8] MODIFICATION AND DISTRIBUTIONS OF CROPS 243 



Important beverages obtained from woody plants include Cacao 

 {Theobroma cacao), the source of cocoa and chocolate, Coffee (various 

 species of Cqffea), and Tea (Camellia sinensis). The Cacao tree is 

 a native of tropical America ; the others originated in the warm 

 parts of the Old World. All are now extensively cultivated in the 

 tropics, and, in the case of Tea, in other warm regions. Fig. 76 

 indicates the main centres of production of Cocoa beans and 

 exemplifies a tropical crop of restricted origin that is now widespread. 

 Fig. 77 gives similar indications for Coffee, over half of which comes 

 from Brazil, whose economy is still bound up with this single crop 

 to an economically unhealthy degree. 



Passing over further categories such as nut-bearing, rubber, and 

 drug plants, whose important products are often obtained from wild 

 sources, we come to the last great one of timbers and cognate forest 

 products. For details of these, reference may be made to such 

 works as that of Zon & Sparhawk or, for the New World, of Record 

 & Hess, both of which are cited at the end of this chapter. 



Besides the timbers employed almost all over the world for con- 

 struction, fuel, and other purposes, important forest products include 

 tanning and dyeing materials and a great assortment of useful gums, 

 resins, oils, preservatives, cork, and latex products — to name only 

 a few. Many of these are taken with fair regularity as a kind of 

 crop, sometimes from planted trees. And whereas in the tropics 

 the vast array of generally mixed timber trees are usually of rather 

 restricted distribution, the relatively few types occurring in temperate 

 and boreal regions are often widely transported and cultivated. 

 Good examples are found among the Conifers that are successfully 

 planted in Europe, which is deficient in native trees for reasons that 

 were discussed in Chapter VI. Such Conifers have often been 

 transported from North America (as in the case of the Douglas 

 Fir, Pseudotsuga taxifolia) or Asia (whence come especially numerous 

 ornamental types, though admittedly these scarcely constitute crops), 

 but do quite well at least as long as Man's influence prevails. Apart 

 from such artificial introduction, there are very few large woody 

 species common to both sides of the Atlantic — in contrast to the 

 situation with numerous herbaceous species especially in the boreal 

 and arctic regions. The tree genera, however, are commonly the 

 same in Europe and the temperate parts of North America and eastern 

 Asia, though some have disappeared from Europe in recent geological 

 ages. 



Forests occupy about one-quarter of the total land-area of the 



