EUKOPEAN TEEES. 329 



some otlier parts of the United States, I believe, and would un- 

 doubtedly thrive in the Southern section of the Union.* 



In the walnut, the chestnut, the cork oak, the mulberry, the 

 ohve, the orange, the lemon, the fig, and the multitude of other 

 trees, which, by their fruit or by other products, yield an annual 

 revenue, nature has provided Southern Europe with a pai-tial 

 compensation for the loss of the native forest. It is true that 

 these trees, planted as most of them are at such distances as to 



a property which it possesses in common with some other firs, the maritime 

 pine, and the European larch. When these trees grow in thick clumps, their 

 roots are apt to unite by a species of natural grafting, and if one of them be 

 felled, although its own proper rootlets die, the stump may continue, some- 

 times for a century, to receive nourishment from the radicles of the surround- 

 ing trees, and a dome of wood and bark of considerable thickness be formed 

 over it. The healing is, however, only apparent, for the entire stump, except 

 the outside ring of annual growth, soon dies, and even decays within its cover- 

 ings, without sending out new shoots. I have observed cases of JJeberwallung 

 at Abetone or Bosco Lungo, but it is everywhere of rare occurrence, and I 

 never saw an instance in the United States, and only a single one in the 

 Austrian woods. In this case it was only partial, and occurred in a large 

 Btump in a fir forest near San Martino di Custozza in Tyrol. 



Rossmassler, Der Waldt, p. 191, describes and figures a case in a Populus 

 alba ten years old, but, p. 342, he says : " Der Lerche und der Tanne, der 

 Fichte und der See-Kief er ist die Ueberwallungeigen." See Rossmassler, p. 

 203. ScHACHT, Les Arbres, 1863, pp. 145, 387. GSppert, Das Ueberwallen der 

 Tannenstocke. Bonn, 1842. 



* At the age of twelve or fifteen years, the cork-tree is stripped of its outer 

 bark for the first time. This first yield is of inferior quality, and is employed 

 for floats for nets and buoys, or burnt for lampblack. After this, a new layer 

 of cork, an inch or an inch and a quarter in thickness, is formed about once 

 in ten years, and is removed in large sheets without injury to the tree, which 

 lives a hundred and fifty years or more. According to Clave (p. 252), the 

 annual product of a forest of cork oaks is calculated at about 660 kilogrammes, 

 worth 150 francs to the hectare, which, deducting expenses, leaves a profit of 

 100 francs. This is about equal to 250 pounds weight, and eight dollars profit 

 to the acre. The cork oaks of the national domain in Algeria cover about 

 500,000 acres, and are let to individuals at rates which are expected, when the 

 whole is rented, to yield to the state a revenue of about $2,000,000. 



George Sand, in the Eistoire de ma Vie, speaks of the cork-forests in South- 

 em France as among the most profitable of rural possessions, and states, what 

 I do not remember to have seen noticed elsewhere, that Russia is the best cus- 

 tomer for cork. The large sheets taken from the trees are slit into thin plates, 

 and xised to line the walls of apartments in that cold climate. On the cultiva- 

 tion and management of the cork oak, see Des Incendiea et de la culture dn 

 Oheneli^ge, in Bevue des Eaux et Forits for February, 1869. 



