110 



was severely injured, it is, nevertheless, recovering, as is shown by 

 the well developed callus on both sides of the injured panel. The 

 tree shown in Figure 12 was killed by the combined effects of tap- 

 ping and wood borers. Figure 13 illustrates a magnificent specimen 

 which has been tapped twice and shows no signs of permanent in- 

 jury. Shortly after this photograph was taken it was tapped a third 

 time and gave a large quantity of latex. In individual cases it is thus 

 difficult to predict the ultimate eft'ect of tapping and the reaction of 

 the tree to injury. 



There is little doubt, however, that the native machete-spiral 

 system of tapping is ruthless compared to the method employed on 

 Hevea hrasiliensis and is gradually killing a large number of trees. 

 This, together with the large amount of gum annually extracted and 

 exported from the chicle areas, and the apparent slow growth of 

 Achras sapota, is gradually exhausting the forests of "wild" virgin 

 sapodilla trees. Areas in which supply of chicle seemed almost in- 

 exhaustible a quarter of a century ago are thus becoming depleted. 

 On the other hand, there are many contractors who maintain that 

 the present demand and consumption is compensated by the rate of 

 growth and healing of Achras sapota and that a sufficient number of 

 young trees come into profitable yield each year to offset to some 

 degree the long interval of time required for a tapped tree to heal. 

 The chief basis for their argument is that certain old chicle conces- 

 sions or areas have been yielding approximately the same amount of 

 gum for almost twenty-five years and that chicle exports have been 

 increasing steadily. To anyone familier with the conditions in such 

 areas and who has had intimate contact with the chicleros, it is ob- 

 vious that the task of maintaining the annual demand is becoming 

 more difficult each }-ear. Chicleros must accordingh^ tap smaller and 

 younger trees each year to meet the demand, and it is not uncom- 

 mon to find trees as small as eleven inches in circumferences which 

 have been completely tapped. To the writer, who has spent several 

 years of observation and experimentation in tropical America, it is 

 obvious that the demand in normal times is greater than the annual 

 production of latex by the sapodilla trees in southern Mexico and 

 Central America, and that under present tapping methods and lack 

 of conser^-ation a time will eventually be reached when the supply 

 is exhausted. Before this condition arrives, however, greater utiliza- 

 tion of favorable adulterants and chicle substitutes by chewing gum 



