70 OF WOOD IN GENERAL. 



whilst as exceptionally liable to the defect he mentions the true 

 Indian Teak (Tectona grdndis), the Australian Tewart (Eucalyptus 

 gomphocdphala), the Riga and Swedish varieties of Pinus sylvestris, 

 and P. austrdlis, the Pitch Pine of the southern United States. 

 Greenheart (Neddndra Rudi<n) commonly develops two crossing 

 heart-shakes for two or three feet up the butt end of the log. 

 One of the worst forms of this defect is when, owing to spiral 

 growth, the shake shifts its direction as we trace it up the stem. 

 It may in this way sometimes be nearly at right angles at one 

 end of the tree to its direction at the other, thus rendering the 

 conversion of a log into plank well nigh impossible. 



It is this hindrance to the conversion of timber into plank that 

 constitutes the main practical importance of all forms of shake, 

 as they do not at first involve any decay, and consequently do 

 not much interfere with the employment of the logs in bulk. 

 Heart-shake, however, is probably in itself an indication of that 

 incipient decay that comes when timber has passed its maturity 

 and the older layers shrink more than the outer. 



Rind-gall. Somewhat allied to cup-shake is the local defect 

 known as rind-gall. This originates from the destruction of part 

 of the bark of a growing tree, whether by another tree falling 

 against it, the scorching of a forest-fire, the knawing of an 

 animal, or even the cutting of initials by some misguided youth. 

 If the cut has penetrated to, exposed, and destroyed the cambium, 

 there may, in spite of the gradual overgrowth of layers of new 

 wood from the margins of the injury, be a local want of cohesion 

 between the exposed wood and that subsequently formed over it. 

 This defect may entirely escape detection from the outside of an 

 unconverted log. 



Decay. Bright-looking wood is generally of better quality 

 than that which is dull ; while any departure from the usual 

 colour of the timber of the species is commonly, as we have 

 already stated, an indication of at least incipient local decay. 

 Discoloured patches, such as occur on the exterior of the butt 

 ends of some masts of the Kauri (or Cowdie) Pine of New 

 Zealand (Agathis austrdlis), will generally be found to be relatively 



