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The response of European forests to the change in summer temperatures : a comparison between normal and warm years, from 1996 to 2006

Loudin, Sarah LU (2012) In Student thesis series INES NGEM01 20121
Dept of Physical Geography and Ecosystem Science
Abstract
This study shows how six different European forests react during the summer to abnormally warm temperatures, from 1996 to 2006.

With the forecasted increase of summer temperatures over Europe, the carbon balance of forests – photosynthesis (GPP), ecosystem respiration and Net Ecosystem Exchange - in likely to change. In this thesis, the photosynthesis and the respiration of six European forests were studied from 1996 to 2006, in order to see how they react to abnormally warm summer temperatures. The parameters used are temperature, vapor pressure deficit and soil water content, precipitation and net radiation. The eddy covariance technique was used to obtain the data. Linear regression was used to find trends and correlations between... (More)
This study shows how six different European forests react during the summer to abnormally warm temperatures, from 1996 to 2006.

With the forecasted increase of summer temperatures over Europe, the carbon balance of forests – photosynthesis (GPP), ecosystem respiration and Net Ecosystem Exchange - in likely to change. In this thesis, the photosynthesis and the respiration of six European forests were studied from 1996 to 2006, in order to see how they react to abnormally warm summer temperatures. The parameters used are temperature, vapor pressure deficit and soil water content, precipitation and net radiation. The eddy covariance technique was used to obtain the data. Linear regression was used to find trends and correlations between the various parameters.

Common responses can be found between the six forests, depending on common features they share, such as phenology (evergreen or deciduous), foliage (needleaved or broadleaved) and location in Europe (the six forests were distributed in Sweden, Germany, France and Italy).
This study shows that the most marked changes in GPP during very warm years are found in deciduous forests. Evergreen forests are characterized by their respiration, which is less sensitive to temperature than those of deciduous forests. Moreover, it was found that the NEE is more often negative (respiration is higher than GPP fluxes, and CO2 is released by the forests) in needleleaved forests than in broadleaved forests. The location also plays a role in the carbon balance of the forests, as respiration is higher in the northern sites. It is less obvious for GPP, for the highest value are found in the central Europe forests (France and Germany). These findings show that if temperatures keep increasing during the summer, both respiration and GPP will be impacted, and marked changes are likely to be seen in the carbon balance. (Less)
Abstract (Swedish)
Popular science
General introduction
Two main activities take place into forests: photosynthesis, or GPP (the uptake of CO2 by plants, which leads to their growth) and respiration (the release of CO2 by those plants). The Net Ecosystem Exchange NEE is the difference between photosynthesis and respiration, and it depends on the nature of the forests and on climate particularities.
With the ongoing climate change, summer temperatures, the highest in the year, are likely to change, and impact the functioning of the carbon cycle in forests.

Methodology
Here, the photosynthesis and the respiration of six European forests were studied from 1996 to 2006, in order to see how they react to abnormally warm summer temperatures. The parameters... (More)
Popular science
General introduction
Two main activities take place into forests: photosynthesis, or GPP (the uptake of CO2 by plants, which leads to their growth) and respiration (the release of CO2 by those plants). The Net Ecosystem Exchange NEE is the difference between photosynthesis and respiration, and it depends on the nature of the forests and on climate particularities.
With the ongoing climate change, summer temperatures, the highest in the year, are likely to change, and impact the functioning of the carbon cycle in forests.

Methodology
Here, the photosynthesis and the respiration of six European forests were studied from 1996 to 2006, in order to see how they react to abnormally warm summer temperatures. The parameters used to analyze the responses are temperature, vapor pressure deficit (the percentage of vapor in the air) and soil water content (the percentage of water in the soil), precipitation and net radiation (light). The eddy covariance technique was used to obtain the data.

Results and findings
Common responses can be found between the six forests, depending on common features they share, such as phenology (evergreen or deciduous forests), foliage (needleaved or broadleaved forests) and location in Europe (the six forests were distributed in Sweden, Germany, France and Italy).
This study shows that the most marked changes in GPP during very warm years are found in deciduous forests. Evergreen forests are characterized by their respiration, which is less sensitive to temperature than those of deciduous forests. Moreover, it was found that the NEE is more often negative (respiration is higher than GPP fluxes, and CO2 is released by the forests) in needleleaved forests than in broadleaved forests. The location also plays a role in the carbon balance of the forests, as respiration is higher in the northern sites. It is less obvious for GPP, for the highest value are found in the central Europe forests (France and Germany).
These findings show that if temperatures keep increasing during the summer, both respiration and GPP will be impacted, and marked changes are likely to be seen in the carbon balance. (Less)
Please use this url to cite or link to this publication:
author
Loudin, Sarah LU
supervisor
organization
alternative title
The response of European forests to abnormally warm summers : 1996-2006
course
NGEM01 20121
year
type
H2 - Master's Degree (Two Years)
subject
keywords
Physical Geography, Geography, eddy covariance, gross primary product, ecosystem respiration, summer temperatures
publication/series
Student thesis series INES
report number
262
language
English
id
3132546
date added to LUP
2012-10-25 00:02:58
date last changed
2012-10-25 00:02:58
@misc{3132546,
  abstract     = {This study shows how six different European forests react during the summer to abnormally warm temperatures, from 1996 to 2006.

With the forecasted increase of summer temperatures over Europe, the carbon balance of forests – photosynthesis (GPP), ecosystem respiration and Net Ecosystem Exchange - in likely to change. In this thesis, the photosynthesis and the respiration of six European forests were studied from 1996 to 2006, in order to see how they react to abnormally warm summer temperatures. The parameters used are temperature, vapor pressure deficit and soil water content, precipitation and net radiation. The eddy covariance technique was used to obtain the data. Linear regression was used to find trends and correlations between the various parameters.

Common responses can be found between the six forests, depending on common features they share, such as phenology (evergreen or deciduous), foliage (needleaved or broadleaved) and location in Europe (the six forests were distributed in Sweden, Germany, France and Italy).
This study shows that the most marked changes in GPP during very warm years are found in deciduous forests. Evergreen forests are characterized by their respiration, which is less sensitive to temperature than those of deciduous forests. Moreover, it was found that the NEE is more often negative (respiration is higher than GPP fluxes, and CO2 is released by the forests) in needleleaved forests than in broadleaved forests. The location also plays a role in the carbon balance of the forests, as respiration is higher in the northern sites. It is less obvious for GPP, for the highest value are found in the central Europe forests (France and Germany). These findings show that if temperatures keep increasing during the summer, both respiration and GPP will be impacted, and marked changes are likely to be seen in the carbon balance.},
  author       = {Loudin, Sarah},
  keyword      = {Physical Geography,Geography,eddy covariance,gross primary product,ecosystem respiration,summer temperatures},
  language     = {eng},
  note         = {Student Paper},
  series       = {Student thesis series INES},
  title        = {The response of European forests to the change in summer temperatures : a comparison between normal and warm years, from 1996 to 2006},
  year         = {2012},
}