17 



There were 93 snail trees recorded. These trees had a total population 

 of 4,137 viable snails and 283 dead snails. The dead snails represented 

 6°/ of the population, and are believed to have died during hibernation. 



According to visual observations this snail population in 1976 is 

 believed to have declined from the previous year. In 1975, snail trees 

 could be identified from several feet away by the unusual shiny appear- 

 ance of the leaves. During 1976, this characteristic was not evi- 

 dent. 



The snail population census was taken again in 1977 in the same 

 grove (Table 2). A total of 227 viable snails were located on 74 

 trees. This represented a 95% reduction in the snail population from 

 the previous year. Mortality within the snail harborages were also 

 greater. Where 6% mortality was recorded in 1976, the 1977 census 

 indicated 20% of those snails reaching the snail harborages died. In 

 1976, there was an average of 45 snails per snail tree compared to an 

 average of three snails in 1977. This reduction is believed due to 

 two major factors. The first factor was a change in cultural practices. 

 The grove originally was maintained with a ground cover, a summer grass, 

 which was believed by the owner to increase the humidity on the ground 

 and in the tree. This practice was replaced by one of total tillage 

 "clean culture." Snail migration from tree to tree and egg deposition 

 in the soil are believed to depend on the ground cover. Also, a tree 

 pruning program was initiated during this time. All trees were hedged 

 with mechanical hedgers in an east-west pattern. This hedging opened 

 up the trees to the drying effects of wind and sun, as well as made the 

 snails more vulnerable to bird predation. 



