Showing papers on "Undergrowth published in 1967"

Electric constants measured in vegetation and in earth at five sites in thailand

Abstract: : Balanced two-conductor open transmission line probes were used to measure effective electric constants in vegetation and in the earth. Effective relative permittivity, and permeability in undergrowth at five dispersed sites were practically unity. Median effective conductivity of the undergrowth varied insignificantly between sites, but showed distinctive variation with frequency, from about 20 + or - 30% at 6 MHz to 300 + or - 30% (micro mho/m) at 100 MHz. In the few instances where measurements were made among mature trees the results were similar to those obtained for undergrowth. The most important parameters influencing vegetation constants were stem spacing (related to stem number density) and intrinsic stem conductivity (estimated to be between 0.05 and 0.5 mho/m). Ground-constant values varied greatly between sites, in a manner consistent with the variation of soil moisture content. Environmental forestry and soil surveys, summarized in the appendices to this report, are useful in explaining or applying the electric-constant results.

Wireworms (Elateridae) in the soils of Pineta of West Bielorussia

Abstract: Soils of various Pinetum types, of areas of burnt pine with birch undergrowth, and of birch forests were found to be characterized by different soil inhabiting wireworms. In stands with similar soil and plant growth conditions (e. g. moisture), wireworm populations were very similar, differing only in their population densities and in the ratio of the dominant species. In different Pineta (xero-, meso-, and hydrophytous types), different Elaterid species pre