This is the time of year our country ancestors claimed the “sap is falling” in trees as if trees were to be sapless until the “sap rises” in the spring.”

Technically, that is not correct. Sap is water and all its diluted stuff within trees.

Truth is the moisture within trees does not vary much during the year.

There will be spring and summer periods when tree moisture is a little higher due to cloudy weather and lots of rain.

Likewise, extended periods of hot, dry weather causes more water loss through leaves and less soil water available to roots, meaning a slightly lowered tree moisture.

But there is water within tree trunks year round and, again, the moisture level does not vary much.

Now, the amount of water, aka sap, moving up and down within trees does slow way down for winter and pick back up with spring growth.

For deciduous trees with no leaves in winter, water movement is nearly halted.

Within evergreen trees, there is still a minute amount of photosynthesis on warm, sunny days so water movement adjusts accordingly.

What we refer to as sap is indeed mostly water.

Pulled up from the ground by roots, upward moving water contains mineral nutrients from soil to feed the leaves with plant hormones added in along the way.

That’s oversimplifying the chemical makeup of sap, but it’ll do here.

Harkening back to high school botany, the thin layer within a tree that carries sap upwards is the xylem, pronounced “zy-lem.”

In the same class, we learned sap moves downward through limbs and trunks via the phloem, pronounced “flo-em.”  I was one of the not-so-scientific students who recalled at test time that “xylem zips it up, phloem flows it down.”

The phloem sap moving down is still mostly water but contains the sugar made within leaves to feed the rest of the tree and to be stored for lean times.

All trees make sugar and send it down in phloem sap; the sugar maple tree species just has a very high level of sap sugar and thus is “tapped” and its sap boiled down to maple syrup.

In some Eastern Europe countries, the sap of birch trees is likewise collected and either consumed as fresh “birch juice” or fermented into a booze of some sort.

Two tree liquids that are not sap at all are latex in rubber trees and pine resin used to make turpentine.

Though not a tree, the Aloe Vera plant’s liquid with so many human uses truly is that species’ sap.

One tree industry here and throughout much of Mississippi that can vouch for year round tree sap is the pulpwood business.

Pulpwood tree trunks have been bought and sold by weight for decades now. The old volume measurement of cords has been relegated to history and firewood. Those buying pulpwood keep up with moisture levels of wood since there is no fiber in water. And there is water in winter wood.
Terry Rector is a spokesman for the Warren County Soil and Water Conservation District.