October i, 1901.] 



THE INDIA RUBBER \VORLD 



3 



RUBBER PLANTING IN COSTA RICA. 



By Th. F. Koschny, (San Carlos.) 



•^T^^O THE Editor of The India Rubber World : In re- 



I spect 10 tenacity of life and the quantity of its yield, 



the Castiltoa e/astica has no equal among other rubber 



producing plants. Moreover, when the tensile quality 



of its product is taken into account, and the low degree of 



shrinkage, its value, as compared with Para rubber, is much 



higher than is generally supposed. 



The Castilloa requires a warm and moist climate. A tem- 

 perature never less than 60° F. and an elevation not over 1200 

 feet above the sea are desirable. There are exceptionally well 

 protected places where it will thrive at an elevation of 1500 

 feet. Native trees are found most abundantly, and in the best 

 state of development, at between 500 and 1000 feet. Near the 

 sea, where the air is impregnated with salt, the trees will not 

 thrive. The annual rainfall should not be less than 80 inches ; 

 the more the better. In the valley of San Carlos, in Costa 

 Rica, I found the greatest abundance of native rubber when I 

 traveled extensively in Central America in 1870; this has an 

 annual rainfall of 160 inches. Not only is plenty of rain desir- 

 able, but it should be well distributed throughout the year. 

 San Carlos, for instance, has, in the two dryest months, March 

 and April, 2 and 4 inches of rainfall, respectively. The Pacific 

 slope of Central America, with its decidedly dry season of six 

 months, is, save in a few favored localities, not adapted for 

 rubber planting. In its native state the Castilloa favors a 

 clay soil and this soil predominates on the Atlantic slope. I 

 have never seen well developed rubber trees on a sandy soil. 



The Castilloa elastica seeds ripen from March to June. The 

 fruit resembles a pie 3 or 4 inches in diameter, with an outer 

 green plate, and consists of a very soft red pulp, in which the 

 seed is imbedded. Each fruit contains from 8 to 15 seeds the 

 size of a pea. At first they will weigh 1000 to the pound ; by 

 the third day they weigh 1500 to the pound. They must be 

 kept moist until planted. They may be planted in nursery 

 beds, or where the trees are intended to stand. The price in 

 San Carlos is §2, gold, for 1000 seeds. 



Lands for planting should be inclined, to allow for drainage. 

 Swamps or very level lands, on which the water stands, are 

 unsuitable. Hillsides too steep for other cultivatien, might be 

 utilized for rubber. The Castilloa elastica is a shade tree, and 

 any other culture than that which is suited to this character- 

 istic will prove a failure. It will grow in the open until about 

 the sixth year, when the top begins to dry off and shoots start 

 up from the lower stump to protect the trunk. It is the stem 

 of the tree that needs protection from the sun's rays. Trees 

 not protected will always perish from the first attempt to ex- 

 tract rubber. I have lost thousands of trees at the first tapping 

 for this reason. Four years ago I planted a few acres in the 

 forest, cutting out the larger trees, where the shade was 

 densest, and setting out the rubber in rows. The young rub- 

 ber trees are now 25 feet high and 5 inches in diameter three 

 feet above the ground. While the rubber tree is so delicate in 

 the open field, it is quite the reverse in the forest. I have trees 

 planted in the forest shade that are covered with scars from 

 tapping, but are yet vigorous enough to yield seeds. The Cas- 

 tilloa is seldom found wild in dense forests of high trees, but 

 in places where high trees are interspersed with lower ones, or 

 with high brush, in such a way that during some part of the 

 day the sun can reach the rubber foliage. These same obser- 



vations, by the way, were made by the German botanist, Rudolf 

 Schlechter, with the Kickxia Africana, in the colony of Lagos, 

 West Africa. 



In planting rubber by my method, rows or paths are cut in 

 the forest, two yards wide and three yards from center to 

 center. In these rows the seeds are planted, without prepara- 

 tion of the soil, about six yards distant. At the selected spots 

 two small holes are made, about six inches apart, and in each 

 one rubber seed deposited and covered with an inch of soil. 

 In case both seeds grow, one plant may be set out elsewhere. 

 If the ground should be cleaned thoroughly, lizards would be 

 more apt to cut off the green shoots as soon as they appeared. 

 After they are eight inches high, the ground may be cleaned 

 around the plants. The rubber grows better when planted in 

 its permanent location, for transplanting means a check to the 

 growth for a month or two. The seedlings should be watered 

 in dry weather. But if nursery seedlings are used, care should 

 be taken, in transplanting, that the tap root of the plant goes 

 down in the ground, instead of being doubled up. The spot 

 where each seed or seedling is planted should be marked with 

 a stake a yard and a half high. As soon as the plants are up, 

 and any necessary replanting has been done, the work of thin- 

 ning out the forest may be taken up, with a view to leaving 

 only so much shade finally that, during some part of every day, 

 the sun may reach every rubber plant. 



The Castilloa may also be planted in open ground, but with- 

 out cutting down weeds or young trees sprouting in the spaces 

 between the rubber plants. These, in the tropics, in a few 

 years form a forest growth sufTicient to shade the rubber ; if too 

 dense, it must of course be thinned out. This method of plant- 

 ing rubber has an advantage in that it forms stronger plants at 

 first, but it is more expensive in the end, because for the first 

 two years six heavy cleanings per year are necessary, and later 

 the free space must be thinned out every year. With forest 

 planting, however, only three slight cleanings are needed the 

 first year — cutting the sprouts of the underbrush and cleaning 

 the ground about the rubber plants in spaces one yard in diam- 

 eter, such as one man can accomplish for one acre per day. 

 For the next three years only two annual cleanings are needed, 

 and for the next three years, only one annually. In the eighth 

 year the Castilloa becomes productive, after which the only 

 work in cleaning is to tear the climbing vines away from the 

 trees to allow the rubber to be extracted. 



The average yield of rubber per tree in the eighth year 

 should not exceed i pound of dry rubber per tree, to avoid in- 

 jury to the tree. The development of all trees in a large plan- 

 tation will not be the same, and some can stand heavier tapping 

 than others. In the tenth year the yield should be 1,'+ pounds; 

 in the twelfth year, 1^2 pound, and after the fifteenth year, 2 

 pounds per year. This is not a calculation of what the trees 

 will yield, but the limit of aunual yield without injury to the 

 health of the tree. 



As for expense of planting in Costa Rica, an estimate may 

 be based on 100 hectares ( = 247 acres). The cost for eight 

 years will be, allowing 50 per cent, for extras over the figures 

 that my own experiences point to, for 25,600 trees, $5300, gold. 

 This includes the cost of the first year's tapping. The yield 

 this year, at i pound per tree, will be 25,600 pounds, worth, at 

 85 cents per pound, $21,680, gold. 



