THE DIFFERENT PROPERTIES OF WOODS 197 



woods varies from the deep black of the heartwood of per- 

 simmon to the almost white wood of holly. When wood is 

 first formed from the cambium layer it has but little color 

 and is called sapwood. Later the wood becomes darker, 

 changing to heartwood. The change in color is due to the 

 infiltration of various coloring materials, oils, gums, tannins, 

 etc., in the walls of the cells of the wood, the color varying 

 with the kinds and amounts of these materials. 



Odor and Taste. Nearly all woods have a characteristic 

 odor and taste. In some, like red cedar, sandalwood and cam- 

 phorwood the odor adds to their value. Rotting wood also 

 has an odor that is characteristic of the species, as has also 

 the smoke of burning woods. Many woods have a pronounced 

 taste willow a bitter taste, chestnut an astringent taste. 

 The taste and odor of woods also aid in their identification,, 



