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Name: Unknown
Status: educator
Grade: K-3
Location: CT
Country: N/A
Date: 9/25/2005
Question:
One of my students asks where the "old sap" goes. What should I tell him?

Replies:
Sapwood carries water and food (nutrients) up and down the tree. The old sapwood becomes heartwood.

http://www.woodmagic.vt.edu/html/Activities/wpa4.htm

Sap flows up to the leaves in the spring, and in the autumn, the sap flows downward to the roots to store the nutrients there.

http://www.michigan.gov/scope/0,1607,7-155-13497_13503_13506-43949--,00.html

http://www.inhs.uiuc.edu/chf/pub/tree_kit/teacher/lespl1.html

Anthony Brach Ph.D.

This explanation should start with the function of sap in the tree, that it is the water that conducts dissolved minerals and other growth products up and down between leaves and other parts of the plant. Sap is there all the time the tree is actively photosynthesizing and growing, and never really gets old and "goes" anywhere. At the end of the growing season the tree stops taking up water and thus sap is no longer present

J. Elliott

The simplest and most straight forward reply would be that sap moves more like a circulatory system so there is really no "old sap". By contrast, water moves in a single direction--usually from the roots to the shoots.

Jim Tokuhisa


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