15. Assessing and Responding to the Effects of
Climate Change on Forest Ecosystems
David L. Spittlehouse
Management of our forest resources requires that we make decisions
now that are based on future unknown climatic conditions . The Intergovernmental Panel on Climate Change (Houghton, Callander, & Varney,
1992) concluded that a 1SC to 4SC warming of the earth's climate and
accompanying changes in precipitation and weather patterns are likely
to occur by the end of the next century. However, there is much disagreement over the validity of the climate predictions, the reliability of
the impact assessments, the economic costs, and our ability to develop
responses (Reifsnyder, 1989; Schneider , 1990, 1994; Ausubel, 1991 ;
Clark , 1991; Cline, 1992; Michaels & Stooksbury , 1992; Waterstone
1993). This debate over climate change, which is confusing to forest
managers and the public, does little to help managers make decisions now
that will have repercussions in 100 years. The uncertainty may, in fact,
discourage forest managers from even considering the issue, particularly
since the planning horizon for many forest management operations is
often 10 years or less (Woodman, 1987).
Neither climate nor ecosystems are static. Organisms, including humans,
have responded to climate changes in the past. The concerns are that
human-induced changes may occur at a greater rate than in the past and
that the changes may be detrimental to our welfare. Ausubel (1991)
suggests that the technologies and social structures that buffer us from
climatic stresses may make the changes irrelevant. Immediate concerns
306
Climate Change on Forest Ecosystems
David L. Spittlehouse
Management of our forest resources requires that we make decisions
now that are based on future unknown climatic conditions . The Intergovernmental Panel on Climate Change (Houghton, Callander, & Varney,
1992) concluded that a 1SC to 4SC warming of the earth's climate and
accompanying changes in precipitation and weather patterns are likely
to occur by the end of the next century. However, there is much disagreement over the validity of the climate predictions, the reliability of
the impact assessments, the economic costs, and our ability to develop
responses (Reifsnyder, 1989; Schneider , 1990, 1994; Ausubel, 1991 ;
Clark , 1991; Cline, 1992; Michaels & Stooksbury , 1992; Waterstone
1993). This debate over climate change, which is confusing to forest
managers and the public, does little to help managers make decisions now
that will have repercussions in 100 years. The uncertainty may, in fact,
discourage forest managers from even considering the issue, particularly
since the planning horizon for many forest management operations is
often 10 years or less (Woodman, 1987).
Neither climate nor ecosystems are static. Organisms, including humans,
have responded to climate changes in the past. The concerns are that
human-induced changes may occur at a greater rate than in the past and
that the changes may be detrimental to our welfare. Ausubel (1991)
suggests that the technologies and social structures that buffer us from
climatic stresses may make the changes irrelevant. Immediate concerns
306