After the Second World War of the past century in Italy extended plantations were carried out. In Southern Italy the Calabrian pine (Pinus laricio Poiret) has been the most used species, for its ability to take root...After the Second World War of the past century in Italy extended plantations were carried out. In Southern Italy the Calabrian pine (Pinus laricio Poiret) has been the most used species, for its ability to take root in many difficult conditions. Currently the extension of this vegetation is about 36,000 hectares, in great part established in Calabria. They have reduced hydrogeological risks, they have carried out an important social role and have improved the landscape and the environment of huge hill and mountain territories. After the realization of these stands, no forest management has been made in order to define purposes and silvicultural operations. All stands are currently vulnerable in order to abiotic (fire, breakages) and biotic (Traumatocampa (--- Thaumetopoea) pityocampa (Denis & Schiff.) and Heterobasidion annosum (Fr.) Bref.) agents. For the future, the silvicultural management of these stands will not be able to avoid planning choices, in order to improve the structural stability and the bioecological functionality and to consider the recent opportunities offered from the agroenergetic field.展开更多
The ecotone, the spatial transition zone between two vegetation communities, is claimed to have more species than the adjoining communities. However, empirical studies do not always confirm higher richness at the ecot...The ecotone, the spatial transition zone between two vegetation communities, is claimed to have more species than the adjoining communities. However, empirical studies do not always confirm higher richness at the ecotone. The ecotone position and structure are dynamic over time and space and it is driven by the changes in climate, land use or their interaction. In this context, we assessed the forest- grassland ecotone of temperate mountains in central Nepal by i) comparing species composition and richness across the ecotone, ii) analyzing if the forestgrassland ecotone is shifting towards the grassland center by colonizing them with trees, and iii) discussing the consequence of changed disturbance regime in the dynamics of this ecotone and the surrounding grasslands. We analyzed vegetation data sampled from belt transects laid across the forest- grassland ecotone in semi-natural grassland patches. Vegetation data consisting of species richness and composition, and size structure and regeneration of the two most dominant tree species, namely Rhododendron arboreum and Abies spectabilis, from the transects, were used to analyze the trend of the forest-grassland ecotone. Forest and grasslands were different in terms of floristic composition and diversity. Vascular plant speciesrichness linearly increased while moving from forest interior to grassland center. Spatial pattern of tree size structure and regeneration infers that forest boundary is advancing towards the grasslands at the expense of the grassland area, and tree establishment in the grasslands is part of a suceessional process. Temporally, tree establishment in grasslands started following the gradual decline in disturbance. We argue that local processes in terms of changed land use may best explain the phenomenon of ecotone shift and consequent forest expansion in these grasslands. We underpin the need for further research on the mechanism, rate and spatial extent of ecotone shift by using advaneed tools to understand the process indepth.展开更多
Twenty-two cases of scoliosis with Harrington-rods broken after operation were treated by rod-sleevemethod. The results of follow-up from 1 year and 3 months to 9 years and 3 months showed that all of thepatients, but...Twenty-two cases of scoliosis with Harrington-rods broken after operation were treated by rod-sleevemethod. The results of follow-up from 1 year and 3 months to 9 years and 3 months showed that all of thepatients, but one patient occurred Harrington-rod rebroken and one’s fixation being removed because ofback pain in 6 months and 5 years and 11 months after rod-sleeve prpcedure, respectively, had no com-plaints. The author also found that the rod underwent a decrease in cross-sectional area of approximately43. 7 % at the ratchet-shaft junction in experimental study on Harrington-rods, and stress unfairly distribu-tion, stress concentration and cyclic loading producing fatigue in metals were proved to be the main cause ofbroken by mechanical analysis of Harrington-rod loaded in the body. In concluson, the rod-sleeve proce-dure was the effective method to keep from, Ha rrington - reds broken.展开更多
文摘After the Second World War of the past century in Italy extended plantations were carried out. In Southern Italy the Calabrian pine (Pinus laricio Poiret) has been the most used species, for its ability to take root in many difficult conditions. Currently the extension of this vegetation is about 36,000 hectares, in great part established in Calabria. They have reduced hydrogeological risks, they have carried out an important social role and have improved the landscape and the environment of huge hill and mountain territories. After the realization of these stands, no forest management has been made in order to define purposes and silvicultural operations. All stands are currently vulnerable in order to abiotic (fire, breakages) and biotic (Traumatocampa (--- Thaumetopoea) pityocampa (Denis & Schiff.) and Heterobasidion annosum (Fr.) Bref.) agents. For the future, the silvicultural management of these stands will not be able to avoid planning choices, in order to improve the structural stability and the bioecological functionality and to consider the recent opportunities offered from the agroenergetic field.
基金financial support from the NOrad's Program for MAsters Studies (NOMA) at Central Department of Botany, Tribhuvan University, Kathmandu, Nepalfunded by the Norwegian Research Council (190153/V10)Grolle Olsens Legat
文摘The ecotone, the spatial transition zone between two vegetation communities, is claimed to have more species than the adjoining communities. However, empirical studies do not always confirm higher richness at the ecotone. The ecotone position and structure are dynamic over time and space and it is driven by the changes in climate, land use or their interaction. In this context, we assessed the forest- grassland ecotone of temperate mountains in central Nepal by i) comparing species composition and richness across the ecotone, ii) analyzing if the forestgrassland ecotone is shifting towards the grassland center by colonizing them with trees, and iii) discussing the consequence of changed disturbance regime in the dynamics of this ecotone and the surrounding grasslands. We analyzed vegetation data sampled from belt transects laid across the forest- grassland ecotone in semi-natural grassland patches. Vegetation data consisting of species richness and composition, and size structure and regeneration of the two most dominant tree species, namely Rhododendron arboreum and Abies spectabilis, from the transects, were used to analyze the trend of the forest-grassland ecotone. Forest and grasslands were different in terms of floristic composition and diversity. Vascular plant speciesrichness linearly increased while moving from forest interior to grassland center. Spatial pattern of tree size structure and regeneration infers that forest boundary is advancing towards the grasslands at the expense of the grassland area, and tree establishment in the grasslands is part of a suceessional process. Temporally, tree establishment in grasslands started following the gradual decline in disturbance. We argue that local processes in terms of changed land use may best explain the phenomenon of ecotone shift and consequent forest expansion in these grasslands. We underpin the need for further research on the mechanism, rate and spatial extent of ecotone shift by using advaneed tools to understand the process indepth.
文摘Twenty-two cases of scoliosis with Harrington-rods broken after operation were treated by rod-sleevemethod. The results of follow-up from 1 year and 3 months to 9 years and 3 months showed that all of thepatients, but one patient occurred Harrington-rod rebroken and one’s fixation being removed because ofback pain in 6 months and 5 years and 11 months after rod-sleeve prpcedure, respectively, had no com-plaints. The author also found that the rod underwent a decrease in cross-sectional area of approximately43. 7 % at the ratchet-shaft junction in experimental study on Harrington-rods, and stress unfairly distribu-tion, stress concentration and cyclic loading producing fatigue in metals were proved to be the main cause ofbroken by mechanical analysis of Harrington-rod loaded in the body. In concluson, the rod-sleeve proce-dure was the effective method to keep from, Ha rrington - reds broken.