. Practical botany. Botany. CHAPTER XXII TIMBER: FORESTRY 361. Coniferous woods. Our native woods ^ are best classified into the two principal groups of soft (or coniferous) and hard The needle-leaved or coniferous trees of the country fur- nish more than three quar- ters of our timber supply. The structure of conif- erous wood, as seen for ex- ample on the end of a beam cut off squarely, or on a new lead pencil, is in one respect less complex than that of most hard woods: the wood is chiefly com- posed of tracheids, long tubular cells with taper- ing ends, and contains no continuous d
. Practical botany. Botany. CHAPTER XXII TIMBER: FORESTRY 361. Coniferous woods. Our native woods ^ are best classified into the two principal groups of soft (or coniferous) and hard The needle-leaved or coniferous trees of the country fur- nish more than three quar- ters of our timber supply. The structure of conif- erous wood, as seen for ex- ample on the end of a beam cut off squarely, or on a new lead pencil, is in one respect less complex than that of most hard woods: the wood is chiefly com- posed of tracheids, long tubular cells with taper- ing ends, and contains no continuous ducts (it may c(3ntain resm passages). The rings plainly seen on tlie cross section of some kinds are due to the dif- ference in diameter of the tracheids formed in early spring and later (Fig. 316). 1 "Timber," Bulletin 10, Division of Forestry, Dept. Agr., 1895. 2 Some of the needle-leaved or coniferous trees, such as the larch and the yew, have rather hard wood; and some broad-leaved trees, such as willows, poplars, tulip trees, and buckeyes, have soft wood; but people who deal in timber usually speak of the two general classes as explained above. 8 From Handbook of the Trees of the Northern States and Canada, writ- ten and published by Romeyn B. Hough, Lowville, New York. 390. Fig. 316. Cross section of typical conif- erous wood of white pine , boundaries between one year's growth, or "annual ring," and the next; the large, roundish white spots are cut-off resin pas- sages. Magnified fifteen diameters. Photo- micrograph by R. B. Houghs. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Bergen, Joseph Y. (Joseph Young), 1851-1917; Caldwell, Otis William, 1869- joint author. Boston, New York [etc. ] Ginn and company
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