Ograniczanie wyników

Czasopisma help
Autorzy help
Lata help
Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 46

Liczba wyników na stronie
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 3 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych:  drzewostany nasienne
help Sortuj według:

help Ogranicz wyniki do:
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 3 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
2
Artykuł dostępny w postaci pełnego tekstu - kliknij by otworzyć plik
Content available

Debowe drzewostany nasienne w Nadlesnictwie Runowo

86%
The rychtal pine is one of the most valuable ecotypes of Scots pine (Pinus sylvestris L.) approved for the breeding purposes in Poland. However, it occupies stands typical for oaks and beeches as shown by the compatibility analysis of species composition in relation to the habitat type in which they occur. Such result raises some doubts in terms of the naturalness of the rychtal pine and calls its history and origin into question. In the present study, we used the set of nuclear microsatellite markers to characterize and compare the gene pool composition of the selected seed tree stands of the rychtal pine with 200−year−old pine trees which grow at the Syców Forest District (SW Poland). We aimed to know to what extent the set of alleles specified for the group of the oldest trees from natural habitats is represented in the younger forest tree stands of the rychtal pine. The analysis of molecular variance (AMOVA) and clustering analysis showed that the gene pool of the studied pine populations was homogenous (FST=0,02%, K=1). The parameters of genetic variation were similar for all populations except for the mean number of alleles. On average, 25 new alleles were found in two rychtal pine seed tree stands as compared to the set of alleles found in the group of old pine trees. However, all alleles defined for old pines were also present in the gene pool of younger rychtal pine forest stands. The differences in the gene pool richness result most likely from quite high differences in the number of individuals analyzed from each population. In conclusion, our results indicate the common origin of the studied Scots pine populations.
The aim of the study was to investigate the structure of forest site types and of soil types of oak seed stands in Poland. The study was comparatively conducted with reference to sessile (Quercus petraea) and common (Q. robur) oaks. As in Poland the seed stands are established only in stands characterized by favourable both growth parameters and timber quality, it was suspected that the results of the study would enable to indicate optimal sites and soil units for oak breeding in Poland. The study was conducted on the basis of data obtained from the SEMEN database (www.bnl.gov.pl) which were broadened by descriptions of the investigated seed stands found in the Forest Data Bank (www.bdl.lasy.gov.pl). For both oak species, the research was conducted with reference to the two types of seed stands: permanent (WDN) and temporary (GDN). In total, 531 stands of Quercus petraea and 2043 of Q. robur located across whole Poland were investigated in the study. It was found that optimal soils as well as forest site types overlap for both investigated oak species only for fresh broadleaved forest (Lśw). For other forest type sites distinct differences for the oak species were found. The optimum for common oak were expanded towards the wet sites (moist broadleaved forest – Lw, and riparian forest – Lł), while for sessile oak towards semi−fertile mixed broadleaved forest (LMśw). It is interesting that seed stands of both oak species overgrow not only fine−textured soils, but significant share of them (ca. 50% area of Q. petraea and 15% of Q. robur seed stands) occurs on sandy soils (Brunic Arenosols mainly). It proves that Brunic Arenosols constitute forest sites enabling production of broadleaved forests characterized by favourable growth parameters and high timber quality. However, it is possible unless the soil have been podzolized by conifers due to podzolized Brunic Arenosols were rarely represented in the oak seed stands and, if so, the stands were characterized by relatively low site index. It was also stated that on podzolized Brunic Arenosols of fresh mixed coniferous forest (BMśw) admixture of oak should enable reducing negatively impact of conifers on a soil.
The programme of testing the progeny of permanent seed stands, parent trees, seed orchards and seedling seed orchards that has been run in Poland enables to determine the genetic value and silvicultural quality of the progeny of components of primary forest material. A better knowledge of population variability and adaptability to particular environmental conditions also allows for the updating and verification of principles regarding the use of the seed base in testing regions, as well as the determination of possibility for forest reproductive material to be transferred. The article presents the research on assessment of survival and growth among progeny from 26 permanent seed stands of silver fir that originates from Lublin, Radom and Łódź Regional Directorates of the State Forests, at four testing grounds located in the Kielce, Suchedniów, Tomaszów and Zwierzyniec forest districts. Each research plot was founded with 4 replicates, each with 3−year−old saplings. After 5 years of growth, mean rates of survival ranged from 70.4% at the Kielce site to 92.7% in Tomaszów. The lowest survival rate (30.5%) was noted for local origin (Starachowice), while the highest (93.8%) characterised the local standard from Zwierzyniec. Mean height varied from 54.1 cm in the case of the Suchedniów to 80.0 cm in the case of Tomaszów, albeit with the shortest firs originating from the Starachowice local standard and the tallest from the Tomaszów local standard. Analysis of variance components revealed that the environmental conditions (described by study area) played major role in shaping the variability. This effect was responsible for around 75% of the variance in height and 60% of that relating to survival. In contrast, origin (genetic factor) was most likely responsible for 7% of the noted variance in height or 4% of that relating to survival.
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 3 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.