The bark is not all one thing. It is made up of two parts; or rather, we should say, there are two barks. There is an outer bark and an inner one. The outer bark has no life in it. It is this outer bark that gives such a roughness to the trunks of some trees, as the elm and the oak. In the birch, you can peel off this bark in strips right around the trunk of the tree. Indians make very pretty boxes of these strips of birch-bark.
The outer bark is a coat for the tree. It covers up the living parts so that they shall not be injured. It does for the tree what our clothes do for our bodies. It is not a perfectly tight coat. It has little openings every where in it. It would be bad for the tree to have this coat on it tight, just as it would be bad for our bodies to have an India-rubber covering close to the skin.
This outer bark is a great protection to the tree through the cold winter. It keeps the cold from killing the trunk and the branches. This coat of the tree covers it all, even out to the end of the smallest twig. The tree looks as if it was dead in winter without its green leaves. But there is life locked up there, just as I told you there is in the seed that is kept through the winter. The life in the tree is asleep as it is in the seed. It is ready to be waked up when the warm weather of the spring shall come. During this winter’s sleep of the tree, the living inner bark and wood are safe, covered up by the tree’s rough coat.
The inner bark.
If you peel off the outer bark, as you can very easily in the birch, you come to the fresh and juicy inner bark. This I have told you is alive. It is full of sap. It has a great deal to do with the growth of the tree. It is by this bark that the wood inside of it is made.
Trees sometimes covered with straw in winter.
You have sometimes seen small trees covered in the winter with straw tied nicely all around them. This is because they are tender trees that are not used to our cold weather. They belong to a warmer climate, and God gave them just such a coat as they needed there. And when we undertake to have such trees here at the north, the coat that God has given them is not enough to keep them from freezing in our long, cold winters. So we have to put another coat over it.
Questions.—What are the parts of the trunk of a tree? Tell about the bark. What is the outside bark for? How much of the tree does it cover and protect? What is said of the life asleep in the trees in the winter? What is said of the inner bark? Why is straw tied around some trees in winter?