the damages due to dwarf mistletoes to the industrial forests encouraged the scientists to evaluate the infection intensity and illustrate the spatial distribution of mistletoes for forest management, wild life and biodiversity conservation. there are two current systems to evaluate infection intensity wich are easier, cheaper, more efficient and authoritative than others in all over the world,...

Brachionus is an suitable live foods for fishes larve of Brachionidae family, in the present study inter and interapopulation variations of two species of family Brachionidae were investigated. For this purpose 90 individuals of geographical populations of these species were collected from different parts of Arak country and for each habitat five ecological factors were examined. Totally eleven...

A field study was conducted over 2 yr to determine the effects of transgenic sweet corn containing a gene from the bacterium Bacillus thuringiensis (Bt) on the diversity and abundance of nontarget arthropods. The Bt hybrid (expressing Cry1Ab endotoxin for lepidopteran control) was compared with near-isogenic non-Bt and Bt hybrids treated with a foliar insecticide and with a near-isogenic non-Bt...

1. A principal bundle 33(X, G) with base space X and group G is called "locally flat" if the structural group G can be reduced to a totally disconnected subgroup GiCG, or in other words: if there exists a totally disconnected subgroup GiQG, a principal bundle 33i(X, Gi) and an injection j: Soi—>33 [l ]. For instance, if a differentiable bundle 33 admits an infinitesimal connection whose curvatu...

this research was conducted to investigate spatial variability and estimate tree attributes in a plantation forest in the caspian region of iran using geostatistical analysis. sampling was performed based on a 50m?125m systematic grid in a maple stand (acer velutinum boiss) 18 years of age using circular samples of 200m2 area. totally, 96 sample plots were measured in 63 hectares and 14.25 hect...

Weibull distribution was used to fit tree diameter data collected from 86 sample plots located in Chinese pine stand in Beijing. To estimate the Weibull distribution parameters, three methods [namely maximum likelihood estimation method (MLE), method of moment (MOM) and least-squares regression method (LSM)] were compared and evaluated on the basis of the mean square error (MSE) and sample size...

Losses of plant species diversity can affect ecosystem functioning, with decreased primary productivity being the most frequently reported effect in experimental plant assemblages, including tree plantations. Less is known about the role of biodiversity in natural ecosystems, including forests, despite their importance for global biogeochemical cycling and climate. In general, experimental mani...