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ARBORETUM AND FKUTICIiTUJVl.

PART HI,

Brussels (where, in consequence of his suggestions to the local authorities, itwas found necessary to cut down from 20 to SO large trees attacked byScolytus destructor in the Park, and from 50 to 60 younger ones in theboulevards), and also during a tour in the north of France this summer(where he found the promenades of elms equally ravaged by the scolyti atDunkirk, Calais, Boulogne sur Mer, Montreuil, Rouen, Havre de Grace, Caen ,St. Lo , Granville, &c.), seen hundreds of young trees in that incipientstate of decay indicated by M. Audouin as arising from the attacks of thescolyti simply for food; and great numbers of these in which the females,having found them sufficiently debilitated, had deposited their eggs, and givenbirth to numerous broods of larvae, which had caused them to be either deador fast dying.

It is scarcely possible to overvalue, in an economical point of view, theimportance of M. Audouin’s discovery, which, if it had been formerly knownand acted upon, might have saved the greater part of the fine elms in thepromenades in many of the principal cities in the north of Europe , which havefallen victims to the ravages of Scolytus destructor, as well as 50,000 youngoaks in the Bois de Vincennes, near Paris , which it has been recently necessaryto cut down in consequence of the attacks of another insect of the same tribe,S. pygmae'us. The practical directions to which it leads, in all cases wherethere is reason to suspect the presence of scolyti, are very simple, and maybe briefly expressed as follows : —

1. The first thing to be done is, to pare away the exterior rough bark witha cooper’s spokeshave, or other convenient tool : this admits of a distinctinspection of the actual state of the trees, which, if there is no trace in theinner bark either of small holes in old trees, or of those superficial furrowswhich the scolyti make for food in young trees (and which may be distin-guished from the natural crevices in the bark by their dark-coloured and deadmargins), may be pronounced to be in a sound and healthy state, and requiringno further attention.

2. If the inner bark exhibits either of the appearances just mentioned, thenext thing to be ascertained is, whether the female has already deposited hereggs in it, and if it contain the larvae of the scolyti: to know which, it isnecessary to cat away portions here and there of the bark down to the actualwood, and examine them; and, if the existence of larvae be proved, thetrees should be cut down, and their bark peeled off', and every fragment of itcarefully burnt.

3. Those trees which, though pierced with exterior superficial holes orfurrows, have no larvae in them, are such as have been attacked by the scolytitor food only ; and, if they be carefully brushed over with coal tar, the smell ofwhich is highly offensive to the perfect scolyti, there is every probability thatthey will be secure from the future attacks of the females ; and that therepetition of the same process in the spring, for a year or two, would enablethem to resume their vigour, and to become healthy trees; for the future fateof which, if, at the same time, the entire removal of all the trees actually diseasedhas been attended to, there would be no need for apprehension. It is in thisway, as we are informed by Mr. Spence, that a great number of the young elmtrees in the boulevards at Brussels , brought into an incipient stage of debilityby the attacks of the scolyti for food, but not yet attacked by the females,were treated in the spring of 1836 with every prospect of a successful result;though, of course, some years must elapse before any absolute deductions canbe drawn from the experiment. The above most important information wascommunicated to us by Mr. Spence in December, 1836.

Recorded Elms. Evelyn, to prove that the elm attains “ a prodigious growthin less than a person’s age,” mentions a tree which he had seen, “ planted bythe hand of a countess, living not long since, which was near 12 ft. in compass,and of a height proportionable.” He mentions elms, “now standing in go°dnumbers which will bear almost 3 ft. square for more than 40 ft. in height-