Leś. Pr. Bad., 2009, Vol. 70 (1): 5-17.

Wpływ cięć rębnych na zagęszczenie, wzrost i stan zdrowotny odnowień naturalnych sosny w warunkach Nadleśnictwa Tuszyma
The effect of final cuts on the density, growth and health condition of pine natural regeneration in the territory of the Tuszyma Forest District

Tadeusz Andrzejczyk, Marta Aleksandrowicz-Trzcińska, Henryk Żybura
Szkoła Główna Gospodarstwa Wiejskiego, Wydział Leśny, Katedra Hodowli Lasu,
ul. Nowoursynowska 159, 02–776 Warszawa, Fax: +48 22 5938113;
e-mail: tadeusz.andrzejczyk@wl.sggw.pl

Abstract. The paper analyses the density, height and height increment and the degree of needle cast (Lophodermium seditiosum) infection of natural pine regenerations in a typical clear-cutting area (60 m wide), the first cutting area (first strip cut, ca 40 m wide) surrounded by stands and undercanopy area, applying the regeneration clear felling, shelterwood felling and soil scarification using a rotary plough, respectively. The studies embraced 2–4 year-old pine regeneration at 12 regeneration sites located in fresh coniferous forest (Bśw) and mixed fresh coniferous forest (BMśw) habitats with typical rusty and rusty podzolic soils. The studies were conducted in the south-eastern region of Poland (Tuszyma Forest District) with the mean atmospheric precipitation sum of ca 650 mm.
It was demonstrated that the form of regenerative cutting had a significant effect on the quantity and quality of pine regeneration. The greatest number and the best growth of seedlings in the the first four years were in the first cutting areas, while the best healthiness – in clear-cutting areas. The most serious needle cast infection of pine occurred in first cutting areas. The health condition of pine regeneration in open areas (clear-cutting and the first cutting areas) improved over time, while it did not change in the areas under the shelter of the canopy. The differences in the height of seedlings in the first cutting areas and in clear-cutting areas gradually disappeared. The self-seedlings growing in a close neighbourhood of stands demonstrated slower growth rate and greater needle cast infection than those growing in more distant locations in the clear-cutting area. The density of seedlings in younger regeneration was the highest in the neighbourhood of timber stand, whereas in older regeneration (4 years-old) the density was uniform over the entire area. In order to enhance the growth and reduce the infection of needle cast in pine regenerations in the first cutting areas, it is necessary to increase their width to the maximal allowable 60 m with a concurrent thinning of the stand on the manipulation strip from the west side of the cutting area, which will provide better area ventilation.

Key words: Scots pine, natural regeneration, pine needle cast, regeneration cut.