Do Your Trees Need Doctoring? -By J. J. Levison, 



Arboriculturist to the 

 Brooklyn, N.Y , Parks 



HOW THE AMATEUR MAY DECIDE FOR HIMSELF WHEN TO CALL IN THE EXPERT WORKER TO 

 SAVE HIS TREES — A GUIDE TO THE CAUSES OF DISEASE AND HOW TO FIGHT OR PREVENT THEM 



THREES, as a rule, die slowly under 

 -*- abuse and neglect, but their decay 

 and ruin are then matters of certain prog- 

 ress. When the ill effects become pain- 

 fully evident, you wonder why and blame 

 the caterpillars or the fungi and sometimes 

 the "tree doctor" whom you engaged, at 

 too late a stage, to save them. Though 

 it requires a lifetime to become expert in 

 all the needs of a tree, yet any one can 



A diseased tree, too far gone to deserve any further 

 attention beyond the ax 



learn very quickly how to tell when a tree 

 is not thriving. Here are the things to 

 look for : 



The "blood," so to speak, of a healthy 

 tree is in most cases green, and if a tree's 

 foliage shows an unnatural pallor during 

 the growing season, the chances are that 

 it is due to one of these three things: 

 (i) insufficient light or moisture, (2) salt in 

 the soil, or (3) foreign gases, particularly 

 illuminating gas. 



Flat fungus growths (or punks) pro- 

 truding from any part of a tree are sure 

 signs of parasitic disease. 



Warts and spotted leaves have their 

 origin in the work of insects or fungi. 



Withering of the leaves, due to the 

 absence of water, may be the apparent 

 result of one or more of these cases: (1) in- 

 sects that suck the sap, from the bark 

 or the leaves, (2) a heavy crown of foliage 

 out of proportion with the root or the 

 supply of moisture in the soil, or (3) fungus 

 diseases that cut off the channels of cir- 

 culation in the tree. 



Defoliation, entire or partial, can gen- 

 erally be traced to leaf-eating insects. 



Holes in the bark with "sawdust" or 

 gummy excretions are indications of boring 

 grubs or beetles. Neglected cavities in 

 the trunk or limbs of a tree are generally 

 found to be receptacles of boring insects 

 and disease. 



The best preventive of disease is constant 

 maintenance of good vigorous growth. 

 Trees want certain quantities of water, 

 light, air, and heat and certain soil con- 

 ditions. In diagnosing your tree's ailment, 

 ascertain whether these conditions are 

 normal or not. Is the soil too dry — or 

 too wet? Are the adjoining trees shad- 

 ing it out? Do the roots receive suffi- 

 cient air, or is the soil about the base of 

 the tree so compact that no air can get 

 in? Is the soil rich in organic material. Is 

 the drainage good or is the tree standing in 

 stagnant water? 



It may not always be the part of wisdom 

 or economy to apply the proper remedy — 

 your tree may be so badly infested with 

 scale or boring insects, or fungi; or it may 

 be so hollow, or so stunted, that saving it 

 becomes a matter of extreme doubt, and 

 certainly one of great expense. In that 

 case, it is, I think, better to dispense with 

 the tree altogether and plant another in 

 its place. The appeal ance of the grounds 

 will be generally improved and moreover 

 there is the certainty of preventing in- 

 sects and disease from spreading to other 

 trees. 



Whether the tree is worth keeping, you 

 must decide for yourself — there may be 

 sentimental reasons that outweigh the 

 practical ones. Assuming, then, the keep- 

 ing of the old tree, let common sense 

 apply to the method of treatment, always 

 with due regard to the principles of the 

 natural growth of the tree. 



First, properly cut off all dead branches 

 and stubs. These are unsightly and 

 carry disease and insects into the tree. 

 The best time to do this work is from 

 August to November. There is just one 

 thing to remember : the cuts must be made 

 close to and even with the trunk and coal- 

 tar applied to the wounds. Do not waste 



time and money on the little dead twigs, 

 and do not over-prune. 



Any cavities or neglected wounds re- 

 quire treatment but not necessarily filling 

 with cement or similar substances. I 

 think there has been altogether too much 

 of this filling. It is justified where the 

 trees are sufficiently well formed and 

 important to warrant the expense and 

 trouble, with cavities that are not too 

 large, and where the practical purposes of 

 eliminating moisture will be served by the 

 filling. If the cavity is a very large one 

 — the opening extending to more than a 

 third of the circumference of the tree — 

 'or if the cavity is only a perpendicular 

 shallow wound where water will readily 

 slide off and never lodge, filling is un- 

 necessary, as a rule. The best practical 

 purposes will be served by the removal of 

 the decayed portion and covering the 

 interior with coal tar, and no more. If 

 fungus has badly attacked the interior, 

 its absolute elimination is doubtful because 

 fungus acts like a cancer penetrating the 

 whole body of the tree with a network of 

 microscopic fibres which can hardly be 

 detected with the naked eye. What is 

 the good of filling a cavity when every 

 trace of disease is not removed and where 

 the remaining portion of the fungus will 

 then go right on developing behind the 

 filling? The shelter provided by the filling 

 will merely favor the growth of disease. 

 For similar reasons, covers of tin or other 

 material nailed over tree cavities do more 

 harm than leaving the cavities exposed. 



Cavities in trees are common even in 

 some of the best keot gardens and will 



This tree was filled. The decayed wood was not removed and on a windy day the tree split and fell 

 165 



