Extreme weather events were analyzed based on the meteorological data from the year of 1967 to 2007 for Yamaguchi, Japan. The responses from landscape trees were also investigated mainly by the analysis of image pixel...Extreme weather events were analyzed based on the meteorological data from the year of 1967 to 2007 for Yamaguchi, Japan. The responses from landscape trees were also investigated mainly by the analysis of image pixel and spectral reflectance. Results show that after the dry, hot and windy summer in 2007, many landscape trees in Yamaguchi City tended to respond the extreme weather events by reducing their leaf surface area and receiving less radiation energy. Premature leaf discoloration or defoliation appeared on some landscape tree species and leaf necrosis occurred on tip and margin of many Kousa dogwood (Cornus kousa) trees at unfavorable sites. Described by image pixel analysis method, the leaf necrotic area percentage (LNAP) of sampled dogwood trees averaged 41.6% and the sampled Sasanqua camellia (Camelia sasanqua) tree also showed fewer flowers in flower season of 2007 than that in 2006. By differential analysis of partial discolored crown, it presented a logistic differential equation of crown color for sweet gum (Liquidambar styraciflua) trees. It suggested that the persistent higher temperature and lower precipitation could be injurious to the sensitive landscape trees at poor sites, even in relative humid area like Yamaguchi.展开更多
Extreme weather events were analyzed based on the meteorological data from the year of 1967 to 2007 for Yamaguchi, Japan. The responses from landscape trees were also investigated mainly by the analysis of image pixel...Extreme weather events were analyzed based on the meteorological data from the year of 1967 to 2007 for Yamaguchi, Japan. The responses from landscape trees were also investigated mainly by the analysis of image pixel and spectral reflectance, Results show that after the dry, hot and windy summer in 2007, many landscape trees in Yamaguchi City tended to respond the extreme weather events by re- ducing their leaf surface area and receiving less radiation energy. Premature leaf discoloration or defoliation appeared on some landscape tree species and leaf necrosis occurred on tip and margin of many Kousa dogwood （Comus kousa） trees at unfavorable sites. Described by image pixel analysis method, the leaf necrotic area percentage （LNAP） of sampled dogwood trees averaged 41.6% and the sampled Sasanqua camellia （Camelia sasanqua） tree also showed fewer flowers in flower season of 2007 than that in 2006. By differential analysis of partial discolored crown, it presented a logistic differential equation of crown color for sweet gum （Liquidambar styraciflua） trees. It suggested that the persistent higher temperature and lower precipitation could be injurious to the sensitive landscape trees at poor sites, even in relative humid area like Yamaguchi.展开更多
Sustainable urban development nowadays requires the consideration of vegetation,particularly green spaces,for thewell-beingof thepopulationand thequalityof life.It iswiththispurpose a studywas conducted in the city of...Sustainable urban development nowadays requires the consideration of vegetation,particularly green spaces,for thewell-beingof thepopulationand thequalityof life.It iswiththispurpose a studywas conducted in the city of Ketou,Benin,to analyze the spatio-temporal dynamics of the wooded landscape and its influencing factors,with a viewto sustainable urban planning.Using remote sensing andGeographic Information Systems,Landsat TM,ETM,and OLI/TIRS satellite images were processed using the Maximum Likelihood Algorithm in Environment for Visualizing Images(ENVI)5.0 to assess land use changes from 2003 to 2023.A socio-economic survey was also carried out on a sample of seventy 70 residents to identify the causes of vegetation changes,their economic impacts,and residents’perceptions.The results reveal six(06)types of land uses which are clear forests,wooded and shrub savannas,mosaics of culture and fallow,land under palm trees,watercourses and built-up areas.These uses have changed between 2003 and 2023,to the detriment of built-up areas,which saw a significant increase in their area,rising from 384 ha in 2003 to 1462 ha in 2013 and from 1462 to 2056 ha in 2023,an increase of(+1672 ha).This shows that the study area has been heavily urbanized.This dynamic is influenced by two(02)direct factors,namely:wood exploitation in various forms(80%)and urbanization(75.7%),and four indirect factors,namely:agriculture(44%),the collection of nontimber forest products(NTFPs),the commercialization ofNTFPs and wood(timber and fuelwood)(12.85%),and crafts(11.42%).Despite the residents’awareness of the environmental impact of vegetation destruction,they continue their actions.This highlights the need for the implementation of new sustainable management strategies,such as reasonable urbanization policies and agricultural methods adapted to the environment.This information remains a contribution to science,which policymakers should consider for the sustainable management of urban tree landscapes for the wellbeing of residents.展开更多
文摘Extreme weather events were analyzed based on the meteorological data from the year of 1967 to 2007 for Yamaguchi, Japan. The responses from landscape trees were also investigated mainly by the analysis of image pixel and spectral reflectance. Results show that after the dry, hot and windy summer in 2007, many landscape trees in Yamaguchi City tended to respond the extreme weather events by reducing their leaf surface area and receiving less radiation energy. Premature leaf discoloration or defoliation appeared on some landscape tree species and leaf necrosis occurred on tip and margin of many Kousa dogwood (Cornus kousa) trees at unfavorable sites. Described by image pixel analysis method, the leaf necrotic area percentage (LNAP) of sampled dogwood trees averaged 41.6% and the sampled Sasanqua camellia (Camelia sasanqua) tree also showed fewer flowers in flower season of 2007 than that in 2006. By differential analysis of partial discolored crown, it presented a logistic differential equation of crown color for sweet gum (Liquidambar styraciflua) trees. It suggested that the persistent higher temperature and lower precipitation could be injurious to the sensitive landscape trees at poor sites, even in relative humid area like Yamaguchi.
文摘Extreme weather events were analyzed based on the meteorological data from the year of 1967 to 2007 for Yamaguchi, Japan. The responses from landscape trees were also investigated mainly by the analysis of image pixel and spectral reflectance, Results show that after the dry, hot and windy summer in 2007, many landscape trees in Yamaguchi City tended to respond the extreme weather events by re- ducing their leaf surface area and receiving less radiation energy. Premature leaf discoloration or defoliation appeared on some landscape tree species and leaf necrosis occurred on tip and margin of many Kousa dogwood （Comus kousa） trees at unfavorable sites. Described by image pixel analysis method, the leaf necrotic area percentage （LNAP） of sampled dogwood trees averaged 41.6% and the sampled Sasanqua camellia （Camelia sasanqua） tree also showed fewer flowers in flower season of 2007 than that in 2006. By differential analysis of partial discolored crown, it presented a logistic differential equation of crown color for sweet gum （Liquidambar styraciflua） trees. It suggested that the persistent higher temperature and lower precipitation could be injurious to the sensitive landscape trees at poor sites, even in relative humid area like Yamaguchi.
文摘Sustainable urban development nowadays requires the consideration of vegetation,particularly green spaces,for thewell-beingof thepopulationand thequalityof life.It iswiththispurpose a studywas conducted in the city of Ketou,Benin,to analyze the spatio-temporal dynamics of the wooded landscape and its influencing factors,with a viewto sustainable urban planning.Using remote sensing andGeographic Information Systems,Landsat TM,ETM,and OLI/TIRS satellite images were processed using the Maximum Likelihood Algorithm in Environment for Visualizing Images(ENVI)5.0 to assess land use changes from 2003 to 2023.A socio-economic survey was also carried out on a sample of seventy 70 residents to identify the causes of vegetation changes,their economic impacts,and residents’perceptions.The results reveal six(06)types of land uses which are clear forests,wooded and shrub savannas,mosaics of culture and fallow,land under palm trees,watercourses and built-up areas.These uses have changed between 2003 and 2023,to the detriment of built-up areas,which saw a significant increase in their area,rising from 384 ha in 2003 to 1462 ha in 2013 and from 1462 to 2056 ha in 2023,an increase of(+1672 ha).This shows that the study area has been heavily urbanized.This dynamic is influenced by two(02)direct factors,namely:wood exploitation in various forms(80%)and urbanization(75.7%),and four indirect factors,namely:agriculture(44%),the collection of nontimber forest products(NTFPs),the commercialization ofNTFPs and wood(timber and fuelwood)(12.85%),and crafts(11.42%).Despite the residents’awareness of the environmental impact of vegetation destruction,they continue their actions.This highlights the need for the implementation of new sustainable management strategies,such as reasonable urbanization policies and agricultural methods adapted to the environment.This information remains a contribution to science,which policymakers should consider for the sustainable management of urban tree landscapes for the wellbeing of residents.
