RIND-GALL AND DECAY. 71 



brittle. They are usually white at first and are then of small 

 extent or consequence ; but when they are yellowish-red, the 

 mischief has gone further; and a decided red or foxy colour 

 indicates a wide-spread decay so serious as to disqualify the 

 timber for purposes of construction. Oak, however, in an 

 advanced state of foxiness and decay is in request for cabinet- 

 work. Such decay is a gradual oxidation, or combustion of the 

 wood, similar to that which it undergoes when exposed to 

 alternations of dry and damp air. In old Beeches, and other trees, 

 it appears to begin in the pith and spread outwards, such wood 

 being known in France as bois rouge ; but it very frequently 

 originates in a broken branch, a rind-gall, or a star-shake reaching 

 the surface, so that air, damp and fungi find access to the wood 

 of the tree. It is this decay spreading from the pith that 

 gradually hollows out old trees ; but this hollowing occurs much 

 earlier in pollards where water and rotting leaves may accumulate 

 in the fork of the crown, or in trees in which broken limbs or 

 other injuries have been neglected. The breaking of a small 

 branch may set up decay, and yet such a druxy knot, as it is 

 termed, may gradually be covered up with sound wood, so that 

 only a slight swelling may indicate the defect at the surface of 

 the stem. Any such excrescence should be removed directly 

 a tree is felled ; as, though the healing over, by excluding 

 further damp, may have checked the mischief, there is no telling 

 from the outside how deep it may have extended, and such a 

 patch of decayed wood, if left to itself, is certain on being laid 

 bare in the process of conversion to absorb more atmospheric 

 moisture and so enlarge itself. 



Fungal attack. All such decay is immensely hastened, and 

 undoubtedly in many cases originated, by the action of fungi. 

 Some of these plants confine their attacks to living trees, others 

 to timber after it is felled ; and of the first-mentioned class some 

 are true parasites, attacking the roots of living and otherwise 

 healthy trees, whilst others are wound-parasites, the minute spores 

 or reproductive germs finding their way into the tree through 

 some wound not produced by the fungus. Holes bored by insects, 



