is varied between 25% and 80%, the 

 latter figure being typical of later 

 stages when Brazilian pepper becomes 

 the community dominant. This commu- 

 nity develops on most marl soils as 

 long as the annual hydroperiod does 

 not exceed 4 months. It appears to 

 be a relatively stable association 

 for 10 to 15 years after it is es- 

 tablished, and there is very little 

 indication that natural forest 

 vegetation will replace it over a 

 reasonable period of time. 



The exotic tree species Brazil- 

 ian pepper ( Schinus terebinthifo- 

 lius ) is the primary hardwood 

 species that colonize abandoned 

 farmlands throughout the study area. 

 In this situation, it frequently 

 becomes established after 3 to 5 

 years and becomes increasingly more 

 important in both abundance and 

 aerial cover over the next 10 years, 

 so that it typically forms a closed 

 canopy layer and excludes most other 

 species. When this occurs, rapid 

 successional changes and a monospe- 

 cific forest community of Brazilian 

 pepper occupies the site. Specific 

 stands of this unusual forest commu- 

 nity are common east of the eastern 

 boundary of Everglades National Park 

 and south of Homestead Airport. 



The forest is characterized by a 

 canopy layer 3.5 to 8 m (12 to 

 26 ft) high and an understory and 

 ground stratum of very few species. 

 Often only shield fern ( Thelypteris 

 normalis ) is present beneath the 

 closed canopy. The soil surface is 

 generally bare and a dense array of 

 dead twigwood and small branches of 

 Brazilian pepper is typically pre- 

 sent between the lower limit of the 

 canopy and the ground. Seedlings of 

 Brazilian pepper are frequent in 

 patches where the canopy closure is 

 less than 25%. Observations indi- 

 cate that this community type is 

 very stable over time, with no clear 



indication that natural forest vege- 

 tation is currently replacing it. 



Mixed Brazilian pepper ( Schinus 

 terebinthifolius ) and guava ( Psidium 

 guajava ) forest vegetation is a typ- 

 ically secondary successional commu- 

 nity on farmlands that have been 

 abandoned for more than 20 years. 

 Stands of this type of forest are 

 the most abundant in the portion of 

 the study area that is south of Fla 

 S.R. 27 and east of Everglades 

 National Park. This successional 

 vegetation occupies both Rockdale 

 loam and Perrine marl soils on which 

 the hydroperiod does not exceed 3 

 months. 



The average vegetation height 

 is between 3.0 and 7.5 m (10 and 25 

 ft), and the relative abundance of 

 both co-dominant species varies gre- 

 atly between stands, but typically 

 Brazilian pepper accounts for 60%. 

 The remaining proportion of the can- 

 opy layer is made up of several oth- 

 er species, principally stranger fig 

 ( Ficus aurea ) and willow ( Salix car- 

 oliniana ) . Understory vegetation is 

 generally absent, but occasionally 

 shield fern ( Thelypteris normalis ) 

 forms a discontinuous ground cover. 

 Seedlings or saplings of native for- 

 est species are absent or rare. 



This type of forest vegetation 

 appears to be quite stable through 

 time with regard to successional 

 shifts in composition or community 

 structure. It is not as common on 

 recently abandoned lands as the 

 Brazilian pepper monoculture or the 

 saltbush-Brazilian pepper community 

 and it appears that the Brazilian 

 pepper-guava forest vegetation is 

 more typical of secondary succes- 

 sions that were initiated in the 

 late 1950s and early 1960s before 

 the regional population of Brazilian 

 pepper was as large and widespread 

 as it is currently. 



126 



