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W pracy wykazano, że dynamika przyrostu grubości zależy od wieku drzewostanu, a nie od liczby drzew w drzewostanie ani też warunków siedliskowych. Przed uruchomieniem elektrociepłowni drzewostany z rejonu Połańca charakteryzowały się dynamiką podobną do kontrolnych. W pierwszym 10-leciu jej działalności nastąpiło wyraźne zahamowanie ich przyrostu grubości, a oszacowane straty wynoszą średnio 21,1%.
W pracy stwierdzono, że jedynie drzewostany Beskidu Żywieckiego (masyw Pilsko-Romanka) do wysokości około 900 m n.p.m. rozwijają się w warunkach, które na podstawie tendencji przyrostowych uznać można za niezakłócone. Największy spadek przyrostu grubości i zahamowa­nie jego dynamiki w okresie 1977-1986 w porównaniu z 10-leciem 1967-1976 stwierdzono w obrębie Szczyrk (masyw Skrzyczne), szczególnie w partiach przygrzbietowych (ok. 1100 m n.p.m.). Wykazano również, że stopień zahamowania dynamiki przyrostu grubości istotnie zależy od wysokości położenia drzewostanu n.p.m. Nie zależy natomiast od wystawy ani też liczby drzew w drzewostanie w obrębie danej wysokości n.p.m.
Sylwan
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2015
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tom 159
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nr 10
The understory, a layer composed predominantly of shrubs that perform an important phytomeliorative function, has rarely been the subject of research on the productivity and biomass. The aim of this paper was to specify the occurrence of understory aged ≥10 years as well as its species composition and the share of individual species in the biomass in the Niepołomice Forest (S Poland). The analysed features were related to the age and site conditions of the stands. The research material consisted of dry biomass of shrubs growing within circular sample plots spaced 500 m apart from each other. Dead and live (damaged and undamaged) shrubs of dbh<7 cm were cut at a ground level to determine their wet mass and samples were taken to determine the dry mass. The mass of live shrubs was calculated based on empirical formulas. 368 sample plots were set up in total. Shrubs (13 species) were observed on 76.1% of plots. Shrubs were the most common in the stands of II and IV age groups (87% of plots). No shrubs were observed on the plots with stands older than 160 years. The most common species was Frangula alnus (56.8% of the plots). Quite common ones included Sorbus aucuparia (27.7%) and Padus avium (12.8%). Cornus sanguinea, Prunus spinosa, Salix caprea and Viburnum opulus were observed on less than 1% of the sample plots. Frangula alnus and Padus avium were inventoried in as many as 8 forest site types. The largest amount of shrubs (10 species) were observed in moist broadleaved forest stands, while the fewest (2 species) in boggy mixed broadleaved and ash−alder swamp stands. Over 56% of the aboveground biomass were live shrubs of dbh <7 cm (868.6 kg/ha), almost 29% (444.1 kg/ha) were shrubs of the dbh ≥7 cm, and around 15% (227.6 kg/ha) of the biomass were dead shrubs. The total aboveground biomass of shrubs in the understory of the analysed stands equaled, on average, to 1,540 kg/ha. 94% of the biomass was the aboveground woody biomass including bark (1,448 kg/ha). The dry mass of leaves amounted to 92 kg/ha (6%). Due to high variability of the understory biomass, the estimation error of its average amount was almost 11.4% for total biomass and 13.5% for leaves.
Sylwan
|
2016
|
tom 160
|
nr 01
The aim of this paper was to determine the dry mass content in the fresh mass of leaves, trunks or branches and in the total woody aboveground biomass of shrubs forming the undergrowth of the stands in the Niepołomice Forest (southern Poland). The variability of the dry mass content in the analysed components was determined. For the prevailing species also its correlation with the individual's height and time at which samples were taken was investigated. The material comprised 744 samples, including 532 wood and 212 leaf samples, taken from the most common five shrub species: Corylus avellana, Frangula alnus, Padus avium, Padus serotina and Sorbus aucuparia. The shrubs were from 1 to 33 years old, and their height ranged from 0.3 to 9.9 m. It was shown that the dry mass content in leaves is significantly dependent on the shrub species, and in the case of F. alnus, P. avium and S. aucuparia on the height as well. The highest dry mass content was found in the leaves of C. avellana (39.3%), whereas the lowest – in F. alnus (25.5%). In case of F. alnus, the dry mass content depends on the time of sampling. The leaves collected in June had a significantly lower dry mass content than the ones sampled in subsequent months of the growing season. The dry mass content in the wood significantly depends on the shrub species and the analysed component, however the species−component interaction does not occur (tab. 4). The dry mass content in the trunk wood ranges from 50.3 (P. serotina and S. aucuparia) to 53.0% (P. avium) and exceeds that of the branch by from 1.0 (S. aucuparia) to 4.0% (P. avium). In the wood samples of F. alnus and S. aucuparia, taken between June and September, the dry mass content averaged at 47.3 and 48.7%, respectively, and was lower than in the samples taken between October and April, for which the respective means were 49.5 and 49.0%. In the case of F. alnus, the observed difference in the mean dry mass content is statistically significant at 0.05 level. The determined values of dry mass content in the fresh mass of individual components of the analysed shrubs can be used to find their dry mass as a basis for the calculation of the amount of accumulated carbon.
Usefulness of eight biometric characteristics for determining the volume increment of standing trees is evaluated. The study material consisted of the results of complete stem analyses of 164 trees from the upper layer of 56 pine stands of age class V and older. They concerned a 56-year period from 16 th to 80 th year of trees' life divided into thirteen 5-year periods. It was found that the variation of the volume increment of trees is explained in 83.2-94.7% by the variation of the height, basal area, and the basal area increment. These characteristics were used in working out the equations permitting to compute the volume increment.
The aim of the study was to develop a site index model for Scots pine stands in southern Poland describing changes in height growth of stand's upper storey over time. The research material contained the height growth data obtained from an analysis of 189 tree stems. The collected material was used to develop the parameters of six dynamic growth equations which allowed to determine site productivity and predict changes in height growth of stands with age. Statistical criteria for assessing the accuracy of mapping empirical data and biological reasonableness were the basis of selection of the equation that best fits changes in height growth of the examined pine stands with age. The developed model can be used to predict the growth rate and determine the site index for Scots pine stands in southern Poland.
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