6.12 HAMMOCKS 



Hilsenbeck et al. (1979) list 

 five (5) types of hammocks (or for- 

 ests) in the east Everglades study 

 area: 



(1) Shark River Slough bayhead 

 forests; 



(2) Taylor Slough bayhead for- 

 ests; 



(3) Bayhead-tropical hardwood 

 forests; 



(4) Tropical hammock forests; 

 and 



(5) Midden forests. 



Shark River Slough bayhead 

 forests typically exhibit 3 strata: 

 a canopy layer between 4 and 10 m, 

 (13 and 33 ft) a shrub layer between 

 0.6 and 3 m (2 and 10 ft), and a 

 ground layer up to 0.6 m (3 ft) 

 (Hilsenbeck et al. 1979). The 



canopy layer generally consists of 

 strangler fig ( Ficus aurea ), red bay 

 ( Persea borbonia ), willow ( Salix 

 caroliniana ) , and wax myrtle ( Myrica 

 cerifera ) . The shrub layer contains 

 elderberry ( Sambucus simpsonii ), 

 myrsine ( Myrsine quianensis^ , wild 

 coffee ( Psychotria sulzneri ) , and 

 dicliptera ( Dicliptera assurqens ). 

 The ground layer is typically com- 

 posed of sawgrass ( Mariscus jamai - 

 censis ) , leather fern ( Acrostichum 

 danaeaefolium ) , swamp fern ( Blechnum 

 serrulatum ) , Boston fern ( Nephrole- 

 pis exaltata ), shield fern ( Thely - 

 pteris kunthii ), bloodberry ( Rivina 

 humilis ) , creeping orchid ( Habenaria 

 nivea) , and melonette ( Melothria 

 pendula ) . 



Taylor Slough bayheads tend to 

 be better developed than Shark 

 Slough bayheads with regard to can- 

 opy closure, species richness, and 

 stratal organization. Also, many of 

 the canopy trees are larger, both in 

 height and diameter. Floristically 

 Taylor Slough bayheads differ from 

 those of Shark Slough in that bald 



cypress ( Taxodium distichum ), poi- 

 sonwood ( Metopium toxiferum ) , cab- 

 bage palm ( Sabal palmetto ) , and even 

 red mangrove ( R hiz op hora mangle ) and 

 buttonwood ( Conocarpus erecta ) may 

 be present in the canopy layer. The 

 shrub layer contains numerous tropi- 

 cal hardwoods such as white stopper 

 ( Eugenia axillaris ), antswood ( Bume - 

 lia reclinata var. reclinata ) , and 

 Spanish stopper ( Eugenia myrtoides ). 

 In the ground layer the unusual 

 species Apteria aphylla (or nodding 

 nixie) is very common. 



Tropical hammock forests repre- 

 sent the upland climax community for 

 the study area and for southern 

 Florida in general. This community 

 develops on organic soils that are 

 sufficiently elevated so that the 

 effective hydroperiod is less than 

 1 month in duration. The best 



developed stands with the tallest 

 and largest trees have no effective 

 hydroperiod except during extremes 

 of flooding, such as associated with 

 hurricanes. The hammock forest 

 canopy is generally closed, usually 

 excluding more than 85% of ambient 

 sunlight. The forests are floristi- 

 cally very diverse both with respect 

 to canopy and understory vegetation. 

 The average height of the vegetation 

 is from 2.8 to 10 m (9 to 33 ft). 



The structure of the hammock 

 forests is generally 2 stratal: a 

 canopy stratum 4.5 to 12 m (15 to 

 40 ft) high, and an understory and 

 ground stratum from ground level 

 to 2 m (7 ft). The canopy layer 

 includes: live oak ( Quercus virqin- 

 iana var. virqiniana ) , strangler fig 

 ( Ficus aurea ), willow bustic ( Diph - 



olis salicifolia ) , wild mastic 



( Mastichodendron foetidissimurrt ) , 



pigeon plum or tie tongue ( Coccoloba 

 diversifolia ) , wild tamarind ( Lysi - 

 loma latisiliqua ) , gumbolimbo ( Bur- 

 sera simaruba ), paradise tree ( Sima - 

 rouba qlauca ), lancewood ( Nectandra 



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