OREGON STATE UNIVERSITY – BI301 – HUMAN IMPACTS ON ECOSYSTEMS – 2002 (needs to be updated for 2009!)

To review lecture notes on global issues in forestry and a history of how we got to be where we are with forests in the PNW (including a discussion of the essential features of old-growth forests in our region), click on deforestation and to review lecture notes on new approaches to forest conservation and management and their relation to biological diversity issues in the Pacific Northwest, click on PNW. Highlighted words or phrases in the Unit Goals and Questions, below,will (eventually) link you to the area in the lecture notes in which the relevant topic was first introduced or explained most fully. However, most topics are discussed in many places. For a comprehensive review, you should look at the lecture notes in entirety, rather than just the areas for which jumps are provided.



1. What is the major cause of deforestation, on a global basis?

2. What is the history of forest use here in the Pacific Northwest, and where has that history left us? What is the future for logging on federal lands in western WA, OR and northern CA?

3. You should understand the basic attributes of old growth forest ecosystems in the Pacific Northwest in terms of their composition, structure, and function. What is important about large live trees, standing dead trees, logs on the ground, and logs in streams in these ecosystems?

4. What are the typical logging and site preparation methods in our region> What kinds of effects do clearcutting and subsequent site preparation have on site fertility, soil erosion, and hydrology, and what causes these effects? How long lasting are they? How can logging practices be modified to minimize these effects?

5. Many of the effects of clearcutting on nutrient, water, and soil losses are relatively short term. Effects of conventional forestry on other aspects of forest composition, function, and structure are longer term, however. What are some examples of these longer term effects?

6. What is the basic philosophy behind "Ecosystem Management"? What are some components of ecosystem management, and what ecosystem benefits may result from these approaches?

6. What is "habitat fragmentation," what are its consequences, and how can it be minimized?


Barney, G. O. 1979. The forestry projections and the environment. In: The Global 2000 Report. [Gives lots of data on forests in various areas of the world, causes of deforestation, projections for the future, and policy recommendations (both scientific and social).]

Eckholm, E. 1979. Planting for the Future: Forestry for Human Needs. Worldwatch Paper No. 26, Worldwatch Institute, Washington, D.C. (Full of facts and figures on world forests causes of deforestation, and ideas for sustainable management of forests.)

Franklin, J. F., K. Cromack, Jr., W. Denison, A. McKee, C. Maser, J. Sedell, F. Swanson, and G. Juday. 1981. Ecological Characteristics of Old-Growth Douglas Fir Forests. USDA Forest Service, PNW Forest and Range Exp. Station, Gen. Tech. Rep. PNW-118. [The original compilation of information on the structure and function of old-growth forests in the Pacific Northwest, and comparison to second-growth forest, with "New Forestry" recommendations. Includes discussion of preserving existing old-growth, "recreating" old-growth, and ideas for incorporating individual old-growth characteristics into managed stands. Most authors are (or were) at O.S.U.].

Hansen, A.J., T.A. Spies, F.J. Swanson, and J.L. Ohmann. 1991. Conserving biodiversity in managed forests. BioScience 41:382-392. (An excellent summary of characteristics of "natural" unmanaged forests, how these influence diversity in the forests, and how these characteristics can be mimicked in managed stands.)

Harris, L. D. 1984. The Fragmented Forest: Island Biogeography - Theory and Preservation of Biotic Diversity. (In addition to giving data on the extent to which forests are becoming fragmented and on why that causes problems for preservation of biodiversity, he discusses how forest management can be modified to avoid fragmentation. Chapter 4 focuses on issues related to old-growth in the Pacific Northwest, with a focus on the Willamette National Forest.)

Likens, G. E., F. H. Bormann, R. S. Pierce, J. S. Eaton, and N. M. Johnson. 1977. Biogeochemistry of a Forested Ecosystem. Springer-Verlag, N.Y. (Discusses results from 15 years of studying biogeochemistry at the Hubbard Brook Ecosystem--input/output budgets, nutrient cycles, etc.; relevant considerations for sustainability of forest harvesting practices.)

Leopold, A. 1949 (and many reprintings). The land ethic In: A Sand County Almanac. Oxford University Press. ["A system of conservation based solely on economic self-interest is hopelessly lopsided. It tends to ignore, and thus eventually to eliminate, many elements in the land community that lack commercial value, but that are (as far as we know) essential to its healthy function..." A beautiful argument for the necessity of ethics in land stewardship that has become a classic.]

Maser, C. 1988. The Redesigned Forest. R. and E. Miles, San Pedro, CA. ("The differences between Nature's design of a forest and our design . . . is examined in Part One. Why we insist on our design is examined in Part Two. Why we are afraid of change is examined in Part Three, and ways to integrate Nature's design with our design in an attempt to achieve sustainable forestry is examined in Part Four." His writing includes many natural history gems, and also a very strong element of personal philosophy.)

Norse, E. 1990. Ancient Forests of the Pacific Northwest. Island Press, Washington, D.C. (A Wilderness Society document that describes current status of old-growth forests, biological values of the forests, threats to the forests, and concludes with a discussion of "sustainable forestry" for the PNW. A lot of verbiage, but some useful information.)

Pimentel, D. et al. 1992. Conserving biological diversity in agricultural/forestry systems. BioScience 42(5): 354-362.

Postel, S. and L. Heise. 1988. Reforesting the earth. In: State of the World 1988. Worldwatch Institute, Washington, D. C. (As usual for Worldwatch publications, loaded with data, this time on global and regional trends in forest cover and their causes, fuelwood resources, effects of deforestation on soil and water resources, trees and global CO2, attempts at large-scale reforestation, and estimates of the amount of reforestation needed to arrest the preceding problems.)

Record of Decision. 1994. Record of decision for amendments to Forest Service and Bureau of Land Management planning documents within the range of the Northern Spotted Owl. U.S. Forest Service and U.S. Bureau of Land Management. (Outlines management strategies for federal forest lands; result of President Clinton's "Forest Summit.")

Saunders, D. A., R. J. Hobbs, and C. R. Margules. 1991. Biological consequences of ecosystem fragmentation: a review. Conservation Biology 5(1): 18-32. (An excellent discussion of physical and biological changes associated with ecosystem fragmentation, and implications for managers.)

Wilson, E. O. 1988. Biodiversity. National Academy Press, Washington, D. C. [A compendium of articles by experts on biodiversity--a useful sourcebook. Topics include estimates of present extinction rates (globally and in certain ecosystems) and prehistoric rates; human dependence on biological diversity; diversity at risk in tropical, temperate, and oceanic ecosystems; economics and ethics; monitoring and conserving biodiversity; role of science and technology in preservation of biological diversity; restoration ecology; and "Ways of Seeing the Biosphere." Each chapter includes references. Should be on every ecologist's bookshelf.]

To return to the master directory for the BI301 home page, click on the box labelled "CONTENTS" at the bottom of this page. For a general reminder on how to move within and among these pages, click "Navigate."

This page is maintained by Patricia Muir at Oregon State University. Page last updated November 25, 2002.