In our cold temperate zone spring means chiefly the changing of the
trees from their naked winter condition to the beautiful green leafy
appearance of early summer. When stripped of their foliage, trees
present to the observant eye a great variety of form. The tall, slender
poplar can easily be distinguished from the spreading elm as far as it
is seen; as, also, can the rough-barked hickory, with its clinging
strips of bark, from the smooth beech.
Usually, the opening of buds seems to take place almost in a single
night, but they really open very gradually. Now, these buds are all
formed the summer before, but they are so small that they are scarcely
noticed in the midst of the many leaves. In the winter, however, they
are readily seen; and, then, when the first warm rains fall in the
spring they start to swell, and gradually grow larger until, suddenly,
they burst through their snug winter coats, and show the tiny, green
leaves that have been concealed in the thick, dark, outer covering.
The buckeye bud is one of the largest of the winter buds. It is covered
with small, pointed, brown scales, which overlap each other, thus
keeping the cold from the more delicate parts within. Underneath these
hard outer scales are thinner, half-transparent ones. Their color is a
delicate pink, and fine veins line them. Snugly wrapped inside these
dainty coats are tiny woolly objects, and when the wool is removed they
are found to be miniature leaves folded together so compactly that they
occupy very little room. If the bud has grown on the end of the twig a
very small flower bud will be enclosed within the leaves; but if it has
grown on the side there will be no flower bud. Since these leaves and
flowers have all been formed the summer before, it is easy to understand
that a few warm days will cause them to grow so that they soon become
too large for their winter covering, and suddenly burst it open.
The trees are forced into a period of inactivity by the cold, so, if a
twig is broken off, and placed in moderately warm water, in a warm,
light place, the buds on it will open just as they do in the spring and
their development may be easily watched.
Often a tree will have a countless number of buds; and since growing
buds need much light and nourishment only the stronger ones will grow,
the weaker ones remaining in a resting state. These resting buds are
called dormant buds, the word dormant coming from the Latin word
“dormio,” which means “to sleep.” The buds often continue in this
dormant state for several years, becoming weaker and weaker all the
time, until finally they die. If, however, the stronger buds are killed
at any time, as by a late frost, the dormant ones suddenly become
active, and grow to take the place of the ones that were destroyed. This
shows us how cleverly trees provide substitutes for cases of emergency.
These dormant buds then might even be compared to the understudies of
the stage.
The regular places for buds to grow are in the axes of the leaves or on
the end of the twigs. Buds, however, can be made to grow on unusual
places. If the tops of the tree are cut off, as we often see them in the
maple, buds will grow on the trunks. Then, if trees are cut down or
blown over, buds will grow on the stumps or from the roots.
Thus, we can see by watching the formation and development of buds, and
the growth of branches, that trees follow certain fixed laws of nature,
modifying these laws only on account of some peculiar external
conditions as, for example, nourishment, light, heat or moisture.
Roberta Irvine Brotherson.