Estimation of forest canopy cover has recently been included in many forest inventory programmes. In this study, after discussing how canopy cover is defined, different ground-based canopy cover estimation techniques are compared to determine which would be the most feasible for a large scale forest inventory. Canopy cover was estimated in 19 Scots pine or Norway spruce dominated plots using th...

We examined UV-B radiation flux and its environmental control within and among streams of northern Michigan. UV-B flux was estimated in streams by plastic dosimetry strips, which allow for the simultaneous and repeated in situ measurement of solar radiation. During the summer of 2004, UV-B flux was measured across depth gradients and along longitudinal transects in seven streams, which were cho...

Maintaining human thermal comfort (HTC) is essential for pedestrians because people outside can be more susceptible to heat stress and heat stroke. Modification of street microclimates using tree canopy cover can provide important benefits to pedestrians, but how beneficial and under what circumstances is not clear. On sunny summer days, microclimatic measures were made in residential streets w...

[1] Forest change is a major contributor to changes in carbon stocks and trace gas fluxes between terrestrial and atmospheric layers. This study compares two satellite estimates of percent tree distribution data sets over China. One estimate is from the Chinese National Land Cover Data Set (NLCD) generated by a multiyear national land cover project in China through visual interpretation of Land...

because soil moisture condition affects vegetation changes hence, monitoring of drought and vegetation changes are among valuable management tools in these ecosystems. nowadays, satellite images are used as a low-cost and fast method for vegetation study in different scales. vegetation change is assessed using vegetation spectral characteristics. this study aimed to analyze and monitor the vege...

Accurate estimates of forest canopy are essential for the characterization of forest ecosystems. Remotelysensed techniques provide a unique way to obtain estimates over spatially extensive areas, but their application is limited by the spectral and temporal resolution available from these systems, which is often not suited to meet regional or local objectives. The use of unmanned aerial vehicle...

forest reserves are one of the most important approaches in ecosystem management in iran. in order to determine the effects of reserve management on plants diversity (woody plants and ground flora) in three zones (core zone, buffer zone, and transmission zone of chamhesar pear forest reserve), we mapped land form units. then 18 main sampling units (20×50=1000 m2) distributed randomly were chose...

Tragacanth Gum is one of the most important medicinal and industrial productsof rangelands and is obtained from the incision of gum tragacanth-producing Astragalusincluding Astragalus keyserlingii. The conservation of Astragalus species in rangelandshas a special place in terms of economic profit and soil conservation. The increase in priceof gum tragacanth in recent years and more attention of...

Abandoned management has caused many sites with free-standing, large oaks (Quercus robur) to become more shaded. This study shows how forest regrowth affects beetle species associated with old oaks in south-eastern Sweden. Beetles were trapped by pitfall traps placed in hollows and window traps placed near hollows in oak trunks in pasture woodlands. We assessed the influence of forest regrowth,...