DEFECTS IN TIMBER CAUSED BY INSECTS 



41 



Fig. 44. — Section of short-leaf pine, showing " blue stain " of sapwood 

 after attack by the southern pine beetle (Dendroetonus frontalis). A, 

 side view ; B, cross section showing stain extending to the heartwood. 

 herious bluing in the log sometimes appears to take place without the 

 aid of insects 



