Understanding the effects of elevation and related factors(climate,vegetation) on the physical and chemical soil properties can help to predict changes in response to future climate or afforestation forcings.This work...Understanding the effects of elevation and related factors(climate,vegetation) on the physical and chemical soil properties can help to predict changes in response to future climate or afforestation forcings.This work aims to contribute to the knowledge of soil evolution and the classification of forest soils in relation to elevation in the montane stage,with special attention to podzolization and humus forms.The northern flank of the Moncayo Massif(Iberian Range,SW Europe) provides a unique opportunity to study a forest soils catena within a consistent quartzitic parent material over a relatively steep elevation gradient.With increasing elevation,pH,base saturation,exchangeable potassium,and fine silt-sized particles decrease significantly,while organic matter,the C/N ratio,soil aggregate stability,water repellency and coarse sand-sized particles increase significantly.The soil profiles shared a set of properties in all horizons:loamy-skeletal particle-size,extreme acidity(pH-H_2O<5.6) and low base saturation(<50%).The most prevalent soil forming processes in the catena include topsoil organic matter accumulation and even podzolization,which increases with elevation.From the upper to lower landscape positions of wooded montane stage of the Moncayo Massif,mull-moder-mor humus and an UmbrisolCambisol-Podzol soil unit sequences were found.展开更多
Invasions by exotic insects and diseases are one of the most important threats to the stability and productivity of forest ecosystems around the world. Lymantria dispar （Lepidoptera： Lymantriidae） in Iran was obser...Invasions by exotic insects and diseases are one of the most important threats to the stability and productivity of forest ecosystems around the world. Lymantria dispar （Lepidoptera： Lymantriidae） in Iran was observed for the first time in 1937 by Jalal Afshar in oak forests of the Guilan state region. Since its introduction, gypsy moth has spread to the northern, western and south-western regions of Iran. The largest outbreaks of gypsy moth occurred in the Talesh Oak forests of the Hyrcanian zone in 1975. The gypsy moth is a highly polyphagous folivore species that feeds on over 300 species of woody plants. Among its most preferred hosts are oaks and aspens. Some trees are resistant to the gypsy moth including honey locust, black locust, silver maple, green ash, dogwood, sycamore, horse chestnut, firs, and tulip trees. Defoliation during severe outbreaks alters the appearance of forest habitats and leads to tree mortality and changes in stand composition. This study was conducted during 2008 and 2009 in an effort to determine the primary host tree species that the gypsy moth infests in the Hyrcanian forests of lran. For that purpose all egg masses in the area were counted and conclusively significant differences in defoliation levels among tree species were found. The primary host tree species of gypsy moth in Iran was Persian ironweed, Parrotia persica.展开更多
基金supported by project CGL2013-43440-R,funded by the Ministerio de Economiay Competitividad of Spain
文摘Understanding the effects of elevation and related factors(climate,vegetation) on the physical and chemical soil properties can help to predict changes in response to future climate or afforestation forcings.This work aims to contribute to the knowledge of soil evolution and the classification of forest soils in relation to elevation in the montane stage,with special attention to podzolization and humus forms.The northern flank of the Moncayo Massif(Iberian Range,SW Europe) provides a unique opportunity to study a forest soils catena within a consistent quartzitic parent material over a relatively steep elevation gradient.With increasing elevation,pH,base saturation,exchangeable potassium,and fine silt-sized particles decrease significantly,while organic matter,the C/N ratio,soil aggregate stability,water repellency and coarse sand-sized particles increase significantly.The soil profiles shared a set of properties in all horizons:loamy-skeletal particle-size,extreme acidity(pH-H_2O<5.6) and low base saturation(<50%).The most prevalent soil forming processes in the catena include topsoil organic matter accumulation and even podzolization,which increases with elevation.From the upper to lower landscape positions of wooded montane stage of the Moncayo Massif,mull-moder-mor humus and an UmbrisolCambisol-Podzol soil unit sequences were found.
文摘Invasions by exotic insects and diseases are one of the most important threats to the stability and productivity of forest ecosystems around the world. Lymantria dispar （Lepidoptera： Lymantriidae） in Iran was observed for the first time in 1937 by Jalal Afshar in oak forests of the Guilan state region. Since its introduction, gypsy moth has spread to the northern, western and south-western regions of Iran. The largest outbreaks of gypsy moth occurred in the Talesh Oak forests of the Hyrcanian zone in 1975. The gypsy moth is a highly polyphagous folivore species that feeds on over 300 species of woody plants. Among its most preferred hosts are oaks and aspens. Some trees are resistant to the gypsy moth including honey locust, black locust, silver maple, green ash, dogwood, sycamore, horse chestnut, firs, and tulip trees. Defoliation during severe outbreaks alters the appearance of forest habitats and leads to tree mortality and changes in stand composition. This study was conducted during 2008 and 2009 in an effort to determine the primary host tree species that the gypsy moth infests in the Hyrcanian forests of lran. For that purpose all egg masses in the area were counted and conclusively significant differences in defoliation levels among tree species were found. The primary host tree species of gypsy moth in Iran was Persian ironweed, Parrotia persica.
