16 BULLETIN 743, U. S. DEPARTMENT OF AGRICULTURE. 



with a spread of about 20 feet when they are of the slender type 

 (PI. V). Such trees as these have trunks 12 to 18 inches thick. 



A tree 50 feet in height may be considered large, and one which is 

 60 feet has probably reached its maximum development under most 

 conditions. The trunk of such a tree may be 4 feet thick, and the 

 crown may be 50 or 60 feet in spread. Probably these dimensions are 

 not attained until a tree is at least 50 years old. 



There are differences in the character of the growth — its stiffness, 

 brittleness. size, and so on — which do not appear of importance in old 

 trees, but which will stand out more prominently when young budded 

 trees are planted in the orchard and must be trained to a desirable form. 

 In some trees the growths are long and slender, supple, and scarcely 

 able to bear their own weight. Ultimately these growths tend to 

 produce descending branches, keeping the crown close to the ground. 

 Other trees make very short, weak growths, seeming to indicate a 

 lack of vigor. In still others the wood is so brittle that the branchlets 

 snap off when bent. The best trees make strong, healthy-looking 

 growths, smooth and round (angular branchlets frequently indicate 

 a weak grower), with the leaves placed about. an inch apart and the 

 axillary buds short, plump, and well developed. 



CULTURAL PRACTICES. 



The amount of systematic attention given the trees by Guatemalan 

 avocado growers is almost negligible. It is of interest, however, to 

 consider the cultural conditions under which the trees occur and the 

 apparent effect of these conditions upon growth as well as fruit 

 production. 



As alread}^ stated, comparatively few avocados in Guatemala are 

 planted intentionally. It speaks well for the climate and soil that 

 trees which develop under such conditions can reach large size and 

 produce fruit. They do not receive the least attention from any one ; 

 the ground is never cleared of weeds or undergrowth, and the tree 

 must in some instances carry on a constant struggle for existence. 



In coffee plantations or in dooryards of the natives, however, con- 

 ditions are more favorable. Especially is this true of coffee planta- 

 tions, since the cultural attention given the coffee bushes necessarily 

 affects the near-by avocado trees as well. Two or three times a j-ear 

 the ground is cleared of weeds with a heavy hoe. It is never culti- 

 vated deeply, and, in fact, the surface beneath avocado trees in 

 many instances is not even scratched, since a heavy mulch of leaves 

 collects and few weeds require to be removed. 



The only pruning practiced is the removal, when the trees are 

 young, of the lower branches, in order that the crown may be formed 

 above the tops of the coffee bushes. This means that the trunk 

 frequently does not give off any branches at less than 8 to 12 feet from 



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