On the Ecology of Mountainous Forests in a Changing Climate: A ...
On the Ecology of Mountainous Forests in a Changing Climate: A ...
On the Ecology of Mountainous Forests in a Changing Climate: A ...
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Model applications 159<br />
simulation studies with <strong>the</strong> FORECE, FORCLIM 1.1, and FORCLIM 1.3 models. Thus,<br />
<strong>the</strong>se three sites are <strong>in</strong>cluded <strong>in</strong> <strong>the</strong> present study as well. Moreover, a slight modification<br />
was applied to <strong>the</strong> climatic data from <strong>the</strong> site St. Gotthard: Under current climatic<br />
conditions (SMA 1901-1970), FORCLIM simulates <strong>the</strong> existence <strong>of</strong> forests at an elevation<br />
<strong>of</strong> 2090 m, which appears to be realistic (e.g. Renner 1982). To obta<strong>in</strong> a site above<br />
timberl<strong>in</strong>e, i.e. at an elevation about 100 m higher than <strong>the</strong> climate station St. Gotthard,<br />
its temperature was lowered by 0.7 °C throughout <strong>the</strong> year, result<strong>in</strong>g <strong>in</strong> <strong>the</strong> site<br />
Gotthard II, where FORCLIM simulates no forest under current climate.<br />
Tab. 6.2: Scenarios <strong>of</strong> climatic change for <strong>the</strong> year 2100 accord<strong>in</strong>g to various sources. All changes are relative<br />
to current climate. The “IPCC” scenario is based on <strong>the</strong> “Bus<strong>in</strong>ess–As–Usual” scenario A <strong>of</strong> fossil<br />
fuel emissions. The “Kienast” scenario is based on steady-state 2xCO 2 GCM runs. The “Regionalized”<br />
scenarios are based on <strong>the</strong> downscaled trends from an uncorrected 100-year (1986-2085) transient run <strong>of</strong><br />
<strong>the</strong> ECHAM GCM for <strong>the</strong> IPCC “Bus<strong>in</strong>ess–As–Usual” scenario A (Cubasch et al. 1992). Bold face<br />
denotes <strong>the</strong> scenarios used <strong>in</strong> <strong>the</strong> present study. Precipitation changes are given as percentages<br />
or as centimeters per month (cm/mo). The standard deviations <strong>of</strong> T and P were assumed not to change.<br />
Scenario T Summer P Summer T W<strong>in</strong>ter P W<strong>in</strong>ter Ref.<br />
IPCC, 2030 (global) +1.5 °C + a few % +1.5 °C + a few % 1<br />
IPCC, 2030 (C. Europe) +2.5 °C -15% +1.5 °C – 1<br />
IPCC, 2100 (global) +3.7 °C – +3.7 °C – 1<br />
IPCC, 2100 (C. Europe) +4.7 °C – +3.7 °C – 1<br />
Kienast +3.0 °C +10% +3.5 °C +10% 2<br />
Regionalized, Bern +2.64 °C +3.98 cm/mo +3.76 °C +3.13 cm/mo 3<br />
Regionalized, Davos +3.28 °C +0.91 cm/mo +3.00 °C +2.14 cm/mo 3<br />
Regionalized, Bever +4.16 °C +3.82 cm/mo +1.48 °C +2.54 cm/mo 3<br />
1 Houghton et al. (1990), Fischl<strong>in</strong> et al. (1994)<br />
2 Mitchell (1983), Mitchell & Lupton (1984), Wigley & Jones (1988), Kienast (1991)<br />
3 Gyalistras et al. (1994), Bugmann & Fischl<strong>in</strong> (1994)<br />
The scenarios <strong>of</strong> future climatic change stem from three sources (Tab. 6.2). First, a scenario<br />
was developed based on <strong>the</strong> report <strong>of</strong> <strong>the</strong> Intergovernmental Panel on <strong>Climate</strong><br />
Change (IPCC, Houghton et al. 1990). This scenario was extrapolated from <strong>the</strong> difference<br />
between <strong>the</strong> regional scenario for central and sou<strong>the</strong>rn Europe and <strong>the</strong> global average<br />
scenario for <strong>the</strong> year 2030 (Tab. 6.2). Second, a scenario similar to <strong>the</strong> one used by<br />
Kienast (1991) was adapted; <strong>the</strong> only difference is that Kienast (1991) applied <strong>the</strong><br />
changes projected for <strong>the</strong> w<strong>in</strong>ter months to <strong>the</strong> climatic parameters <strong>of</strong> December through<br />
February, whereas <strong>in</strong> <strong>the</strong> present study <strong>the</strong>se changes are used to modify <strong>the</strong> climatic<br />
parameters <strong>of</strong> <strong>the</strong> six “w<strong>in</strong>ter” months October through March <strong>in</strong> accordance with IPCC