218 THE CENTRAL AMERICAN RUBBER TREE 



which the trees are to occupy, as by this means trans- 

 planting is avoided and the growth of the seedUngs is not 

 checked. When this plan is adopted the land is cleared 

 and staked according to the distances at which the seeds 

 are to be planted, e.g., 6 by 6 ft., 5 by 10 ft., 9 by 9 ft., 

 6 by 12 ft., etc. Six to ten seeds are then sown in small 

 raised heaps of soil at each stake. The time of sowing 

 should be chosen so as to avoid a period of drought 

 during the early stages of development, and in situations 

 where there is a distinct, dry season, the plants should 

 be well established before the rains are over. The seed- 

 Imgs are carefully examined during the first six months, 

 and at least half of them are removed, leaving the best 

 specimens. This thinning out is continued so that at the 

 end of the second year only a single plant is left at each 

 stake. Further thimiings should take place from time 

 to time as the trees develop, until at the end of the sixth 

 year only about 400 selected trees remain per acre. In 

 some instances the trees, one at each stake, are allowed 

 to grow until the end of the fifth year, when the best 400 

 m each acre are selected, and the rest are tapped to 

 death and cut out during the next year. Sometimes, 

 however, the thinning-out process is not properly carried 

 out, and it is stated that on some estates in Mexico there 

 are over 1,000 eight-year-old trees per acre. 



Three different methods have been tried in cultivating 

 Castilloa trees. In the first experiments the seedlings 

 were planted out under shade, but it was found that, 

 although the growth in height was rapid imder these 

 conditions, the increase in the thickness of the trunk 

 was very slow, and moreover the trees were generally 

 liable to disease. 



Planting the trees under partial shade has also been 

 tried. In this plan a few high trees are left standing 

 when the ground is cleared for the plantation, in order 

 to afi'ord some shelter dming the dry season, when the 

 Castilloa trees have shed their leaves and are exposed to 

 the scorching sun. This method approximates more 

 nearly than the first to the conditions under which Castilloa 

 trees occur naturally, and it has given good results on 

 some plantations, especially where the soil is liable to 

 become hard and baked if exposed to the sun. 



The third method is to sow the seeds at stake in the 



