OPEN :: Home

Recent Submissions

Item

The influence of different thinning methods on dominance coefficients of future crop trees in even-aged Scots pine stands

(Instytut Badawczy Leśnictwa, 2014-03) Zachara, Tadeusz; Instytut Badawczy Leśnictwa, Zakład Hodowli Lasu i Genetyki Drzew Leśnych, Sękocin Stary

The research aim was to evaluate the influence of different thinning methods on future crop tree growth. Investigations were conducted on permanent Scots-pine experimental plots, established in 1960s and 1970s in Kozienice, Łąck, Parciaki and Janów Lubelski Forest Districts. To assess the response to thinning of future crop trees, their dominance coefficients were used. These are defined as quotients for each given future crop tree diameter and average stand diameter (WP1), the average dominant layer diameter (WP2) and the average diameter of 100 thickest trees per hectare (WP3). The difference between each coefficient value at the beginning and at the end of the measurement period was used as a measure of the thinning effect. On Kozienice, Łąck and Parciaki plots the differences between treatments were significant, especially in the period after first thinning. The increase of WP3 coefficient occurred in a case of strong thinning – TS1 and TS2. On plot Parciaki also the moderate thinning TU1 and TU2 had a significant influence on change of this coefficient. On plot Janów Lubelski the influence of treatment has not been stated in the first 5-year period but in the next one. Analyses of changes in the dominance coefficients confirmed the hypothesis that the WP3 coefficient is very useful as it is the most stable indicator of future crop-tree position in a stand. On Kozienice, Łąck and Parciaki plots the significant differences between treatments were stated, especially in the period after first thinning. The influence of thinning treatment on the plot Janów Lubelski was not considered for the first 5-year period but in the next one. All reactions to thinning were slower on this plot, possibly because of the relatively poor site conditions. This was a long-term effect. The results obtained suggest that very intense thinning of Scots pine stands should only be implemented under a restricted set of conditions – in healthy, not neglected, forest stands. Classical moderately-selective thinning is preferable to intense thinning and is the most convenient option for pine stands.

Item

The influence of plant spacing on growth and survival of Scots pine in various habitats during a 40 year period since stand establishment

(Instytut Badawczy Leśnictwa, 2014-06) Gil, Wojciech; Instytut Badawczy Leśnictwa, Zakład Hodowli Lasu i Genetyki Drzew Leśnych, Sękocin Stary

The aim of this research was to characterise the influence of plant spacing on the survival and growth of pines in dry and fresh coniferous forest habitats after almost 40 years since stand establishment. In this study, we compared seven types of spacing, including square, rectangular and triangular configurations, with initial densities ranging from 6944 units/ha to 15 625 units/ha. The research covered two sites where no tending interventions of selective character were performed throughout the growth period. We found that habitat conditions had an influence on tree survival as well as growth in thickness and height in the pine forest stands. In the less fertile habitat, where competition between trees was less intense, about 1,5 to 2 times more trees survived than in the more fertile habitat. Pines growing in the fresh coniferous forest were taller and had substantially larger diameter breast heights (dbh) in comparison to pines of the dry coniferous forest. Additionally, habitat conditions had an influence on the spacing effect correctness of the analysed features. In the poorer habitat this influence was stronger, which showed in a greater differentiation of the analysed parameters as compared to the more fertile habitat. Average dbh values of all trees on the Płock surface increased with decreasing initial density and ranged from 8,24 cm in variant A (15 625 units/ha) to 9,79 cm in variant C (6944 units/ha). On the Łąck surface, trees growing at a lower density (variants C and E) were significantly thicker than trees growing at densities between10 000 units/ha and 15 625 units/ha (spacing variants A, B, F, G). Furthermore, our results showed a significant influence of habitat conditions and plant spacing on the thickness of pines belonging to the 1st biosocial class. Moreover, we found a positive influence of triangular-shaped spacing on the trees' thickness increment in the fresh coniferous forest, which confirms reports from other authors. Hence, we can deduce that triangular spacing enables trees to make better use of their surrounding space which positively impacts on their growth parameters. Based on these results, we can conclude that, in pine forests, there is a significant influence of habitat conditions on tree survival and growth in thickness and height. This study also showed significant differences between the types of plant spacing and their effect on pine shafts in the II age class. However, a relationship between height growth rate and initial density was not observed. In both of the investigated habitats, the highest trees were observed at densities around 11 500 units/ha with triangular spacing enhancing this effect.

OPEN Repository

23002 archived items

Institutional Communities

Recent Submissions

Browse by

Date

Author

Affiliation

Subject

Publisher

License