132 ESTJUEY TO THE FOEEST BY INSECTS. 



voracity also. I^ot many years ago the pines on thousands oi 

 acres of land in !North Carolina were destroyed by insects not 

 known to have ever done serious injury to that tree before. In 

 such cases as this and others of the like sort, there is good reason 

 to believe that man is the indirect cause of an evil for which he 

 pays so heavy a penalty. Insects increase whenever the birds 

 which feed upon them disappear. Hence, in the wanton destruc- 

 tion of the robin and other insectivorous birds, the hipes iTnplumis, 

 the featherless biped, man, is not only exchanging the vocal or- 

 chestra, which greets the rising sun for the drowsy beetle's even- 

 ing drone, and depriving his groves and his fields of their fairest 

 ornament, but he is waging a treacherous warfare on his natural 

 allies.* 



* In the artificial woods of Europe insects are far more numerous and de- 

 structive to trees than in the primitive forests of America, and the same remark 

 may be made of the smaller rodents, such as moles, mice, and squirrels. In 

 the dense, native wood, the ground and the air are too humid, the depth of 

 shade too great, for many tribes of these creatures, while near the natural 

 meadows and other open grounds, where circumstances are otherwise more fa- 

 vorable for their existence and multiplication, their numbers are kept down by 

 birds, serpents, foxes, and smaller predacious quadrupeds. See a curious arti- 

 cle on the wild mammalia useful to man, by Asbjornsen, in the Noi'sJce Land- 

 mandsbog, 1866, p. 85. In civilized countries these natural enemies of the 

 worm, the beetle, and the mole, are persecuted, sometimes almost extermina- 

 ted, by man, who also removes from his plantations the decayed or wind-fallen 

 trees, the shrubs and underwood, which, in a state of nature, furnished food 

 and shelter to the borer and the rodent, and often also to the animals that 

 preyed upon them. Hence the insect and the gnawing quadruped are allowed 

 to increase, from the expulsion of the police which, in the natural wood, pre- 

 vent their excessive multiplication, and they become destructive to the forest 

 because they are driven to the living tree for nutriment and cover. The forest 

 of Fontainebleau is almost wholly without birds, and their absence is ascribed 

 by some writers to the want of water, which, in the thirsty sands of that wood, 

 does not gather into running brooks ; but the want of undergrowth is perhaps 

 an equally good reason for their scarcity. 



On the other hand, the thinning out of the forest and the removal of under- 

 wood and decayed timber, by which it is brought more nearly to the condition 

 of an artificial wood, is often destructive to insect tribes which, though not in- 

 jurious to trees, are noxious to man. Thus the troublesome woodtick, for- 

 merly very abundant in the Northeastern, as it unhappily still is in native for- 

 ests in the Southern and Western States, has become nearly or quite extinct in 

 the former region since the woods have been reduced in extent and laid more 

 open to the sun and air. — Asa Fitch, in Report of New York Agricultural So- 

 ciety for 1870, pp. 363, 364. 



