144 EXPERIMENT STATION. [Jan. 



ELECTRICAL RESISTANCE OF TREES. 



G. E. STONK AND G. 11. CHAPMAN. 



It has long been known that trees offer considerable resistance 

 to electric currents, but at the time our experiments were under- 

 taken we were not aware that much attention had been given to 

 this subject, especially regarding the influence of certain factors 

 on resistance. The effect of lightning strokes indicates that trees 

 possess relatively high resistances, and that there is a difference 

 in the resistance of their various tissues. Little or no data 

 appear to be available concerning this subject, nor so far as we 

 know concerning the resistance of different trees at different 

 seasons of the year. 



In a former publication ^ we have given the results of some 

 observations on the electrical resistance of trees, and the numer- 

 ous data which we obtained by passing electrical currents 

 through trees and various plants helped to give us some idea of 

 their electrical resistance. Our object in carrying on these ex- 

 periments "was to determine whether there were any variations 

 in the electrical resistance of different sides of a tree trunk as 

 regards points of the compass. Originally it was our purpose 

 to learn whether the electrical resistance varied greatly from 

 month to month durinnf the vear, and if so, what causes led to 

 this variation ; in fact, to stufly the effects of various influences 

 on electrical resistance. But the temporary suspension of our 

 work, made necessary by moving from one laboratory to an- 

 other, and the change of assistants interrupted our plans some- 

 what, and the original idea of our investigation was not fol- 

 lowed. 



It miglii he supposed that since the several sides of a tree are 

 exposed differently to light and heat they would show slight 



' Injviries to Shade Trees from Electricity, by G. E. Stone, Mass. Agr. Exp. Sta., Bui. No. 91. 

 1903. 



