AMERICAN FOREST TREES 5 



evergreen, and yet are true hardwoods. In a test of hardness they 

 stand near the top of the list. 



There are more species of hardwoods than of softwoods in this 

 country ; but the actual quantity of softwood timber in the forests greatly 

 exceeds the hardwoods. Nearly two hundred species of the latter are 

 seldom or never seen in a sawmill, while softwoods are generally cut and 

 used wherever found in accessible situations. 



As in the case of needleleaf trees, there is much variation in actual 

 hardness of the wood of different broadleaf species. Some which are 

 classed as hardwoods are softer than some in the softwood list. It is 

 apparent, therefore, that the terms hardwood and softwood are com- 

 mercial rather than scientific. 



Palm, cactus, and other trees of that class are not often employed 

 as lumber, and it is not customary to speak of them as either hardwoods 

 or softwoods. 



Sapwood and Heart-wood Practically all mature trees contain 

 two qualities of wood known as sap and heart. The inner portion is 

 the heartwood, the outer the sap. They are usually distinguished by 

 differences of color. 



The terms are much used in lumber transactions and are well 

 understood by the trade. The two kinds of wood need be described 

 only in the most general way, and for the guidance and information of 

 those who are not familiar with them. Differences are many and 

 radical in the relative size and appearance of the two kinds of wood in 

 different species, and even between different trees of the same species. 

 No general law is followed, except that the heartwood forms in the 

 interior of the tree, and the sapwood in a band outside, next to the bark. 

 In the majority of cases young trees have little heartwood, often none. 

 It is a development attendant on age, yet age does not always produce it. 

 Some mature trees have no heartwood, others very little. 



The two kinds of wood belong to needleleaf and broadleaf trees 

 alike; but palms, owing to their manner of growth, have neither. Their 

 size increases in height rather than in diameter. With palms, the oldest 

 wood is in the base of the trunk, the newest in the top ; but in the ordinary 

 timber tree the oldest wood is in the center of the trunk, the youngest 

 in the outside layers next the bark. It is the oldest that becomes heart- 

 wood, and it is, of course, in the center of the tree. The band of sapwood 

 is of no certain thickness, but averages much thicker in some species 

 than in others. The sapwood of Osage orange is scarcely half an inch 

 thick, and in loblolly pine it may be six inches or more. 



Heartwood is known by its color. The eye can detect no other 

 difference between it and the surrounding band of sapwood. There is 



