By early fall (September) the trees were bare of leaves. In late Novem- 

 ber several trees had broken tops following a heavy snow fall. The bark had 

 curled away from the insertion slits for an inch or more exposing the wood. 

 There was no tendency toward cracking, although the bark appeared 



loose. 



Gray birch killed with sodiutii arseiiite tabs. Treated several months earlier, 

 the tops tceakeiied by decay have broken off during an early winter storm. 



To test bark loosening, long vertical slits were made through the bark 

 with the linoleum knife. When ne:x;t examined several weeks later, some of 

 the bark had fallen off and the rest could easily be picked off by hand. 

 Wood in the upper one third of the tree was considerably weakened by decay. 



Red Pine 



A plot of 16 red pine trees in a 30-year-old plantation was selected and 

 tieated with l/2~gram tabs. The average diameter was 5 inches and the height 

 32 feet. The date of treatment was July. 1952. Browning of the foliage was 

 seen on the first revisit to the plot 10 days later. 



In Octobej, examination showed all tops brown and apparently dead. 

 By the latter part of February the bark was loosened from the insertion 

 point upward, the top 10-15 feet showing bare wood with only patches of 

 bark still clinging to the stem. The wood in the top was infested with insects, 

 and birds, especially woodpeckers, were seen actively working on it. 



Two of the treated trees were cut to observe evidence of the path of 

 chemical action. One had received two insertions and in the other a single 

 tab had been used. The ujjward effect was shown by darkened strips which 

 followed a spiral path toward the top. The strips increased in width as they 

 approached the top so that whexe two insertions were made they merged 



12 



