Chemistry Reference
In-Depth Information
1 Introduction
Widespread forest mortality is a worldwide phenomenon, and scientists
researching possible causes often arrive at the conclusion that effects of climate
change are behind much of the forest dieback.
1,2
In the past two decades,
warmer temperatures and decreased precipitation have been identified as the
main causes for pest outbreaks, increased forest fire frequency and extended
drought-related stress.
3,4
Climate change is an important factor leading to forest dieback and tree
species migration as they relate to drought, water stress, early snow melt,
reduced snow cover, pest outbreaks and fire risk.
1,2,5,6
Forest ecosystems are
facing many stresses, both natural and human-caused that can contribute to
changes in forest dynamics. Anthropogenic stressors are often related to land
conversions for agriculture or urbanisation, fire suppression or initiation, and
pollution. Natural stressors may include severe drought, waterlogging and cold,
and secondary insect attacks and diseases of stem and root fungi.
7
Although
some forests might have a positive response to increased carbon dioxide
emissions and longer growing seasons,
8,9
this response appears to be regional or
temporary as current global forest loss is exceeding forest gain
10
(Figure 1).
d
n
1
r
2
n
g
|
8
Figure
1
This map shows the locations of forest dieback documented in a
2010 publication.
2
An interactive version of this map, including
details of forest type, dieback causes and extents and original data
sources can be found at: http://app.databasin.org/app/pages/datasetPage.
jsp?id5b2947eeae2e5488a86eacf0fcd4df7a4 (Source: Dr. Joerg Steinkamp,
Biodiversity
and
Climate
Research
Centre,
Wendy
Peterman,
Conservation Biology Institute).
11
