YIELD OF BLED TREES. 



157 



volatile oils may evaporate, a channel is formed near the place where the exudation occurs by 

 making two converging cuts and inserting two pieces of wood, which conduct the resin into a nar- 

 rower channel down to the box. Otherwise there seems to be no difference in the two methods. 



Yield. In experiments regarding the yield, the following results were obtained on sixteen 

 trees, from 90 to 110 years old, under various conditions. During nine years of chipping there 

 was obtained of resin (per tree and year) the amounts given in the statement following: 



The last figure gives 75 pounds per tree altogether, or 25 per cent more than the average 

 product in American practice. An 80 year-old growth, which was rented for twenty years, fur- 

 nished in the tenth year of orcharding still a net rent of $12 to $18 per acre. 



The scrape contains less spirits of turpentine, is mixed with chips of wood, and therefore 

 obtains only two-thirds of the price paid for the dip. The amount of scrape depends, in the first 

 place, on the surface of the chip; also on the temperature during the fall, warm weather producing 

 more dips. 



During the nine years of experimental chipping there were obtained for each 100 pounds of 

 dip the following amounts of scrape : 



From the gathering to the distillation of the resin a loss averaging about 3 per cent was 

 experienced by the evaporation of the oil of turpentine. No other resin seems to be so rich in 

 turpentine as that of the black pine, 100 pounds of resin yielding 14 to 20 pounds of spirits and 

 60 pounds of rosin. 



During the same experiment, in the course of nine years, the following percentages of loss in 

 the trees by death or windfalls occurred : 



Trees from 50 to 100 years old are tapped ten or twelve years before they are to be cut. The 

 business is carried on upon a rent system per tree and year, under contract prescribing the 

 dimensions and gradual extension of the chip and the time for chipping (usually till September 

 30) and scraping (not later than October 30), with heavy penalties in case of damage or excess of 

 conditions. The total production in 1880 which has probably not materially changed since was 

 estimated at 13,288,000 pounds of resin, producing 9,260,000 pounds of rosin, 2,425,000 pounds of 

 spirits, with an aggregate money value of about $300,000. 



French practice. Turpentine orcharding in France is carried on with more care than in any 

 other country. The first difference between the methods in the United States and in France is 

 that in the latter it is largely practiced in young plantations specially planted and protected for 

 this particular business. The maritime pine (Finns pinaster L. synou., P. maritima), which has 

 been used in the celebrated plantations on the sand dunes along the coast and in the Landes of 

 Gascouy for over 2,000 square miles, furnishes the bulk of naval stores produced in France. The 

 boxing or tapping is begun when the trees are 20 to 25 years old and is continued for a great 

 inaiiy years. Trees have been known to have been boxed for more than two hundred years. 



