Trends in forest fuel accumulation in pine forests of Kyiv Polissya in Ukraine

Abstract At present, forest fire research is becoming especially relevant in Ukraine. This study examines patterns of forest fuel accumulation in pine (Pinus sylvestris L.) stands that grow in different soil conditions with different pine stand structure. To estimate the load of forest fuel of different fractions, a combined methodology was used: the weighing method and the FIREMON (fuel load estimation) method. It was found that increase in surface forest fuel loads is not directly proportional to forest stands’ age. Fractional size distribution, capacity and loads of forest fuel depend on several factors, among which the greatest role is played by forestry characteristics of the pine stand. It was determined that in the forest site conditions of type C (fairly rich soils) in Kyiv Polissya, the share of forest litter compared to pine stands that grow in poor soil conditions (A) is smaller, ranging from 41% to 76% of the total forest fuel load. The mass proportion of the duff layer varies from 15% in young forest stands to 43% in mature stands. It was established that changes in forest fuel fractions for 1, 10, 100 and 1000 hours varied insignificantly with age rate. The share of substratum woody debris of 10 and 100 hours was insignificant and depended more on the forestry treatment regime on these sites. The mass proportion of coarse woody debris (1000 hours) was also insignificant, varying from 0% to 5.9% of the total load of surface fuel.