Page:Timber and Timber Trees, Native and Foreign.djvu/54

 CHAPTER VI.

ON THE DEFECTS IN TREES—( Continued).

woody layers of irregular growth are found in timber, especially if there be alternation of colour extending 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 tenacity. Such logs should on no account have the preference of selection for important services in works of construction, 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 equatorial 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