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 129<br />
Tab. 5.4: Advantages and deficiencies <strong>of</strong> various data sources for a model validation study. The follow<strong>in</strong>g<br />
rank<strong>in</strong>g is used for <strong>the</strong> criteria: Spatial and temporal coverage: + high, – low; Climatological gradient: +<br />
data conta<strong>in</strong> a climatological gradient <strong>in</strong> time or space; – no climatological gradient can be derived from<br />
<strong>the</strong> data; Management: + low, – high; Mapp<strong>in</strong>g: + data can be mapped easily to an output <strong>of</strong> <strong>the</strong> model,<br />
– data can not be mapped directly to model output; Correspondence: + data corresponds to <strong>the</strong> output <strong>of</strong> a<br />
mixed-age, mixed-species forest gap model <strong>of</strong> unmanaged stands, – data is from ano<strong>the</strong>r type <strong>of</strong> forest or<br />
ano<strong>the</strong>r scale; Effort required: + effort for provid<strong>in</strong>g data and simulat<strong>in</strong>g <strong>the</strong>se conditions is low, – major<br />
effort is required.<br />
Criterion<br />
Yield<br />
tables<br />
Iventories<br />
Forest<br />
reserves<br />
Tree<br />
r<strong>in</strong>gs<br />
Pollen<br />
data<br />
Remote<br />
sens<strong>in</strong>g<br />
Phytosociol.<br />
descriptions<br />
Spatial coverage ? + – – – ++ +<br />
Temporal coverage + – (+) ++ ++ – –<br />
Climatological gradient – + (+) ++ ++ + +<br />
Management – – + ? + – +<br />
Mapp<strong>in</strong>g ++ + + + – – +<br />
Correspondence – + + – – – +<br />
Effort required – – – + – – +<br />
conditions that <strong>the</strong> model has not been developed for, would constitute a truly <strong>in</strong>dependent<br />
source <strong>of</strong> data; <strong>the</strong> forests simulated by FORCLIM could be compared to those<br />
simulated by o<strong>the</strong>r forest gap models and to descriptions <strong>of</strong> <strong>the</strong> near-natural forests <strong>of</strong> <strong>the</strong><br />
area. Therefore, <strong>in</strong> a second validation experiment <strong>the</strong> performance <strong>of</strong> FORCLIM shall be<br />
exam<strong>in</strong>ed along a latitud<strong>in</strong>al gradient <strong>in</strong> eastern North America (section 5.4).<br />
5.3 Behaviour <strong>of</strong> FORCLIM <strong>in</strong> central Europe<br />
5.3.1 Derivation <strong>of</strong> <strong>in</strong>put data<br />
The scheme developed by Rehder (1965) and Ellenberg (1986) on <strong>the</strong> dom<strong>in</strong>at<strong>in</strong>g species<br />
<strong>in</strong> near-natural forests <strong>of</strong> central Europe is redrawn <strong>in</strong> Fig. 5.1. The climatological space<br />
spanned by annual mean temperature and annual precipitation sum <strong>in</strong> Fig. 5.1 ranges<br />
from <strong>the</strong> alp<strong>in</strong>e timberl<strong>in</strong>e (bottom) to <strong>in</strong>subrian and mediterranean forests (top) and from<br />
<strong>the</strong> dry timberl<strong>in</strong>e (left) to humid forests (right).<br />
This climatological space with <strong>the</strong> associated forests presents a challenge to <strong>the</strong> FORCLIM<br />
model: FORCLIM can not be applied directly to simulate <strong>the</strong>se forests because it requires<br />
climatic <strong>in</strong>put data <strong>of</strong> monthly resolution (cf. Appendix III). However, if <strong>the</strong> annual cycle