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T. Number of times per year it is best to tap each tree to get 
the best results. 
n. Number of trees per day one man will be able to tap. 
Some planters think it will be more profitable to plant for a 
period of ten or fifteen years only while others have confidence in 
the future beyond that time. 
If trees are planted too close together they grow tall and have 
small leaf area and under these conditions the bark does not 
grow quickly as on trees planted wider apart. 
Effect of Close Neither does the new bark form and grow over 
Planting. the tapped surface as quickly as in wider plant- 
ing and it is now found necessary to rest a too 
closely planted forest, while continuous tapping can be made on 
wider plantings. Photo No. 10 shows trees that were planted too 
thickly with the result that the usual tapping area having been 
cut the renewed bark is too thin to tap so that experiments are 
being made in tapping up to 12 feet high. The trees are usually 
considered large enough to be tapped when they are twenty inches 
in circumference three feet from the ground, but one grove that 
I saw that was planted 10x10 or 436 to the acre, although large 
enough in circumference when five years old, the bark was found 
to be too thin to tap. On another plantation they were tapping 
two groves of the same age, 8^ years, one planted 12x24 or 148 
per acre (see Photo No. 11), and the other 12x12 or 296 per 
acre. The 12x24 trees gave an average yield of 3 pounds per tree 
while the 12x12 trees averaged a little less than i$i pounds and 
gave less on second tapping, thus acre for acre, the yield was 
about the same. The yield of rubber from each tree for each 
day's tapping was almost double from the trees in the 12x24 plant- 
ing as compared with the 12x12 planting and as each coolie makes 
80 tappings per day in either grove the cost of collecting a pound 
of rubber is nearly double in the grove more thickly planted. 
Photo No. 7 is a grove planted 11 years ago 24x24 or 74 per 
acre. In talking with the gentleman who planted these trees he 
stated that if he were planting for himself he 
Widest Planting, would plant at least 24x24 (74 per acre), and 
perhaps 30x30 (46 per acre). That he would 
do this with the idea of making good profit twenty years from 
now as well as in the earlier years. Photo No. 12 shows eleven 
year old trees planted 60 to the acre. Eight hundred trees in this 
planting averaged a yield for the year of seven pounds or 420 
pounds of rubber per acre. 
Trees in Malaya usually attain a circumference of 20 inches 
three feet from the ground in from four to five years. 
Growth. In Ceylon a few trees will reach this size in five to six 
years, many in six to seven years, and are tapped at the 
base when they measure twenty inches. 
