Eddy covariance measurements carried out in Portugal on intensive eucalypt
stands managed as coppice (Rodrigues et al. 2011) over an 8-year period were
used to evaluate the impact of two dramatic events in relation to NEE and GPP .
These were the occurrence of intense and prolonged drought in 2004 and 2005
(mentioned above) and tree felling in 2006 when trees with an average height of
20 m reached the end of a 12-year productive cycle (Fig. 4.8).
The eddy covariance instrumentation was installed at the top of a 33 m tower.
The effects of drought were seen mainly in 2005, the year in which the total NEE
(357 gCcm
−2 ), GPP (1255.1 gCcm
−2
), and TER (898.48 gCcm
−2 ) decreased
drastically relative to the typical year of 2002 (865 gCcm
−2 , 2206 gCcm
−2 , and
1340 gCcm
−2 , respectively) by means of tight stomatal control, a typical
regime-imposed evapotranspiration . The effect of this drought was similarly felt in
a holm oak forest (Pereira et al. 2007) in which the values of NEE , GPP , and TER
, measured by eddy covariance method with a closed-path system, were 38 gCcm
−2 ,
Fig. 4.7 Analyzer for
measuring soil respiration
Fig. 4.8 Eucalypt trees in the
Setúbal Peninsula, managed
as coppice for pulp and paper
production, with an average
height of 20 m
126
4 Exchange of Energy and Mass Over Forest Canopies
stands managed as coppice (Rodrigues et al. 2011) over an 8-year period were
used to evaluate the impact of two dramatic events in relation to NEE and GPP .
These were the occurrence of intense and prolonged drought in 2004 and 2005
(mentioned above) and tree felling in 2006 when trees with an average height of
20 m reached the end of a 12-year productive cycle (Fig. 4.8).
The eddy covariance instrumentation was installed at the top of a 33 m tower.
The effects of drought were seen mainly in 2005, the year in which the total NEE
(357 gCcm
−2 ), GPP (1255.1 gCcm
−2
), and TER (898.48 gCcm
−2 ) decreased
drastically relative to the typical year of 2002 (865 gCcm
−2 , 2206 gCcm
−2 , and
1340 gCcm
−2 , respectively) by means of tight stomatal control, a typical
regime-imposed evapotranspiration . The effect of this drought was similarly felt in
a holm oak forest (Pereira et al. 2007) in which the values of NEE , GPP , and TER
, measured by eddy covariance method with a closed-path system, were 38 gCcm
−2 ,
Fig. 4.7 Analyzer for
measuring soil respiration
Fig. 4.8 Eucalypt trees in the
Setúbal Peninsula, managed
as coppice for pulp and paper
production, with an average
height of 20 m
126
4 Exchange of Energy and Mass Over Forest Canopies