Taming Our Forests

NURSE TREES

On some of this land the nurse trees can make reforestation possible without any assistance from us. That problem of the nurse trees is a very special one. If a seedling can be spared the strain of fighting for its life while it is very young, it has a better chance to grow to a fine, upstanding, valuable tree. The problem is the same that meets every human parent who must decide whether to send his child to school or into the mill. The white birch and beech stands that grow so easily in Michigan and Wisconsin, enrich the land they grow in and protect the other trees that come after them.

The aspen is a good example of a nurse tree. It is low-growing with a thin crown that does not cast a heavy shade. Its trunk is not even thick enough for good firewood. It grows from the Arctic to the Ohio River and from the Atlantic to the Pacific. It is almost useless as timber, but where a forest is destroyed by fire, as some 40 million acres have been, the aspen comes back quickly to shade the soil. Under protection, young trees of the better kinds grow up, push their way through the low roof of leaves, and form a higher leaf canopy of their own. The higher they reach into the sun, the denser the shade they cast upon their aspen nurses below. Now aspen can root in sand or clay and live in spite of wind and drought and cold, but it can't survive deep shade. Its service is done when it has taken burnt-over cut-over wasteland and held it till other trees have started and are on their way to maturity. Then it dies and leaves all the sun and rain and plant food to those young trees it has brought up.

Nurse trees, birch.