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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Parameter sensitivity & model validation 145<br />
Tab. 5.5: Derivation <strong>of</strong> FORCLIM parameters for <strong>the</strong> tree species <strong>of</strong> eastern North America from <strong>the</strong> data<br />
used <strong>in</strong> <strong>the</strong> models FORENA (Solomon 1986) and LINKAGES (Pastor & Post 1985).<br />
Parameter(s) Transformation rule Reference<br />
sType cf. Appendix VI Pastor & Post (1985)<br />
kDm, kHm, kAm, kDrT none Solomon (1986)<br />
kG<br />
recalculated from equation developed <strong>in</strong> Solomon (1986)<br />
Appendix II<br />
kDDM<strong>in</strong>, kDDMax recalculated accord<strong>in</strong>g to correction formula Solomon (1986)<br />
developed <strong>in</strong> chapter 3<br />
kWiT cf. Appendix VI Solomon (1986)<br />
kNTol assigned from LINKAGES parameters Pastor & Post (1985)<br />
kBrow “FALSE” = 1, “TRUE” = 3 Solomon (1986)<br />
kLy, kLa “1” = 3, “2” = 7 Solomon (1986)<br />
kLQ cf. Appendix VI Pastor & Post (1985)<br />
5.4.2 Simulation experiments<br />
At each <strong>of</strong> <strong>the</strong> 10 locations, 200 patches were simulated dur<strong>in</strong>g 1200 years (cf. section<br />
2.2.2). It should be noted that this is a much larger sample size and a longer time span<br />
than <strong>the</strong> one used by Solomon (1986), who simulated only 10 patches over 400 years<br />
with <strong>the</strong> current climate.<br />
Both <strong>the</strong> FORCLIM-E/P and <strong>the</strong> FORCLIM-E/P/S models were run along <strong>the</strong> transect <strong>in</strong><br />
order to <strong>in</strong>vestigate <strong>the</strong> importance <strong>of</strong> explicitly modell<strong>in</strong>g soil organic matter dynamics<br />
and nutrient availability. At all locations a mesic silt loam with a field capacity (kFC) <strong>of</strong><br />
30 cm was simulated. For <strong>the</strong> model variant FORCLIM-E/P, nitrogen availability at all locations<br />
was assumed to be 100 kg/ha. No disturbances such as w<strong>in</strong>dthrow or fire were<br />
simulated. The steady-state species composition <strong>of</strong> <strong>the</strong> simulated forests was estimated by<br />
averag<strong>in</strong>g <strong>the</strong> output from <strong>the</strong> years 1000–1200 <strong>of</strong> each patch.<br />
5.4.3 Results & discussion<br />
TUNDRA-WOODLAND TRANSITION AND NORTHERN BOREAL FOREST<br />
Fig. 5.10 summarizes <strong>the</strong> steady-state species compositions along <strong>the</strong> nor<strong>the</strong>rn part <strong>of</strong><br />
<strong>the</strong> gradient. <strong>On</strong>ly few and stunted trees grow at Churchill and Shefferville, correspond-