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Are small-scale overstory gaps effective in promoting the development of regenerating oaks (Quercus ithaburensis) in the forest understory?
Year:
2014
Source of publication :
New Forests
Authors :
Cooper, Arnon
;
.
Moshe, Yossi
;
.
Osem, Yagil
;
.
Zangy, Ela
;
.
Volume :
45
Co-Authors:


 

Facilitators :
From page:
843
To page:
857
(
Total pages:
15
)
Abstract:
We investigated the effect of small-scale overstory gaps on the ecophysiology and growth of Quercus ithaburensis saplings. The study aim was to characterize how changes in daily exposure to direct beam radiation affect photosynthetic performance in the short term and growth and biomass partitioning in the long term. Using individual net-houses, the following treatments were applied: (a) Unshaded (daily irradiance = 100 %), (b) shading net with no gap (Shade-daily irradiance = 6 %), (c) shading net with 1 h gap allowing direct beam radiation (11:00 am–12:00 pm, Shade+1-irradiance = 20 %), (d) shading net with 3 h gap (11:00 am–2:00 pm, Shade+3-irradiance = 44 %). The experiment was performed in an irrigated field. We measured growth, biomass allocation, leaf traits, daily courses of leaf gas exchange and water potential. Oak dry-weight increased while height to dry-weight ratio and specific leaf area decreased with increasing daily exposure to direct beam radiation. Leaf chlorophyll content was less affected. Higher net carbon assimilation rates (A), stomatal conductance (gs) and A/gs were associated with higher instantaneous photosynthetic photon flux density (PPFD) throughout the entire experimental PPFD range. However, during gap-hours, while exposed to saturating radiation levels of similar level (ca. 1,800 µmol photon m−2 s−1), A in the Shade+1 oaks was about half that of the Shade+3 oaks and nearly one-third that of the Unshaded oaks. Patterns of gs, intercellular CO2 (Ci) and quantum efficiency of photosystem II pointed towards the possibility of a metabolic limitation. In conclusion, oaks benefited significantly from small scale overstory gaps though their capacity to utilize transient saturating radiation levels decreased with decreasing gap duration. © 2014, Springer Science+Business Media Dordrecht.
Note:
Related Files :
Ecology
forest management
Forestry
Leaf chlorophyll content
photosynthesis
Plant acclimation
Stomatal conductance
Show More
Related Content
More details
DOI :
10.1007/s11056-014-9441-9
Article number:
0
Affiliations:
Database:
Scopus
Publication Type:
article
;
.
Language:
English
Editors' remarks:
ID:
32225
Last updated date:
02/03/2022 17:27
Creation date:
17/04/2018 01:08
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Are small-scale overstory gaps effective in promoting the development of regenerating oaks (Quercus ithaburensis) in the forest understory?
45


 

Are small-scale overstory gaps effective in promoting the development of regenerating oaks (Quercus ithaburensis) in the forest understory?
We investigated the effect of small-scale overstory gaps on the ecophysiology and growth of Quercus ithaburensis saplings. The study aim was to characterize how changes in daily exposure to direct beam radiation affect photosynthetic performance in the short term and growth and biomass partitioning in the long term. Using individual net-houses, the following treatments were applied: (a) Unshaded (daily irradiance = 100 %), (b) shading net with no gap (Shade-daily irradiance = 6 %), (c) shading net with 1 h gap allowing direct beam radiation (11:00 am–12:00 pm, Shade+1-irradiance = 20 %), (d) shading net with 3 h gap (11:00 am–2:00 pm, Shade+3-irradiance = 44 %). The experiment was performed in an irrigated field. We measured growth, biomass allocation, leaf traits, daily courses of leaf gas exchange and water potential. Oak dry-weight increased while height to dry-weight ratio and specific leaf area decreased with increasing daily exposure to direct beam radiation. Leaf chlorophyll content was less affected. Higher net carbon assimilation rates (A), stomatal conductance (gs) and A/gs were associated with higher instantaneous photosynthetic photon flux density (PPFD) throughout the entire experimental PPFD range. However, during gap-hours, while exposed to saturating radiation levels of similar level (ca. 1,800 µmol photon m−2 s−1), A in the Shade+1 oaks was about half that of the Shade+3 oaks and nearly one-third that of the Unshaded oaks. Patterns of gs, intercellular CO2 (Ci) and quantum efficiency of photosystem II pointed towards the possibility of a metabolic limitation. In conclusion, oaks benefited significantly from small scale overstory gaps though their capacity to utilize transient saturating radiation levels decreased with decreasing gap duration. © 2014, Springer Science+Business Media Dordrecht.
Scientific Publication
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