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Cechy biometryczne podrostów dębowych pochodzenia naturalnego rosnących pod osłoną drzewostanów sosnowych

100%
Zybura H., Pewniak B.
Sylwan
|
2017
|
tom 161
|
nr 06
The objectives of the study was to investigate and compare the characteristics of oak advance−growth of various age present under Scots pine canopy and growing on the mesic mixed coniferous (BMśw) or mesic mixed deciduous (LMśw) forest site types. The study was conducted in Kolumna Forest District (central Poland) in 21 Scots pine stands ca. 90 years of age, and with a well−developed oak advance−growth. The study sites were divided into 4 groups depending on the age of oak: 15, 20, 25 or 30−years−old. The empirical data concerned trees frequency (per unit area), average breast height diameter, height and basal area. The dependence of these characteristics on type of the main stand and advance−growth was then determined by statistical analysis. Above all, an attempt was made to determine the impact of forest site type conditions on the characteristics of oaks advance−growth. Results show that oaks are present at the density that makes the possibility of the advance−growth development into the stand real. Trees in the upper storey are found to exert a great influence on the silvicultural value of advance−growth trees. In particular, the density of trees in the main stand is a feature found to affect greatly the layer of oak advance−growth.
2
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Wykorzystanie dolnych warstw drzewostanu w planowaniu hodowlanym

100%
Zybura H., Pewniak B.
Sylwan
|
2016
|
tom 160
|
nr 10
Currently observed climate change creates favourable conditions for the development of not only deciduous species (oak and beech), but also some coniferous (e.g. fir). In the Scots pine stands growing on fertile forest site types one can observe the dynamic development of the under−canopy layers composed of those species. Oak or beech saplings are often characterized by good silvicultural value. Also silver fir creates a well−developed cover under Scots pine trees. Beech and fir as the most shade−tolerant tree species are able to handle the conditions under Scots pine. They can grow for a long time under the cover without damage to their height or diameter growth. Especially, a dynamic growth of oaks can often be observed on fresh mixed coniferous and fresh mixed broadleaved habitats. Oak layers in Scots pine stands are generally created in the way of natural regeneration with remarkable contribution of the jays, which spread the seeds even at considerable distances from the old trees. The corresponding intensity of thinnings supports to shape the proper silvicultural value of such under−canopy storeys. Observations on growth of such stand layers in the Scots pine stands in eastern and central Poland consider the desirability of including them in the next generation of stands. Their presence contributes to improvement of the biological stability of the stands, and also leads to increased productivity. By implementing to the forest practice the model of semi−natural silviculture, one wants to consider the possibility of using the saplings currently existing under the Scots pine as a component of the future stand. Knowledge about the silvicultural value and the impact on growth of lower layers will enable to develop the principles of proper cultivation of the multi−storey stands.
3
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Cechy jakościowe podrostów dębowych rosnących pod osłoną drzewostanów sosnowych

80%
Aleksandrowicz-Trzcinska M., Pewniak B., Zybura H.
Sylwan
|
2018
|
tom 162
|
nr 04
Scots pine stands in central Poland are now seen to be experiencing dynamic development of lower layers formed by oaks. The under−canopy natural renewal taking place in this way is sometimes characterised by good silvicultural quality, and could therefore be taken advantage of in the process of stand conversion. The study assess the quality of existing undergrowth layers of oak present in older stands of Scots pine, most especially from the point of view of their suitability for subjection to further silvicultural measures. The research material was collected in 10 objects where site type was classified as mesic mixed coniferous site type (BMśw) as well as in 11 ones with mesic mixed broadleaved forest (LMśw) site type. In each site type, 2 or 3 stands were selected to typify undergrowth layers aged 15, 20, 25 or 30 years. Assessment of oak undergrowth trees was made on the basis of 4−point scale in case of trunk or crown quality and vitality, and on a 3−point scale when vitality and the development trend were concerned. Next we selected the trees with future potential characterised by the highest quality from the point of view of all studied traits. A further determination concerned the influence on the traits in these best trees of the oak understorey that was exerted by biometric features of both the sheltering Scots pine stand and the undergrowth itself. The studied undergrowth oaks are of either very good or good quality. Around 90% of these young trees could be assigned to 1st or 2nd quality class with the respect of all of analysed traits. Furthermore, fertility of the site type was found not to have any influence on the quality of the young oaks. However, where the number of trees identified as having future potential is concerned, influence was demonstrated for density of trees in both stand and the undergrowth layer, as well as their height, breast−height diameter and basal area. Oaks forming the lower layer beneath Scots pine stands are thus characterised by good quality and growth trends, to the extent that this suggests allowing further growth to take place, with inclusion within the main stand or next generation.
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