Early spring is a tricky time for plants due to the combination of sunny but still quite cold days.
As plants respire, they release
Photosynthesis releases oxygen whereas respiration releases CO2.
Almost half of the total biomass of a tree may be allocated to the roots.
A complex microbiota lives belowground, releasing carbon dioxide to the soil.
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.
High soil moisture leads to decreased photosynthesis.
In boreal upland forests, low soil moisture decreases the rate of photosynthesis.
Plants open its stomata to avoid losing too much water.
Plant closes its stomata to avoid losing too much water.
De-hardening in spring involves gradual re-hydration of the cells, recovery of photosynthetic capacity and a tight control of water loss.
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.
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).
In some part of the stems, some photosynthesis may also occur.
At low air humidity, a plant closes its stomata to prevent transpiration. The action also decreases photosynthesis
Carbon becomes locked as part of the accumulating plant biomass as plants grow.
What is the source of carbon that is assimilated in photosynthesis?
Plant respiration captures CO2.
Unlike photosynhesis, plant respiration captures atmospheric oxygen and releases carbon dioxide.