494 ULMUS CAMrKSTllIS. 



the braiicht'S may be cut froiu the stem, except a small tuft at the top: and still 

 the tree will y^Yi)\v vigorously, aliordini:;. where ihat mode ut' leediiig cattle is con- 

 sidered protitahlc, an ample crop of branches every three or four years. When 

 headed down to the heii,du often or twelve feet, it is very prolific of branches, as 

 a ]iollard. and will live and be productiv(% in this state, for a great number of 

 years. When grown exclusively lor the timber of its trunk, however, it re(juires 

 to be allowed a considerable amplitude of head; perhaps not less tiian one third 

 of its whole height. The timber, in this case, is found to be far more comjiact 

 and durable, though not so curiously veined and variously coloured as it is when 

 the tree is allowed to produce branches from the ground upwards. The timber 

 of the elm, not being remarkable for its durability, is. in old trees, very com- 

 monly found decayed at the heart; and this is generally the case, even when 

 the exterior circnmference of the trunk is in a healthy and vigorous state, and 

 prolific of branches. The most profitable age for felling the elm is between 

 seventy and eighty years; and if the trunk is disbarked a year before it is cut 

 down, the wood will be more thoroughly seasoned."* 



Accidents^ Diseases, and Insects. The Ulmns campestris, from the straight- 

 ness, toughness, and strength of its trunk, in proportion to its head, is not liable 

 to be injured by high winds, except at an advanced age, in yielding at the roots, 

 an accident which much more frequently befalls this tree than the American 

 species, as was fairly tested on Boston Common, in the memorable gale of Sep- 

 tember, 1815, when several English elms, in the Mall, were uprooted, while the 

 native species, by their side, withstood the blast with but slight injury. The 

 European elm, however, is subject to many diseases, and is very liable to be 

 attacked by insects. The principal disease with which it is assailed, is a species 

 of ulceration, appearmg on the body of the tree, according to Michaux, " at a 

 height of three or four feet from the ground, and which discharges a great quan- 

 tity of sap." " The disease penetrates gradually," he adds, ' into the interior 

 of the tree, and corrupts its substance. Many attempts have been made to cure 

 it in the beginning, and to arrest its progress, but hitherto without success. The 

 best treatment is to pierce the tree to the depth of two or three inches, with an 

 auger, in the very heart of the malady, which is manifested by the flowing of 

 the sap." The matter discharged by this ulcer has been analysed by M. Vau- 

 quelin, and found to contain carbonates of lime, potash, and of magnesia, and sul- 

 phate of potash. The mode of treatment recommended in the " Nouveau Cours 

 d' Agriculture," is to pierce the ulcer as above advised by Michaux, and then to 

 dress the wound with powdered charcoal, or a mixture of cow-dung and clay. 

 This species, when grown in an unsuitable soil, that is, in one which is either 

 excessively wet or extremely dry, is very subject to a disease called carcino7na. 

 It shows itself by the extravasated cambium forming long, black streaks down 

 the bark, and by its sweetness, attracts numerous insects, of several tribes, to feed 

 upon it. Mr. Spence thinks that this disease, very probably, is caused by the 

 scolyti. "I have seen," he says, in a communication to Mr. Loudon, "many 

 elms pierced by these insects, where the extravasated cambium partly oozed out 

 in white masses, like gum, or manna, and partly formed long, black streaks down 

 the bark, and numerous insects were attracted to feed on it." 



Among the insects attacking the Ulmus campestris, is what is vulgarly called 

 the elm flea, (Haltica.) which devours the leaves, but is said to do no serious 

 injury to the tree itself. It is a beautiful little insect, covered with a brilliant 

 cuirass of green and gold, and having the thighs of its hinder legs so large as to 

 appear almost round. They are so lively and so quick in their movements, that, 

 hough a branch may appear covered with them one moment, the next they will 



* Arboretum Britannicum, iii., p. 1384. 



