Showing papers on "Undergrowth published in 1990"

Mean canopy flow in an oak forest and estimation of the foliage profile by a numerical model

Abstract: The interaction of flow with the canopy structure is shown for an oak forest with hornbean trees (Carpinus betulus) as dense undergrowth using a large sample of 15 min mean profiles for the winter (without leaves) and the summer period (with leaves). The usefulness of the canopy flow index is analysed.

Recultivation of Phytotoxic Miocene Sands

Abstract: The aim of the present investigations was to determine the reasons of poor results of post-mine land (Łeknica on the Nysa Łuzycka) reclamation by means of forest planting. Miocene sands containing pyrite FeS2 constitute soil formative rock of post-mine dumps. H2SO4, which strongly acidifies the soil, is formed as a result of pyrite oxidation. Big doses of lime used for deacidification improved pH, but pine trees were still growing poorly or died out at all, thogh doses of NPK were used as in normal practice. Experiments carried out in 1986 – 1989 of additional fertilization proved that the main reason of poor land reclamation was the insufficiency of nitrogen which could be assimilated by plants. The dose of 100 kg N/ha. in the form of ammonium nitrate improved the pine growth radically and resulted in a very quick undergrowth between the rows and that in turn stopped the previous intensive erosion.