larch crop at forty to sixty years old, and though it is often exceeded, yet in many more instances I believe that at present prices the return will be less, even when disease has not seriously deteriorated the value of the trees by the scars and cankers which disfigure the trunks.
Diseases of the Larch
Though it is not within the scope of this work to describe the diseases of trees, yet an exception must be made in the case of the larch, because it is a subject of such vast economic importance that it may truly be said, that the losses of all other trees, from all kinds of diseases, whether induced by climatic causes, by insects, or by fungi, do not collectively approach the loss caused to English landowners by larch disease. In using this term without qualification ] mean the disease caused by the fungus usually known as Peziza Willkommii, but which is now named by mycologists Dasyscypha calycina, and which is perhaps best described in English by the name "Canker," or " Blister." This began to attract attention in this country about 1859, when the Rev. M.T. Berkeley[1] made known its existence in England, and Charles M'Intosh in 1860 wrote a small book on larch disease, though what he described more especially was heart-rot, a very different thing from canker.
Hartig and de Bary were the first to describe the fungus. Prof. Marshall Ward in his Timber and some of its Diseases, published in 1889, described it more fully; and since then Mr. Carruthers, Dr. Somerville, and other scientific writers have written largely on the subject. In the Gardeners' Chronicle, 1896, are many interesting articles respecting the larch disease by J.S.W., Sir Charles Strickland, A.C. Forbes, and C.Y. Michie; and an excellent paper on it with coloured illustrations, by Mr. Geo. Massee, appeared in the Journal of the Board of Agriculture for September 1902.
The most practical observations on the larch disease I know of, are in Mr. A.C. Forbes's excellent work on English Estate Forestry, pp. 289–307 (1904). These should be studied carefully by every one who is in any degree interested in the subject. After giving a summary of the more important opinions and facts noticed in connection with this disease, he says—and I entirely agree with him—that the disease is as much the result as the cause of the bad health and unthrifty condition of many plantations throughout the country; and that the temporary debility which is induced by the conditions under which planting is conducted is largely responsible for a great deal of disease. He goes on to say that the practically permanent nature of the blister, when once established, renders the result of this temporary debility a much more serious matter than it otherwise would be. If the return to normal health and growth were accompanied by the disappearance of the disease, little harm would be done, but the existence of a blister, once established, is perpetuated indefinitely, and in most cases only ceases with that of its host, so that the occurrence of a blister on the stem of a young tree is much more serious than it would be on a branch or older stem. Cases commonly occur of the disappearance of
- ↑ Gard. Chron. 1859, p. 1015.
