High soil moisture leads to decreased photosynthesis.
In boreal upland forests, low soil moisture decreases the rate of photosynthesis.
A complex microbiota lives belowground, releasing carbon dioxide to the soil.
De-hardening in spring involves gradual re-hydration of the cells, recovery of photosynthetic capacity and a tight control of water loss.
Almost half of the total biomass of a tree may be allocated to the roots.
Carbon becomes locked as part of the accumulating plant biomass as plants grow.
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.
As plants respire, they release
At low air humidity, a plant closes its stomata to prevent transpiration. The action also decreases photosynthesis
What is the source of carbon that is assimilated in photosynthesis?
In some part of the stems, some photosynthesis may also occur.
Transpiration decreases as air becomes drier.
Plant respiration captures CO2.
Unlike photosynhesis, plant respiration captures atmospheric oxygen and releases carbon dioxide.
Early spring is a tricky time for plants due to the combination of sunny but still quite cold days.
The annual cycle of photosynthesis mainly follows
the changes in air temperature.
the changes in light.
the changes in CO2 concentration.
the changes in soil temperature.
Photosynthesis of a tree canopy is driven or influenced by
the total leaf area (LAI).
photosynthetically active solar radiation (PAR).
soil moisture (REW).
air temperature (T).
air humidity (VPD).