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Wang F.,Shandong Forestry Research Academy
Beijing Linye Daxue Xuebao/Journal of Beijing Forestry University | Year: 2013

Transpiration cooling has been considered as a dissipation process of heat energy in trees for a long time. The direct result of transpiration cooling failure should be high leaf temperature. This paper aims to study the transpiration failure by monitoring the leaf temperature of sweetgum (Liquidambar styraciflua) with thermography. By measuring the water content, leaf imaging temperature, leaf stomata conductance and the RGB values in local area of same sweetgum leaves, transpiration failure was observed differentially after major veins severed. According to thermography analysis, significant high temperature area was early detected on the major veins severed sweetgum leaves. There was consistence among the lower water content, smaller leaf stomata conductance and reddened leaf lamina. This suggested that the persistent transpiration cooling failure induced the protective responses in the stressed area where is farthest to the water source and cause the red or purplish red area on severed leaves. By comparison, it significantly differs from characteristics which appeared on the similarly severed sasanqua camellia (Camellia sasanqua) leaves.


Wang F.,Shandong Forestry Research Academy | Wu D.,Shandong Forestry Research Academy | Yamamoto H.,Yamaguchi University | Xing S.,Shandong Agricultural University | Zang L.,Shandong Agricultural University
Ecological Informatics | Year: 2016

Platycladus orientalis (L.) Franco is a beautifully crown-shaped evergreen tree species used for ornamental cultivation. These trees are also important afforestation plants at hill sites containing calcareous parent rocks and exhibit high tolerance to drought and barren sites. However, Platycladus orientalis trees with abnormal crowns, such as fusiform and torch-form, have been identified at sites with extreme drought and barren hills in Shandong, China, although the abnormal crowns does not reduce the ornamental value of these trees. In the present study, we used the RGB imaging and geographical statistical analyses through the construction of meteorological indices. The results indicate that variations of abnormal Platycladus orientalis crowns are associated with both the internal metabolism of these trees and the external environment. Crown shapes are strongly affected by the local dry, hot and windy meteorological environment, particularly individuals planted at poor hill site conditions. In response to extreme events of drought, high temperature and strong winds, the twigs and scale leaves of Platycladus orientalis typically wilt from the lower part to the upper part of the crown. The fusiform and torch-form crowns are formed through the wilting of partial twigs and scale leaves to avoid the entire wilt of the trees, thereby saving the life of the tree at the expense of partial twigs and scale leaves. © 2016 Elsevier B.V..


Wang F.,Shandong Forestry Research Academy | Wu D.-J.,Shandong Forestry Research Academy | Zhai G.-F.,Haoshan Forest Farm | Zang L.-P.,Shandong Agricultural University
Guang Pu Xue Yu Guang Pu Fen Xi/Spectroscopy and Spectral Analysis | Year: 2015

Water and energy metabolism of plants is very important actions in their lives. Although the studies about these actions by using thermography were often reported, seldom were found in detecting the health status of forest trees. In this study, we increase the measurement accuracy and comparability of thermo-images by creating the difference indices. Based on it, we exam the water and energy status in stem of Chinese arborvitae (Platycladus orientalis (L.) Franco) by detecting the variance of far infrared spectrum between sap-wood and heart-wood of the cross-section of felling trees and the cores from an increment borer using thermography. The results indicate that the sap rate between sapwood and heartwood is different as the variance of the vigor of forest trees. Meanwhile, the image temperature of scale leaves from Chinese arborvitae trees with different vigor is also dissimilar. The far infrared spectrum more responds the sap status not the wood percentage in comparing to the area rate between sapwood and heartwood. The image temperature rate can be used in early determining the health status of Chinese arborvitae trees. The wood borers such as Phloeosinus aubei Perris and Semanotus bifasciatus Motschulsky are the pests which usually attack the low health trees, dying trees, wilted trees, felled trees and new cultivated trees. This measuring technique may be an important index to diagnose the health and vigor status after a large number of measurements for Chinese arborvitae trees. Therefore, there is potential to be an important index to check the tree vigor and pest damage status by using this technique. It will be a key in the tending and management of ecological and public Chinese arborvitae forest. © 2015, Science Press. All right reserved.


Wang F.,Shandong Forestry Research Academy | Yamamoto H.,Yamaguchi University | Li X.,Shandong University | Zhang J.,Northeast Normal University
Ecological Informatics | Year: 2014

The ornamental value of many trees is often based on their special colour, shape and structures. Its autumn leaf colour makes sweet gum (Liquidambar styraciflua L.) a favourable ornamental tree species for landscape beautification and urban greening. In addition to specific genetic control, to some extent, environment plays an important role in sweet gum colour changes. In this study, leaf-reddening events in the individual leaves and crowns of sweet gum trees were studied by analysing the ecology of sweet gum trees planted on a gradient of soil types, by comparing pruned and unpruned trees, by severing certain leaf veins and by measuring the snapping strength of the petiole. High-temperature areas on the severed leaves were detected using thermography. Low stomatal conductance and high leaf temperature rapidly appeared at the stressed area in severed lobes because of water stress and a related transpiration-cooling failure, especially in direct sunshine or on dry, hot summer days. The consistent relationship between the reddened and high-temperature areas indicates that a persistent transpiration-cooling failure resulted in local-area reddening on sweet gum leaves and the formation of a protective layer with high anthocyanin content. A significant relation between the snapping strength of the petiole and leaf reddening suggests that a persistent water imbalance during the formation of the abscission zone accelerates the sweet gum leaf reddening. Namely, a persistent transpiration-cooling failure during the defoliation process induces protective responses of the leaf. The rapid water loss of sweet gum juvenile leaves indicates that the reddening of the leaves may be a sensitive response to the changing properties of the leaf cuticle. © 2013 Elsevier B.V.


Wang F.,Shandong Forestry Research Academy | Omasa K.,University of Tokyo | Xing S.,Shandong Forestry Research Academy | Dong Y.,Shandong Forestry Research Academy
Ecological Informatics | Year: 2013

Thermography has been used in many fields to perform non-invasive temperature measurements of natural objects. In this paper, thermography was used to determine the temperature of leaves, stems and branch kerfs of Japanese spindle (Euonymus japonicus Thunb.) and glossy privet (Ligustrum lucidum Ait.) in the city of Jinan in China during winter. The temperatures of the leaves, stems and branch kerfs were monitored as the temperature decreased after the sample was subjected to hand heating or after the branch was cut. Differences in the specific heats and the latent heats of the leaves, branches and stems with different water contents and transpiration capacities were confirmed. The significant temperature difference obtained after hand heating between different leaf sections with varied water contents made it easy to obtain the thermal images, which were clear and exhibited reduced systematic errors. After hand heating, a significantly higher temperature was found at the major vein system of both Japanese spindle and glossy privet. This increased temperature difference made it possible to detect the water and the thermal state of these leaves. Therefore, it was possible to detect scorched area of the leaves, the twig dieback and the sap warming phenomenon in the leaves using thermography. In addition, the leaf bending phenomenon observed in Japanese spindle leaves during the deep freezing process indicates that the leaf scorch symptoms result from water stress and a lack of sap warming. © 2013 Elsevier B.V.


Wang F.,Shandong Forestry Research Academy | Omasa K.,University of Tokyo
Ecological Informatics | Year: 2012

Trees grow in changing environments and are usually injured by many external factors including both abiotic and biotic. Leaf scorch is a main symptom for many landscape trees when they are stricken by meteorological extreme events, such as summer drought, strong typhoon and winter freezing and so on. In the study, the internal angle of injured area (IAIA) was defined in relation to vein lines and measured non-destructively for some landscape tree species. Meanwhile, the leaf scorch area percent (LSAP) and percent of scorched central vein (PSCV) were also determined from RGB images. Positive relationships between IAIA and LSAP and between PSCV and LSAP were found. The larger IAIA values for scorched leaves and smaller IAIA values for spot/anthracnose diseased leaves of the studied trees indicated that IAIA may be used as a diagnosing index of leaf scorch symptoms. © 2012 Elsevier B.V.


Wang F.,Shandong Forestry Research Academy | Zhang J.,Northeast Normal University
Natural Hazards | Year: 2015

During the process of climate change in East Asia since the 1980s, increasing climate influence and meteorological hazardous events occurred, such as persistent drought, strong typhoon, and intercurrent meteorological extremes. The maximum temperature and persistence of rain-free days rose during the most recent 30 years in many cities in China. The combination of these extremes may evidently decrease the threshold of tree responses to the extreme stresses, even cause pine wilt in the area. By studying the geographic distribution of pine wilt disease, climate change characteristics, and the relationship between resin excretion and meteorological hazardous events, the relationship between pine wilt events and the summer droughts and strong typhoons in East Asia was investigated. The spatial and temporal consistency of the prevalence of pine wilt disease with climate change characteristics in both China and Japan suggests that pine wilt is related to local environmental variance. After extreme summer drought and strong typhoons, the ability of pines to excrete oleoresin was often reduced, and deaths were observed. The special adaptive characteristics of pines to meteorological hazard events during climate change, such as stopping or reducing resin excretion, may be the key of their wilt. © 2015, Springer Science+Business Media Dordrecht.


Wang F.,Shandong Forestry Research Academy
Chinese Journal of Applied Ecology | Year: 2012

The occurrence and prevalence of pine wilt disease cause huge losses to Japan, China, and South Korea in East Asia, and have received concerns from many countries. By the methods of field observation and meteorological data analysis, this paper studied the characteristics of the occurrence and prevalence of pine wilt disease and their relations to the meteorological disaster events. In Japan, China and South Korea, the meteorological extreme events of persistent summer drought and strong typhoon could trigger the occurrence of pine wilt. In extremely dry and hot environment, pine trees often appeared energy metabolism imbalance and entire tree wilt. However, in the years with lower temperature and more rainfall, less or nearly no pine wilt event occurred. It was suggested that before the attack by pine wood nematode and its vectors, the vigor of the pines had already declined, and thus, pine wilt disease could be confined in the areas often hit by summer drought and strong typhoon events. In the areas with suitable natural environment characterized by less summer drought and strong typhoon events and no improperly enlarged pine planting, there would be little possibility of widespread occurrence of pine wilt disease.


Wang F.,Shandong Forestry Research Academy
Journal of Forestry Research | Year: 2010

The effects of major veins severing on morphological and physiological features of sweetgum (Liquidambar styraciflua L.) leaves were investigated by observing leaf color change and measuring leaf temperature, green/luminance (G/L) value of half-lobes, leaf stomata conductance, and water content in Yamaguchi University, Japan. The palmately veined leaves of sweetgum (Liquidambar styraciflua L.) were found more sensitive to the major vein severing than that of other species. Major veins severing resulted in serious water stresses, as indicated by the persistent reddening and/or advanced reddening of local leaf, lower leaf stomatal conductance, and higher leaf temperature, etc. Severed leaf can be clearly divided into non-severed area, transitional area, and stressed area, which the three areas have different colours and temperature. The major vein barrier can also be seen clearly. The persistent reddening and advanced reddening seem consistent with the phenomenon of red crown top of some sweetgum trees and may have similar mechanism. © 2010 Northeast Forestry University and Springer-Verlag Berlin Heidelberg.


Wang F.,Shandong Forestry Research Academy
Natural Hazards | Year: 2014

Environment plays an important role in the interaction between host and pathogen and in the expression of diseases. Climatic differences among East Asia, Eastern USA, the Mediterranean and Northern Europe were compared against differences in the prevalence of pine wilt disease. This disease was prevalent in East Asia where there are frequent summer droughts and typhoons. Northern Europe (EEM) has a mild climate with very few summer droughts and tropical cyclone impacts and no pine wilt disease. The Mediterranean occasionally suffers climatic extremes, and pine wilt disease occurs infrequently and in localized area. The Eastern USA has climatic variability intermediate between Northern Europe and East Asia. Hurricanes are fewer and weaker compared to typhoons in Japan, China and Korea. Pine wilt disease occurs only in exotic pines in the USA. The climate of Hokkaido in Japan, where there is no pine wilt disease, is similar to that of the Eastern USA. With special stress adaptability, pines (Pinus spp.) usually respond to the meteorological extremes entirely and excrete large amount of resin. Disturbing by the hazardous summer drought and strong rainless typhoons (foehn-like typhoon), water and energy imbalance of pines often occurred so as to halt the resin excretion and trigger them into wilt. © 2014 Springer Science+Business Media Dordrecht.

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