There are few data on fine root biomass and morphology change in relation to stand age. Based on chronosequences for beech (9-140 years old), oak (11-140 years) and alder (4-76 years old) we aimed to examine how stand age affects fine root biomass and morphology. Soil cores from depths of 0-15 cm and 16-30 cm were used for the study. In contrast to previously published studies that suggested th...

Many isoprenylated flavonoids have been isolated from Japanese mulberry tree (Moraceae). Among them, kuwanons G (1) and H (2) were the first isolated active substances exhibiting a hypotensive effect. These compounds are considered to be formed through an enzymatic Diels-Alder type reaction between an isoprenyl portion of an isoprenylphenol as the diene and an alpha, beta-double bond of chalcon...

Within-stand variation in understory species composition and biomass was studied in 16 even-aged stands of mixed Red Alder Sitka Spruce Western Hemlock (Alnus rubra Picea sitchensis Tsuga heterophylla) forest. The sites were upland sites, and the stands were 28-39 years old. We compared understory within three categories of microsite types: Red Alder-dominated, conifer-dominated, and mixed alde...

This study determined nitrification activity and nitrifier community composition in soils under stands of red alder (Alnus rubra) and Douglas fir (Pseudotsuga menziesii) at two sites in Oregon. The H.J. Andrews Experimental Forest, located in the Cascade Mountains of Oregon, has low net N mineralization and gross nitrification rates. Cascade Head Experimental Forest, in the Coast Range, has hig...

Monoculture causes nutrient losses and leads to declines in soil fertility and biomass production over successive cultivation. The rhizosphere, a zone of usually high microbial activities and clearly distinct from bulk soil, is defined as the volume of soil around living roots and influenced by root activities. Here we investigated enzyme activities and microbial biomass in the rhizosphere unde...

Analysing tree susceptibility to uprooting one has to compare external power acting on a tree with its resistance to uprooting (critical moment). The critical uprooting moment for a tree depends on both plant parameters and substratum. Results of an assessment of critical moments of studied pine and black alder tree stands are presented in this paper. Field studies consisted of uprooting trees ...

quantifying spatial structure is one of the most important components, describing natural ecosystems and their biodiversity. in this study, a set of indices and functions related to spatial structure using 102 established plots with an area of 1000 m2 were presented. to achieve spatial structure of carpinus-fagus type, a set of indices (clark & evans, uniform angle, shannon-wiener, mingling and...

Species-specific basic density (BD) data are necessary to improve the indirect methods of biomass determination. The tree components (e.g., bark, branches, roots) is studied much less than that stem wood. Nevertheless, ignoring specific BD values these in calculations can lead errors. study aims investigate variation aboveground and belowground by studying a total 162 gray alder (Alnus incana (...