Wang Fei, Haruhiko Yamamoto
Shandong Forestry Research Institute, Ji'nan 250014, China.
Guang Pu Xue Yu Guang Pu Fen Xi. 2010 Nov;30(11):2914-8.
Noninvasive detection of temperature with thermography from natural things has been used in many fields and it was attempted to detect the temperature for leaves and branches of trees in the present paper. Leaf and twig temperatures were monitored during the increasing process of temperature under the direct sunshine heating. The difference of specific heat and latent heat from leaves and twigs caused by different water content and transpiration capacity were measured. Not only the leaf temperature, scorch and branch dieback were detected, but the transpiration cooling fail of sweetgum (Liquidambar styraciflua L.) leaves was successfully measured by using thermography. In this study, the local water stress characteristics on sweetgum leaves from specially designed vein severing became special materials for studying the leaf temperature or transpiration failure. The temperature gradient on severed leaf made the thermo image taking easy, with less systematical error. Direct comparison between non-severed lobes and vein-severed lobes on the same leaf lamina makes it more comparable. According to thermography analysis, significant high temperature area was observed and there existed the consistence between high temperature area and the reddened leaf lamina.
利用热成像技术对自然物体进行非侵入式温度检测已在许多领域得到应用，本文尝试对树木的叶片和树枝温度进行检测。在阳光直射加热下温度上升过程中，对叶片和嫩枝温度进行了监测。测量了因不同含水量和蒸腾能力导致的叶片和嫩枝比热和潜热的差异。不仅检测到了叶片温度、焦枯和树枝枯死情况，还通过热成像成功测量了胶皮糖香树（Liquidambar styraciflua L.）叶片的蒸腾冷却失效情况。在本研究中，通过专门设计的叶脉切断处理，胶皮糖香树叶片上的局部水分胁迫特征成为研究叶片温度或蒸腾失效的特殊材料。切断叶脉的叶片上的温度梯度使得热成像拍摄变得容易，且系统误差较小。同一叶片薄片上未切断叶脉的叶瓣与切断叶脉的叶瓣之间的直接比较使其更具可比性。根据热成像分析，观察到显著的高温区域，且高温区域与变红的叶片薄片之间存在一致性。
