plant diversityis essential to maintain the health of planet's ecosystems. conservation of biodiversity is necessary for the ecological stability and productivity in natural ecosystems. the aim of this research was to study the biodiversity and richness of plant species (including trees, shrubs and grasses) related to the environmental factors (soil and physiography) in the forests of zagros, w...

Ultraviolet resonance Raman spectroscopy has been used to characterize the polycyclic aromatic hydrocarbon composition of a series of distillates of coal-derived liquids. The UV Raman spectra easily monitor changes in the polycyclic aromatic hydrocarbon composition as a function of distillation temperature. Specific species, such as pyrene, can be determined by judicious choice of excitation wa...

Abstract The casks that have contained for a certain time Sherry wines are known as Casks ® and their use value increased in recent years, they confer unique organoleptic properties to the distillates beverages aged inside them. During seasoning, these yield compounds from wood into wines, at same time, retain some which, turn, transferred casks, so acts transfer vector between two alcoholic be...

Fires in mountain big sagebrush [Artemisia tridentata spp. vaseyana (Rydb.) Beetle] plant communities historically shifted dominance from woody to herbaceous vegetation. However, fire return intervals have lengthened with European settlement, and sagebrush dominance has increased at the expense of herbaceous vegetation in some plant communities. Management actions may be needed to decrease sage...

This paper evaluated the capacity of SPOT VEGETATION time-series to monitor herbaceous fuel moisture content (FMC) in order to improve fire risk assessment in the savanna ecosystem of Kruger National Park in South Africa. In situ herbaceous FMC data were used to assess the Normalized Difference Vegetation Index (NDVI), Normalized Difference Water Index (NDWI), Vegetation Dryness Index (VDI), Im...

Growth of herbaceous plants responds sensitively and rapidly to climate variability. Yet, little is known regarding how climate warming influences the growth of herbaceous plants, particularly in semi-arid sites. This contrasts with widely reported tree growth decline and even mortality in response to severe water deficits due to climate warming around the world. Here, we use the relatively nov...

The accurate determination of the preexisting ammonia or of the amide nitrogt.n of tobacco is rendered difficult by the volatility of nicotine which distils over more or less completely when the standard procedures for the estimation of these forms of nitrogen are employed. A number of attempts has been made to devise methods whereby corrections for the nicotine content of such distillates may ...

Western juniper (Juniperus occidentalis ssp. occidentalis Hook) encroachment into mountain big sagebrush (Artemisia tridentata spp. vaseyana (Rydb.) Beetle) steppe has reduced livestock forage production, increased erosion risk, and degraded sagebrush-associated wildlife habitat. Western juniper has been successfully controlled with partial cutting followed by prescribed burning the next fall, ...

Woody plant encroachment has degraded grassland and savanna ecosystems worldwide by decreasing herbaceous production and diversity, and altering these physiognomies toward woodlands. This study evaluated the long-term efficacy of fire and herbicide restoration strategies used in the southern Great Plains to reduce Honey mesquite (Prosopis glandulosa) dominance, restore a grassland/savanna physi...

Ecosystem responses to key climate drivers are reflected in phenological dynamics such as the timing and degree of "green-up" that integrate responses over spatial scales from individual plants to ecosystems. This integration is clearest in ecosystems dominated by a single species or life form, such as seasonally dynamic grasslands or more temporally constant evergreen forests. Yet many ecosyst...