Researches on Cellulose, 3). The balance is made 

 up of lower carbohydrates, chiefly pentosans and 

 hexosans, and small amounts, of protein and mineral 

 ash. The moisture content of pine varies from 

 about 5 per cent in very fat wood to 30-40 per 

 cent or more in some classes of lean wood, average 

 air-dry wood containing about 20 per cent of 

 moisture. This is an important consideration in all 

 calculations. 



Classification of Wood Waste 



It is well to have in mind the various classes 

 of wood waste which are available. The mill waste, 

 which represents about 35 per cent of the original 

 tree, is chiefly sawdust, slabs and edgings. The 

 sawdust is usually low in oleoresin content, be- 

 cause the average saw lumber is lean. Moreover, 

 its fine state of division allows more or less volati- 

 lization of the turpentine. The slabs are available 

 in large quantities and offer one of the most con- 

 venient forms of raw material. Their percentage 

 of bark is of course very high and its removal is 

 a problem to be considered. Furthermore, the 

 slabs come from the outer sapwood of the tree, 

 where the oleoresin content is lowest. The richest 

 slabs are those from the "box face" of trees which 

 have been tapped for gum spirits of turpentine. 

 The waste remaining in the forest is abundant, 

 but is not so accessible. Large branches, tree- 

 tops and occasional logs left by the lumbermen 

 afford raw material in a form compact enough 

 for handling. Stumps usually have a high oleoresin 

 content and offer a great bulk of solid rich wood. 

 Their utilization is of special significance in cases 

 where the land is being cleared for agricultural 

 purposes. Uprooting of the stumps and perhaps 

 freeing from dirt and roots must be taken into 

 account. The most attractive class of forest waste 

 is the "dead and down" material known as "light- 

 wood." After the period of turpentine orcharding, 

 the exhausted trees are in many cases allowed 

 to remain until they fall. The bark and. the outer 

 sapwood decay and in five to fifteen years there is 

 left a resinous log, which resists the natural process- 

 es of disintegration for long periods. This explains 



