No definite relation exists between the annual rings of growth and the amount of sapwood. Within the same species the cross-sectional area of the sapwood is very roughly proportional to the size of the crown of the tree. If the rings are narrow, more of them are required than where they are wide. As the tree gets larger, the sapwood must necessarily become thinner or increase materially in volume. Sapwood is thicker in the upper portion of the trunk of a tree than near the base, because the age and the diameter of the upper sections are less. COUNT 5
QSN1 What part of a tree is the cross-sectional area of the sapwood approximately proportional to? ANS1 crown QSN2 Are more rings necessary if they're narrow or wide? ANS2 narrow QSN3 As a tree grows bigger, if the sapwood layer doesn't increase in volume, what will it become? ANS3 thinner QSN4 In what part of the tree trunk is the sapwood layer thinnest? ANS4 near the base QSN5 Along with the smaller diameter of the upper trunk, what factor leads to thinner sapwood higher up a tree? ANS5 age