CONTENTS. 



Page. 



Outline of trip. _ . _. 9 



The Androscoggin region and its sijruce forests 11 



Dead and dying spruce . . - - . . 13 



Some characteristics of the dying and dead spruce 14 



Causes of decay and death . - - - 14 



Relation of insects to the trouble . 15 



The spruce-destroying beetle 15 



Description of the destroyer.. 16 



Life history of the beetle 17 



How it passes the fall, winter, and spring 17 



When activity commences in the spring. ... . . . 17 



The summer period . 18 



Summary of life history 18 



Explanation of diagram. 19 



Special features of the beetle's work ._ 20 



Kind of trees attacked . . . 20 



How and when the attack is made . . 20 



Its work in and beneath the bark _..._. ... 20 



The distinctive, visible evidences of the spriace destroyer's work. _ 22 



Pitch tubes ... .... 22 



Appearance of the leaves . _ 22 



Appearance of the twigs _ 22 



Appearance of the bark and wood 32 



Woodpecker work 23 



A common fungus on the bark of dead trees 23 



The principal natural enemies of the spruce-destroying beetle ... 24 



A parasitic enemy 24 



A predaceous beetle 24 



Birds as enemies of the beetle _ . 25 



A fungous disease of the beetle. 26 



Climatic conditions 26 



The principal insect allies of the spruce destroyer . 26 



The spruce Polygraphus 26 



The spruce Tetropium 27 



Other insects ... . 27 



Historical references ... _ 28 



Remedies and methods of prevention 30 



Review of proposed methods 30 



Stripping off and burning the bark 30 



Destruction of dead trees 31 



Girdling trees 31 



Investigation of the girdled-tree method 31 



Hack-girdled and peeled spruce 31 



Report on girdling experiments, by Mr. Austin Carj' 32 



Comments on Mr. Cary's work 40 



Suggestions and recommendations 41 



Methods of reducing the number of beetles .; 42 



Utilization of dead spruce . 45 



Importance of harvesting the matured crop of spruce 46 



Summary 47 



