Population parameters of brown hare (Lepus europaeus L.) in regions of the species highest density in Poland

The paper presents the selected indicators of hare populations in Poland. The material consisted of 528 hares acquired during traditional hunts. For each hunted hare we specified its weight, sex and age. All individuals were classified into two age groups: the first comprised juveniles (up to 12 months of age), while the other – adults (over 12 months). The ratio of young individuals in relation adults varies a lot (26−56%). The males to females ratio was approximately 1:1 with a slight advantage in favor of females. Reproductive rate was between 0.36 and 1.26, while reproductive success – 0.7−2.7. Average weight of hunted hares ranged between 3.42 and 4.32 kg. No significant differences in body weight were noticed within gender groups (Z=1.298, p>0.05, Mann−Whitney U test). However, they were found within the age groups (Z=–9.657, p <0.05, Mann−Whitney U test)

Occurrence of black cherry (Prunus serotina Ehrh.) in the State Forests in Poland

Among the invasive tree species identified in Polish forests, black cherry (Prunus serotina Ehrh.) appears to pose the greatest threat. The objective of this study was i), to determine the abundance of this species in the forests managed by the State Forests National Forest Holding (PGLLP) and ii), to characterise the ecological conditions that it is found in. The source data was obtained from the State Forests Information System (SILP) database. In Polish forests, black cherry mostly occurs as an understory plant and is present in a total area of 99,185 hectares, which is 1.4% of the forest area under the management of the PGLLP. Although Prunus serotina can be found within a wide range of habitats, it most commonly occurs on sites that can be considered average in terms of fertility (mixed coniferous and mixed deciduous types) developed primarily on rusty soils (podzols)

Age tables for silver birch (Betula pendula Roth) trees for early succession stands on abandoned agricultural lands

The paper presents the tables for indirect determination of the age of silver birch (Betula pendula Roth) trees basing on easy to measure dendrometric parameters. We elaborated empirical formulae that enable determination of tree age using total tree height, breast height diameter and stump diameter as the predictors. Data was collected in 40 pure silver birch stands growing on former farmlands in Mazowsze region (central Poland). Sample material consisted of data from the stem analyses of 200 trees and measurements of 600 stumps. Obtained equations explain 70−86% of the age variability. The best fit was achieved for joint use of total tree height and breast height diameter as the independent variables