• 12 



CULTIVATION AND YIELD. 



The tree is usually raised from seed, the large sweet acorns produc- 

 ing' trees of full aud regular growth aud yielding the finest cork, while 

 the small bitter acorns produce trees of a coarse and inferior nature. 



The most approved method of planting, which is otherwise carried 

 on like other nut planting, appears to be in furrows or belts, 5 to 7 feet 

 apart, between rows of grapeviues, which afford shelter. Two or more 

 acorns are placed 20 to 40 inches apart in the furrows. No further cul- 

 tivation is necessary, excepting the usual thinning as circumstances 

 require. The first harvest usually takes place a*t the age of 40 years, 

 at which time the plantation should contain about 700 trees per acre. 

 The yield of this first crop is about 7 pounds per tree, worth about 30 

 cents, so that the first crop may be estimated at about $200 per acre. 

 At 50 years the plantation should contain about 200 trees per acre, 

 which is reduced to 100 trees at 75 years, and 40 trees at 120 years, 

 when thinning ceases or replanting begins. The average yield per 

 harvest for the period from the age of 40 to the age of 120 years may 

 be considered a little more than 50 pounds per tree, and the gross; 

 income about $225 per acre. 



The yield of cork steadily increases with the age and size of the tree. 

 At the age of 120 years over 100 pounds per tree is expected, and excep- 

 tional cases are on record where a single tree furnished 500 and even 

 1,000 pounds of cork bark at a single harvest. 



Since manufactured cork costs in France 9 cents per pound, its value 

 is almost doubled by the manufacture. 



HARVEST. 



The cork of commerce is by no means the natural product of the 

 tree, but an abnormal development of the bark layers under certain 

 treatment. The natural cork is entirely useless for tlie purposes of 

 manufacture, being too coarse, deeply furrowed, full of siliceous deposits 

 and very irregular, and sometimes so woody aud dense that it does not 

 float. This " wild " cork, which the French call liege male is developed 

 as the tree grows until it attains a diameter of from 6 to 10 inches. It 

 should then be removed, leaving the interior denser, darker, and softer 

 cork layer, which is called the liber, or mother layer, from which the 

 cork of commerce develops more or less evenly. (See Pis. I and II.) 



There is no difficulty in removing the bark while in sap — an opera- 

 tion which can be also facilitated by beating with a mallet around the 

 trunk ; but in its removal it is necessary to be careful of the inner layer, 

 or bast, for, if injured, no cork would be produced at that place. For 

 the same reason it is also necessary to clear the liber, or bast, entirely 

 of the " wild " bark, making a smooth, uninjured surface of the mother 

 layer. 



