Assessment of the assimilation potential (by carbon) of urban green areas (on the example of the city of Penza)

   The dependence of carbon assimilation in mixed plantings of the Penza city on the influence factors used in the ROBUL algorithm was studied. Specific carbon assimilation in the city by 99 % depends on the forest cover of the residential area, assimilation age rank and average conversion coefficient. The first factor has the greatest influence, while the conversion coefficient has the least one. The average carbon assimilation by the tree stand of the residential zone was 0.199 t/year/ha (43.6 kg/year/person). The highest indicators were in districts with forest park zones, the lowest ones were in districts with development not earlier than 2000. A positive carbon balance is observed relative to respiration of the population, but this balance is negative within the administrative borders of districts. A comparison of specific carbon assimilation at the Penza agglomeration sites calculated using the ROBUL algorithm and the obtained general regression assimilation model (RMA) showed no significant differences between them with a significant difference in the labor intensity of obtaining results in favor of the RMA model. The PMA model can be used to determine the temporal dynamics of carbon assimilation based on the planned area and composition of plantations. For the maximum possible share (42.6 %) of the green residential area of the Penza city, the potential carbon assimilation according to the RMA model for mixed species is 0.44 t/year/ha and is achieved in 40 years from tree planting, after which there is a decrease due to self-cutting.