34 



peared as if the oak primers might do considerable injury to these 

 trees. But the trees are certainly not injured, and very likely 

 in most cases they have been benefited by this removal of the 

 twigs from the top branches. Since 1896 the oak pruners. have 

 been so well held in check by their natural enemies that they have 

 not been conspicuous. When branches are injui'ed by insects or 

 over shadi]ig to such an extent that they die, they are removed 

 (when weakened by decay) by the action of the wind, or are 

 broken down by the collection of ice and snow upon them. 



The Guardians of the Fokest. 

 If the insects and other creatures which feed upon the trees and 

 their products were allowed by nature to increase unchecked, they 

 would soon destroy all the forests from the face of the earth. 

 Although when in normal numbers they may be a benefit to the 

 trees, it is still true that, when abnormally numerous insects con- 

 stitute a most serious danger to forests ; therefore the creatures 

 which feed upon insects and so hold them in check should lie pro- 

 tected, as the guardians of the forest. 



In the first warm days of early spring, when nature is roused 

 from her winter sleep and the crude sap is coursing sluggishly 

 through the branches, moving toward the unopened buds, slow- 

 crawling reptiles and batrachians awaken from their winter sleep. 

 From every pool and swamp in the forest is heard the croaking of 

 the frogs. The little Hyla pipes its high treble, the flat baritone 

 of the wood frogs swells the chorus, and from the margins of dark 

 pools here and there the deep boom of an early bull-frog accent- 

 uates the chorus like a bass drum in an orchestra. As the buds 

 burst and the little leaves begin to appear, the tree frogs leave the 

 pools and ascend the trees. The larger species scale the trunks, 

 sitting here and there like ugly excrescences on the trees, but un- 

 observed because of their protective coloring, and feeding on insects 

 which they find on the trunks and branches. The little squirrel 

 tree frogs (Hyla sqidrrela), sticking to the limbs and twigs as flies 

 stick to a wall, leap in bird-like flight among the branches, gather- 

 ing tiny insects there. The wood frogs glean from the dead leaves 

 on the ground and from the undergrowth their share of the tree's 

 enemies, while at the edge of the wood our old friend the toad sits 

 patiently at the foot of some huge tree in the early morning light, 

 snapping up unfortunate caterpillars that descend the trunk. 



With the opening of the leaves the insect hordes increase. Bark 

 lice swarm on the trunks, plant lice appear on leaf, twig and stem. 



