We evaluated how historical storm events have shaped the current forest landscape in three Pyrenean subalpine forests(NE Spain).For this purpose we related forest damage estimations obtained from multi-temporal aerial...We evaluated how historical storm events have shaped the current forest landscape in three Pyrenean subalpine forests(NE Spain).For this purpose we related forest damage estimations obtained from multi-temporal aerial photographic comparisons to the current forest typology generated from airborne Li DAR data, and we examined the role of past natural disturbance on the current spatial distribution of forest structural types.We found six forest structural types in the landscape: early regeneration(T1 and T2), young even-aged stands(T3), uneven-aged stands(T4) and adult stands(T5and T6).All of the types were related to the timing and severity of past storms, with early-regeneration structures being found in areas markedly affected in recent times, and adult stands predominating in those areas that had suffered lowest damage levels within the study period.In general, landscapes where high or medium levels of damage were recurrent also presented higher levels of spatial heterogeneity,whereas the opposite pattern was found in the less markedly affected landscape, characterized by thepresence of large regular patches.Our results show the critical role that storm regimes in terms of timing and severity of past storms can play in shaping current forest structure and future dynamics in subalpine forests.The knowledge gained could be used to help define alternative forest management strategies oriented toward the enhancement of landscape heterogeneity as a measure to face future environmental uncertainty.展开更多
With the help of ARC/INFOR and ERDAS software, based on the information from forest resources distribution maps and TM images, four indices were chosen to analyze spatial pattern changes of forest landscape of Luoning...With the help of ARC/INFOR and ERDAS software, based on the information from forest resources distribution maps and TM images, four indices were chosen to analyze spatial pattern changes of forest landscape of Luoning County, Henan Province from 1983 to 1999. The results showed that: 1) The number and total area of patches were rapidly increased with time changes. The fragmentation degree of the landscape was increasing greatly. 2) The area of some forest patch types, especially shrub forest, economic forest, Populus spp. forest, Quercus spp. forest, sparse forest, deserted grassland etc. had been greatly changed. 3) The fragemation degree of each forest patch type became greater from 1983 to 1999. 4) The transition probabilities of deserted forest, economic forest, Pi-nus tabulaeformis forest, Populus spp. forest exceed 85%,Robinia pseuoacacia forest, deserted grassland, 65% and Quercus spp. forest, non-forest, shrub forest had smaller ones, which were 26.5%, 29.1% and 45.3%, respectively. The main transition trends of various patches were non-forest and Quercus spp. forest. During the course of transition, the types that 50% of area was remained were Quercus spp. forest, non-forest and shrub forest. According to above analyses, the main driving forces, such as the management policies, market economy factors and influences of human activities etc. were brought out.展开更多
基金Financial support for this study was provided by the Spanish Ministry of Economy and Competitiveness through the project RESILFOR(AGL2012-40039-C02-01)LC and JRGO were both supported by Ramón y Cajal contracts(RYC-2009-04985 and RYC-2011-08983)
文摘We evaluated how historical storm events have shaped the current forest landscape in three Pyrenean subalpine forests(NE Spain).For this purpose we related forest damage estimations obtained from multi-temporal aerial photographic comparisons to the current forest typology generated from airborne Li DAR data, and we examined the role of past natural disturbance on the current spatial distribution of forest structural types.We found six forest structural types in the landscape: early regeneration(T1 and T2), young even-aged stands(T3), uneven-aged stands(T4) and adult stands(T5and T6).All of the types were related to the timing and severity of past storms, with early-regeneration structures being found in areas markedly affected in recent times, and adult stands predominating in those areas that had suffered lowest damage levels within the study period.In general, landscapes where high or medium levels of damage were recurrent also presented higher levels of spatial heterogeneity,whereas the opposite pattern was found in the less markedly affected landscape, characterized by thepresence of large regular patches.Our results show the critical role that storm regimes in terms of timing and severity of past storms can play in shaping current forest structure and future dynamics in subalpine forests.The knowledge gained could be used to help define alternative forest management strategies oriented toward the enhancement of landscape heterogeneity as a measure to face future environmental uncertainty.
文摘With the help of ARC/INFOR and ERDAS software, based on the information from forest resources distribution maps and TM images, four indices were chosen to analyze spatial pattern changes of forest landscape of Luoning County, Henan Province from 1983 to 1999. The results showed that: 1) The number and total area of patches were rapidly increased with time changes. The fragmentation degree of the landscape was increasing greatly. 2) The area of some forest patch types, especially shrub forest, economic forest, Populus spp. forest, Quercus spp. forest, sparse forest, deserted grassland etc. had been greatly changed. 3) The fragemation degree of each forest patch type became greater from 1983 to 1999. 4) The transition probabilities of deserted forest, economic forest, Pi-nus tabulaeformis forest, Populus spp. forest exceed 85%,Robinia pseuoacacia forest, deserted grassland, 65% and Quercus spp. forest, non-forest, shrub forest had smaller ones, which were 26.5%, 29.1% and 45.3%, respectively. The main transition trends of various patches were non-forest and Quercus spp. forest. During the course of transition, the types that 50% of area was remained were Quercus spp. forest, non-forest and shrub forest. According to above analyses, the main driving forces, such as the management policies, market economy factors and influences of human activities etc. were brought out.
