Forest performs various environmental functions and significantly improves quality of the environment. At the same time, it is affected by a number of negative factors, fires, in particular. As a result, forest may partially or completely lose its valuable capabilities. Thus, one of its environmental functions is to produce oxygen and deposit carbon. Forests damaged by fires lose these basic capabilities. Dynamics in the wood stock is closely related to changes in carbon deposits and oxygen production.
The aim of the study was to assess the carbon losses in the young pine stand damaged by fire, located in the Left-Bank Forest-Steppe zone.
Materials and Methods
We studied a young pine stand damaged by a surface fire in 2011, located in the Vasyshchevo Forestry in Zhovtneve Forestry Enterprise in fresh fairly infertile site conditions. We calculated deposited carbon in the trunks on three permanent plots with different levels of fire damage to trees (height of bark char on the trunks was 1.21 m, 0.95 m and 0 m - control). At that, two methods were used. The first methodological approach was based on the assessment of the deposited carbon in overground phytomass on the plots damaged by fires and on the control one. To evaluate carbon sequestration in the stem wood, we applied the dendrochronological methods.
Having used P. Lakyda’s standards, we found out that the loss of deposited carbon in the fire-damaged stands was 22–30% comparing to the control data. The dendrochronological methods enabled us to discover that the carbon content in trunks of the trees varies during their ontogenesis and increases with age. The accumulation of carbon in the stem wood does not significantly differ during the pre-fire period (2006–2010) between the control and damaged stands. However, we observed a major difference during the after-fire period (2011–2017). An increase in the amount of carbon in the stems of the pine stand brought about an intense dieback of the trees weakened after fire. As the forest was gradually getting sparser, the trees that remained alive got more light and better root nutrition. During the post-fire period the difference between the amount of carbon in the stem wood on the control plot and that in the stems in the damaged stands was 20%.
Having estimated the deposited carbon loss caused by fires, based on the phytomass stock, and compared it with that on the control plot, we came to the conclusion that the loss of carbon varies from 22% to 30% on plots with different damage level.
We revealed regression relations between height and diameter of trees on the one hand and deposited carbon in the aboveground phytomass of a tree on the other, approximated by curves of the 2nd order. The correlation increases with decreasing of the level of damage caused to stands by fire.
By means of the dendrochronological methods we discovered a 20 percent increase of the amount of deposited carbon in the stem wood of the trees damaged by fire as compared to that on the control plot. It occurred due to a better root nutrition and light which survived trees began to get after the damaged trees died.
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