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Wyświetlanie 1-3 z 3
Tytuł:
Długotrwałe efekty różnego nasilenia trzebieży selekcyjnej w drzewostanie sosnowym
Long-term effects of different thinning intensity in young Scots pine stands
Autorzy:
Zachara, T.
Powiązania:
https://bibliotekanauki.pl/articles/986702.pdf
Data publikacji:
2017
Wydawca:
Polskie Towarzystwo Leśne
Tematy:
lesnictwo
hodowla lasu
drzewostany sosnowe
zabiegi pielegnacyjne
trzebiez selekcyjna
sosna zwyczajna
Pinus sylvestris
wzrost roslin
jakosc hodowlana
scots pine
silviculture
tending cuts
basal area increment
stand resistance
Opis:
The paper describes a case study of thinning experiment established in 1976 with a use of random block design in 21−year−old Scots pine stand in Janów Lubelski Forest District (south−eastern Poland). The stand was subjected to no thinning (control variant K), weak thinning with removal of 10% of basal area (variant S1), strong thinning with removal of 30% of basal area (variant S3) and extreme thinning, where only future crop trees and some reserve trees were left (variant TE). S1 and S3 treatments were repeated each 5 years, while in TE treatment the 20−year interval was applied. During the period of 40 years all trees were measured each 5 years and current basal area increment was calculated for the whole stand and for future crop trees population. The relative increment of future crop trees population calculated as a percentage of stand total increment was taken into account too. Data were subjected to ANOVA and differences were compared with Tukey test. The results showed that total stand increment was not influenced by thinning intensity. The future crop trees increment was significantly higher in a case of extreme thinning in comparison to weak thinning and to the control treatment during the first 20 years of experiment (age 21−41). During the second 20 years (age 41−61) only relative basal area increment of future crop trees population was significantly higher on the plots with extreme thinning in comparison to other treatments. The results suggest that a weak thinning brings no silvicultural effect meant as increased growth of previously selected future crop Scots pines. Strong or very strong thinnings give a long−term growth effect and they can be acceptable, but in healthy and well−tended young pine stands only.
Źródło:
Sylwan; 2017, 161, 09; 730-737
0039-7660
Pojawia się w:
Sylwan
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Retrospektywna analiza wzrostu i przyrostu drzew w 30−letnim drzewostanie jodły kalifornijskiej (Abies concolor Eng.)
Retrospective analysis of growth and increment of trees in 30−years−old stand of white fir (Abies concolor Eng.)
Autorzy:
Beker, C.
Flieger, K.
Turski, M.
Powiązania:
https://bibliotekanauki.pl/articles/994778.pdf
Data publikacji:
2012
Wydawca:
Polskie Towarzystwo Leśne
Tematy:
lesnictwo
drzewostany sosnowe
sosna kalifornijska
Abies concolor
wzrost roslin
dynamika wzrostu
przyrost wysokosci
przyrost piersnicowego pola przekroju
przyrost miazszosci
white fir
growth
height
breast height diameter
basal area
volume
Opis:
The paper presents the results of the retrospective research on the height and diameter growth of trees in a 30−year−old white fir (Abies concolor Eng.) stand growing in the mixed broadleaved forest habitat in the Forest Experimental Station in Siemianice. The research concerned the volume and functionally related parameters including height, diameter at breast height and basal area.
Źródło:
Sylwan; 2012, 156, 12; 902-907
0039-7660
Pojawia się w:
Sylwan
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Określanie wybranych cech drzewostanów sosnowych z wykorzystaniem chmur punktów pozyskanych w procesie automatycznego dopasowania cyfrowych zdjęć lotniczych
Estimating selected characteristics of Scots pine stands based on point clouds derived from automatic matching of airborne images
Autorzy:
Hawryło, P.
Powiązania:
https://bibliotekanauki.pl/articles/986689.pdf
Data publikacji:
2017
Wydawca:
Polskie Towarzystwo Leśne
Tematy:
lesnictwo
fotogrametria
zdjecia lotnicze
automatyczne dopasowanie zdjec lotniczych
chmura punktow
drzewostany sosnowe
wysokosc Loreya
pole powierzchni przekroju piersnicowego
zasobnosc drzewostanu
dokladnosc szacowania
modele predykcyjne
area−based approach
forest inventory
lorey's height
basal area
growing stock volume
Opis:
Recent research show that image−derived point clouds (IPC) can be successfully utilized in the context of estimation of selected forest parameters. However there are still some topics for further investigation in the context of using archival data. Particularly, in case of forest stands in Poland the number of such studies is limited. This study investigates the usefulness of airborne IPC for estimation of Lorey's height (H), basal area (G) and growing stock volume (V) of Scots pine stands. Additionally, the accuracy of predictive models is analyzed for images acquired in the same year as the field reference data were collected (2015) and for archival images acquired in 2012. The study was performed in Janów Lubelski Forest District (south−eastern Poland) on approximately 7,800 ha. The measurements from 94 circular plots were used as the reference data. The Area Based Approach and multiple linear regression were used to create predictive models. For each analyzed dependent variable variety of IPC characteristics were evaluated to select the most accurate predictive models. The best model for each variable was selected based on Akaike Information Criteria and RMSE. The same predictor variables were used for both years of aerial images aquisition. For models comparison the one−sided bootstrap test was used. The RMSPE for H, G and V in case of images acquired in 2015 amounted to 5.3, 16.3 and 17.3%, respectively. Analogically, the relationship between predicted and observed values (R2) amounted to 0.96, 0.47 and 0.81. The finally selected models had three, one and two predictors for H, G and V, respectively. The difference between accuracy of models based on aerial images from 2012 and 2015 was not statistically significant for all analyzed variables. The obtained results show high potential of using airborne image−derived point clouds for forest inventory activities in Scots pine dominated stands.
Źródło:
Sylwan; 2017, 161, 09; 707-714
0039-7660
Pojawia się w:
Sylwan
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-3 z 3

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