ABSTRACT

The temporal evolution of the electrical signal generated by Pinus halepensis was measured in a sample of 15 trees. Weekly experiments were carried out during a long-term campaign lasting over a year, while trials with a high frequency of measurements were also performed during several days. In the latter case, day-night oscillations of the electrical magnitudes were observed. Additionally, punctual meteorological events such as rainfall and electrical storms affect the electrical signal as well.

The measured electrical intensity grows exponentially with the voltage. In fact, no electrical intensity that exceeds the threshold of 0.01 μA is gathered when voltage values are lower than 0.6 V. In general, higher electrical signals were gathered during the rainy seasons with moderate temperatures; while very low signals, including few measures of zero intensity, were obtained during the most stressful periods over the year, mainly by mid-summer.

There is a strong correlation between the rainfall and the electrical signal. The rain-intensity correlation, together with sustained intensity values during the reproductive period in spring, suggests that this electrical magnitude could be an indicator of the physiological state of the tree and thus used for in situ and minimally invasive forest monitoring.

摘要

在 15 棵树的样本中测量了黑松产生的电信号的时间演变。在持续一年多的长期活动中每周进行一次实验，同时在几天内也进行了高频率测量的试验。在后一种情况下，观察到电幅度的昼夜振荡。此外，降雨和电风暴等准时气象事件也会影响电信号。

测得的电强度随电压呈指数增长。事实上，当电压值低于 0.6 V 时，不会采集到超过 0.01 μA 阈值的电信号。通常，在温度适中的雨季采集到的电信号较高；虽然在一年中压力最大的时期（主要是仲夏）获得了非常低的信号，包括很少的零强度测量值。

降雨量与电信号之间存在很强的相关性。降雨强度相关性以及春季生殖期间持续的强度值表明，这种电强度可以作为树木生理状态的指标，因此可用于原位和微创森林监测。