The Turkey oak (Quercus cerris L.) is one of the least known species of trees of alien origin introduced to forests in Poland. Its natural geographical range embraces southern Europe and Asia Minor. It started to be grown on the Polish lands in 1813, planted primarily in parks and gardens, mostly in the western part of the country. On the basis of the present authors’ own field search, the literature, and unpublished data, it was possible to collect information about 22 places of occurrence of the Turkey oak in the woodland areas of Poland. A map of the distribution of this species is presented and the characteristics of its most extensive localities in forests are given. The oldest and most robust tree stands comprising Quercus cerris, planted in the fertile riverside habitats of the Oder river valley, have reached the age of 130-150 years. In those conditions the Turkey oak attains a height of 37 m and a breast-height diameter of up to 120 cm. Because of frequent frost damage and a low quality of trunks, it is of no productive significance in forestry. Even so, it is an interesting example of an alien oak species which, like the well-known Q. rubra, shows the ability to expand in a woodland environment.

The paper presents the results of vegetation studies of ecological lands “Bogdanka I” and “Bogdanka II”, located in the NW part of Poznań. The investigation was conducted during two growth seasons: 2012 and 2013. The vegetation of both ecological lands consists 69 plant communities, including 60 plant associations, belonging to 13 phytosociological classes. The syngenesis of most plant communities is natural (69.6%), mainly natural auxochoric (55.1%). The share of seminatural plant communities, mainly meadows, is 10.1%. From the anthropogenic plant communitities, there is more of xenospontaneous (13%), and less of segetal and ruderal (7.2%). The most natural character of plant communities is the feature of forest plant communities occurring in the river banks as well as littoral vegetation from Phragmitetea class. The most precious plant communities are Carici elogatae-Alnetum, Fraxino-Alnetum, Selino carvifoliae-Molinietum caerulae, Nasturtietum officinalis and Angelico-Cirsietum oleracei. The occurrence of 20 associations considered as threatened in Poland and 24 in the Wielkopolska region confirms high conservation values of the studied object.

The time within which, accordingly to its application, machine works, and an object of work and working groups are under load, is the effective active time. The purpose of the research was the order statistics of effective active time of limbing and conversion at chainsaw use in two technology and two habitat variants. The effective active time of limbing and conversion of one tree was most frequently from 0.5 s to 10.49 s in variant in which the limbing included tree crowns and only thicker branches cutting and the conversion included rods meant for chipping. The strong tree’s branching in fresh mixed coniferous forest had influence on the prolonged limbing time. The share of S_2a assortment in total volume of harvested wood had influence on the conversion time, besides the number of wood assortment cutting.

The paper presents an evaluation of health condition of selected oak stands in the Włoszakowice Forest Division based on a synthetic tree damage index. Field work was conducted in 2007-2008. In order to perform this task seven experimental sites were established, with 25 trees from Kraft’s age classes I-III evaluated in each. It was found that the overall health condition of most stands deteriorated in 2008 in comparison to 2007.