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Referring to the Czarnowskis formula describing tree-stand height growth rate, a definition of height growth benchmark of site quality and a formula for its calculation have been developed. Besides, a formula connecting the height growth benchmark of site quality and the annual tree-stand biomass production has been constructed. The above benchmark was developed on premises that in clear-cut managed stands: (1) product values for annual maximum height growth and the age at which it takes place as well as (2) tree-stand height at which the annual height growth rate reaches maximum values are specific for any tree species irrespectively of the site quality. A formula connecting annual biomass production and height growth benchmark of site quality has been developed on premises that the highest possible annual biomass production as calculated for given tree species in a forest community is no lower than the site productivity. The coefficients values applied in respective formulae were calculated basing on data taken from the growing stock tables for five tree species: Scots pine, Norway spruce, European fir, European beech, and English oak. In total, the data for 148 height curves were taken into consideration while the annual biomass production was analyzed for 23 tree-stands. The developed formulae are of use for practical purposes however their applicability is to be restricted in the same way as restricted is the applicability of the growing stock tables that have been used for these formulae identification.
Basing on natural conditions a formula was worked out permitting to compute the normal annual precipitation in any point of Poland defined by the geographic co-ordinates and elevation with mean accuracy of 6% and maximum error below l6% in relation to data obtained in 66 stations of the Institute of Meteorology and Water Management during 1951-1970. This formula may be identified using other sets of data fulfilling the criteria defined in the paper.
On the basis of data from 46 growth and yield tables it was shown that in even-aged monospecific tree stands the product of the maximal current annual height measurement and the age of height growth culmination is species-specific and in analysed samples was not related to the site quality expressed by the site class. It was also shown that the above mentioned relationships can occur also in tree stand of a more complex structure than the analysed ones.
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Podstawowe zalozenia w nauczaniu hydrologii lesnej

75%
Sylwan
|
2002
|
tom 146
|
nr 12
69-79
Formula describing capillary porosity of organic soils in relation of density by volume and shrinkage by volume was verified and extended. Formulas describing shrinkage of organic material in relation of its selected physical properties were given too. Coefficients occurring in that formulas were evaluated on the basis of investigations of organic material drawn from top layers of soils formed on Istebnian sandstone, which is covered by spruce forest stand.
This article describes cyclic changes in the soil water storage that take place within developmental stages of the stands managed by clear−cutting system. The aim of the paper is to present possibilities of studying these changes and their significance for the dynamics of waterlogging of forest ecosystems and water outflow from the forest. Soil water storage (SWS) in forest soils undergoes cyclic changes that can be divided into short−term, seasonal and long−term. Short−term changes, calculated on a daily basis, and seasonal, covering the entire growing season, can be identified and analyzed based on stock values measured over relatively short periods. Studying long−term cycles in this way is practically impossible, as there are no long−term measuring sequences. However, it is possible to use water−balance equilibrium in atmosphere−stand−soil (A−D−G) for this purpose. The dependent variables include increments of soil water storage, while independent ones are represented by the biometric features of stands and hydro−climatic factors. The balance equations should be built separately for SWS supply and losses. In the recharge phase the increase of the SWS after single rainfall, the amount of potential interception proportional to the plant surface and the weight of the forest litter as well as rainfall intensity and duration, which determine the level of its use are taken into account. SWS losses are explained by the rates of plant transpiration, linearly dependent on the amount of biomass produced and evaporation from the soil surface, which is a function of the amount of solar energy and wind velocity within the stand. They are modulated in relation to the conditions above the canopy that in turn depend on biometric characteristics of the stand. Taking into account the hydro−climatic conditions above the canopy ensures that the ceteris paribus condition is met. Recognition of long−term SWS cycles is possible due to the knowledge of stand dynamics manifested by changes in the value of its biometric features. The identification of equations according to the above−mentioned indications was carried out many times with very high compliance in the conditions of even−aged low−energy stands. The occurrence of long−term SWS cycles raises a number of questions regarding the forest ecosystem functioning, description of forest sites, silvicultural systems applied as well as the ability to control the water balance in forest ecosystems. The hydrological conditions in the forest ecosystem are shaped mostly upon selecting silvicultural system to be implemented. It results in specific changes in biometric features in the subsequent stand development stages modulating the components of the A−D−G balance and, as a consequence, soil water relations. The impact of ongoing stand tending is limited. However, forest drainage, tree felling uncovering soil surface and sudden changes in the forest structure trigge
16
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Podstawowe zalozenia w nauczaniu hydrologii lesnej

63%
Sylwan
|
2004
|
tom 148
|
nr 06
59-67
The interception of simulated rainfall of variable intensity by beech and spruce trees was measured in laboratory conditions. The results of the measurements were employed for verification of an empirically derived formula describing the relationship between interception of rainfall by plants and the size of the interceptive surface and duration of the rainfall. The effectiveness of the formula was confirmed. The usefulness of the methodology developed by us for the further research directed towards refinement of the formula was confirmed, too.
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