Wood Tree

Formation A tree increases in diameter by the formation, between the old wood and the inside bark, of new woody layers which envelop the entire stem, living branches, and roots. Where there are patent annual seasons, this can happen in clearly visible layers, known as expansion rings or annual rings, as can be seen on the end of a log; where there is no seasonal difference, the layers of new wood are uniform and not readily discernible. Within a enlargement ring it may be possible to see two more or less well-defined parts. The part bordering the centre of the tree is more open textured and almost invariably lighter in color than that near the outer portion of the ring. The inner portion is formed early in the season, when growth is moderately rapid; it is known as early wood or spring wood. The outer portion is the late wood or summer wood, being shaped in the summer. In white pines there is not much dissimilarity in the different parts of the ring, and as a result the wood is very consistent in texture and is easy to work. In hard pines, on the other hand, the late wood is extremely dense and is deep-colored, presenting a very decided contrast to the soft, straw-colored early wood.