CHAPTER VI. 



ON THE DEFECTS IN TREES (Continued}. 



WHERE woody layers of irregular growth are found in 

 timber, especially if there be alternation of colour extend- 

 ing over many of them, they may be considered to 

 indicate that the tree was not at all times in a healthy 

 state, but that it had suffered from some cause, or from 

 the failure in the nourishment it required to perfect the 

 layers with regularity. 



Any departure, therefore, from the natural colour 

 peculiar to the species, whether it embrace one or more 

 concentric circles, or be locally situated, is prejudicial 

 to the wood, and generally, if tried under the adze 

 or plane, it will be found brittle and deficient in 'tena- 

 city. Such logs should on no account have the preference 

 of selection for important services in works of construc- 

 tion, but should rather be used for minor purposes. I 

 have noticed this defect in many varieties of trees, but in 

 none is it more conspicuous than in the Kauri of New 

 Zealand, these noble Pines being peculiarly liable to this 

 whenever they stand exposed upon the north or equa- 

 torial side. 



We occasionally see, spots in timber, quite foreign in 

 colour to that which is natural to it ; they may be seen 

 in all parts, but are most common at or upon the butt- 

 end of the log. These are not often of a very serious 



