[al-bur-nuh
m] 
sapwood (sāp'w d') Pronunciation Key
The younger layers of new wood produced by the interior side of the vascular cambium within a tree trunk. Sapwood is active in the conduction of water and is usually lighter in color than heartwood. |
alburnum
outer, living layers of the secondary wood of trees, which engage in transport of water and minerals to the crown of the tree. The cells therefore contain more water and lack the deposits of darkly staining chemical substances commonly found in heartwood. Sapwood is thus paler and softer than heartwood and can usually be distinguished in cross sections, as in tree stumps, although the proportions and distinctness of the two types are variable in different species
Learn more about alburnum with a free trial on Britannica.com.