in order to study the qualitative, quantitative characteristics of a pure common populus alba stand in polkalleh & a mixed stand of populus alba & populus nigra in karchegan, two 30-year-old stands were selected with a plantation interval ( spacing) of 2.5 × 1.5 m in each of which 30 pcs of 2 are samples were randomly selected. in each sample pc all the trees diameters were measured using a dia...

Current West Virginia coal mining regulations emphasize reforestation as a preferred postmining land use on surface mined areas. Some mined sites reclaimed to pasture are being converted to forests. In the spring of 2001, we compared the establishment and growth of five hardwood tree species on a reclaimed West Virginaia surface mine with compacted soils and a heavy grass groundcover. We plante...

neuromelanin (nm) pigment accumulates with age in catecholaminergic neurons in man, and the ventral substantia nigra dopaminergic neurons that are the most vulnerable to degeneration in parkinson's disease (pd) contain the greatest amount of this pigment. in vitro data indicate that nm pigment is formed from the excess cytosolic catecholamine that is not accumulated into synaptic vesicles via t...

Beetles (Scolytinae) form intimate associations with a taxonomically and functionally diverse suite of nematodes that are phytopathogens, fungal feeders, entomoparasites. Despite their ubiquity, the ecological significance in lifecycles economically important bark ambrosia beetle species (Curculionidae: Scolytinae) associated plant diseases remains largely unexplored. Thousand cankers disease (...

Thousand cankers disease (TCD) is a new disease of black walnut (Juglans nigra L.) in the eastern United States. The disease is caused by the interaction of the aggressive bark beetle Pityophthorus juglandis Blackman and the canker-forming fungus, Geosmithia morbida M. Kolarik, E. Freeland, C. Utley & Tisserat, carried by the beetle. Other insects also colonize TCD-symptomatic trees and may als...

Emerald ash borer (Agrilus planipennis Fairmaire) (Coleoptera: Buprestidae), an invasive phloem-feeding pest, was identified as the cause of widespread ash (Fraxinus) mortality in southeast Michigan and Windsor, Ontario, Canada, in 2002. A. planipennis reportedly colonizes other genera in its native range in Asia, including Ulmus L., Juglans L., and Pterocarya Kunth. Attacks on nonash species h...