124 PROTECTION OF WOODLANDS. 



of the Spruce moth, of some Tortricidce, and of the almost wing- 

 less female imago of the Winter moth (Cheimatobia brumata). 



Good viscous tar or patent glue should remain sticky and 

 active for at least 6 to 8 weeks, neither running in consequence of 

 getting washed by rain or from the melting influence of a hot 

 sun, nor oxidising or getting covered with a superficial skin. 

 Although its composition is supposed to be a secret, it must be a 

 rather open one, as it is extensively manufactured by over a 

 dozen firms (Messrs Polborn in Berlin, Miitzell in Stettin, &c.). 

 A hundredweight costs about 7s. 6d., and on the average this 

 quantity is about enough to do 2-^ acres, although this depends 

 on the average girths of the stems, as young crops require a larger 

 quantity per acre than older woods. Before the operation of 

 ringing the stems with tar is carried out, the bark is cleaned, or 

 " reddened " as it is called in the case of the Scots pine, with 

 scrapers, so that a girdle at breast-height of about four inches in 

 breadth is scraped clear of all rough bark, whilst, at the same 

 time, care is exercised not to damage the tree by scraping too 

 deep. By this scraping, the patent tar bites on to the bark much 

 more easily, and at the same time a much less quantity is required 

 per stem. This cleaning of the stems should take place during 

 the course of the winter and the spring in all crops where inspec- 

 tion and revision have shown that many caterpillars are hibernating 

 on the ground (Pine moth), or that deposits of eggs have beeu 

 numerous (Spruce moth), and only later on, about the end of 

 March and the beginning of April, should the formation of the 

 rings of viscous tar be carried out, when the soil temperature 

 ascends to about 40 to 45 Fahr., and the caterpillars begin to be 

 impelled to ascend the trees. The gluey tar may be applied with 

 hard brushes, but better results are obtained through the use of 

 small wooden spuds about 1 to 1-^ inches broad, smoothing off being 

 performed with a similar spud hollowed to a depth of about th of 

 an inch. With good patent tar one operation should remain 

 active and effective, even although the period during which the 

 caterpillars ascend the stems may, from one reason or another, 

 be unduly prolonged. 1 Should it be convenient to undertake a 



1 In August 1892, during a summer of much more than the average heat and 

 dryness, I found the rings of patent tar, that had been placed round Spruce in the 

 Bavarian forests during April as a protection against the " Nun " or Spruce moth, 

 still perfectly sticky and active, although this was quite a month after the necessary 

 time. Trans. 





