Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 37

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

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 paper analyzes the changes of forest fragmentation in the Western Pomerania region (NW Poland). The analysis was carried out basing on maps from 16th and 18th century as well as 1930s, when the forest cover in the studied area was the lowest. The historical area of forests was assessed on the basis on Hartnack utilization maps. The analysis of numerical maps was car− ried out in the GUIDOS program, which enables to evaluate the fragmentation of the forests through Morphological Spatial Pattern Analysis (MSPA) that describes the geometry of patches and their interconnectivity. The program calculated the forest areas classified for the seven cat− egories according to their functions in the landscape (MSPA classes). In the 15th century the forests coverage was around 52.5%. There was a significant loss of forest area between the 16th and 18th century, and in the 18th century they occupied 24.7% of the researched area. Because of the economic changes in the country that took place after the World War II, the forest area in Pomerania increased to 33.7%. It was found that changes in the forest area in the examined period resulted in a decrease in the area classified as forest interior (CORE) and an increase in the boundary area (EDGE). Taking into account the equidistant of 1 km2, the area occupied by the core patches dropped in the analysed period from 59.9% to 35.6%. At the same time the spa− tial isolation of many patches increased, which was reflected in an increase in the area classified as ‘islands' (ISLET). Their share in relation to the entire forest area increased from 4.4% to 23.6%. This could be particularly seen in the area of Pyrzycko−Stargardzka Plain and Choszczno Lakeland, where in the 1930s the so−called forest islands constituted the entire forest area of these mesoregions. The MSPA analysis enabled to specify forest patches classes, which can be useful for landscape characterization, including the patch and corridor model. The fragmenta− tion of forests can be objectively assessed using GUIDOS and it can make the output results obtained in GIS programs complete.
The paper presents the results of an introductory historical analysis in occurrence of mid-field ponds on the situated in the area (9039 km2) of younger plaistocene landscapes of Pomerania. The analysis was based on the comparison of topographical maps from 1888 and 1980. Loss of the ponds was presented in relation to respective mesoregions and the character of surface features, taking into consideration the water surface size and melioration works conducted in the drainage basin area. For the analysis purposes mid-field ponds located in the areas which usage in compared periods has not changed were chosen.
The paper present the results of apreliminary historical analysis of changes in the occurrence and dimensions of ponds situated in the region of younger Pleistocene landscapes of Pomerania. The analysis was based on the comparison of topographical maps from 1888 and 1980. The area under study - 3200 km2 - covered the region of the end moraine along with a fragment of fluvial plain zone of Myślibórz Lake District. Basing on the analyses of cartographic materials, the location of ponds with various forms of utilisation was established, their size and character of the surrounding zone was determined, the scale of pond disappearance was calculated and the area of its greatest intensity was established. It was found that out of 5433 ponds present on maps from the end of 19lh century merely 31 % were left by the 80-ies of the 20th century. Majority of the ponds disappeared on the field area, the least on the built-up areas. Among 2690 midfield ponds, which in both the 19th and 20th century were located on the field areas 59 % disappeared completely, part of them underwent the process of land forming and only 28 % retained open water surface.
Mezoregion Wzgórz Bukowych, położony na Nizinie Szczecińskiej charakteryzuje się zróżnicowaniem rzeźby terenu i skomplikowaną budową geologiczną. Wysokości bezwzględne sięgają 80–140 m n.p.m., z kulminacją Bukowca 147 m. Wysokości względne przekraczają 60 m, przy spadkach stoków ponad 30° w strefach głębokich rozcięć w dolinach denudacyjnych Obszar ten odwadniany jest przez wiele niedużych cieków, o powierzchniach zlewni nieprzekraczających 5 km2. Charakterystyczną cechą dolin cieków są płaskie odcinki koryt, których geneza związana jest z krótkotrwałymi postojami masywu lodowca. Do oceny zróżnicowania rzeźby zlewni posłużono się Numerycznym Modelem Terenu, wykonanym na podstawie map topograficznych 1:10 000. Opracowany model pozwolił na ocenę zróżnicowania rzeźby terenu wybranych zlewni cieków, w tym analizę nachylenia stoków oraz przebiegu profili podłużnych koryt.
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.