EJPAU, 2005, Volume 8, Issue 4
Forestry

The paper presents results of measurements of horizontal shearing of soil, made by the help of wheel bevameter on four types of forest sites, i.e. fresh mixed coniferous forest (fMCF), boggy mixed pine forest (bMPF), moist mixed broadleaved forest (mMBF) and moist broadleaved forest (mBF), with consideration of different moisture variants. On the basis of obtained data two relationships were determined: between soil horizontal deformation and the circumferential (driving) force as well as between slip and the coefficient of adhesion. Grouping of the investigated soil according to their shearing stresses was made by Ward’s method of agglomerative cluster analysis. For each of the obtained agglomeration new data of slip vs. coefficient of adhesion were calculated.

The productivity of grand fir (Abies grandis Lindl.) was estimated under mountain conditions of Poland. Investigations concerned 7 provenances of this species from the regions of its natural range (Salmon River, Indian Creek, Buck Creek, Bear Mountain, Eagle Creek, Crescent Creek, Santiam Summit). It was found that provenance (origin) has a decisive effect on the productivity of grand fir. The results of a 27-year study on its genetic and silvicultural values unmistakably indicate that under site conditions of the Beskid Sšdecki Mts. the provenances from the Salmon River, Indian Creek, Buck Creek and Bear Mountain are characterized by a better growth. The provenance Salmon River from the Vancouver Island in British Columbia in Canada turned out to be especially valuable in respect of productivity. Its stand volume reached 143 (m³ ha). While the provenances Crescent Creek and Santiam Summit reached the smallest volume, 41.5 and 77.0 (m³ ha) respectively.

The purpose of the performed experiments was to determine the time consumption of the removal of single Scots pine branches in relation to their thickness, vitality and height of pruning. Branches were cut with the assistance of special handsaws of the ARS and Buchman type. These saws are characterised by the highest efficiency from all the applied saws which have been subjected to investigations so far. Trees were pruned to the height of 5 meters along consecutive 1 meter-long segments. The test comprised 50 branches for each 1 m long section of the trunk. Measurements comprised the thickness of branches as well as the time needed to remove them.

Research on the growth of the introduced giant fir (Abies grandis Lindl.) on a forest farm in the mountains (Myslenice Forest District, the Beskid Sredni Mts, The Western Carpathian Mts) has indicated the productive, protective and utility capabilities of this fast-growing species.

Organic matter from ectohumus horizons of soils under Norway spruce stands may be divided into two parts: (1) able to absorb such an amount of water that its weight by volume together with absorbed water is over 1 Mg·m^-3, and (2) unable to attain such absorption. In the litter horizon (Ol) and fermentation horizon (Of) the mean time of water absorption by organic matter, able to attain its assumed level, depended on the development phase of a Norway spruce stand. Organic matter taken from soils under stands of age classes I and II turned out to have the best water absorption properties. The assumed water absorption was attained by organic matter in the shortest time in the following cases: in the litter horizon (Ol) from under the 35-year-old stand, in the fermentation horizon (Of) from under the 14-year-old stand, and in the humification horizon (Oh) from under the 21-year-old stand. Ranges of the mean time of water absorption were: for the litter horizon (Ol) from 1.66 to 4.14 days, for the fermentation horizon (Of) from 0.79 to 3.12 days, and for the humification horizon (Oh) from 0.63 to 1.19 days. The relationship between the percentage of organic particles, unable to attain the assumed water absorption, and the stand age in the litter horizon (Ol) was similar to that of the fermentation horizon (Of). The matter taken from the youngest stands, i.e. 14-28 years of age, was characterized by the smallest amount of organic particles unable to attain the assumed water absorption. The amount of these particles expressed in per cent of sample’s total weight was: in the litter horizon (Ol) from 1.55 to 16.16%, in the fermentation horizon (Of) from 5.72 to 26.50%, and in the humification horizon (Oh) from 0.27 to 3.36%. Water properties of organic matter in the litter (Ol) and fermentation (Of) horizons were significantly correlated with the index of the degree of decomposition expressed by the ratio between nitrogen and carbon – (N/C) 1000. No such relationship was found in the humification horizon. This study is of a practical importance for forest hydrology.

The performed investigations aimed at determining the proportion of juvenile, maturing (transitory) and mature wood in the radial cross section of pine stems derived from the maturing stands of the II, III and IV age classes. The experiments comprised spruce trees from the areas of the southern distribution range of this tree species in Poland. The division into juvenile, maturing and mature wood was based on the proportion of late wood in annual rings.

Regularity was found to occur in the examined experimental material which consisted in the inversed proportionality of the width of annual rings and the proportion of late wood. In the case of older trees, the plotted curves describing the width of annual rings constituted nearly a mirror reflection of the curve characterising the proportion of late wood in the annual increments of trees for thickness. Results obtained for the radial cross sections of the youngest tree trunks (II age class) deviated quite distinctly from the above-mentioned principle.