Models for modal man-made pine stands characteristics dynamics in the Left-Bank Forest-Steppe of Ukraine

Abstract

Introduction

In today’s environment, the development of regulatory and informational materials for evaluating and forecasting the growth of modal stands is relevant. This is particularly important considering zonal features that determine the degree of ecosystem function performance, allowing for a more objective evaluation of growth and the control of forestry measures' efficiency. Scots pine (Pinus sylvestris L.) is among the most resilient tree species. However, pine stands in the Left-Bank Forest-Steppe possess specific characteristics that necessitate detailed research.

The study aimed to reveal the growth and productivity features of modal man-made pine stands in the Left-Bank Forest-Steppe of Ukraine.

Materials and Methods

To develop growth tables, information from the compartment database “Forest Fund of Ukraine” of the Production Association “Ukrderzhlisproekt” (for Forest-Steppe parts of Kharkiv and Sumy regions), data from observations at 33 sample plots in pine stands for State Specialized Forest Enterprise (SSFE) “Forests of Ukraine”, Branches “Lebedyn Forestry”, “Konotop Forestry”, “Okhtyrka Forestry”, “Trostyanets Forestry” (Sumy region), “Zhovtneve Forestry”, “Chuguyevo-Babachansk Forestry”, State Enterprises “Vovchansk Forestry” and “Skrypayivske Educational and Research Forestry” (Kharkiv region), and 13 permanent monitoring plots in SSFE «Forests of Ukraine», Branches “Zhovtneve Forestry”, “Skrypayivske Educational and Research Forestry”, NNP “Slobozhanskyy” (Kharkiv region) were used. Additionally, a sample plot located in the SSFE “Forests of Ukraine”, Branch “Guty Forestry” (Kharkiv region) was used, where 12 model trees were felled and measured. The sites were predominately located in fresh poor (A₂) and relatively poor (B₂) forest site conditions, as well as fresh relatively fertile (C₂) site conditions.

Average tree heights and growing stocks were approximated using the Mitscherlich function. The transition from relative to absolute values was executed based on the basic height values of the modified scale of M.M. Orlov for 80-year-old stands of seed origin. An allometric function was employed to model average diameter, factoring in age and stand height.

Results

The research established patterns in the dynamics of the main forest evaluation indicators. The height growth of man-made pine stands occurs within one site index class of the general site index scale. However, at a younger age, growth tends to slow down. Stands in the Left-Bank Forest-Steppe exhibit slightly more intensive height growth at 20–30 years of age, resulting in larger diameters and growing stocks compared to modal pine stands in Prydniprovskyi Northern Steppe according to V.M. Lovynska.

Conclusions

The developed regional growth tables objectively characterize dynamics, considering regional growth features of modal pine stands in the Left-Bank Forest-Steppe of Ukraine. These tables can serve as a basis for addressing scientific and practical forestry tasks.

Modal man-made pine stands demonstrate relatively high productivity. The height growth of such stands occurs within one site class of the general site scale, with growth slowing down at younger ages, particularly in fresh poor conditions (A₂). Quantitative maturity of modal man-made pine stands in A₂, B₂ and C₂ is determined by the average change in stock occurring at 55, 45 and 40 years old, respectively. The productivity of modal man-made pine stands in the Left-Bank Forest-Steppe surpasses that of the Prydniprovskyi Northern Steppe of Ukraine, likely due to better moisture availability.

2 Figs., 3 Tables, 28 Refs.