224 STUDIES OF TREES 



KEY 



I. WOODS WITHOUT PORES CONIFERS OR 

 SO-CALLED " SOFTWOODS " 



A. Woods with resin ducts. 



1. Pines. Fig. 144. Resin ducts numerous, prominent, 

 fairly evenly distributed. Wood often pitchy. Resinous 

 odor distinct. Clear demarcation between heart and sapwood. 

 There are two groups of pines soft and hard. 



(a) Soft Pines. Wood light, soft, not strong, even-textured, 

 very easy to work. Change from early wood to late wood 

 is gradual and the difference in density is not great. 

 (6) Hard Pines. Wood variable but typically rather heavy, 

 hard and strong, uneven textured, fairly easy to work. Change 

 from early wood to late wood is abrupt and the difference 

 in density and color is very marked, consequently alternate 

 layers of light and dark wood show. The wood of nearly 

 all pines is very extensively employed in construction work 

 and in general carpentry. 



2. Douglas fir. Resin ducts less numerous and conspicuous 

 than in the pines, irregularly distributed, often in small 

 groups. Odorless or nearly so. Heartwood and sapwood 

 distinct. The wood is of two kinds. In one the growth 

 rings are narrow and the wood is rather light and soft, easy 

 to work, reddish yellow in color; in the other the growth 

 rings are wide, the wood is rather hard to work, as there is 

 great contrast between the weak early wood and the very 

 dense late wood of the annual rings. 



Douglas fir is a tree of great economic importance on the 

 Pacific Coast. The wood is much like hard pine both in its 

 appearance and its uses. 



3. Spruces. Resin ducts few, small, unevenly distributed; 

 appearing mostly as white dots. Wood not resinous; odor- 

 less. The wood is white or very light colored with a silky 

 luster and with little contrast between heart and sapwood. 

 It is a great deal like soft pine, though lighter in color and 

 with much fewer and smaller resin ducts. 



