2-2-7- Step 7: Estimating Oxygen production by trees in the study area
Oxygen is produced through photosynthesis process:
\begin{equation} {6CO}_{2}\ \left(264\ g\right)+\ 6H_{2}\text{O\ }\left(108\ g\right)+light\rightarrow C_{6}H_{12}O_{6}\ \left(180\ g\right)+\ {6O}_{2}\ \left(193\ g\right)\ \rightarrow\ Amylase\ (162\ g)\nonumber \\ \end{equation}
Respiration :(CH2O)n+nO2→n(CO2)+n(H2O)+energy
As shown in the photosynthesis equation, plants absorb 264 grams of CO2 to produce 193 grams of O2 and 162 grams of dry matter in the form of fiber and starch (Blankenship, 2014). On the other hand, plants respiration process consumes some produced oxygen in the photosynthetic process according to the chemical equation of respiration; therefore, the net production of oxygen by trees is a function of producing oxygen during photosynthesis minus the amount of oxygen consumed during respiration (Nowak et al., 2007).
Also, since the net oxygen production by a tree over a year is directly related to the amount of carbon released by the tree, the amount of oxygen produced is tied to the accumulation of tree biomass. Therefore, if the amount of carbon dioxide absorbed during photosynthesis exceeds the carbon dioxide due to respiration during the year, it accumulates in carbon trees (carbon sequestration). Thus, a tree that has a net carbon accumulation during a year, it also produces net oxygen (Nowak et al., 2007).
The net annual amount of oxygen produced is estimated according to Equation (-) (Nowak et al., 2007). According to the relation (1), the amount of oxygen production (O2) in kilograms per year is calculated by multiplying the net precipitation of carbon (C) (in kilograms or grams) by the ratio of the atomic weight of oxygen to carbon (32/12=2.67).