FOREST PROTECTION 19 



Protective measures are: 

 Screens of wire or lath over nursery beds. The mesh must be fine, 

 and the distance between the lath must not exceed % inch. 

 Shooting some birds, keeping the balance scared off. 

 . Coating the seeds in red lead (very efficient), one poimd of red 

 lead being sufficient to cover seven pounds of coniferous seeds. 

 Shortening the period of exposure by planting the seeds in late 

 spring after three to eight days mulching. 

 VI. — WooDPFXKERS. Woodpcckers withdraw the larva> of wood boring 

 insects from their mines with the help of a long, thin tongue. They 

 withdraw useful as well as harmful insects. They do damage by 

 opening cones and by eating the seeds thereof. 

 The damage done by picking holes into the cambiima layers of 

 certain trees is small. The holes made in sound yellow poplars 

 rather denote a high quality than the presence of defective tim- 

 ber. The holes made in oak and chestnuts are usually made in 

 rotten or decaying wood, or in wood of no commercial value. 

 There exist four theories attempting to explain the curious girdles 

 of holes made by the woodpecker, 

 a. — Incubator Theory. 



Holes are picked to invite the ovipositing of insects in such holes, 

 b. — Napkin Theory. 



The woodpecker cleans its beak from particles of rosin, 

 c. — Calendar Theory. 



Due to observation that woodpecker returns at regular inter- 

 vals to same tree, 

 d. — Sap-sucking Theory. 



