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Mikroklima in Buchenbeständen – Teil I: Photosynthetisch aktive Strahlung

Mayer, Helmut; Holst, Thomas LU and Schindler, Dirk (2002) In Forstwissenschaftliches Centralblatt 121. p.301-321
Abstract
Meteorological investigations were carried out in forests in the southwestern part of the Swabian Alb

(SW Germany) to analyze the influences of exposition and silvicultural treatment on the microclimate

within various stands of beech (Fagus sylvatica L.). The measurements were taken as part of an interdisciplinary

project on the effects of climate and forest management on structures and processes within

beech dominated deciduous forests. Near-surface stations for continuous recording of meteorological

variables in forests provide the basis of the investigations. Two each were installed on two opposite

slopes (NE and SW) of a narrow valley: one within a control plot (no silvicultural... (More)
Meteorological investigations were carried out in forests in the southwestern part of the Swabian Alb

(SW Germany) to analyze the influences of exposition and silvicultural treatment on the microclimate

within various stands of beech (Fagus sylvatica L.). The measurements were taken as part of an interdisciplinary

project on the effects of climate and forest management on structures and processes within

beech dominated deciduous forests. Near-surface stations for continuous recording of meteorological

variables in forests provide the basis of the investigations. Two each were installed on two opposite

slopes (NE and SW) of a narrow valley: one within a control plot (no silvicultural thinning) and one

within a silviculturally treated plot (strong shelterwood felling). Meteorological towers on each control

plot provided data for the analysis of climatic conditions above the beech stands and within their

canopies. The experimental design is well-suited for investigation of not only the influence of exposition,

but also the effects of forest management and phenophases on the microclimate within differently

handled beech stands. The plant area index PAI is used to characterize the canopy.

The present article deals with the photosynthetically active radiation PAR at the near-surface stations

and above the stands as a reference. PAR is measured horizontally. Above the stands, differences to PAR received parallel to the slopes can be estimated by use of model calculations for the incoming

solar radiation G due to the fact that PAR/G is almost constant (1.937 µmol/J) above the stands.

For PAR and the PAR-interception within the canopy in the year 2001, the following results are

discussed: mean diurnal courses in one month within the leafless period (February) and the vegetation

period (August), daily mean values over the whole year and monthly mean values. For the leafless

period the results show the influence of the exposition of both slopes on PAR at the near-surface

stations and the PAR-interception. In the vegetation period, however, the influence of the fully developed

canopy was more significant than exposition. With increasing PAI, results from regression analysis

for the entire investigation period indicate a linear decrease of PAR/G below the canopy as well as an

exponential increase of PAR-interception within the canopy and a logarithmic decrease of the PARtransmission

through the canopy. The extinction coefficient k for PAR shows a tendency towards

logarithmic decrease with increasing PAI. (Less)
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author
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Fagus sylvatica L., PAR, exposition, forest management, PAI, PAR/G, PAR-interception, PAR-extinction, PAR-transmission
in
Forstwissenschaftliches Centralblatt
volume
121
pages
301 - 321
publisher
Springer
external identifiers
  • scopus:52649118052
ISSN
0015-8003
language
German
LU publication?
no
id
ec88bbce-8616-4aa5-ba64-bb0a9f7078ce (old id 707516)
date added to LUP
2007-12-14 13:58:30
date last changed
2017-09-13 14:12:44
@article{ec88bbce-8616-4aa5-ba64-bb0a9f7078ce,
  abstract     = {Meteorological investigations were carried out in forests in the southwestern part of the Swabian Alb<br/><br>
(SW Germany) to analyze the influences of exposition and silvicultural treatment on the microclimate<br/><br>
within various stands of beech (Fagus sylvatica L.). The measurements were taken as part of an interdisciplinary<br/><br>
project on the effects of climate and forest management on structures and processes within<br/><br>
beech dominated deciduous forests. Near-surface stations for continuous recording of meteorological<br/><br>
variables in forests provide the basis of the investigations. Two each were installed on two opposite<br/><br>
slopes (NE and SW) of a narrow valley: one within a control plot (no silvicultural thinning) and one<br/><br>
within a silviculturally treated plot (strong shelterwood felling). Meteorological towers on each control<br/><br>
plot provided data for the analysis of climatic conditions above the beech stands and within their<br/><br>
canopies. The experimental design is well-suited for investigation of not only the influence of exposition,<br/><br>
but also the effects of forest management and phenophases on the microclimate within differently<br/><br>
handled beech stands. The plant area index PAI is used to characterize the canopy.<br/><br>
The present article deals with the photosynthetically active radiation PAR at the near-surface stations<br/><br>
and above the stands as a reference. PAR is measured horizontally. Above the stands, differences to PAR received parallel to the slopes can be estimated by use of model calculations for the incoming<br/><br>
solar radiation G due to the fact that PAR/G is almost constant (1.937 µmol/J) above the stands.<br/><br>
For PAR and the PAR-interception within the canopy in the year 2001, the following results are<br/><br>
discussed: mean diurnal courses in one month within the leafless period (February) and the vegetation<br/><br>
period (August), daily mean values over the whole year and monthly mean values. For the leafless<br/><br>
period the results show the influence of the exposition of both slopes on PAR at the near-surface<br/><br>
stations and the PAR-interception. In the vegetation period, however, the influence of the fully developed<br/><br>
canopy was more significant than exposition. With increasing PAI, results from regression analysis<br/><br>
for the entire investigation period indicate a linear decrease of PAR/G below the canopy as well as an<br/><br>
exponential increase of PAR-interception within the canopy and a logarithmic decrease of the PARtransmission<br/><br>
through the canopy. The extinction coefficient k for PAR shows a tendency towards<br/><br>
logarithmic decrease with increasing PAI.},
  author       = {Mayer, Helmut and Holst, Thomas and Schindler, Dirk},
  issn         = {0015-8003},
  keyword      = {Fagus sylvatica L.,PAR,exposition,forest management,PAI,PAR/G,PAR-interception,PAR-extinction,PAR-transmission},
  language     = {ger},
  pages        = {301--321},
  publisher    = {Springer},
  series       = {Forstwissenschaftliches Centralblatt},
  title        = {Mikroklima in Buchenbeständen – Teil I: Photosynthetisch aktive Strahlung},
  volume       = {121},
  year         = {2002},
}