eI 2 a o >| SNINTVO. nn ree nets eee re iit ae RM A a a a a ee ae a a a a a ae Ce , WBS LY i Se) 0 ‘7 H TO FORESTS > E, A. CALKINS i : 1898 i _ ee ee ee ee Cee ee LIBRARY Michigan State University PLACE IN RETURN BOX to remove this checkout from your record. TO AVOID FINES return on or before date due. MAY BE RECALLED with earlier due date if requested. DATE DUE DATE DUE DATE DUE 5/08 K:/Proj/Acc&Pres/CIRC/DateDue.indd Senior Arricultural Thesis "CAUSES OF DAMAGE TO FORESTS." bY \ oo 1° . ‘. EL A. Qplkins, Class of ‘98, Michigan Agrizultural College, aq Avrioultural College, Hicnh. THESIS CAUSES OF DAMAGE TO FORESTS, Perhnans no problem of the prescnt is of greater importance than that of forest preservation. Tre growing demand for timber and the constantly decreasing, supply nas at last avrakoned interest in this matter, anc forest dacfen- eration and regeneration are promising subjects for the seier- tist of the future. Snaring in this general intercst, the writer has urder- taken a little local investigation into some of the causes of injury to trees and tho seneral causes of forest destruction. This investigation bas been decicedlly Local in charecter, and necessarily limited in extent. saperinental vork was impos-— sible, and what was done was by personal observation, supple- monted with a limited amount of reading. The observations, however, were quite extensive, and were confined to the for- sts adjoining the College and one visit to Genesee County. They cover a period of three onths time, when the means of crvation were the pest. Although the vork vas not as complete as could have been desired, it was instructive and revealod some interesti points about local rorest areas, as well as about forest areas in general. Both normal and abnovral causes, whether confincda to a single tree or to Whole tracts of trees, were observed 94303 Ke and will be ineluded in this article. Nor was the observation confined to rorest tracts alone, but the observation of fores trees, whether in landseanc, roadside or pasture, was ineluded, “or they are there subjcct to the same lavs as in the primeval 2 C2 forest. The various causes may be divided into: Wounds , Floods, Twinings Vines, Lrainage, Freezing, Drought, Hleetric Currents, Cutting of Tizrber, Storms, Pasturing Forests. Wounds. This term avplies to any contusion ofr the cortex of a tree, that extends through the came to the roody tissue beneath. Wounds are a prolific caise oF damage ani ciccase in trees. Their natural tenéeney is to heal with but little esulting injury, but so much depends on conditions that this seldom occurs. The main healing function of the tree lies in the inner layers of cortical perenchyma and cambiun. Ir it be wounded in the growing scason these cells and the ex- posed woody cells commence to repair tne injury at onee. The woody cells exuzes a fluid that supplements, for the time being, the destroyed cortex, The cami cells exposed apout the round multiply anc readilv forn a callus about it that will grow over the exposed part, and may in time entirely eover it. If a tree is srirdled this action cannot take placc, and the tree will eventually die unless the round be proteatect from air and kevt moist by sore covering. The process or healing can also bc hastened by shielding the vound from the 3. air, as tne healing is not then dependent upon the surrounding camviurn alone, but may procecd irom caibliu2 cells still rensin- ing on the voody portion. This action is normal, and will oceur only when the cclls are in a@ fsrowing and moist ecndition. If the wound ocetws wen the tree is cormant, no exudation will take place from the woody cells, anda tne cortical and cambium cells will not form a callus until the grovirg season arrives. while the exposed cells of both cortex and wood Will become dryv, and the woody portion may creck. Again, when the cortex berins to remedy the evil the process is men slower than it would have been had the injury occurred in the season of rrovth. This healing action depends mucn on tne age. and vigor of a tree. Old or weak trees recover Im:eh clover than voung and vigorous ones. T en the characteristics of species aiters tke action mich. For instance, the beecn grows slowly and has thin bark; hence heals slowly then wouncec anc has a tendency to result badly. Or the other hand the povlar is a rapid growing tree, and will readilv recover from a wound that would permanently injure a beech. Primarily, wounds are injuries from woich no tree can Tully recover. They damere the wounded portion vor eccnonie purposes, aii eaunot fail to imvair tre vigor of a tree cven thourh they be not severe. If on a branen or in tie top of a tree they weaken the same, and the wounded pomtion dies to the first sound branch or sub-oranchn. If on the trunk or root of a tree thev so weaken tre vortion that it cannct re- sist tne wind. Aside from these direct injuries, wounds leave a tree sbject to sibseauent deteriorating arencies, if they rave not normally healed, If they are cxnosed to the elements tney eventually vield to coeay, whieh in turn invites sapro- phytes and various insects. These nasten the destruction by weakening the wounccod portion and are soon fslloved pv birds in quest of food and animals that nest in hollows of trees, Incidental to these azencics comes the action of the natural elements. The wounded sortion, perforated by inseets, tim nelled by birds and animals ana decaying from saprophnytes, is at the same time subjected to moisture and oxidation, whieh favor tne attacks of fungi anc bacteria. Then it may become waterscaked and freeze ss that the adjoining parts of the tree are split. Under the combined action of a vart or all these agensies tc rourd becolecs a serious injury to tre tree end a cente~ fror whien disease may spread. Various Vounds. Or the various wounds observed the following are most cormon: Wouncins by Maple Borers. A great muitber of Acer saccharinum that had been wounde2 by borers were observed in the voods east of No. 7 Collese Fa~r. These trees had nearly all recovored fairly weil - a result that was no doubt due to the cortex protcctiing the injured portion after the wound. But in some instances the trees were seriouslv injured. The borer tends to make bud wounds because of his habit of burroving around the trunk - thus having a girding erfect. The depredations of this inscet arc by ne means frenceral. In no other place ‘yac it done mich Gamage, and even in the woods noted avove his work was con- fined to the trees standing on te clevated crouid. C1 e Cutting and Hauling Timber. hany injuries wcsiult rrom handling timber ina forest. They are mostliv caused by cutting and hauling. The rounds teay be from detached, paerered or glazed trunks meds i: fell- ing trees, or trey mey be erusnec or harked roots and trunks cue to hauling loss. Wnatsoever tneir cause, they mav result in serious damare ana are unually large vounds. From opserva- ° tions mace it was evicent that many of the beeches with weak, deceved bottoms had reccived the primary injury rrom falling trees, fellen cither by nature or the roodsman. x Vounds. Tt is hard to find a forest in the populous parts of the state that has net been injured by ax wounds on the trecs., wo forest visited ves free from sueh vouneds. The oaks have nuf- fered most, no foubt because they nave at some time becn sortec by the timbcr insvectors. Some of these wounds are healed, others arc leasing to the final death of the trees, vet whatever their condition these wounds have injurec a sec- tion of each tree for its fullest utilitv. Barking by Animals. Barking by Rabbits, sauirrels and mice is) 20onfined to younr deciduous trece. Rabbits and mice prefer the cortex of tender shoats of younr fruit bearing trees, but will eat of less valatable shrubs when stressed for food. Their work may be severe. The squirrel is known to damage Conifers by removing the younr cones and buds. In the observations mace several elumps of small Acer saccharinunm that had been girdled by rox squirrels for severe 21 successive seasons were found. The squirrel may also gnaw his way into the trunks of larcce trees if there is somethine edible trere to invite the attempt. Ww poping the lavle,. This wound ils usuaeliy not of a serious nature teerause nace close to the growing season and is usually small. But when the old method of ax tanning was used it was rather narsh. By that method a fev vears sufficed to surround the tree with sears and wounds, which greatly weakencd the tree. Defoliation b-- Insects. Tris is a wound of a serious nature, becau..e it removes froi the tree cscential organs or growth and organs that have eonsumcd @ preat amount of the rescorve food of the trec in cir Dormation. Onee removed, the tree nuts forth a new foliase for the season thus robbing tc cortex of its frovth and the development of the tree for the time being is erresten. Thoin defoliavior may bEe rollove? pv a seconi ieLroliaticn or by drourht or some other adverse coneition, and the virtually imaire2 tree is kilied. Defoliation is caused br insects or iungi, and may be causcd at any time in tho proving season. The result of an attack depends upon the season. Yhen tne tree is froving most rapidlv the result is most disastrous. Twinine Vines. The grape and bitter sveet may injure trees by srow- ing into them. The injurics by the latter are superficial. It docs not imnpair the health of a tree but alters its orn and retards its growth by twining tightly about its stem, even to being ovco»prown by the develop:zent or the host plant. Its action is corfined to younr trecs and shrubs. The grane docs not injure the stem but tends to smother the tops of trecs. It grows rapidly and has abundant foliage, and may so over— shadow the host tree as to eause its branches to die from disuse and gonerally tiapair its visor. The grave mav erev into the largest forest trecs. Freezing. rreezing may burst tne soundect tree. probably irom sudden chenzes of temerature tho outer cni inner layers or the tree acquire cifferent temperature, and stresses are thus set up which the tree cannot resist and it splits open. Such cracks are long, anc if extending tc the cortex usually fail to heal, as the rounded edges are Kept in motion by svay- ing oc the trunk. Nlectric Currents. During the present year Prof. Woodvorth discovered & sisall Acer rucrun groving near en electric rire that had "short—circuited" the wire with the earth. The tree was badclv Cha»red at the point of contact and gives warning of a new source of danger to park and roadside trecs. TCrms. Storms are a prolific cause of damare to forests. Tornadoes may even aestroy largo tracts of standing timber by tearing the trees entirely from the eartn. Aside from such djestmiction the milder winds rreatly injure lergre trecs in the expose? forests of central Michiran. The Oaks are observed to suffer most in this resyect, especially those that reach far above the surrounding trees. These trees are in- varlably dying in the tops, «nd when cut show the effects in their shaky hearts, That wines cause this is shown from the facts that smaller trees growing with the larre ores ere entirely sound. Lightning also destroys many trees bry rendine 8. oo them, often to srlinters. Srew ant sleet tend to destroy the branches of trees, more es vecially evergreens, by clinging to them beyond their vovers to resist. Trees with several brenches thus destroved have beon seen, Hail praises the cortex of vouns and tender shoots of trees, and may lead to a bed form of tree, or prediszvose tne tree to action of fursi. Floods. Floods are equally injurious to shrubs or large trees. Floating ice will bark large trees, and drifting mat- ter of any Kind may so collect as to overwhelin large trcos in its path and break them off or tear them trom the carth. This is esvecially so vith small growth wiich may be otserved to be absent alone the barks of streaus. In the observations mace it was olserved that the action of Aarift rad teristed and broken the young forest trees wherever they were in its path. Drainare. Drainage effcets forests by producing abnormal conditions, or by altering existing concitions. As with anv other living organism the change of normal conditions of ecrowth for the tree to abnormal results in impaired vigor of the saizre. Drainage is reittoval of free water from the soil. Normally, such trees as Larix Ancricana require an abundance of free water and a cold, humic soil. If a tract bearing these trees be drained the frec water is removed, and at the same time the soil is mace warmer, andi oxidation of the humus is made possible. The Lavorable conditions are made unravor-—- able and decline of such a forest results. This result is true of any tree that prefers suen 2 soil. wWhetsoever the eg) e conditions drainare changes them, and the rorest is immcireg ina greater or less degree. Drought. prougnt is cften a result of draining, or is made possible by dralinase. Then areinage is the nrimary carse. Bit drought primarily say Kill trees: py liniting the supply cf water and, indirectiy, the supply of plant food also. beath or injury from these causes is termed "top-drying" and extends from the top of the tree aown ard. Repeated droughts or severe oncs will at once effectually destroy the tree. Thinnins of forests. The management of the small forest areas of Michi- ean tends strongly to injurious effects. They are usually gall isolated areas, cubjecet to all tne detrimental influ- enccs hereinbefore mentioned, and the death of trees is corron. These trees the owner aims to utilize, and they are felled as soon as beyond recoverv, trus injuring the surrounding trees and mocifying their conditions of growth. Light and heat is iet in upon their trunks. Natural pruning is altered and the trees grow into poor forms. Branehes intertwire, and rubs and natural rafts are common. From the chenges of light crooked trunkr an’ spreading tons resnlt, end the sun's heat may scoreh or check the cortex upon limbs or trunk, forring wounds. ULvon injury is addcc injury. Even the normal con- ditions are so changed as a result of abnormal causes that the natural recuperative powers of the forest are impaired and degeneration is cortain. Pasturing of Forests. The practice of pasturing dconestic animals on tirbex lands is the most vides>read cause of damare to forests. Swine are, perhaps, lccst dotrimental. They damage the young growth mainly by eating the tender shoots cnd roots, an” by consunins the supply of sceds, such as acorns, becen nuts, ctc., thus cutting off the reserve growth of young plants. No doubt ther alter the conditions cf growth by tcaring wo the soil and allowing rayid oxidation and evavoration. Cattle ere more destruotive. Naturally they do not take to forests easily, but if pressed for food they will resort to brovsing and so Cestroy many of the younger trecs. Even though crasses be apundant they will breek dovn and tramp upon the 31.all growth in their efforts to rid thersclves of insects. Sheep are fond of browsing, and are the most destructive of domestic animals beeause of their persistent feeding on the bmish—-vood . Further than this, sheep oftcn assemble about the roots of trees, in the leaf mold, to rid themselves of insects and enjoy the shade, and therefore bark and bruise the roots. But the greatest evil of pasturing is the advent of grasses. All that grass requires in order to anvear is suniight. On the south side of forests it makes its first appearance. IT dorestic animals have access to the forest, thev pasture where grass is found and soon destroy the young trees, letting in more light, whicr, in turn, favors the growth of grass In this way the grass will in time oceuvy the whole rorest and modify the general conditions, vith the result that the forest will dceline. Let pasturing be withheld, however, and the rorest trees will ezain refrain the ground. A) SN MICH gigi”