A tree takes on in winter the temperature of the surrounding air. In cold weather the water in buds and trunk and cambium freezes solid. Ice crystals form in the intercellular spaces where they have ample room, and so they do no damage in their alternate freezing and thawing. The protoplasm stiffens in excessive cold, but when the thermometer rises, life stirs again. Motion, breathing and feeding are essential to cell life.
It is hard to believe that buds freeze solid. But cut one open in a freezing cold room, and before you breathe upon it take a good look with a magnifier, and you should make out the ice crystals. The bark is actually frozen upon a stick of green stove wood. The sap that oozes out of the pith and heart wood was frozen, and dripped not at all until it was brought indoors.
What is meant by the freezing of fruit buds in winter, by which the peach crop is so often lost in Northern States? When spring opens, the warmth of the air wakes the sleeping buds. It thaws the ice in the intercellular spaces, and the cells are quick to absorb the water they gave up when winter approached. The thawing of the ground surrounds the roots with moisture. Sap rises and flows into the utmost twig. Warm days in January or February are able to deceive the tree to this extent. The sudden change back to winter again catches them. The plump cells are ruptured and killed by the "frost bite." It is a bad plan to plant a tender kind of tree on the south side of a house or a wall. The direct and the reflected warmth of the sun forces its buds out too soon, and the late frosts cut them off. There is rarely a good yield on a tree so situated.
There is no miracle like "the burst of spring." Who has watched a tree by the window as its twigs began to shine in early March, and the buds to swell and show edges of green as their scales lengthened? Then the little shoot struggled out, casting off the hindering scales with the scandalous ingratitude characteristic of infancy. Feeble and very appealing are the limp baby leaves on the shoot, as tender and pale green as asparagus tips. But all that store of rich nutritive material is backing the enterprise. The palms are lifted into the air; they broaden and take on the texture of the perfect, mature leaf. Scarcely a day is required to outgrow the hesitation and inexperience of youth. The tree stands decked in its canopy of leaves, every one of which is ready and eager to assume the responsibilities it faces. The season of starch making has opened.
Cut some twigs of convenient trees in winter. Let them be good ones, with vigorous buds, and have them at least two feet long. You may test this statement I have made about the storing of food in the twigs, and the one about the unfolding of the leafy shoots. Get a number of them from the orchard—samples from cherry, plum and apple trees; from maple and elm and any other familiar tree. Put them in jars of water and set them where they get the sun on a convenient window shelf. Give them plenty of water, and do not crowd them. It is not necessary to change the water, but cutting the ends slanting and under water 57o