteria. Assume that the efficiency of both the bacteria and fungi is 45% and that all of the litterfall is decomposed, calculate whether there would be net immobilization or mineralization of nitrogen and the mass of nitrogen involved (use the values for "on leaves").
4. Suppose that additional nitrogen is not available from the surrounding environment. How much of the litterfall could be decomposed?
5. Suppose all the fungal mycelium produced under the conditions in ‘d’ are consumed by mites (C/N of 6:1) and 25% efficient. How much nitrogen will be immobilized/mineralized?
6. Suppose any additional nitrogen released by the mites were taken up by the fungi and used to decompose some of the remaining litter (assume no nitrogen left in litter). How much additional litter could be decomposed?
7. Repeat steps c-e for phosphorus (C/P for mites is 8/1)

1. Assuming that the figures used in question 1 are fairly representative of the actual forest and that the situation described is in steady state, what does this mean for the nutrient cycles within the organic layer of the forest soil?
2. Refer to figure 18-15. Explain in your own words what these data illustrate and how that process might work.
3. Both humans and a variety of forest mammals consume salmon during their annual runs. Using the data in chapter 16 and assuming a conversion efficiency of 25%, would salmon nitrogen be immobilized or mineralized by these mammals consuming salmon? Suppose a growing family (camping in a fish camp) consumed a meal of 12 lb of salmon, and the total mass of the family was 560 lb. Assume that they all ate as much salmon as they possibly could. Calculate how much nitrogen would be retained/released by this family.
4. Your favorite conifer tree is not looking as perky as usual. Closer examination shows that the needles have a yellowish color, especially the new growth. You give it some fertilizer, but if anything it speeds up the decline. What do you think is going on?
5. Calculate the amount of water needed to produce the above ground biomass we calculated in workshop #1 given an average of 275 liters of water needed per kg above ground biomass. If you were to build a cubical tank to hold all this water, how big would it be?
6. Go to this web site (http://www.gdrc.org/uem/co2-cal/co2-calculator.html) and calculate your yearly carbon dioxide emissions. Using information from the FACE website, calculate how many hectares of forest are needed to offset your carbon emissions.