The dynamic of final cutting volumes in pine stands in Ukrainian Polissia

Abstract

Introduction

In the conditions of Ukraine with the deficit of mature forests, rational harvesting is the most acceptable. The latter is based on the calculated volume of the final felling – annual allowable cutting, which ensures the involvement of only mature and overmature forest stands in the felling and does not decline over time. The annual allowable cutting is performed by economic sections, the main technical and silvicultural indicator of which is the age of final felling, based on the reasonable age of maturity.

Scots pine stands (Pinus Sylvestris L.) occupy more than two million hectares in Polissia; they perform important protective functions and are the source of raw materials. Therefore, forecasting the use of forest resources in the pine forests of Polissia is relevant.

The aim of the research was to calculate the annual allowable cutting in pine stands of Polissia for a 90-year period within the pine operational forests in Polissia, as well as other categories included in the calculation of the annual allowable cutting for a 110-year period.

Materials and Methods

The calculations were performed according to the current Methodology for Determining the Annual Allowable Cutting Rate (2000) on the basis of the distribution of areas and growing stocks of pine stands by age and site classes at operational forests and forests with a special forest use regime. The database of Ukrderzhlisproekt Production Association as of 01.01.2021 served as the data source. The invariability of the total area of pine forests and their distribution by categories was assumed. The program (in Excel) developed at the Department of Forest Inventory and Forest Management of NULES of Ukraine was used.

Results

Estimated annual allowable cutting for operational forests in the first calculation period is uniform use – 14,064 ha, 1^st by age groups – 12.462 ha and 2^nd by age groups – 15,715 ha, rational – 11,402 ha; for other forest categories: 3,131 ha, 1,472 ha, 2,782 ha, and 1,240 ha respectively.

For forests with a special forest use regime, the rational method (1,240.4 ha and 1,172.6 ha) of annual allowable cutting estimation is used in the first two periods; from the third period, it is possible to use the normal one.

Under the condition of implementation of the proposed maturity ages (91–100 years for operational forests of the 1^st site class and above), the decrease in the estimated allowable cutting in the first period will be 30% due to the depletion of the exploitation fund, in the second period this decrease is almost leveled off. A better dimensional and qualitative structure and performance of ecological functions are predicted if the proposed maturity ages are implemented.

The maturity age of pine stands in root rot foci is determined by taking into account the amount of afforestation of formerly arable lands and the age of forest stands affected by root rot. In pine stands, pathological processes in the root rot foci reach the maximum among those of the VI–VII age classes. In this regard, it is proposed to set the age of maturity of pine stands affected by root rot in operational forests at 51–60 years in Polissia and Forest-Steppe, as it will contribute to a significant reduction in the area of the stands affected by root rot and accelerate the leveling of the age structure of pine forests.

Conclusions

For pine economic sections in Polissia, it is most appropriate to use rational felling, and as soon as in the 3rd calculation period it is possible to switch to normal felling. We suggest that the calculations of annual allowable cutting are to be carried out by aggregated economic sections, as it will promote an increase in the volume of forest use. Despite a temporary decrease in the estimated annual allowable cutting in the first calculation period (by 30%), the proposed increase in the age of maturity for operational pine forests of the 1^st site index and above to 91–100 years will provide an opportunity to both improve the performance of ecological and protection functions by pine forests and obtain better dimensional and qualitative structure of stands.

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