خيارات البحث
النتائج 1 - 3 من 3
Direct and Indirect Effects and the Long-term Risks of Air Pollution on Forest Ecosystems: A Call for Caution in Proper Diagnosis of Causes
1993
Skelly, J.M. (The Pennsylvania State University, (USA). Department of Plant Pathology)
Forest Scientists must recognize that numerous diseases and insect occurrences as well as more subtle environmental stresses are prevalent as causes of changes in forest health. Their interactions often lead to "natural" declines of individual tree species or site-species declines of multiple species. The role of air pollution should be carefully investigated in an integrative sense with these other endemic and sometimes epidemic outbreaks of biotic agents and environmental stresses.
اظهر المزيد [+] اقل [-]The Swiss National Forest Inventory, an information for the assessment of the condition and long-term changes of Swiss forest
1993
Brassel, P. (Swiss Federal Institute for Forest Snow and Landscape Research, Birmensdorf (Switzerland))
The national forest inventory of Switzerland is a large-scale assessment of the condition and changes in Swiss forests. Some of the most important advantages of the NFI are its permanence, the long-term and flexible inventory design, the high data-quality and the compatibility with the damage inventory.
اظهر المزيد [+] اقل [-]Direct and indirect effects and the long term risks of air pollution on forest ecosystems: the role of forest health monitoring
1993
Innes, J.L. (Swiss Federal Institute for Forest Snow and Landscape Research, Birmensdorf (Switzerland))
Monitoring of forest health represents an important part of programmes assessing the actual and potential impact of air pollution and climate change on forests. The available information indicates that variation between years is high, indicating that long term time series will be required to identify trends in forest condition.
اظهر المزيد [+] اقل [-]