Johnson, D. W. 1997. Role of Process Models in Developing Environmental
Guidelines for Sustainable Energy Output from Forests.
pp.213-220 In: Pentti Hakkila, Maija Heino and Essi Puranen (eds.), Forest Management for Bioenergy. Research paper 640. The Finnish Forest Research Institute. Vantaa, Finland.
Simple empirical models - like yield curves - are seldom questioned
because they are not subject to manipulation based upon the user, and users
know the bounds of their applicability quite well. Process models can
certainly be used to understand what might underly such simple empirical
models. However, because they are too complex to yield consistent results
from one user to another and because they do not adequately simulate some
important nutrient cycling processes, they should not, in this author's
opinion, be
directly used to develop environmental guidelines. These models have
considerable heuristic value, however, and should be used to guide our
research and explore the collective implications of our current
understanding of ecosystem processes.