Almost half of the total biomass of a tree may be allocated to the roots.
As plants respire, they release
Photoinhibition means the decrease in photosynthesis due to
exposure to excess of light.
exposure to excess of CO2.
exposure to shortage of soil moisture.
exposure to high temperature.
The effect of light on photosynthesis has a clear saturating pattern: more light results in more photosynthesis but eventually leaves cannot take full advantage of all the extra light.
When there is low soil moisture, plants close its stomata pores which then decreases photosynthesis.
In some part of the stems, some photosynthesis may also occur.
A complex microbiota lives belowground, releasing carbon dioxide to the soil.
Early spring is a tricky time for plants due to the combination of sunny but still quite cold days.
De-hardening in spring involves gradual re-hydration of the cells, recovery of photosynthetic capacity and a tight control of water loss.
Transpiration decreases as air becomes drier.
At low air humidity, a plant closes its stomata to prevent transpiration. The action also decreases photosynthesis
Leaf area increases with stand age, resulting in a decreasing rate of photosynthesis in the stand.
An increment in leaf area increases also the photosynthesis of a tree stand. However, the relationship is saturating.
Plant respiration captures CO2.
Unlike photosynhesis, plant respiration captures atmospheric oxygen and releases carbon dioxide.
Photosynthesis of a tree canopy is driven or influenced by
photosynthetically active solar radiation (PAR).
the total leaf area (LAI).
soil moisture (REW).
air temperature (T).
air humidity (VPD).
In general, the more carbon dioxide that is available to the plant, the faster the rate of photosynthesis - if other factors are favourable.