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Wyszukujesz frazę "forest function" wg kryterium: Temat


Wyświetlanie 1-2 z 2
Tytuł:
The influence of variability of water resources in lowland forests on selected parameters describing the condition of trees
Autorzy:
Tyszka, J.
Stolarek, A.
Fronczak, E.
Powiązania:
https://bibliotekanauki.pl/articles/11996.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
variability
water resource
lowland forest
climatic function
hydrological function
selected parameter
tree condition
periodical change
stand condition
extreme climate
water condition
river list
habitat condition
tree stand
Opis:
The influence of water conditions on the condition and growth of tree stands has been analysed in the context of the climatic and hydrological functions forest plays. Long observational series obtained for precipitation, outflow and depths below the surface of the water table have been put together with measured increases in the breast-height diameters of Scots pines and the severity of crown defoliation observable in selected tree species growing on the Polish Lowland, in order to determine the overall scope to the reaction stand condition manifests in the face of ongoing variability of water conditions within forest. An overall improvement in the condition of stands over the last 20 years does not disguise several-year cyclicity to changes capable of shaping the situation, i.a. departures from long-term mean values for precipitation totals and groundwater levels. The condition of stands is seen to worsen in both dry and wet years. Analysis of the degree to which pine, spruce and broadleaved stands experience defoliation points to spruce stands responding most to extreme hydro-climatic conditions. Extreme situations as regards water resources were seen to involve a response over two-year time intervals in the case of coniferous stands. Unsurprisingly, optimal growing-season (June-September) precipitation totals correspond with long-term average figures, while being slightly higher for spruce (at 384 mm), than for Scots pine or broadleaved species (375 mm). The relationships reported gain confirmation in analysis of periodic change in breast-height diameter increments characterising Scots pines, whose growth is seen to depend closely, not only on precipitation, but also above all on the depth of the water table in the summer half-year. Optimal depths of the water table proved to be different, being around 20 cm below ground in the case of marshy coniferous forest, 80 cm in wet habitats, and 135 cm in fresh habitats. Depending on the possibilities for water to soak into the rooting zone of trees there were even twofold differences in measured growth increments in Scots pine (as the dominant species in Poland’s lowland habitats). The maintenance of stable water conditions (as the most variable environmental factor in forest) should be an overriding aim of management activity in this habitat. When account is taken of the influence of the state of water resources on biomass production, and then on the intensity of evapotranspiration and the absorption of carbon dioxide from the atmosphere, it is seen how important it is to achieve improvements in water conditions in forests, as such an important factor in combating climate change.
Źródło:
Papers on Global Change; 2014, 21
2300-8121
1730-802X
Pojawia się w:
Papers on Global Change
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ocena ekonomiczna retencyjnych właściwości lasu
Economic valuation of the water storage capacity of forests
Autorzy:
Tyszka, J.
Powiązania:
https://bibliotekanauki.pl/articles/989798.pdf
Data publikacji:
2015
Wydawca:
Polskie Towarzystwo Leśne
Tematy:
lesnictwo
lasy
retencja wodna
mala retencja wodna
ocena ekonomiczna
forest
water storage
price of water
valuation of the water−storage function
Opis:
The article attempts to calculate the economic value of the natural water storage capacity of forests. The impact of forests on the volume of the river runoff and on the delay of the water cycle from the precipitation to the runoff was an indicative measure of storage capacity of the forest. Data from long−term research aimed at determining forest−water interactions in small catchments were used. Four weakly−correlated parameters of runoff characteristics were determined, reflecting the scale of retention capacities of forested areas. These parameters included mean annual runoff (HR), coefficient of the annual runoff irregularity of (HRmax/HRmin), summer to winter half−year runoff ratio (HL/HZ) and the volume of the discharge (Wq/Sq). Equations were developed interpreting the range of changes of the parameters with the increase of forest cover from 0 to 100% (fig. 1−3), and the volume of water stored by the forest per 1% of the forest cover per year was calculated. Using simplifying assumptions, the total volume of water stored per hectare of the forest in the average year was calculated to 9.05 m³. The unit cost of 1 m³ of water was determined on the basis of the lowest price which the State Forests (in the territory of the Garwolin Forest District) spent to increase the volume of the water stored in small reservoirs. No difference was made between natural and artificial water storage in terms of utility. According to such simplified calculations, the natural storage capacity of forests was estimated at 1,089 PLN per year. Apart from the water storage function, forests provide other benefits resulting from a wide range of hydrological, water−protecting effects. Water resources safeguard, inter alia, the sustainable development of forests: affect the climatic conditions, reduce the level of environmental contamination. These functions can be intensified through the use of appropriate methods of forest management.
Źródło:
Sylwan; 2015, 159, 06; 483-490
0039-7660
Pojawia się w:
Sylwan
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-2 z 2

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