554 



RELATION TO ENVIRONMENT. 



Fig. 504. 



Spawn of the "mushroom" as it make 

 its way through the wood of the tree. 



story of these "wood-destroying" fungi in the living tree. 



Branches broken by snow, 

 by wind, by falling timber, 

 provide entrance areas where 

 the spores, lodging on the 

 heart-wood of broken timber, 

 or on a bruise on the side 

 of the trunk, which has 

 broken through the living 

 part of the tree lying just 

 beneath the bark, provide 

 a point for entrance. The 

 living substance (protoplasm) 

 in the spawn exudes a 

 "juice" (enzyme) which dis- 

 solves an opening in the wood cells and permits the spawn to 

 enter the heart of the tree, where decay rapidly proceeds as a 

 result. But very few of these plants can enter the tree when 

 the living part underneath the bark is unbroken. 



These observations suggest useful topics for thought. They 

 suggest practical methods of prevention, careful forestry treat- 

 ment, and careful lumbering to protect the young growth when 

 timber trees are felled. They suggest careful pruning of fruit 

 and shade trees, by cutting limbs smooth and close to the trunk, 

 and then painting the smooth surface with some lead paint. 



1040. Scavenger members of the forest societies. While 

 many of the mushrooms are enemies of the forest, "they are, at 

 the same time, of incalculable use to the forest. The mushrooms 

 are nature's most active agents in the disposal of the forest's 

 waste material. Forests that have developed without the guid- 

 ance of man have been absolutely dependent upon them for 

 their continual existence. Where the species of mushrooms are 

 comparatively few which attack living trees, there are hundreds 

 of kinds ready to strike into fallen timber. There is a degree of 

 moisture present on the forest floor exactly suited to the rapid 

 growth of the mycelium of numbers of species in the bark, sap- 



