NOTES ON THE PROPERTIES OF WOOD. / 



were created whilst the tree was growing. It is asserted that they are 

 effected by frost. They look at first straight or capillary and enlarge with 

 each heavy cold. They show themselves mostly longitudinally, on a swell- 

 ing of the stem, and make the tree useless. 



The splits in the heart of a tree must not be confounded with holes 

 caused in felling. There is no clanger with the latter beyond that they 

 diminish the length of the timber. 



Often in the trunk of a stem a particular irregularity is found in 

 the non-juxtaposition of two successive annual rings. 



This fault is caused by the strong winds, which affect it in the point 

 where the flexion of the stem has its maximum. 



It will also arise when the tree has not sufficient nourishment, by 

 which two layers are prevented from growing well together. It shows itself 

 in incomplete dark rings. If these are only in the sap-wood, they may 

 be looked upon as rmimportant ; but when they are, on the contrary, in 

 the heart-wood, and accompanied with the dial, they betray a serious 

 defect in the tree. 



In some cross sections of an oak we often notice circular bands of 

 a different colour from the remainder of the section, sometimes white, 

 yellow, red, or brown. The texture of these bands appears loose, even 

 spongy, and betrays signs of decomposition. It is found in the best 

 qualities of wood, and it cannot be cured. The reason for this decay is 

 not definitely known. Some persons suppose it to arise when the sap 

 wood is prevented by severe cold from developing itself into good wood. 

 When this evil is in the heart, it looks like a whitish circle, and is 

 called the moon. Wood from such trees ought not to be used, because 

 it will soon decay. When the faulty bands are straight, and the shades 

 of colour are less observed, the vice is not so dangerous. 



Druxy knots are caused by woodpeckers, by lopping, and by dead and 

 broken branches, which make holes in the tree : into these the water 

 runs, decomposes, and directs the evil towards the inner stem. If w T e 

 find on a tree a swelling or depression, we may conclude that the con- 

 dition of the tree is bad. Such trees are olten found with the sap 

 running out of their armpits. Among the various rots engendered by 

 the knots, we have the following : — 



Wet rot is composed of porous fibre running from the knot into the 

 trunk of a tree. This rot is of brown colour and has an offensive smell. 

 This evil is often found with white spots, the latter of watery subs- 

 tance. When it has yellow flames it is very dangerous. Black coloured 

 knots are easily cured, and unimportant. 



We find wounds on trees which have been effected by the fall of a 

 neighbouring tree ; from the friction of a cartwheel by which the bark 

 was torn. If this wound does not reach beyond the bark, it has no bad 

 effect upon the wood ; but should it have damaged the ligneous portion 

 of the stem, the wood soon assumes a green-like colour, and begins to 

 decompose. 



