NOTES ON CONTINENTAL FORESTRY. 177 



woodlands, has proved such a very destructive insect in Germany, 

 that it must henceforth be classed along with the Pine moth, the 

 Nun or Black Arches, and the Pine Owlet-moth, as among the 

 worst enemies of the German woodlands. It did immense 

 damage in the forests near Nuremberg in 1892-96, and in 

 Friedesdorf in 1893-95, while more recently a series of dry 

 summers led to very destructive attacks in the Letzlinger Heide, 

 in North Germany, from 1899 to 1903. The hot, dry summer 

 of 1 90 1, favourable to the insect, brought the culmination of 

 the attacks; but the cold wet May and June of 1902, and the 

 natural increase in parasitic Ichneumonidce and TachincB that 

 generally takes place after three years of any such insect calamity, 

 stopped further damage. 



Although the pine woods attacked were chiefly young crops, 

 20 to 40 years old, it was found that the portions twice stripped 

 bare of foliage by the caterpillars were quite past saving, and 

 had to be felled as soon as possible to keep down bark and 

 cambial beetles {Hylesini). The consequence was that in 1903 

 and 1904, in place of an annual fall of 2,220,000 cubic feet, 

 41,370,000 cubic feet had to be felled on about 21,500 acres, 

 of which about 17,000 acres had been entirely denuded of 

 foliage. 



In combating this attack, it was found that the best plan 

 was to try and destroy the pupae during winter. Grease-ringing 

 the stems to prevent the ascent of caterpillars blown dow^n by 

 wind, etc., did not prove effective, as at most only about one-fourth 

 of the caterpillars are thus brought to the ground. Driving in 

 swine was out of the question throughout the whole of the area 

 infested, as about 50,000 would have been needed, so that this 

 plan could only be adopted near villages. There, however, free 

 pannage was given, and rewards to the swineherds. Hens were 

 also bought and kept in the woods, and proved useful, although 

 many of them died from diphtheria and soft crop, or were 

 carried off by foxes, hawks, etc. Over large areas, however, the 

 best means was found to be the removal of the soil-covering 

 of dead foliage and moss, which could be sold locally as litter. 



The Letzlinger Heide is a poor sandy stretch between Berlin 

 and Hanover, where sylvicultural measures of prevention are 

 hardly applicable. "One reads in text-books — (i) underplanting; 

 (2) mixed crops; (3) protection of this insect's enemies. But where 

 can these measures be carried out? Protecting its enemies — of 

 VOL. xvin. M 



