EFFECT OF TOPPING OX YIELD OF COFFEE 6 
tional primary laterals be produced. The normal function of lateral 
branches is to produce fruit and only occasionally is any fruit pro- 
duced on an upright stem. In addition to producing fruit, primary 
laterals may also produce from axillary buds secondary lateral 
branches, which are similar in function to the primaries. 
When growth is allowed to take its normal course, the original 
upright trunk bends under the weight of a heavy crop and various 
new upright branches develop from the axillary buds. These are 
similar in structure to the original stem, developing primary laterals, 
which in turn produce fruit. The tendency to develop secondary 
laterals varies somewhat with the variety, but on ordinary Arabian 
coffee, the growth of which has been unchecked by topping, the 
amount of secondary lateral growth is not very great. In conse- 
quence, by far the larger part of the crop is normally produced on 
primary rather than on secondary laterals. If upward growth is 
checked by topping and by the removal of new uprights as they 
appear, the production of secondary laterals on the primaries is 
greatly stimulated, and a large amount of such growth develops. 
For all practical purposes only flowers, fruit, and secondary lateral 
branches ma}' be expected to develop from the primary laterals, 
though observations at the station revealed two instances in which this 
failed to hold true. A tree which was topped at 4 feet in December, 
1910. and the growth of which was forced into the laterals by the 
removal of all subsequently developing uprights, was observed in 
May. 1916, to have developed three "upright* branches from near 
the tip of a primary lateral. Their structure was that of the up- 
right, not the lateral, and their lateral branches were in pairs and 
arose from extra-axillary buds. The position of these " upright * 
branches was more nearly horizontal than perpendicular and one 
showed a marked tendency to produce laterals in a somewhat hori- 
zontal plane. In 1918 a second, tree was noted with several similar 
uprights arising from a lateral. These uprights were rather 
spindling and lacked the vigor of the normal upright. Although in 
the case of neither tree was the development that of the wholly nor- 
mal or typical upright, it partook more of the nature of the upright 
than of the lateral. 
TREATMENT 
The field selected for testing the effect of topping contained 161 
trees at the beginning of the experiment in December, 1910. These 
had been set in the summer of 1908. The size of the seedlings at 
transplanting time was such as to indicate that the seed had been 
derived presumably from the 1906 crop. The variety was Blue 
Mountain of Jamaica, typical of the ordinary Coffea arabica and 
indistinguishable in appearance and habit of growth from the Porto 
Rican variety. 
The trees were set in 24 short rows of unequal length. Rows 1 and 
2 were left untopped, rows 3 and 4 were topped at 6 feet, and rows 
5 and 6 at 4 feet. In the same alternating sequence the remaining 
18 rows were similarly treated. The first of each of the four pairs of 
untopped rows received no pruning whatever, all suckers and growth 
