152 EXPERIMENT STATION RECORD. 



Practical results of the cup and gutter system of turpentining, C. H. Hertv 

 t /'. S. Dept. Agr., Bur. Forestry Circ. 34, pp. 7, figs. 5).— The cup and gutter system 

 of collecting crude turpentine was described at length in an earlier publication of the 

 Bureau (E. S. R., 15, p. 46). 



Since the publication of that bulletin further practical experiments in the use of 

 this system have been carried out, and the present circular covers this work, together 

 with improvements which have been made and an account of the defects in the sys- 

 tem which have been discovered during the past 3 years. 



The plat of timber described in the bulletin previously referred to as a " first-year 

 crop" has been worked 2 more years as a "second-year crop" and as a "third- 

 year crop." The results show that where the cup and gutter system was used the 

 trees yielded $1,284.04 per crop, or over 30 percent more than trees boxed in the 

 usual manner. 



A study has also been made of the relative condition of the trees on the cupped 

 and boxed areas. During the period of 3 years 78 trees on the boxed area have blown 

 down and 217 died. On the cupped area 44 trees have blown down and 150 died. 

 Only 8 of the 44 cupped trees were blown down because of being turpentined, while 

 the fall of 59 of the 78 trees blown down on the boxed half was due to boxing. 



The productive surface lost from all causes averaged from 30 to 50 per cent more 

 on boxed trees than on cupped trees. Much the greater part of this loss in both 

 cases was due to "dry face" and the rate of increase in dry face after the first year 

 was greater in the cupped than in the boxed trees and was thought to be due to the 

 higher number of faces per tree on the cupped half. 



improvements have been made in the cups used for catching the resin. They are 

 now made by machinery, with astiffer, much drier clay, which prevents the seepage 

 of resin. With experience dippers are able to collect more gum per day from the 

 cups than from boxes. Another improvement is the use of the broadax for facing. 

 For this purpose the usual setting of the broadax on the handle is reversed, so that 

 in hewing the beveled side is next to the tree. 



Another improvement is to have one man make both incisions for the gutters 

 instead of employing right-handed and left-handed axmen for making the two. An 

 instance is cited in which one laborer prepared 1,700 faces in one day and the work 

 was well done. Zinc nails have been substituted lor iron nails for hanging the cups. 

 These are much softer than the iron nails and do not injure the saws when the trees 

 are afterwards made into lumber. 



Experimental tapping of para rubber trees at the botanic gardens, Singa- 

 pore, R. Derry {Agr. Bid. Straits ami Fat. Mala;/ States, 3 {1904), -Vos. 9, pp. 339- 

 379; 11, pp. 442-463). — Tabular data are given on the results secured in an extensive 

 series of experiments in tapping para rubber trees, which were planted in 1886 to 

 1888 and which have an average girth of 2.5 to 4.5 ft. at 3 ft. from the ground. 



Better results have been secured from morning tapping than from evening tapping, 

 although the evening work commenced as late in the day as possible. It is believed 

 that the flow of latex depends entirely upon the pressure of water within the tree 

 and this is affected to some extent by the contraction and expansion of the tree. It 

 has been noted that a tree 3 ft. in girth at 3 ft. from the ground which measured 

 exactly 3 ft. at 6 a. in. would by afternoon on bright days contract a maximum of 

 0.5 in. and by 6 p. m. or soon afterwards expand to the early morning measurement. 



On wet days also there was considerable expansion in the tree and the flow of the 

 latex was considerably increased, but contained an unusually high percentage of 

 water. In wet weather it seems best to tap some hours after a storm. It has been 

 found that latex from a big tree produces a much thicker biscuit of prepared rubber 

 than the same amount of latex from a small tree, irrespective of age. 



Experiments in tapping by the herring-hone method confirm in general the opinion 

 as to the advantage of alternate over daily tapping. 



