THE DESTRUCTION OF WOOD BY FUNGI 



By A. H. REGINALD BULLER, D.Sc, Ph.D. 



{Professor of Botany at the University of Manitoba) 



Millions of tons of wood are produced every year in the forests 

 of the world. Observation, however, tells us that the sum-total 

 of wood upon the surface of the earth remains fairly constant 

 from year to year and from century to century. We must 

 conclude, therefore, that there are destructive agencies at work 

 by which millions of tons of wood are destroyed annually. 

 Regarded in this light the problem of what these destructive 

 agencies are, and how they act, becomes of general scientific and 

 economic interest. 



The balance between the amount ol wood formed by trees 

 and that destroyed in a given period of time, such as a century, 

 has not always been kept. An excess in production over 

 destruction led to the formation of the Coal Measures. There 

 is no reason to suppose that the assimilatory activity of trees 

 during the Carboniferous Period was materially greater than 

 now, if similar climates be taken into account. The accumulation 

 of wood seems to have been due to the geological conditions 

 having been unfavourable to the destructive agencies, and in 

 particular to fungi. The dead parts of trees, which are deposited 

 on the floors of most forests at the present day, are kept con- 

 stantly moist or wet, so that the cell-walls contain imbibed water, 

 whilst the cell-lumina are chiefly filled with air. Under these 

 conditions the wood-destroying fungi flourish, and cause even 

 the giants of the forest to rot and disappear within a com- 

 paratively few years after death. The exact manner in which 

 coal accumulated during the Carboniferous Period has been a 

 matter of dispute, but there can be no doubt that the forest trees 

 grew for the most part in low-lying, swampy regions. Palaeo- 

 botanists have also found fungus hyphae in! fossil wood, so that 

 it seems probable that wood-destroying fungi were quite 

 common in those early times. Possibly some day the fruit- 

 bodies of Fomes or other species of Polyporei, attached to tree- 

 trunks, will be discovered, but so far nothing of the kind has 



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