219 



excrescences and phenomena of loosening of bark and wood occur also in 

 healthy trees, with corresponding conditions in the place of growth, but in- 

 crease in the tan disease to an extreme manifestation. 



The remedies are apparent, and extensive aeration of the soil chiefly 

 promises success. 



The Girdling of the Red Beech. 



According to the description given by Th. Hartig^ the disease named 

 in this heading, which I have not known from my own observation, should 

 be included here. Hartig found in a beech grove, 20 years old, that many 

 trunks, beginning about one to two metres above the ground and extending 

 to the top of the tree, were surrounded at intervals of 30 to 100 cm. with an 

 almost circular, somewhat spirally running roll as thick as a quill. These 

 rolls were proved to be overgrowth phenomena in wounds caused originally 

 by lenticel excrescences. The formation of cork had extended further and 

 further backward into the bark until it reached the wood and for a year or 

 two years the formation of wood was arrested at this point. No appreciable 

 injury due to the disease, which occurs only in very well grown sapling 

 groups and there especially on trunks of the first or second class, could be 

 confirmed. 



Root Disease of the True Chestnut (Mai nero). 



This disease, very common in France, manifests itself, according to 

 Delacroix-, most strikingly in damp, impervious soil and in grafted trees. 

 The leaves lose their dark green color and the branches begin to dry up at 

 the tips. The nuts only partially ripen and remain in the burrs. Delacroix 

 found that the mycorrhiza of the fine roots had changed, as if diseased, and 

 had assumed, as he thinks, a parasitic character because the amount of 

 humus was deficient. The mycelium then grows into the larger roots up to 

 the base of the trunk and then, in the trunk, upward to the branches. A 

 secretion containing tannic acid results from the injuries to the roots and 

 trunk. In this weakened condition, the trees ofifer a suitable centre for in- 

 fection by other parasites, as, for example, Polyporns sulfureus and Armil- 

 laria mellea as well as Sphaerella maculiformis. 



I include this disease at this point because of the results of a thorough 

 investigation which I had an opportunity to make with material from Ren- 

 nes. The explanatory letter sent by M. Crie stated that the dying branch- 

 wood had an odor indicating fermentation if broken, or the bark removed, 

 and he suspected a conversion of the tannin, whereby glucose and alcoholic 

 fermentation took place. The pieces of branches sent were thickly covered 

 with Hchens and the leaves showed a browning which extended from the 

 edge deep into the intercostal fields. 



1 Hartig-, Th., Vollstandig-e Naturgeschichte der forstlichen Kulturpflanzen, p. 

 211. Berlin 1852. 



2 Delacroix, G., La maladie des chataigniers en France. Bull soc. mycol. de 

 France XIII, 1897, p. 242. 



