CORK 435 



ground can be stripped for their bark. Trees commonly attain an age of 

 from 100 to 500 years or more. They generally grow on the lower slopes 

 of mountains and on the poorer and more rocky soils which are unsuit- 

 able for agriculture. The best cork is said to be produced from the drier 

 and more rocky soils. 



In 1858 several cork oaks were introduced in this country and have 

 grown well in the Southeastern States. The experiments were not suffi- 

 ciently extensive, however, to determine any positive results regarding 

 the possible introduction and growth of the tree in America. 



There has not been any disposition evidenced either by the cen- 

 tralized or, local governments in Spain to exercise any supervision over 

 the cork forests except as noted above. They are such an important 

 factor in producing wealth that the owners of cork oak forests realize 

 their importance and give them excellent care. The general method of 

 handling has been practically the same for the past several centuries and 

 it is not likely that there will be any marked changes in the general 

 methods either of cultivation of forests or in the methods of stripping. 







HARVESTING THE BARK 



All trees that are vigorous and healthy, from 5 to 6 in. and up in diam- 

 eter, are stripped. Trees are stripped of their bark every six to eleven 

 years, with an average of about eight to nine years. In the lowlands, 

 where the soil is richer, the cork is thicker and more spongy and, there- 

 fore, of less value. The firm and heavier cork, which is much more 

 desirable, is produced only on higher and drier soils in very open groves. 

 This product is considered to be of superior quality even though much 

 thinner. Young trees, generally speaking, produce the best quality of 

 cork, although the first stripping, called ",virgin " cork, is of very inferior 

 grade and is used only for granulated cork. It is usually hard, thin, 

 dense and tough, and very irregular. Trees as young as twenty years of 

 age have, in special cases, been subjected to the stripping of their bark, 

 but, ordinarily, the age of first stripping is much older than this, as the 

 trees in Spain grow very slowly, and it is often from thirty to fifty years 

 before trees will attain a diameter of 6 in. The first stripping does not 

 injure the growth; on the other hand, it seems to stimulate further 

 development of both the bark and wood growth. 



There is no definite rule regarding the age at which trees no longer 

 continue to yield commercial cork. Growers in Spain estimate that 

 commercial cork is produced from trees up to three hundred to five hun- 



