Wyniki wyszukiwania - BazTech

Ograniczanie wyników

Znaleziono wyników: 2

Liczba wyników na stronie

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych: forest conversion

Sortuj według:

Ogranicz wyniki do:

Spontaneous regeneration of the Carpathian beech forest in planted pine stands of the Roztocze National Park (the Roztocze Highlands, south-east-Poland)

Maciejewski Z.

Polish Journal of Ecology

2011

Vol. 59, nr 2

235-248

Directions and the scope of changes in the species composition of individual layers in secondary pine communities belonging to the class Querco-Fagetea Br.-Bl. & Vlieg. 1937 (tree stand, shrubs and vascular plants of the herb layer) observed at two study plots over almost 40 years (from 1971 until 2009) are discussed. Both tree stands were planted and they are in the phase of spontaneous regeneration towards a potential natural community . the Carpathian beech forest Dentario glandulosae-Fagetum Oberd. 1953. Species with greater light requirements (pine Pinus sylvestris L., aspen Populus tremula L., oak Quercus robur L., ecologically alien to the potential plant community, retreat from the tree and shrub layers. The share of tree species typical of the potential community (beech Fagus sylvatica L., hornbeam Carpinus betulus L., sycamore Acer pseudoplatanus L.) - in the tree stands increases. The rate of changes is particularly high for beech, while regression symptoms are noticed for fir Abies alba Mill.: a decrease in the abundance and share of fir in both tree-stands was recorded. A decrease in the abundance and frequency of the majority of species, including species characteristic of deciduous forests (class Querco-Fagetea) and beech forests (order Fagetalia sylvaticae Pawł.1928), and an increase in species typical of alder-ash riparian forests (alliance Alno-Ulmion Br.-Bl. & Tx. 1943) and nitrophilous communities were observed in the herb layer. Conversion treatment may reinforce the artificial character of the community because the species composition, as well as the spatial and age structure of the tree stands, can be arbitrary and therefore artificially formed during conversion (arbitrary applied size and order of regeneration clumps and areas). When anthropogenic communities are left undisturbed, processes affecting all phytocoenotic layers are activated and spontaneous forest regeneration usually begins. Therefore, tree-stand conversion used as a tool to restore natural community is not effective.

Conversion of instable primary forests in the lusatian post-mining landscape

Ertle C., Bartelt D.

Zeszyty Naukowe. Inżynieria Środowiska / Uniwersytet Zielonogórski

2007

nr 133 (13)

84-94

In the federal state Brandenburg in Germany about 464 000 ha of mainlymiddle aged Scots pine stands are planned to be converted. In addition, instable broad leaved forests like disintegrating monocultural birch and poplar stands on dumps of lignite mining need conversion. Forest owners feel unsure regarding the silvicultural treatment in these stands. Therefore, research is needed to develop strategies for a forest conversion practice in primary forests on dumps within the mining landscape. The urgency of conversion of primary dump stands with regard to the tree species exists in the decreasing order: poplar, birch and Scots pine. While conversion of young primary pine forests into mixed broad-leaved forests is not advisable because of unfavourable site conditions, suitable timber stands on dumps represent favourable pioneer crops appropriate for conversion. Derived from investigations practical advises are given about kind, strength and time of preparatory thinning for under planting and ongoing thinning. The nutrition potential of the soil substrate has to be considered. Furthermore, height growth and leave mass of under planted oaks are indicators for the forest treatment.