January 21, 1869. 1 



JOURNAL OP HOHTICDLTURE AND COTTAGE GARDENER. 



41 



LICHENS ON FRUIT AND OTHER TREES. 



rN mniiy parts of the country the spread of 

 Lichens on trees, which only a few years 

 ago appeared healthy and comparatively free 

 from these parasites, has given rise to doubts 

 whether the improved cultivation of the coun- 

 try, with the consequent removal of large 

 breadths of woodland, may not in some de- 

 gree have tended to render what remains 

 more susceptible of disease. A specimen 

 has been sent to me by a gentleman, who 

 informs me of the rapid spread of a species of Lichen, of a 

 silver-grey colour, which tlireatens to cripple the growth 

 of many kinds of forest trees to which it attaches itself, 

 as well as that of Oaks, and Silver, Spruce, and other Firs ; 

 and its injurious effects, naturally enough, create alarm in 

 the minds of all interested in such trees. The Lichen is 

 probably an Evernia, but instead of following out its bo- 

 tanical characters I will here consider what conditions may 

 have led to its rapid increase of late years, and the means 

 most likely to arrest its progress, or in some degree di- 

 minish its ill-etl'ccts. 



This Lichen, unlike the canal weed (Anacharis alsinas- 

 trum), which threatened so much mischief twenty years 

 ago or less, is not of foreign origin, for it is. doubtless, the 

 same species as that which has at all times found a home 

 on aged trees when in a declining condition, Apple and 

 other fruit trees being, perhaps, as much affected as any. 

 In no instance, that I am aware of, have attempts to check 

 its gro^vth or destroy it been so perseveringly made as 

 in the case of orchards infested with this parasite, and 

 the partial success attending the means adopted serve as 

 an inducement to resort to them in some of those cases 

 where valuable timber plantations are in danger of dying 

 prematurely ; but at least an mquiry into the causes likely 

 to promote the growth of Lichen, and whether such causes 

 are in any degree under the control of the cultivator, may 

 help us to suggest a remedy, more especially if the locaUties 

 where it has been most troublesome were fairly reported 

 upon. In the meantime, let us judge as well as we can of 

 the case now before us. A short twig of Oak. apparently 

 of the growth of 180.5, was completely matted over with 

 this Lichen, forming a coat as long, close, and thick as 

 the coat of a bullock : a small shoot from the twig, 2 or 

 3 inches long, apparently of the growth of If^lii;, was free 

 from the Lichen, and a similar growth of IMfw, lengthening 

 the shoot to ."> or inches altogether, was also free, but of 

 course stunted in appearance. No doubt this is a bad 

 specimen, but there may be plenty like it ; and as I was 

 informed that it was taken from a tree that ought still to 

 have been in its prime, I conjecture some causes have 

 been at work favouring the growth of the parasite to an 

 unusual degree. What these conditions are it would be 

 well to inquu-e ; and in venturing an opinion I may state 

 that I by no means coincide with the view taken by many, 

 that the cause is the land not being drained, for though 

 firmly believing that draining has done an immense amount 

 of good to the country generally. I often think its advo- 

 No. 408.— Vol. XVL, New Seeies. 



cates go beyond the proper bounds in extolling its benefits, 

 and attribute to want of draining evils which ought to bo 

 ascribed to other causes. In the case of this Lichen making 

 its appearance in more than ordinary abundance during 

 the last year or two, assuredly non-drainage of the land is 

 not the only reason for its abundance ; on the contrary, we 

 often enough see it nn trees planted in the driest situations, 

 both as regards soil and atmosphere. Some other cause 

 must therefore exist. 



Happening to be near the western coast of England a 

 few months ago, I could not but notice the \yeather-beaten 

 appearance of the trees and hedges, the former all leaning 

 landwards, and the latter stunted and apparently only 

 dragging on a wretched existence, although the land seemed 

 as good as could be desired, as evidenced by the abundant 

 crops of corn, grass, and Potatoes. The trees and hedges, 

 however, wore free, or nearly so, of moss, the bark being 

 cleaner and exliibiting signs of better health than might 

 have been expected : the cause of this was apparent enough 

 — the sea air, laden with saline matter, was not favourable 

 to the growth of this Lichen : hence its non-appearance. On 

 the other hand, in districts which I could point out. where 

 the trees are much more robust, they are affected with 

 Lichen, even in places where damp stagnant air could not 

 be attributed as the cause, for it would be no easy task to 

 obtain water by sinking for it, and the situation, too, both 

 elevated and exposed. 



As the air of the coast is so fatal to tliis parasitical 

 growth, it would be well if we could imitate it elsewhere, 

 but as this cannot be done, our remedy must be something 

 else as unfavourable as possible to the low class of vegeta- 

 tion to which the Liclien belongs, and the most available 

 substance is lime, which, when scattered freely over objects 

 affected with Lichen, destroys it to a considerable extent, 

 and I imagine if the remedy were repeated often enough it 

 would effect a cure. I am not sure that a too hasty re- 

 moval of the parasite would be advantageous, as probably 

 the bark of the tree would be too delicate to endure all at 

 once full exposure, but a good dusting of quicklime, so as 

 to clog up the Lichen in a sort of limy mass, would form a 

 covering which would fall away by degrees as the season 

 advanced, and the Lichen lost its hold of the tree. This 

 mode of treatment is adopted in the Kentish orchards with 

 benefit. Advant.age being taken of a mild moist morning 

 in April, a ladder is set against the tree to be operated on, 

 and a person ascends to the top, scatters over the branches 

 quicklime, which, adhering by the moisture, remains 

 there till it has effected the object desired. Of cunrse, 

 much of tlie lime finds its way through the branches 

 and falls to the ground, but it does no harm there ; on the 

 contrary, it may be useful. The lime, of course, ought to 

 be fresh and good, and if the operation is performed when 

 there is no wind, and the operator ascends above his v.ork, 

 there is not so much difficulty and annoyance from the 

 lime as might be expected, and the destruction of para- 

 sitical growth is an object well worth the trial. Even 

 amongst a group of forest trees whore their progress is im- 

 peded by Lichens, the qidcklime application might without 

 any serious outlay be tried, and very likely with advantage. 



No. lOM.— Vol. XLI., Old Series. 



