178 AMERICAN FOREST TREES 



of every ring of growth in a tree that was over twenty-four feet in diam- 

 eter, and it is shown that during certain periods of years the tree grew 

 three or four times as rapidly as during other periods. 



The wood of bigtree is very light, soft, moderately strong, brittle, 

 sumnierwood thin and dark rendering the rings of annual growth easily 

 seen; the medullary rays are thin, numerous, and very obscure. The 

 wood is light to dark red, the thin sapwood nearly white; it works easily, 

 splits readily, and polishes well. It is very durable in contact with the 

 soil. Trunks lie in the woods long periods before decay seriously attacks 

 them; but forest fires hollow them, and finally burn them up. Enor- 

 mous depressions are found in the forest where logs once lay, but which 

 disappeared long ago, judging by the size of trees which have since 

 grown in the depressions. The interior of some large trunks which 

 have been worked up on sawmills showed the scars of forest fires centuries 

 ago. The annual rings which covered one such scar showed that the 

 burning took place 1,700 years ago. 



Not much can be said for the commercial uses of bigtree. Many 

 a species of insignificant size is much more useful. Considerable quan- 

 tities have been cut by sawmills. The waste is great, heavy trunks 

 crushing badly in fall. Logs are so large that many of them are split with 

 gunpowder to facilitate handling them. Some of the wood has been 

 exported for lead pencils; other has been used for fence posts, shingles, 

 and grapevine stakes, while the soft bark has been worked into novelties. 



MACNAB CYPRESS (Cupressus macnabiana) is a California tree of limited range 

 and little commercial value. It grows in Napa, Lake, Mendocino, and Trinity 

 counties; is often little more than a branching shrub, but the largest specimens may 

 be thirty feet high and fifteen inches in diameter. The wood is light, soft, and 

 usually of slow growth. The medullary rays are numerous but thin, and the bands 

 of summerwood are distinct. The cones are generally less than one inch long, and 

 the seeds have narrow wings. The foliage is grayish which is due to white glands in 

 the leaves. Forest foliage is fragrant. The tree is known as white cedar, Shasta 

 cypress, and California mountain cypress. 



