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Impacts of canopy structure on the sub-canopy solar radiation under a Deciduous forest based on fisheye photographs

寒旱区科学:英文版 2023年第3期15卷 150-160页

作者： YanLin Zhang XiaoLin Feng XiaoLi Chang LiMin Tie School of Earth Sciences and Spatial Information Engineering Hunan University of Science and TechnologyXiangtanHunan 411201China

forest canopy in a Deciduous forest has significant sheltering effects on the sub-canopy solar radiation,significantly influencing the energy balance of snow and permafrost beneath the forest and their spatial distribution.This study employs a digital camera mounted with a fisheye lens to acquire photographs at various times in a growth cycle of the forest canopy at three selected sites in a Deciduous forest near the Greater Khingan Mountains forest Ecological Station,Northeast China.The vegetation types and conditions at the selected sites include P1 in Ledum-Claopodium-L.dahurica,P2 in Carex tato-L.dahurica,and P3 in Betula fruticosa-L.dahurica.After necessary image processing,these photographs were used to identify the canopy structure and its impacts on the sub-canopy solar radiation.Results show that fisheye photographs can successfully capture the forest canopy structure and are useful in estimating the sub-canopy solar radiation.The order of sheltering effects from the largest to the smallest on sub-canopy solar radiation at three selected sites is P3,P1,and P2,highly depending on the canopy density.Then sub-canopy solar radiation was calculated using fisheye photographs and an algorithm validated by in-situ observed solar radiation beneath the canopy at P1 and P3.The results are reasonable,although the accuracy seems compromised due to the mismatch of conditions for calculation and observation.Results also show that the mean annual solar radiation above the canopy was about 148.3 W/m2 in 2018,and the mean annual solar radiation values beneath the canopy were about 90.0,123.8,and 61.0 W/m2 at P1,P2,and P3,with only 60%,84%,and 42%of the total solar radiation penetrating through the canopy,respectively.Even in winter,when the trees are leafless,the canopy sheltering effects cannot be ignored in dense forests.Despite the limitations,fisheye photographs and related algorithms are useful in investigating the forest canopy structure and its impacts on sub-canopy solar radiation.

关键词： Solar radiation forest structure Fisheye photograph Sub-canopy Deciduous forest

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Deforestation and fragmentation trends of seasonal dry tropical forest in Ecuador: impact on conservation

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forest Ecosystems 2021年第3期8卷 615-627页

作者： Carlos A.Rivas JoséGuerrero-Casado Rafael M.Navarro-Cerillo Instituto de Ciencias Básicas Universidad Técnica de ManabíPortoviejoManabíEcuador Department of forest Engineering Laboratory of DendrochronologySilviculture and Global Change–DendrodatLab–ERSAFUniversity of CordobaCampus de RabanalesCrta.IVkm.396E-14071 CordobaSpain Departamento de Medicina Veterinaria Facultad de Ciencias VeterinariasUniversidad Técnica de ManabíPortoviejoManabíEcuador Department of Zoology University of CordobaCampus de Rabanales14071 CordobaSpain

Background:Fragmentation and deforestation are one of the greatest threats to forests,and these processes are of even more concern in the tropics,where the seasonal dry forest is possibly one of the most threatened ecosystems with the least remaining surface area.Methods:The deforestation and fragmentation patterns that had occurred in Ecuadorian seasonal dry forests between 1990 and 2018 were verified,while geographic information systems and land cover shapes provided by the Ecuadorian Ministry of the Environment were employed to classify and evaluate three types of seasonal dry forests:deciduous,semi-deciduous,and transition.The study area was tessellated into 10 km2 hexagons,in which six fragmentation parameters were measured:number of patches,mean patch size,median patch size,total edge,edge density and reticular fragmentation index(RFI).The RFI was also measured both outside and inside protected natural areas(unprotected,national protected areas and protected forest).Moreover,the areas with the best and worst conservation status,connectivity and risk of disappearance values were identified by means of a Getis-Ord Gi*statistical analysis.Results:The deforestation of seasonal dry forests affected 27.04%of the original surface area still remaining in 1990,with an annual deforestation rate of−1.12%between 1990 and 2018.The RFI has increased by 11.61%as a result of the fact that small fragments of forest have tended to disappear,while the large fragments have been fragmented into smaller ones.The semi-Deciduous forest had the highest levels of fragmentation in 2018.The three categories of protection had significantly different levels of fragmentation,with lower RFI values in national protected areas and greater values in protected forests.Conclusions:The seasonal dry forest is fragmenting,deforesting and disappearing in some areas.An increased protection and conservation of the Ecuadorian seasonal dry forest is,therefore,necessary owing to the fact that not all protection measures have been effective.

关键词： Deciduous forest Semi-Deciduous forest Remnant forest Patch isolation Habitat loss Protected areas

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deciduous AND deciduous-EVERGREEN forestS IN NORTHEAST CHINA

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Journal of Northeast forestry University 1991年第1期2卷 9-16页

作者： Chou Yiliang Liu JianweiNortheast forestry University Northeast forestry University China

Two types of forests in Northeast China is divided in this paper, that is, the Deciduous forests in the northern part and the deciduous-evergreen forests in the eastern part. Both distributions of the two types of forests have also been presented. Meanwhile, the development and succession as well as components of forests have been studied in detail. In the end, the vertical distribution of the Deciduous forests have been shown, in which, the near-temperate cold temperate deciduous coniferous forests are distributing in the low elevation area between 450m-600m from the northto the south, the typical Siberian cold temperate deciduous coniferous forests are widely distributing from 450m-820m in the north to 600m-1050m in the south, the humid cold temperate deciduous coniferous forests can only be found in high elevation area from 820m-l 100m in the north to 1050m-1380m in the south, the cold temperate deciduous coniferous open forests can seldom appear at the top of a few peaks.

关键词： Deciduous forest deciduous-evergreen forest Succession Distribution Component

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