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Chapter 7: Forests and Wildlife
Big Question
Can We Have Them and Use Them Too?
Lesson 7 / ESRM 100 / University of Washington
Forestry: Keeping Our Living Resources AliveFor both forests and commercially valuable wildlife, the
traditional goal has been the maximum sustainable
yield.
This goal is based on traditional concepts: belief in the
balance of nature.
Lesson 7 / ESRM 100 / University of Washington
Modern Conflicts overForestland and Forest Resources•What’s “natural” and what isn’t?•Growing trees has become a profession called
silviculture.•Civilizations have literally been built on wood.•Forests also have had religious, spiritual, and aesthetic
importance.
Lesson 7 / ESRM 100 / University of Washington
Clearcutting
Lesson 7 / ESRM 100 / University of Washington
Muir and Pinchot
At the heart of the conflict are the two different kinds of
values, utilitarian and nonutilitarian. John Muir (with
Theodore Roosevelt at his left, in the left-hand photo)
and Gifford Pinchot (right) personify the two viewpoints.
Lesson 7 / ESRM 100 / University of Washington
Hetch Hetchy
The dam at Hetch Hetchy led to one of the greatest
arguments between Muir and Pinchot.
Lesson 7 / ESRM 100 / University of Washington
Controversial Questions
•Should a forest be used only as a resource to provide
materials for people and civilization?•Should a forest be used only to conserve natural
ecosystems and biological diversity?•Can a forest be managed for timber harvest and also
meet recreation, landscape beauty, and spiritual needs? •Can we achieve sustainable forests?•What role do forests play in our global environment?•What is “natural” in a forest?•How much old growth do forests need?
Lesson 7 / ESRM 100 / University of Washington
International Aspects of Forestry
Lesson 7 / ESRM 100 / University of Washington
Plantation Forestry
Lesson 7 / ESRM 100 / University of Washington
Are the World’s ForestsShrinking, Growing, or Neither?We lack enough information to accurately evaluate the
situation, but this situation has begun to change with
remote sensing and geographic information systems.
Lesson 7 / ESRM 100 / University of Washington
Indirect Deforestation
A more subtle cause of the loss of forests is indirect
deforestation--the death of trees from pollution or
disease.
Why trees are dying appears to involve a number of
factors.
Acid rain, ozone, and other air pollutants weaken trees
and make them more susceptible to disease.
Global warming could cause widespread damage.
Lesson 7 / ESRM 100 / University of Washington
Wildlife ManagementTraditional Wildlife ManagementModern conflicts about wildlife are similar to those
about forests.
How has wildlife been faring?
Many species of wildlife have declined greatly in
abundance, some have become endangered, and some
have gone extinct.
Lesson 7 / ESRM 100 / University of Washington
Bison on the Range and Then Mostly off the RangeHow many bison were there to begin with? Perhaps 50
million?
Lesson 7 / ESRM 100 / University of Washington
Test Case: Pribilof Island Reindeer
The islands seemed perfect for introduced reindeer:
lots of plants and no predators.
Lesson 7 / ESRM 100 / University of Washington
Decline of the Pribilof Island ReindeerEven so, something went very wrong with the Pribilof
Islands reindeer. Population initially increased, then
declined severely.
Lesson 7 / ESRM 100 / University of Washington
Improved Approaches toWildlife ManagementFour principles of wildlife conservation:•a safety factor in terms of population size;•concern for the entire community of organisms and all
the renewable resources;•maintenance of the ecosystem of which the wildlife are
a part; and•continual monitoring, analysis, and assessment.
Lesson 7 / ESRM 100 / University of Washington
Time Series and Historical Range of VariationHow do we decide what is a sustainable population if
the natural population is always changing?
One answer is to consider a range of population levels
natural. A time series of population estimates provide
the historical range of variation.
Such records exist for only a few species.
Lesson 7 / ESRM 100 / University of Washington
Example: American Whooping Crane
In the late 1930s, the population was 14. The number
born that year was also counted.
We can use this historical range to estimate the
probability of extinction.
Lesson 7 / ESRM 100 / University of Washington
The American Whooping Crane's RecoveryPrediction of extinction was very low: less than one in a
billion.
As predicted, whooping cranes have continued to
increase.
Breeding programs have further boosted the number of
whooping cranes.
Lesson 7 / ESRM 100 / University of Washington
Managing Two or More Species at a Time: Do Predators Matter?It appears that predators probably play a smaller role
than we thought—for example, Hudson’s Bay Company
trapping records suggest Canadian lynx do not neatly
control the abundance of Arctic hares.
Lesson 7 / ESRM 100 / University of Washington
Large Influence of Some Predators
Predators can have large effects in some cases. For
example, m0squito fish can greatly reduce mosquito
abundance.
An absence of predators can have a major effect, too.
Introduced Asian water buffalo in Australia increased
too rapidly, causing large die-offs. In this case, not just
the water buffalo but also their habitat suffered.
