Reduction of carbon absorption capacity of forest stands in Zhytomyr Polissya due to the pine stands mortality

Abstract

According to the signed climate Paris Agreement, Ukraine is faced with the task to prevent the global average air temperature from rising above 2,0 °C in order to avoid an increase in droughts, extinction of certain species of plants and animals, drying up and diseases of tree species, etc. To preserve and increase the number of natural carbon sinks, scientists pay attention in particular to the system of improving forest, soil, and other natural resources management. Among thirty main forest-forming species in Ukraine, Scots pine (Pinus silvestris L.) is the predominant tree species, in Zhytomyr Polissya, in particular, its amount is 388,4 thousand hectares, which is 59 % of all tree plantations. To establish the carbon absorption capacity of pine plantations of Zhytomyr Polissya, we have laid temporary test squares (CCIs) in state-owned enterprises: Baran Forestry hunting enterprise; Belokrovytsia Forestry; Gorodnitsky Forestry; Emilchinskoye Forestry; Zhytomyr Forestry; Korostensky hunting enterprise; Malinsky Forestry; People's Specialized Forestry; Novograd-Volyn Experienced Forestry; Ovruch Specialized Forestry; Olevsky Forestry; Slovenian Forestry Agribusiness. According to the methods of P. I. Lakida, A. A. Storochinsky, O. I. Poluboyarynova, A. S. Atkin, A. I. Kobzar, we established a phytomass of pine plantations in a completely dry state and obtained conversion coefficients that made it possible to estimate the difference between CO2 emissions and carbon sequestration. The statistical analysis showed homogenous average height, but not for other indicators. We found a very asymmetric right distribution in terms of age, density, bonity, Volume of the trunk, and phytomass, moderate distribution in terms of average diameter and left distribution for average height. The excess factor indicated an acute vertex distribution by density and a flat-top distribution by all other indicators. The total area covered by forest vegetation of pine forest areas is 388.4 thousand hectares (according to the latest accounting for 01.01.2011), with a total stock of stem wood 102.7 million m3, accumulate in their phytomass 23.5 million tons of carbon. The density of the phytomass per 1 m2 of forested vegetation is 52.7 kg. Medieval pine plantations absorb the most carbon in Zhytomyr Polissya — 12.1 million tons. In recent years, there has been an increase in lost areas covered with forest vegetation under pine trees due to the damage by biotic, abiotic and anthropogenic factors. The loss of pine forest plantations for various reasons reduces the carbon absorption capacity of Zhytomyr Polissya forests, as pine stands are the vast majority in the study area - 59%. It is established that pine forest plantations of Zhytomyr Polissya in their phytomass accumulate 23.5 million tons of carbon per year. The density of carbon per 1 m2 of forested vegetation is 25.7 kg. It is found that medieval pine plantations absorb the most amount of carbon in Zhytomyr Polissya — 12.1 million tonnes. It has been established that lost forest plantations due to anthropogenic, biotic and abiotic factors,between 2010 and 2018, could sequestrate 0.17-0.33 million tonnes of carbon in their phytomass reducing the level of CO2 pollution from 10 to 47 %.