CHOICE OF SHADE TREES. 41 



realization of the importance of an experimental determination of the 

 cultural functions and relative utility of the numerous species of shade 

 trees. The introduction to the East Indies of the more valuable of the 

 American leguminous shade trees has not been attempted, to say noth- 

 ing of a general canvass of the tropical arboreal flora of this family, 

 a botanical undertaking now most desirable if the culture of coffee and 

 other agricultural crops of the Tropics is to receive the assistance 

 which this branch of science might be able to furnish. No mere cata- 

 logues of species or sj^stematic studies in the ordinary sense of the 

 words will, however, suffice for this purpose. Trees which give 

 promise of eligibility should be thoroughly investigated in their native 

 countries with reference to soils, altitudes, and climatic conditions, 

 size, habits, and rates of growth, immunity from disease, quality and 

 value of wood, fruits or other products, facility of propagation, and 

 all other facts bearing upon their availability in agriculture. Such 

 preliminary knowledge will be of great value in avoiding expense 

 and delay in the experiments necessary in selecting the best species for 

 different regions and climates. Many tropical leguminous trees are 

 deciduous; in some countries species deciduous in the dry season will 

 probably be best, in others those which lose their leaves in the rains. 

 One species, Adenanthera pavonina, drops its leaves both at the begin- 

 ning and at the end of the rainy season. Many close their leaflets at 

 night, and thus permit more thorough ventilation. The quick-growing 

 species are short lived; there is, however, no reason why, as with 

 cacao, two or three species of shade trees might not be planted with 

 coffee, some to be cut away when the} r had reached the limit of useful- 

 ness, the more desirable and longer-lived species to remain as per- 

 manent shade. 



It is not desirable at this point to attempt a discussion of the uses 

 and products of leguminous trees which might bo used for shade, 

 although this is a subject likely to prove of much importance . since 

 trees yielding edible or otherwise useful fruits ma} 7 occupy no more 

 space and require no more attention than those yielding no direct 

 returns. The appended list of species which have been planted with 

 coffee either as shade trees or as catch crops includes the available 

 information on the above point. This information is of necessity frag- 

 mentary, but it may prove of use for the practical planter as well as 

 for those who may be interested in the increase of knowledge likely 

 to have so important a bearing upon the development of tropical 

 agriculture. 



CONCLUSIONS. 



A canvass of the subject of shade in coffee culture shows that there 

 is no basis in reason or in observed fact for the belief that shade is a 

 general necessity for the coffee plant, even when grown at low eleva- 



