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On the Ecology of Mountainous Forests in a Changing Climate: A ...

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130 Chapter 5<br />

<strong>of</strong> <strong>the</strong> monthly variables shows a reasonably constant pattern over <strong>the</strong> whole climatological<br />

space, <strong>the</strong>n it is possible to provide <strong>the</strong> climatic <strong>in</strong>put data required by forest gap<br />

models such as FORCLIM.<br />

The climatological data from <strong>the</strong> 12 sites presented <strong>in</strong> Appendix III were analysed for<br />

<strong>the</strong>ir annual cycles (Fig. 5.2). The monthly mean temperature can be predicted well from<br />

<strong>the</strong> annual mean temperature because <strong>the</strong> temperature amplitude, i.e. <strong>the</strong> difference between<br />

<strong>the</strong> temperature <strong>of</strong> <strong>the</strong> warmest and <strong>the</strong> coldest month, does not vary much among<br />

<strong>the</strong> climate stations. The monthly precipitation sum can be expressed adequately as a<br />

fraction <strong>of</strong> <strong>the</strong> annual precipitation sum. The standard deviations <strong>of</strong> <strong>the</strong> two variables are<br />

more difficult to predict, with better results for temperature than for precipitation. Specifically,<br />

<strong>the</strong> two sites on <strong>the</strong> sou<strong>the</strong>rn slope <strong>of</strong> <strong>the</strong> Alps (Airolo and Locarno) had to be<br />

excluded from <strong>the</strong> analysis <strong>of</strong> <strong>the</strong> standard deviation <strong>of</strong> precipitation because <strong>the</strong>y exhibit<br />

a pattern strongly different from <strong>the</strong> one at <strong>the</strong> stations on <strong>the</strong> nor<strong>the</strong>rn slope <strong>of</strong> <strong>the</strong> Alps.<br />

mean temperature (°C)<br />

annual<br />

10<br />

6<br />

2<br />

Psil<br />

Ocar, Qpub, Csat<br />

Qrob/pet, (Fsil)<br />

Qrob/pet,<br />

(Fsil)<br />

Pexc, Psil<br />

Pexc, Pcem<br />

Fsil<br />

(Fsil), Qpub, Csat<br />

Fsil, (Qrob/pet)<br />

Fsil, (Aalb), (Pexc)<br />

Pexc<br />

Pexc<br />

-2<br />

400<br />

800 1200 1600<br />

annual precipitation sum (mm)<br />

2000<br />

Fig. 5.1: Dom<strong>in</strong>at<strong>in</strong>g tree species <strong>in</strong> a space spanned by <strong>the</strong> annual precipitation sum and<br />

<strong>the</strong> annual mean temperature accord<strong>in</strong>g to Rehder (1965) and Ellenberg (1986). Key to<br />

species: Aalb – Abies alba; Csat – Castanea sativa; Fsil – Fagus silvatica; Ocar – Ostrya<br />

carp<strong>in</strong>ifolia; Pcem – P<strong>in</strong>us cembra; Pexc – Picea excelsa; Psil – P<strong>in</strong>us silvestris; Qpet –<br />

Quercus petraea; Qpub – Quercus pubescens; Qrob – Quercus robur. The dash-spotted l<strong>in</strong>e<br />

close to <strong>the</strong> bottom <strong>of</strong> <strong>the</strong> graph <strong>in</strong>dicates <strong>the</strong> approximate location <strong>of</strong> <strong>the</strong> alp<strong>in</strong>e<br />

timberl<strong>in</strong>e.

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