On 18 January 2017 a catastrophic avalanche destroyed the Rigopiano Gran Sasso Resort&Wellness(Rigopiano Hotel)in the Gran Sasso National Park in Italy,with 40 people trapped and a death toll of 29.This article de...On 18 January 2017 a catastrophic avalanche destroyed the Rigopiano Gran Sasso Resort&Wellness(Rigopiano Hotel)in the Gran Sasso National Park in Italy,with 40 people trapped and a death toll of 29.This article describes the location of the disaster and the general meteorological scenario,with field investigations to provide insight on the avalanche dynamics and its interaction with the hotel buildings.The data gathered in situ suggest that the avalanche was a fluidized dry snow avalanche,which entrained a sligthtly warmer snow cover along the path and reached extremely long runout distances with braking effect from mountain forests.The avalanche that reached the Rigopiano area was a‘‘wood-snow’’avalanche—a mixture of snow and uprooted and crushed trees,rocks,and other debris.There were no direct eyewitnesses at the event,and a quick post-event survey used a numerical model to analyze the dynamics of the event to estimate the pressure,velocity,and direction of the natural flow and the causes for the destruction of the hotel.Considering the magnitude and the damage caused by the event,the avalanche was at a high to very high intensity scale.展开更多
Compared with the undamaged Phyllostachys edulis,the wood mechanical properties of bended bamboo for 4-year-old by frost and snow were studied. It was shown that the wood mechanical properties of bended Phyllostachys ...Compared with the undamaged Phyllostachys edulis,the wood mechanical properties of bended bamboo for 4-year-old by frost and snow were studied. It was shown that the wood mechanical properties of bended Phyllostachys edulis were equivalent to or a little less than those of the undamaged bamboo. The bending strength(MOR) of moderately bended bamboo and the modulus of elasticity in static bending(MOE) of heavily bended bamboo were 125.8 MPa and 10 978.9 MPa respectively in the culm base,and compared with those of undamaged Phyllostachys edulis wood,the differences were significant. However,the other mechanical properties including tensile strength parallel to grain,compressive strength parallel to grain and shearing strength parallel to grain etc. Between bended and undamaged bamboo wood,the difference were not significant. The study results could provide data supports for the proper ways of rational cutting,process and utilization of bended Phyllostachys edulis wood.展开更多
An abrupt ice and snow storm disaster which occurred in the spring of 2008 severely destroyed forests over a surprisingly large portion of southern China. A transect crossing Jinggang Mountain-Jitai Basin-Yushan Mount...An abrupt ice and snow storm disaster which occurred in the spring of 2008 severely destroyed forests over a surprisingly large portion of southern China. A transect crossing Jinggang Mountain-Jitai Basin-Yushan Mountain-Wuyi Mountain was selected as the study area. The authors integrated field data collected in two field surveys to analyze the impacts of the disturbance on forests. The following results were obtained. （1） The extent of damage to plantations along the transect decreased in the order of slash pine 〉 masson pine 〉 mixed plantation 〉 Chinese fir. Slash pine is an introduced species from southern America which is characterized by fast growth, low wood quality and rich oleoresin, and showed a damage rate of 61.3% of samples, of which 70.4% cannot recover naturally. Masson pine is the native pioneer species of forests with harder wood, and 52.5% were damaged due to turpentine, of which 60.9% cannot recovery naturally. Chinese fir is a local tree species and samples showed a rate of 46% and a relative rate of 32.5%, lower than the mixed plantation. （2） From west to east along the transect, we can see that evergreen broad-leaved forest of the western transect on Jinggang Mountain showed the lightest damage extent, and a Cryptomeria plantation at an altitude of 700 m was severely destroyed while Chinese fir showed light damage below 700 m and relatively severe damage above 900 m. Masson pine and slash pine in the central transect in Jitai Basin were damaged severely due to turpentine activities, and closed natural secondary deciduous broad-leaved forest was damaged severely due to high ice and snow accumulation on intertwined shrubs. Masson pine aerial-seeding plantations below 400 m along the eastern transect in Xingguo and Ningdu counties were nearly undamaged for small tree sizes, and Chinese fir at 500-900 m altitude showed a lighter damage extent. However, masson pine which was distributed above 400 m and planted in the 1960s, was severely damaged due to turpentine.展开更多
文摘On 18 January 2017 a catastrophic avalanche destroyed the Rigopiano Gran Sasso Resort&Wellness(Rigopiano Hotel)in the Gran Sasso National Park in Italy,with 40 people trapped and a death toll of 29.This article describes the location of the disaster and the general meteorological scenario,with field investigations to provide insight on the avalanche dynamics and its interaction with the hotel buildings.The data gathered in situ suggest that the avalanche was a fluidized dry snow avalanche,which entrained a sligthtly warmer snow cover along the path and reached extremely long runout distances with braking effect from mountain forests.The avalanche that reached the Rigopiano area was a‘‘wood-snow’’avalanche—a mixture of snow and uprooted and crushed trees,rocks,and other debris.There were no direct eyewitnesses at the event,and a quick post-event survey used a numerical model to analyze the dynamics of the event to estimate the pressure,velocity,and direction of the natural flow and the causes for the destruction of the hotel.Considering the magnitude and the damage caused by the event,the avalanche was at a high to very high intensity scale.
文摘Compared with the undamaged Phyllostachys edulis,the wood mechanical properties of bended bamboo for 4-year-old by frost and snow were studied. It was shown that the wood mechanical properties of bended Phyllostachys edulis were equivalent to or a little less than those of the undamaged bamboo. The bending strength(MOR) of moderately bended bamboo and the modulus of elasticity in static bending(MOE) of heavily bended bamboo were 125.8 MPa and 10 978.9 MPa respectively in the culm base,and compared with those of undamaged Phyllostachys edulis wood,the differences were significant. However,the other mechanical properties including tensile strength parallel to grain,compressive strength parallel to grain and shearing strength parallel to grain etc. Between bended and undamaged bamboo wood,the difference were not significant. The study results could provide data supports for the proper ways of rational cutting,process and utilization of bended Phyllostachys edulis wood.
基金National Natural Science Foundation of China, No.40971281 International Science and Technology Cooperative Program of China, No.2006DFB91920 National Key Project of Scientific and Technical Supporting Programs, No.2006BAC08B00 Acknowledgments We express our thanks to Mr. Fan Zhewen, who is the director of the Remote Sensing Center of Jiangxi province, and Mr. Qiu Zuozhen, who is the director of the Mountain-River-Lake Office of Ji＇an City, for their help in the field investigation, and Prof. Wang Hongqing for logistic support. We also gratefully acknowledge the local governments of Jinggangshan City, Taihe County, Xingguo County and Ningdu County, especially Mr. Tang Xiongjie and Ms. He Qingping, for facilitating the field survey and data collection.
文摘An abrupt ice and snow storm disaster which occurred in the spring of 2008 severely destroyed forests over a surprisingly large portion of southern China. A transect crossing Jinggang Mountain-Jitai Basin-Yushan Mountain-Wuyi Mountain was selected as the study area. The authors integrated field data collected in two field surveys to analyze the impacts of the disturbance on forests. The following results were obtained. （1） The extent of damage to plantations along the transect decreased in the order of slash pine 〉 masson pine 〉 mixed plantation 〉 Chinese fir. Slash pine is an introduced species from southern America which is characterized by fast growth, low wood quality and rich oleoresin, and showed a damage rate of 61.3% of samples, of which 70.4% cannot recover naturally. Masson pine is the native pioneer species of forests with harder wood, and 52.5% were damaged due to turpentine, of which 60.9% cannot recovery naturally. Chinese fir is a local tree species and samples showed a rate of 46% and a relative rate of 32.5%, lower than the mixed plantation. （2） From west to east along the transect, we can see that evergreen broad-leaved forest of the western transect on Jinggang Mountain showed the lightest damage extent, and a Cryptomeria plantation at an altitude of 700 m was severely destroyed while Chinese fir showed light damage below 700 m and relatively severe damage above 900 m. Masson pine and slash pine in the central transect in Jitai Basin were damaged severely due to turpentine activities, and closed natural secondary deciduous broad-leaved forest was damaged severely due to high ice and snow accumulation on intertwined shrubs. Masson pine aerial-seeding plantations below 400 m along the eastern transect in Xingguo and Ningdu counties were nearly undamaged for small tree sizes, and Chinese fir at 500-900 m altitude showed a lighter damage extent. However, masson pine which was distributed above 400 m and planted in the 1960s, was severely damaged due to turpentine.
