Rensselaer Semi-Weekly Republican, Volume 41, Number 44, Rensselaer, Jasper County, 12 February 1909 — DENTISTRY FOR TREES. [ARTICLE]

DENTISTRY FOR TREES.

Interesting Work Done Nowadays to Preserve Trees From Decay. What Is tree surgery? In so far as It applies to the cement work done a good answer would be that It is the practical application of dentistry to trees. But this answer would not cover the many branches of the profesion, consisting of trimming, chaining, packing, scraping, spraying and fertlizing. Tree surgery is in fact an advanced development of arboriculture. Both fruit and shade trees are valued now as never before, and the fact has become generally kneiwn that by skilful methods of the tree surgeon it is possible to give new lease of life to trees which apparently had reached their limit of existence. It is safe to say that almost any tree of medium age may be saved by these methods. Of the many branches embraced in this work the cement filling forms by far the largest and most important part. The practice of filling cavities with cement has long been in use, but when carried out along the usual lines it only serves to add to the original trouble. The method of sealing up the decayed section simply increases the decay. Many examples may be seen where the bark at one side of the cavity was covered by the cement, no regard having been paid to drainage or the subsequent healing of the wound. As the cement did not stick to the wood and the swaying of the tree by the wind often enlarged the crack between the wood and the filling water penetrated behind the cement and decay wen ton even more rapidly than before.

The tree grows in girth by the deposit of a thin layer of new wood between the wood and the bark. There are three layers in this coat —the middle one being composed of thin forming tissues known as “cambium.” The inner- Bide of this layer forms new wood, the outer new bark. It is this new lhyer and the layers of the four or five previous years which are known as the sapwood, and form the active section of the trunk and branches. The cells of these inner rings are gradually covered by the yearly deposits of new growth, and from living sapwood becomes heartwood, which 1b dead and serves merely as a strong framework for the living parts of the tree and as storehouses for exess material. This is the reason why hollow trees may often be found Iq a flourishing condition when the heartwood may have entirely disappeared. However, a landscape tree in this condition, deprived of the shelter of its fellows, is in grave danger, for a high wind or a heavy snowfall may find it an easy victim. After a mass of decay has been removed from the interior of the rotting trunk there remains a shell of living sapwood and bark. Into this cavity a steel brace Is Inserted and bolted in place. This gives the tree a stability which by the decay of the supporting heartwood it had lost. Now comes an important-operation,- the-cut-ting of the water sheds which prevent the entrance of moisture. The watersheds consist of a deep groove cut about an, inch inside the edge and opening to the ground below. The cement, being packed tightly into tnese grooves, forms a channel -over which the water flows, to be let out at the base. The cavity is then wired 1 throughout, the wire being stretched from nails driven into the wood, and acting as re-enforcing for the cement. This work having been completed, the cement is made as moist as possible, and then built out into the original outline of the tree. The bark which has been cut back for an inch or so In order to prevent bruising while the? work is in progress will eventually cover the filled in wound, the tree thus regaining its normal appearance In the case of exceptionally large cavities the opening is covered by large strips of zinc. The cement is; then forced down into every crevice and allowed to set, after which the. zinc is removed and a coat of fine finishing oement put on and painted the color of the bark. By this method the tree surgeon is enabled to build out* trees where fully half the wood may have been destroyed by lightnlny or from some other cause. This treatment serves as a fine example of the healing powers or nature, for it is remarkable how Qttickly these wounds will heal when protected from moisture and further decay by the cement filling insured by the watersheds.— Cement Age. 11