130 THE GYPSY MOTH. 



stance has been used abroad, especially in Germany, for 

 several years past. The government forestry authorities of 

 Bavaria employ it to prevent the ascent of the nun moth. 

 This insect in 1890 devastated the German forests to such 

 an extent that * ' three thousand men were employed to check 

 its ravages, and in one instance it was necessary to cut and 

 burn a strip of timber four miles broad by five miles long to 

 prevent further devastation." * 



It was ascertained by experiment that the application of 

 this insect lime did not injure the trees, nor has any injury 

 been observed to trees where it has been used in this country. 

 Though the death of three or four young trees has been 

 reported and credited to the injury caused by liming, it is 

 possible that the primary injury was caused by too deep scrap- 

 ing of the bark. In such a case the oil contained in the lime 

 might penetrate the liber and cambium of the inner bark and 

 eventually destroy the life of the tree. There is no necessity 

 for scraping a smooth-barked tree. Though over 40,000 

 trees have been banded in the work in Massachusetts, these 

 are the only cases where injury is believed to have resulted. 

 This agrees with the experience of the foresters in Ger- 

 many, f 



* Dr. R. Hartig in "Forstlich — naturwissencliaftliche Zeitschrift," January, 

 1892. 



t " The excellent results of the lime-rings for the prevention of larvce ascending 

 the stem and feeding on the foliage of our forest trees has been proven during the 

 past ten years. Not content with this, however, — for it became our duty to see if 

 the lime itself did not injure the tree, — we examined the different layers of the bark, 

 and can confidently assert that no harm to the most tender trees has been done by 

 liming them. 



" We firmly believe that the man who scrapes the bark off" the trees can do more 

 harm in one hour than he could by ringing trees with lime the rest of the year ; and 

 we would therefore recommend for the work, men who know the difference between 

 the inner and outer bark of trees infested, and especially warn them to be careful of 

 smooth-barked trees, from which they have to remove only such mosses and lichens 

 as are found on them. On the trees — Dr. R. Hartig says — that were limed twenty- 

 five years ago no bad results have been observed. In fact, on the part of the tree 

 where the ring was laid on, the growth of wood was larger than either above or below, 

 which he ascribes to the action of the lime on the outer bark, softening it somewhat 

 and giving freer circulation of the sap in the inner bark. 



•' Only in instances where the bark was scraped to the quick has the lime pene- 

 trated, and therefore all harm must be ascribed to the scraping knife and not to the 

 lime. 



" There is, therefore, no occasion for alarm as regards the ringing of trees with 

 insect lime to preserve them from the ravages of insects of all kinds." — (Translated 

 from "Forstlich— naturwissenchaftliche Zeitschrift," July 7, 1892.) 



