Filters
How Do Pollen Grains of Convallaria majalis L. Respond to Different Habitat Conditions?
To date, the effect of habitat conditions on the characteristics of pollen has not been extensively investigated; however, it needs to be remembered that it may be highly significant for the quality of their generative reproduction success. It was decided to conduct the analyses on Convallaria majalis as a common species, naturally found in many different forest habitats. Moreover, the investigations covered pollen morphology and for the first time also the variability of pollen grains in this species. The plant material came from 98 natural sites located in Poland, in nine differing forest habitats. In total, 2940 pollen grains were analyzed in terms of five quantitative features (i.e., the length of the longest and shortest polar axes–LA and SA, exine thickness–Ex, the LA/SA and Ex/LA ratios) as well as the following qualitative ones: pollen outline and shape, sulcus type and exine ornamentation. Our studies revealed that the most important pollen characteristics in C. majalis included sulcus type, exine ornamentation, distribution and size of perforations, LA and pollen shape. The study showed the response of pollen to different habitat conditions found in the nine investigated habitats. The Ex/LA ratio and Ex were these pollen characteristics, which exhibited the most marked response to the different habitat conditions. Pollen from two habitats, moist mixed coniferous forest and upland mesic broadleaved forest, exhibited the most distinct characteristics.
The Impact of Road Investments on the Forest Environment - Case Study: The Impact of Asphalt Roads on the Health Condition and Growth of Trees
The study was conducted within the framework of the R&D project entitled “Environmental aspects of reconstruction and construction of forest roads using selected asphalt binders”. The aim of this study was to determine the impact of an asphalt road segment located in the Przymuszewo Forest District, the Regional Directorate of the State Forests in Toruń, Poland (53°57′24.14″ N, 17°34′38.30″ E), on growth increments and health condition of trees in a 60-year-old pine stand. The first stage of the investigation required laboratory analyses and field observations to assess the impact of mineral filler and asphalt mixtures on roadside habitats. Chemical analyses were performed on samples of wood and soil collected from transects located at three distances from the asphalt road, as well as dendrological and dendrometric analyses in circular sample plots of 0.02 ha in analogous transects parallel to the selected asphalt pavement. Analyses of soils and wood showed no negative environmental impact associated with the road. Contents of all the assayed elements in wood were lower compared to their contents in soil, which indicates their markedly reduced phytoextraction. Statistical analyses showed that the asphalt road has an effect on the adjacent forest mass, but that this effect is statistically insignificant with respect to the mean annual increments diameter at breast height and the defoliation of trees growing at various distances from the road.