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首页> 外文会议>International Symposium on Nondestructive Testing of Wood; 20000913-20000915; Sopron; HU >In vivo electric soundings of standing trees
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In vivo electric soundings of standing trees

机译：站立树木的体内电测深

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Electrical potentials of natural origin have been studied in standing trees for several years. Voltage is measured by means of non-polarising electrodes, positioned at different heights and directions in the trunk. Characteristic time variations correlated with physiological functions have been found such as daily, seasonal, yearly etc. (Morat et al. 1994, Koppan 1996, Koppdn et al. 1999, Koppan et al. 2000 a). A comparison with a direct sap-flow measuring technique (Granier 1987) showed that the electrical potential difference records give information about the physiological activity of standing trees (Koppan et al. 2000 b). The electrical potential differences of natural origin are influenced by many environmental factors, first of all by microclimatological conditions. As a first approximation the trunk itself is to be considered as a cylindrical structure. Consequently its electrical resistivity distribution is assumed to be cylindrical, i.e. it is expected to be a two-dimensional model. The experienced inhomogeneities shown by these natural potential differences oriented us to investigate the internal electrical structure of the trunk in another way, too. Namely, instead of recording these natural potential differences, potential differences, due to current electrodes on the surface of the trunk of living trees, are measured. In the geophysical practice there exist several techniques, which can be applied to this problem. In the poster presentation an overview about some classical geo-electric techniques are shown. Some of these methods are useful in determination the centre of the bulk resistivity within the trunk of a standing tree. The results of such an inhomogeneity mapping (that is comparing the results measured on the surface of the trunk at different site but at the same height) can be directly transformed into resistivity dimensions (Weidelt and Weller, 1997). This geoelectric method would offer an in vivo non-invasive technique. It cannot give such detailed pictures as the high-frequency tomographs, but it may give important auxiliary information to the application.
机译：在站立的树木中研究天然来源的电势已有数年。电压是通过非极化电极测量的，该电极位于躯干中的不同高度和方向。已经发现与生理功能相关的特征性时间变化，例如每天，季节性，每年等（Morat等，1994； Koppan，1996； Koppdn等，1999； Koppan等，2000a）。与直接树汁流量测量技术（Granier 1987）的比较表明，电势差记录提供了有关立木生理活动的信息（Koppan等人2000 b）。自然界的电势差受许多环境因素的影响，首先受微气候条件的影响。作为第一近似，躯干本身被认为是圆柱形结构。因此，假定其电阻率分布是圆柱形的，即，预期它是二维模型。这些自然电势差显示出的经验不均匀性也使我们以另一种方式研究躯干的内部电气结构。即，代替记录这些自然电势差，而是测量由于在活树的树干的表面上的电流电极而引起的电势差。在地球物理实践中，存在几种可以应用于该问题的技术。在海报展示中，概述了一些经典的地电技术。这些方法中的某些方法可用于确定立木树干内的体电阻率中心。可以将这种不均匀性映射的结果（即比较在不同位置但高度相同的树干表面上测得的结果）直接转换为电阻率维度（Weidelt和Weller，1997）。这种地电方法将提供一种体内非侵入性技术。它不能提供像高频断层扫描仪这样的详细图片，但可以为应用程序提供重要的辅助信息。

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