The role of ectomycorrhizal (EM) fungi in forest soil function and tree productivity has become an increasingly important topic for research in light of possible direct large-scale degradation of EM populations in the forests of Europe (Arnolds, 1991). Although there is a rapidly growing body of information being assembled from laboratory studies using pure culture syntheses, there is relativel...

Nitrogen (N) enrichment of tropical ecosystems is likely to increase with rapid industrial and agricultural development, but the ecological consequences of N additions in these systems are not well understood. We measured soil Noxide emissions and N transformations in primary rain forest ecosystems at four elevations and across two substrate types on Mt. Kinabalu, Borneo, before and after short...

Estimates of forest net primary production (NPP) demand accurate estimates of root production and turnover. We assessed root turnover with the use of an isotope tracer in two forest free-air carbon dioxide enrichment experiments. Growth at elevated carbon dioxide did not accelerate root turnover in either the pine or the hardwood forest. Turnover of fine root carbon varied from 1.2 to 9 years, ...

Declining forest health has been observed during the past several decades in several areas of the eastern USA, and some of this decline is attributed to acid deposition. Decreases in soil pH and increases in soil acidity are indicators of potential impacts on tree growth due to acid inputs and Al toxicity. The Cherry River watershed, which lies within the Monongahela National Forest in West Vir...

Quantitative knowledge of stabilizationand decomposition processes is necessary to understand, assess and predict effects of land use changes on storage and stability of soil organic carbon (soil C) in the tropics. Although it is well documented that different soil types have different soil C stocks, it is presently unknown how different soil types affect the stability of recently formed soil C...

Tropical pastures present multiple barriers to tree regeneration and restoration. Relict trees serve as "regeneration foci" because they ameliorate the soil microclimate and serve as safe spots for dispersers. Here, we describe another mechanism by which remnant trees may facilitate pasture regeneration: the presence of seed banks in the canopy soil that accumulates from decomposing epiphytes w...

the C/N ratio is used to characterize living and dead organic matter. The total C accumulated in biomass is Increasing atmospheric CO2 concentrations, and widespread deposition of N to terrestrial ecosystems has increased the focus on soil generally limited by the availability of N. Forest trees C and N pools. The aim of this study was to estimate the size and are often adapted to N limited con...

Nearly 8 million dry tons (7 256 000 t) of municipal sewage sludge are produced each year in the USA by the more than 15 000 publicly owned treatment plants and the tonnage is increasing. Municipalities are faced with increasing cost of incineration, decreasing land for and increasing costs of landfills, and environmental concerns over ocean dumping. Under the circumstances, the attractiveness ...

Depth profiles potassium and its isotope ratio (K/K) were investigated in several forest soils from different geological and climatic backgrounds. The ratio was found not to be constant (0.0117 %) but varied appreciably from 0.0085 to 0.0167 % among different soils. Possible factors affecting variability of K/K values were considered by a multivariate factor analysis which suggested that aqueou...

The aim of this work is to model the occurrence and intensity of calcium carbonate loss in calcareous forest soils under Mediterranean conditions. We have used 193 Spanish forest soils found on limestone parent material considered highly calcareous materials. This data set came from FOREDAF, a database containing 2200 complete soil profiles and all of them covered by forest stands (mainly domin...