Mikroklima in Buchenbeständen - Teil I : Photosynethetisch aktive Strahlung
(2002) In Forstwissenschaftliches Centralblatt 121(6). 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 microchmate 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... (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 microchmate 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 telling). 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 olJ-1) 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 PAR-transmission through the canopy. The extinction coefficient k for PAR shows a tendency towards logarithmic decrease with increasing PAL.
(Less)
- author
- Mayer, Helmut ; Holst, Thomas LU and Schindler, Dirk
- alternative title
- Microclimate within beech stands - Part I : Photosynthetically active radiation
- publishing date
- 2002-12
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- Exposition, Fagus sylvatica L., Forest management, PAI, PAR, PAR-extinction, PAR-interception, PAR-transmission, PAR/G
- in
- Forstwissenschaftliches Centralblatt
- volume
- 121
- issue
- 6
- pages
- 21 pages
- publisher
- Springer
- external identifiers
-
- scopus:0036953062
- ISSN
- 0015-8003
- DOI
- 10.1046/j.1439-0337.2002.02038.x
- language
- German
- LU publication?
- no
- id
- b44ef625-e290-4737-b420-5591ffc1ef2d
- date added to LUP
- 2022-07-12 09:40:14
- date last changed
- 2022-07-12 12:24:16
@article{b44ef625-e290-4737-b420-5591ffc1ef2d,
abstract = {{<p>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 microchmate 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 telling). 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 olJ<sup>-1</sup>) 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 PAR-transmission through the canopy. The extinction coefficient k for PAR shows a tendency towards logarithmic decrease with increasing PAL.</p>}},
author = {{Mayer, Helmut and Holst, Thomas and Schindler, Dirk}},
issn = {{0015-8003}},
keywords = {{Exposition; Fagus sylvatica L.; Forest management; PAI; PAR; PAR-extinction; PAR-interception; PAR-transmission; PAR/G}},
language = {{ger}},
number = {{6}},
pages = {{301--321}},
publisher = {{Springer}},
series = {{Forstwissenschaftliches Centralblatt}},
title = {{Mikroklima in Buchenbeständen - Teil I : Photosynethetisch aktive Strahlung}},
url = {{http://dx.doi.org/10.1046/j.1439-0337.2002.02038.x}},
doi = {{10.1046/j.1439-0337.2002.02038.x}},
volume = {{121}},
year = {{2002}},
}