FIRE-BLIGHT AND WINTER KILLING.Theseare two entirely different processes. TheFire Blight(of the middle and western States), is a disease of the circulatory system, induced by a freezing of the sap whilethe tree is in a growing and excitable state. It alwaysmustoccur before the leaves are shed in the autumn. Winter-killing is of two kinds—resulting from severe cold, and from untimely heat. The loss of tender shrubs, roses, etc., at least, before they are fully established, and of half-hardy fruit-trees, is occasioned by the winter sun shining warmly upon them while frozen, and suddenly thawingthem. The point of death is usually near the surface of the ground, where the under-ground bark and upper bark come together. Whole orchards are destroyed in this way; and, if examined, the bark may be foundsprung offfrom the wood. This may occur at any time during the winter.We are in doubt whether the winter-stored sap exists in a state to be affected by the expansion of the freezing fluids of the tree. If the expansion of congelationdidproduce the effect, it should have been moregeneral, for there are fluids in every part of the trunk—all congeal or expand—and the bursting of the trunk in one place would not relieve the contiguous portions. We should expect, if this were the cause, that the tree wouldexplode, rather than split. Capt. Bach, when wintering near Great Slave Lake, about 63° north latitude, experienced a cold of 70° below zero. Nor could any fire raise itin the housemore than 12° above zero. Mathematical instrument cases, and boxes of seasoned fir, split in pieces by the cold. Could it have been the sap inseasoned fir woodwhich split them by its expansion in congealing?We quote a paragraph from Loudon—“The history of frosts furnishes very extraordinary facts. The trees are often scorched and burnt up, as with the most excessive heat, in consequence of the separation of the water from the air, which is therefore very drying. In the great frost in 1683, the trunks of oak, ash, walnut, and other trees, were miserably split and cleft, so that they might be seen through, and the cracks often attended with dreadful noises like the explosion of fire-arms.”We don’t exactly know whether to take the first part as Loudon’s explanation of the facts in the second.There can be no doubt that the nature of the summer’s growth, very much determines the power of a tree to resist the severity of winter. When there is but an imperfect ripening in a cold and backward season, the tissues formedwill be feeble, and the juices stored in them thin. Now the power to resist cold, among other things, is in proportion to the viscidity of the fluids in a plant.It is highly desirable that the chemical researches which have revolutionized the art of cultivation, should be pushed into themorbid anatomyof vegetation. A close, exact analysis of all the substances in an injured condition, will save a vast deal of bootless ingenuity and fanciful speculation.
Theseare two entirely different processes. TheFire Blight(of the middle and western States), is a disease of the circulatory system, induced by a freezing of the sap whilethe tree is in a growing and excitable state. It alwaysmustoccur before the leaves are shed in the autumn. Winter-killing is of two kinds—resulting from severe cold, and from untimely heat. The loss of tender shrubs, roses, etc., at least, before they are fully established, and of half-hardy fruit-trees, is occasioned by the winter sun shining warmly upon them while frozen, and suddenly thawingthem. The point of death is usually near the surface of the ground, where the under-ground bark and upper bark come together. Whole orchards are destroyed in this way; and, if examined, the bark may be foundsprung offfrom the wood. This may occur at any time during the winter.
We are in doubt whether the winter-stored sap exists in a state to be affected by the expansion of the freezing fluids of the tree. If the expansion of congelationdidproduce the effect, it should have been moregeneral, for there are fluids in every part of the trunk—all congeal or expand—and the bursting of the trunk in one place would not relieve the contiguous portions. We should expect, if this were the cause, that the tree wouldexplode, rather than split. Capt. Bach, when wintering near Great Slave Lake, about 63° north latitude, experienced a cold of 70° below zero. Nor could any fire raise itin the housemore than 12° above zero. Mathematical instrument cases, and boxes of seasoned fir, split in pieces by the cold. Could it have been the sap inseasoned fir woodwhich split them by its expansion in congealing?
We quote a paragraph from Loudon—“The history of frosts furnishes very extraordinary facts. The trees are often scorched and burnt up, as with the most excessive heat, in consequence of the separation of the water from the air, which is therefore very drying. In the great frost in 1683, the trunks of oak, ash, walnut, and other trees, were miserably split and cleft, so that they might be seen through, and the cracks often attended with dreadful noises like the explosion of fire-arms.”
We don’t exactly know whether to take the first part as Loudon’s explanation of the facts in the second.
There can be no doubt that the nature of the summer’s growth, very much determines the power of a tree to resist the severity of winter. When there is but an imperfect ripening in a cold and backward season, the tissues formedwill be feeble, and the juices stored in them thin. Now the power to resist cold, among other things, is in proportion to the viscidity of the fluids in a plant.
It is highly desirable that the chemical researches which have revolutionized the art of cultivation, should be pushed into themorbid anatomyof vegetation. A close, exact analysis of all the substances in an injured condition, will save a vast deal of bootless ingenuity and fanciful speculation.