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Abstract
Introduction
Pine plantations of Polissya zone, especially pure pine stands created on former arable lands, are sharply declined by annosum root rot (Heterobasidion annosum (Fr.) Bref.). Now the main forest pathology background in forests of Polissya of Ukraine is formed by permanent foci of forest diseases. Since 2007, the foci area increased by 30 %, from 90.9 thousand ha to 117.3 thousand ha. In the overall structure of the stands, in which pathological processes have been detected, 72 % of the area (84.7 thousand ha) is occupied by pine forests affected by the root rot. The largest areas affected by the disease are concentrated in the forests of Chernihiv (28.7 thousand ha), Zhytomyr (14.2 thousand ha), Kyiv (14.8 thousand ha), Volyn (11.9 thousand ha) and Rivne (11.1 thousand ha) regional departments of forestry and hunting.
The aim of the study was to analyse the current state and productivity of pine forests in Gorodotske Forestry Enterprise in Volyn Polissya, to evaluate their use of forest site potential and to determine the reserve for increasing their productivity.
Materials and Methods
The study was performed according to methods generally accepted in Ukrainian forestry and forest inventory (Vorobyov (1967), Ostapenko & Herushinskiy (1975), Anuchin (1982)). Analysis of the current state and productivity of pine forests in the enterprise was carried out using the subcompartment database of the production association “Ukrderzhlisproekt” as of 01.01.2011. The effectiveness pine stands’ use of forest site potential was determined by the method of M. M. Vedmid and V. A. Gavrilova (1969, 2004). The most productive (II site class and higher) and fully stocked (the stocking was 0.8 and higher) stands by the subcompartment database of “Ukrderzhlisproekt” were used as local standards.
Results
In the forest fund of Gorodotske Forestry Enterprise the area covered with forest vegetation is 28.2 thousand ha, the area of Scots pine plantations is 19.3 thousand ha (68 %), including 19.0 thousand ha of healthy ones and 0.3 thousand ha of pine stands affected by annosum root rot (99 % and 1 % of the area of pine plantations of the enterprise). In most cases, annosum root rot affects fully stocked pine stands, the area of which is 58 %. The main part of pine stands affected by the root rot grows in fresh fairly infertile oak-pine sites (48 %) and in fresh infertile pine sites (38 %). Pine stands of I and II site classes dominate in the root rot affected pine forests (46 and 42 % of the area respectively); 84 % of the areas are middle-aged plantations.
The maximum advantages of forest site potential are used by the healthy pine forests in the VI and VII age classes and by root rot affected pine stands in the IV age class, in which the site potential is higher than in healthy stands. This can be explained by the fact that the root rot affects pine stands mainly with high site class (I and Ia) and high stoking (0.8–0.9) (50 and 58 % of the area respectively). These were plantations of the IV age class in the forest fund of the enterprise, in which the disease was found when trees have not suffered significant losses of wood.
Conclusions
The stock volume of healthy modal forest stands was on average 10-12 % higher than of diseased ones. In general, healthy pine stands used the site potential more efficiently. The weighted average for use of forest site potential by healthy pine stands of the enterprise was 73 %. For the root rot infected pine stands it was 69 %. The general reserve of productivity of pine stands in the enterprise is 1,697.1 thousand m3, including 1,666.0 thousand m3 in healthy stands and 31.1 thousand m3 in the stands affected by annosum root rot.
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