Fall brings the mir­a­cle of leaf­less aspen trees

Serve Daily - - EMPOWERING LIBERTY - By Ed Helmick

In the sum­mer I wrote about the amaz­ing aspen forests and their fam­ily root sys­tem. In the fall we see the colors of the aspen groves as eye candy that we rush out to pho­to­graph each year. Now, as we move into the win­ter months, there is an­other unique fea­ture of the aspen trees to amaze us: chloro­phyll in the bark.

When we think of chloro­phyll, we nor­mally think of tree leaves. The aspen tree is un­usual in that the tree bark has a high con­cen­tra­tion of chloro­phyll that is ca­pa­ble of car­ry­ing out pho­to­syn­the­sis and the pro­duc­tion of car­bo­hy­drates nor­mally re­served for leaves. This is a re­mark­able adap­ta­tion to the en­vi­ron­ment in which the aspen trees live. They must not only sur­vive but thrive in a cli­mate of rel­a­tively cool summers and cold win­ters at an al­ti­tude of al­ti­tude of 5,000 to 12,000 feet. The cre­ator has en­abled the aspen to pro­duce food even in the win­ter months.

Aspen bark is very thin and the chloro­phyll layer lies within about 1/32 inch of the ex­te­rior sur­face of the bark. The ex­te­rior sur­face is called the peri­d­erm, and when you brush the tree bark with your hand, the white that comes off on your hand is the dead peri­d­erm cells. The pho­to­syn­thetic layer com­prises only about 5 per­cent of the to­tal vol­ume of the bark of an aspen tree but ac­counts for 30 to 50 per­cent of the car­bo­hy­drate pro­duc­tion as the leaves.

This in­di­cates the im­por­tance of the bark to the nu­tri­tion of the tree and how un­usual it is from other trees that lose their leaves and be­come dor­mant dur­ing win­ter. This also gives the aspen tree a head start in spring growth.

This car­bo­hy­drate re­source does not go un­no­ticed dur­ing the hard win­ters and be­comes a food source for for­est wildlife. Deer and elk strip the bark from aspen trees when grass is not avail­able. Bur­row­ing an­i­mals such as go­phers dig and feed upon the roots. The amaz­ing aspen tree is a mir­a­cle for the whole for­est.

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