Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 24

Liczba wyników na stronie
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 2 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych:  cechy taksacyjne
help Sortuj według:

help Ogranicz wyniki do:
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 2 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
The development of the transportation network brings both benefits and threats. Much attention is paid to soil contamination with trace elements, difficulties in animal migration, noise propagation or synanthropisation of the vegetation cover. This paper deals with the effect of provincial road No. 150 on inventory characteristics of neighboring Scots pine stands in the Notecka Forest (western Poland) – one of the larger forest complexes in Europe. Twelve rectangular experimental sites were established perpendicular to the road axis, called belt transects. Each transect consisted of 3−4 plots located at different distances from the pavement edge (fig.). Measurements and estimations were recorded for the plots. Values from all belt transects were approximated within plots at the same distance from the road and then compared using statistical methods. Observations were conducted in Scots pine stands growing on fresh coniferous forest (Bśw) and fresh mixed coniferous forest (BMśw) sites. Reduced stand density that resulted in decreased basal area, volume and growth rates were observed in the immediate vicinity of the road compared to the forest interior. Individual trees were thicker, but more often burdened with defects decreasing timber value. Any considerable effect of the road on tree height wasn't observed. The above mentioned changes were more evident in poorer habitat conditions, while the location in relation to the road had no significant effect. Modified lighting conditions are probably the main cause of these changes. At the edge of Scots pine stands in the Notecka Forest, a unique ecotone has formed under the influence of the provincial road.
Rosnące zapotrzebowanie społeczne na pozagospodarcze funkcje lasu zmusza leśników do poszukiwania metod równoważenia znaczenia wszystkich funkcji. Do realizacji nowych zadań leśnictwu niezbędne są dane, które pozwolą określić zdolność lasu do spełniania wielostronnych funkcji i aktualny stopień ich realizacji. Jednym ze sposobów pozyskania takich informacji może być opracowanie punktowej metody oceny funkcji lasu. Prezentowana praca jest próbą weryfikacji opracowanej metody waloryzacji funkcji lasu, polegającej na analizie funkcji lasu w zależności od takich cech jak typ siedliskowy lasu, gatunek panujący oraz wiek gatunku panującego.
In most of European countries, basic information about forests that is used for its monitoring and formulation of national policies comes from the National Forest Inventories (NFIs). Assessment of forest resources at the national level was initiated in Poland in 2005. In 2014, the second cycle of NFI was completed. Since 2010, results of NFI are the main source of information about the amount of forest resources in Poland, their structure and condition. In the paper, we analyse the indicators of forest structure. Classification of forest categories (forested, temporary non−forested, related to forestry), vertical stand structure, species composition and age structure determined directly from NFI's sample plots were compared with descriptions of stands in which plots are located. Data from more than 29,000 NFI sample plots measured in 2010−2014 were analysed. Our results demonstrate that the share of temporary non−forested areas (resulting from management practices) assessed from NFI plots is higher than this based upon the stands description (3.9% and 1.8% respectively). We also observed that results of NFI show the huge discrepancy in percentage of land related to forestry (forest roads generally) in forests of private property comparing to cadastral data (1,2% and 0,04% respectively). Most of forests in Poland (92% based on NFI) are single−layer stands. But it should be emphasised that NFI indicate more than twice higher share of two−layer stands (4.8%) than that resulting from description of stands in which samples are located (2.2%). However, only one third of NFI plots located in two−generation and uneven−aged stands was assessed in the same way. On 80% of sample plots dominant species was in accordance with stand description. On 85% plots there were compatibility of the age of dominant species with age recorded in forest management plans. The results of our research confirm that description of the entire diversity of forests by any of the indicators is not practically possible. Simplifying the forests description occurs during NFI measurements as well as within forest management planning. However, some issues need clarification and additional analysis when NFI is used as a source of forest structure. NFI plots with maximal size of a few hundred square meters seem to be too small to observe vertical structure of stands. On the other hand, it should be recognized whether division of the sample plots into smaller sections does not cause overestimation of the area of temporary non−forested land.
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 2 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.