The aim of this study was to analyse changes in the health status of ash stands belonging to the age classes VI and VIII growing in optimal site conditions and to compare the ash dieback with other age classes in the Jesionowe Góry Nature Reserve. Our research was conducted during the growing season in 2006 and 2007 on 22 permanent and 54 temporary sample plots. The health condition of the stands and the structure of natural regeneration were determined with a one-year interval. The amount of damage was defined using leaf loss, pest infestation and shoot dieback. Based on our estimation of natural regeneration, the capability for stand evolution in the future was determined.
The aim of this study was to determine how thermal conditions affect the speed of sound wave propagation, in trunks of living alder Alnus glutinosa (L.) Gaertn. trees. This method in practiced when diagnosing the presence of intern.al decay in standing trees. Field work was carried out four times at different temperatures (+13°C, +3°C, -7°C and -16°C) using an lmpulse Hammer. There was a significant correlation between the thermal conditions and the speed of sound wave propagation. Therefore, temperature must be taken into account to correctly diagnose tree health and timber quality.
Contemporary models of light conditions on the forest floor can be divided into two categories: undercanopy models that allow the light conditions in a stand under the canopy to be simulated, and models that take into account shielding from the side. Under-canopy models precisely estimate the availability of wavelengths of light spatially distributed under the canopy of stands: however, these models require a large amount of data on the spatial structure of forest stands. The other class of models describe the light conditions on a particular open surface. These incorporate shielding from the side and are easier to use as they require less data than under-canopy models. In practice, in forest conditions, such models require data on the size, shape and geographical location of surveyed surfaces (e.g. gaps and cut areas) and on the height of the surrounding stand. Often, these data are available in databases, such as the State Forest Information System (SKP), orcan otherwise be obtained relatively easily (and inexpensively). Compared to under-canopy models, these models provide a cheap way to obtain useful information on variation in the light environment that affects the microclimate for regenerating plants on clearcuts and canopy gaps.