De-hardening in spring involves gradual re-hydration of the cells, recovery of photosynthetic capacity and a tight control of water loss.
The annual cycle of photosynthesis mainly follows
the changes in CO2 concentration.
the changes in air temperature.
the changes in light.
the changes in soil temperature.
Photosynthesis of a tree canopy is driven or influenced by
air temperature (T).
photosynthetically active solar radiation (PAR).
soil moisture (REW).
the total leaf area (LAI).
air humidity (VPD).
Plants open its stomata to avoid losing too much water.
Plant closes its stomata to avoid losing too much water.
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.
A complex microbiota lives belowground, releasing carbon dioxide to the soil.
Almost half of the total biomass of a tree may be allocated to the roots.
Carbon capture is performed by the green parts of plants via photosynthesis.
In general, the more carbon dioxide that is available to the plant, the faster the rate of photosynthesis - if other factors are favourable.
To transform atmospheric CO2 into organic molecules, plants can use the energy from
Early spring is a tricky time for plants due to the combination of sunny but still quite cold days.
High soil moisture leads to decreased photosynthesis.
In boreal upland forests, low soil moisture decreases the rate of photosynthesis.
Transpiration decreases as air becomes drier.
As plants respire, they release
Photosynthesis releases oxygen whereas respiration releases CO2.
When there is low soil moisture, plants close its stomata pores which then decreases photosynthesis.