08.09.2014 Views

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 ...

SHOW MORE
SHOW LESS

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

The forest model FORCLIM 63<br />

D (cm)<br />

300<br />

Fagus silvatica<br />

gH (m)<br />

60<br />

D (cm)<br />

300<br />

Larix decidua<br />

gH (m)<br />

60<br />

200<br />

gH<br />

40<br />

200<br />

gH<br />

40<br />

100<br />

D<br />

20<br />

100<br />

D<br />

20<br />

0<br />

0<br />

100 200<br />

Time (years)<br />

0<br />

300<br />

0<br />

0<br />

100 200<br />

Time (years)<br />

0<br />

300<br />

Fig. 3.6: The maximum growth equation (Eq. 3.15) simulated for beech (Fagus silvatica,<br />

left) with kG s = 191 cm/year, kHm s = 45 m, and kDm s = 225 cm, and larch (Larix<br />

decidua, right) with kG s = 170 cm/year, kHm s = 52 m, and kDm s = 185 cm. D c (0) is<br />

1.27 cm, and <strong>the</strong> discrete time step (∆t) is one year.<br />

F<strong>in</strong>ally, from <strong>the</strong> evaluation <strong>of</strong> Eq. 3.13 when ∂gH c /∂D c = 0 at gH c = kHm s and<br />

D c = kDm s , <strong>the</strong> parameters kB 2,s and kB 3,s can be expressed as functions <strong>of</strong> maximum<br />

height and maximum diameter alone:<br />

kB 2,s = 2 · (kHm s – 137)<br />

kDm s<br />

(3.16)<br />

kB 3,s = –<br />

kB 2,s<br />

2 · kDm s<br />

(3.17)<br />

Light growth factor<br />

The calculation <strong>of</strong> <strong>the</strong> light growth factor follows <strong>the</strong> descriptions by Botk<strong>in</strong> et al.<br />

(1972a,b) and Shugart (1984): Beer's ext<strong>in</strong>ction law is used to calculate <strong>the</strong> available light<br />

at <strong>the</strong> height <strong>of</strong> cohort c as a function <strong>of</strong> leaf area <strong>in</strong>dex:<br />

gAL gHc = e - kLAtt ⋅ gCumLA gHc (3.18)<br />

where gCumLA gHc is <strong>the</strong> cumulative leaf area <strong>in</strong>dex at <strong>the</strong> height <strong>of</strong> cohort c (Eq. 3.19),<br />

summed over all cohorts based on <strong>the</strong> relationships given <strong>in</strong> Eq. 3.20 & 3.21 for calculat<strong>in</strong>g<br />

<strong>the</strong> double-sided foliage area (gFolA c ) from foliage dry weight (gFolW c ) (Burger<br />

1945-1953):

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!