1390 ARBORETUM AND FKUTICETUJVI. PAKTJI1. 



Brussels (where, in consequence of his suggestions to the local authorities, it 

 was found necessary to cut down from 20 to 30 large trees attacked by 

 Scolytus destructor in the Park, and from 50 to 60 younger ones in the 

 boulevards), and also during a tour in the north of France this summer 

 (where he found the promenades of elms equally ravaged by the scolyti at 

 Dunkirk, Calais, Boulogne sur Mer, Montreuil, Rouen, Havre de Grace, Caen, 

 St. Lo, Granville, c.), seen hundreds of young trees in that incipient 

 state of decay indicated by M. Audouin as arising from the attacks of the 

 scolyti simply for food; and great numbers of these in which the females, 

 having found them sufficiently debilitated, had deposited their eggs, and given 

 birth to numerous broods of larvae, which had caused them to be either dead 

 or fast dying. 



It is scarcely possible to overvalue, in an economical point of view, the 

 importance of M. Audouin's discovery, which, if it had been formerly known 

 and acted upon, might have saved the greater part of the fine elms in the 

 promenades in many of the principal cities in the north of Europe, which have 

 fallen victims to the ravages of Scolytus destructor, as well as 50,000 young 

 oaks in the Boisde Vincennes, near Paris, which it has been recently necessary 

 to cut down in consequence of the attacks of another insect of the same tribe, 

 S. pygmae v us. The practical directions to which it leads, in all cases where 

 there is reason to suspect the presence of scolyti, are very simple, and may 

 be briefly expressed as follows : 



1. The first thing to be done is, to pare away the exterior rough bark with 

 a cooper's spokeshave, or other convenient tool : this admits of a distinct 

 inspection of the actual state of the trees, which, if there is no trace in the 

 inner bark either of small holes in old trees, or of those superficial furrows 

 which 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 dead 

 margins), may be pronounced to be in a sound and healthy state, and requiring 

 no further attention. 



2. If the inner bark exhibits either of the appearances just mentioned, the 

 next thing to be ascertained is, whether the female has already deposited her 

 eggs in it, and if it contain the larva? of the scolyti : to know which, it is 

 necessary to cut away portions here and there of the bark down to the actual 

 wood, and examine them; and, if the existence of larvae be proved, the 

 trees should be cut down, and their bark peeled off, and every fragment of it 

 carefully burnt. 



3. Those trees which, though pierced with exterior superficial holes or 

 furrows, have no larvae in them, are such as have been attacked by the scolyti 

 for food only ; and, if they be carefully brushed over with coal tar, the smell of 

 which is highly offensive to the perfect scolyti, there is every probability that 

 they will be secure from the future attacks of the females ; and that the 

 repetition of the same process in the spring, for a year or two, would enable 

 them to resume their vigour, and to become healthy trees ; for the future fate 

 of which,if, at the same time, the entire removal of all the trees actually diseased 

 has been attended to, there would be no need for apprehension. It is in this 

 way, as we are informed by Mr. Spence, that a great number of the young elm 

 trees in the boulevards at Brussels, brought into an incipient stage of debility 

 by 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 can 

 be drawn from the experiment. The above most important information was 

 communicated to us by Mr. Spence in December, 1836. 



Recorded Elms. Evelyn, to prove that the elm attains " a prodigious growth 

 in less than a person's age," mentions a tree which he had seen, " planted by 

 the 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 good 

 numbers which will bear almost 3ft. square for more than 40ft. in height." 



