306 



THE GARDENERS' CHRONICLE OF AMERICA. 



HERE, THERE AND EVERYWHERE 



"WINTER INJURY" OF TREES. 



It is a matter of common observation that many of our forest 

 and cultivated trees suffer at times from the effects of severe 

 cold, of sudden and extreme temperature changes in winter. 

 Properly the term "Winter Injury" must include injury to all 

 parts of the tree, such as winter killing of the tips of branches, 

 root injury and injuries tu the trunk; but in this paper oidy the 

 latter will be considered. 



Uf injuries to the trunk there ma}- be said to lie tlircc types — 

 frost clefts, sun scald and crown rot. 



Frost clefts or craclvs are, as their name indicates, longitudinal 

 cracks in the trunk formed under the inlluence of extreme cold. 

 They are usually, though not always, evident externally, pro- 

 ducing a corresponding crack in tlie bark. 



Such cracks are believed to be due to a greater contraction of 

 the tree trunk in a tangential direction than in a radial direction. 

 Professor Miiller Thuegan offers an explanation of this uneiiual 

 contraction in the anatomical structure of the trunk. A cross 

 section of any woody stem shows radiating lines of fibro-vascular 

 bundles, composed of comparativelj' firm cells, separated from 

 each other by strips of softer tissue, the medullary rays. Lou- 

 traction of a tree trunk under the inlluence of cold is due to a 

 loss of water consequent to freezing; tlie medullary tissue loses 

 water more readily, and thus contracts nifire rapidly tlian the 

 tissue of the cascular biuidles, then, would naturally resist a 

 tendency to radial contraction; tangential contraction, on the 

 other hand, could readily take place, due to tlie interspersion be- 

 tween the bundles of the easily contracting mc<Iullary rays. 

 When the tension differences thus set up become great enough — 

 in other words, when the cold reaches a sufficiently great degree, 

 a frost crack is formed. 



These cracks close on thawing and usually heal rapidly, but 

 until entirely healed will reopen with a less degree of cold than 

 tliat which caused the original injury. Thus, if proper weather 

 conditions prevail the same crack may be reopened during several 

 successive seasons. Since every time the ei'ack reopens the healed- 

 over surface is ruptured, and in the new tissue formed at the siib- 

 sequent healing, is laid down over this, the result of projecting 

 frost I'idsc or. as tlie (icrnians express it CTrost leister"!. Two 

 such frost ridges on an oak trunk are shown in the accompanying 

 pliotograph. 



The occurrence of a few mild winters in succession is necessary 

 to the permanent liealing of a frost crack. It is, of course, 

 unnecessary to state that even after healing at the surface the 

 crack still persists in the interior of the tree. 



Often after a severe winter injured areas in the bark may be 

 observed. In such places the bark appears discolored, dead and 

 loosened from the tree, often s]ilit open, exposing the wood be- 

 neath. On examination it is fouml lliat (cotex canibinin I and 

 sometimes a portion of the sap wood has been killed. Such in- 

 jury is almost invariably confined to the soutliwest of the tree. 

 Since this is the sunn}' side, the injury is popularly called "sun 

 scald," and has been ascribed to the action of the sun in warm- 

 ing up the tissue from a condition of severe cold. In the present 

 state of knowledge on this subject it is unsafe to make any as- 

 sertion as to the exact manner in which this injury takes place, 

 but it is undoubtedly due in some way to the interaction of cold 

 with heat from the sun's rays. Papid thawing cannot be the 

 cause, since, contrary to the ])0pular belief, the rate of thawing 

 of frozen tissue has no effect on the nature or degree of injury 

 from freezing. That the injury is dependent upon a peculiar set 

 of climatic factors is evident from the fact that it is unusually 

 severe and widespread in certain seasons, and entirely absent in 

 others. 



Sun Scald is a serioiis trouble with fruit growers, fruit trees 

 being particularly susceptible. The initial injury is often fol- 

 lowed by canker and wood-destroying fungi, making the matter 

 doubly serious. 



Sun Scald occurs chiefly on the trunk or at the crotch of main 

 branches. A similar injury is often observed at the base, or 

 crown, of the tree. This also differs from the above type of in- 

 jury in not being confined to the southwest side. It seems that 

 the tissue at the crown of a tree is particularly tender and sus- 

 ceptible to injury from freezing, .'^ince this type of injury is 

 usually followed by wood-destroying fungi, it has been popularly 

 designated as (^omi Pot. foliar Rot or Collar Blight, the initial 

 cause of the injury being lost sight of in the consideration of the 

 evil that follows. This type of injury is in reality little different 

 from the former tyjie and the same relative susceptibilit.y of 

 varieties may be noted. Certain varieties of apple trees, es- 

 pecially the King, seem to be subject to Crown Rot. even under 

 the most favoralile conditions. 



Obviously, the condition of the tree will inlluence its suscepti- 

 bility to winter injury. 



Trees which have made a late growth and have entered the 

 winter in an unripened state are particularly liable to injury. 

 Weather favoring late growth in the fall is thus as much of a 

 factor as severe or changeable weather in winter. 



Unfortunately, in this ease we are dealing with factors beyond 

 our control, and preventive or remedial measures are necessarily 

 unsntisfac torv. — 'J'icc 'I'nll{. 



WITHDRAW PROTECTION FROM EUROPEAN STARLING. 



In its annual report for the last fiscal year, the Bureau of 

 ]^>iological Survey of the U. S. Department of Agriculture reports 

 as follows on the European starling: 



Introduced into the United States nearl}' twenty-five years 

 ago, the European starling has gradually extended its range from 

 Kew York City, and now it is found in the neighboring States 

 of Connecticut. Kew Jersey. New Y'ork, Penns.ylvania and Massa- 

 chusetts. During its migrations in search of food it ranges much 

 farther from the original center and occurs in considerable num- 

 bers as far south even as the District of- Columbia. 



The starling is markedly insectivorous, especially in summer, 

 and preys upon many noxious varieties. In this respect it is to 

 be classed among our useful birds. So far as is known, it has not 

 proved destructive to grain crops, but it is known to be very 

 fond of small fruits, and as it associates in large flocks, it is 

 likely to become a pest to the orchardist. In addition, it prefers 

 tree cavities, boxes, or recesses in buildings for nesting sites, 

 and thus is brought into direct competition with certain of the 

 useful native birds, more ]iarticulaiiy the bluebird, iiiir]de mar- 

 tin, white-bellied swallow, house wren and flicker. 



The bird is steadily extending its territory, and it will be wise 

 to withdraw all protection from it, as has already been done in 

 Connecticut, New Jersey, New York and Pennsylvania, including 

 the center of its abundance, with a view of checking its increase 

 and spread. The shipment of these birds from one State to an- 

 other has been prohibited under heavy penalty by act of Congress. 

 Under ordinary circumstances, even after all protection is with- 

 drawn, the bird will probably prove to be capable of taking care 

 of itself. That ultimately it will spread over a large part of the 

 United States is highly probable. 



A VISIT TO A SNAKE FARM, 



One of the most interesting places in Brazil is the Iiistituto de 

 Butantan. situated among the ilar Mountains, several miles from 

 Sao Paulo, the second largest city of the republic. This institu- 

 tion, which costs the Brazilian government more than $40.(in0 a 

 j'ear, studies the snakes of the countr.v, extracts the poison from 

 those that are venomous, and changes it into a serum that will 

 cure those who are bitten by snakes. 



There are only two such institutions in the world, the other 

 lieiiig at Calcutta. India. The Brazilian farm is fourteen years 

 old. Within the last year the government has built a line new 

 building that contains a very excellent medical and rhcniical 

 laboratory. 



Outside the building, in a long, rectangular plot, surrounded by 

 an iron fence and a cemented moat, are sixteen or twent.v bee- 

 hive-shaped structures of cement; cement paths connect them^ 

 with one another and with the moat. Each of these has four 

 small doors, with a hole in the centre. Every morning an at- 

 tendant comes round with a long rod. which has a bent iron hook 

 on the end. puts it in at the door holes, and removes the doors. 

 Slowly the snakes come out to creep in the grass, bask in the sun 

 or swim in the pool. In another park at the side of the building 

 there are more such houses. In that park are trees, and it is a 

 remarkable sight to watch those trees. At first you see nothing 

 but the trees; but the longer you watch them, the more wriggly 

 tliev become, for they are alive with snakes! The farm has aliout 

 l.."i(K1 snakes corralled for research purposes. — Ijj-ih(iii(i< . 



FERTILIZER RESOURCES OF THE UNITED STATES. 



In discussing the fertilizer resources "f the United States, the 

 Bureau of Soils, U. S. Department of Agriculture, in its annual 

 report for the fiscal year ending .June 30. 1914. says in part: 



While the extraction of pota.sh from such natural silicates as 

 the feldspars is quite feasible ph.ysically, it is not practicable- 

 economicallv, unless some other salable product is produced in the 

 same operation. An investigation into the use of feldspar in the 

 fixation of atmospheric nitrogen showed promise of a practical 

 method of producing ammonia simultaneously with potash from 

 feldspar. The most prcmisina; Aniericnn source of iiotasli. how- 

 ever, is the annual crop of giant kelps on the Pacific coast. Work- 

 ing maps have now been made of nearl.y all the commercially 

 available kelp beds from the Cedros Islands to the Shumagins, 

 off the Alaskan coast. The area of these beds assre.zates nearly 



