Forestry has always had to plan for the long term against
a backdrop of rapidly changing social and physical environments. If forest productivity and other forest values are to
be sustained in the face of global change, management policies must make unprecedented use of the knowledge base
that has been developed on forest ecosystem dynamics and
response to disturbance. From a scientific perspective, Forest Service activities should work in concert with other national environmental efforts to monitor changes in the physical and chemical environment over time.
Managers should be particularly alert for the potential
of ozone damage to reduce productivity in eastern forests
and also for increased nitrate leaching to acidify soils, streams
and lakes, a phenomenon now occurring in the Colorado
Front Range and California's San Bernardino Mountains as
well as in the northeast (Fenn et al. 1998). Given the combined effects of harvest removals and acid deposition in many
areas, forest soils should be monitored for impending deficiencies in calcium, magnesium, and potassium. Finally, intervals between timber harvests may need to be lengthened
in some forests and whole-tree harvesting techniques reduced
in areas where they are now practiced.
Our National Forests, of course, must continue to serve
values beyond wood production, including biodiversity conservation and recreational and aesthetic needs. If global
changes force plant and animal species to migrate to new
regions over the next century, National Forests must be prepared to play an important role by providing relatively continuous and undisturbed corridors through which species can
move. And if forest declines at the southern edge of species'
ranges require them to migrate, forest managers must be
alert to the possibility that human intervention may be needed
to help species reach suitable new habitat.
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