Larsen. of the schooner Papeete, planted 1 00 coconuts there on 

 3 1 May 1922. he found "Pukatea and Tauhinu trees, et cetera 

 60 to 80 feet high;" that is, Pisonia grandis and Toumefortia 

 argentea, but no "Tou" trees (Cordia subcordata). By 1935 

 only Pisonia remained (Fosberg, 1936); thus, the last natural 

 Toumefortia must have been eliminated by Pisonia. 



Along some coasts (Long, Nake, South). Toumefortia 

 overhangs the water, its roots immersed at high tide. We found 

 floating debris up to 20 m inland within dense Toumefortia 

 forest, indicating that this hardy shrub can withstand periodic 

 storms and high tides. If a rosette of Toumefortia leaves is 

 placed in fresh water, it droops within an hour, indicating that 

 its tissues require a high salt concentration in order to maintain 

 turgidity (personal observation). Perhaps decreased salinity in 

 the ground water, coupled with reduced light intensity in 

 advanced serai stages, contribute to the eventual disappearance 

 of Toumefortia in the center of coral islands. 



Associations with Birds : Toumefortia is a favored roosting 

 and breeding site for most of Caroline's seabirds. The taller the 

 trees, the greater the bird diversity they harbor: scrub contained 

 four species (36%) and forest, nine (82%). Sooty terns nest in 

 tight colonies in its shade, its canopies support large populations 

 of red-footed boobies (PI. 51) and great frigatebirds 

 (Subchapter 1.2, this volume), and its branches are favored by 

 white terns (Figs. 34-36). Toumefortia leaves provide nesting 

 material for noddies. 



Cordia Forest (1.39 ha) (Fig. 22; PI. 27) 



General Distribution : Cordia does not form "the main 

 native woodland" on Caroline Atoll, as implied by Clapp & 

 Sibley ( 197 la) and stated by Stoddart & Gibbs (1975, p. 104). 

 It occupies far less area than Toumefortia or Pisonia (Table 9). 

 Cordia is generally mixed with other emergents: monotypic 

 Cordia forest covers only 1.39 ha, while Toumefortia or 

 Pisonia containing substantial amounts of Cordia total 

 25 .89 ha. In toto. this is less than 1 0% of Caroline' s woodlands, 

 and Cordia is usually subdominant. We treat Cordia forest as 

 a separate plant community because of its increasing rarity on 

 Pacific atolls, which makes Caroline's groves an increasingly 

 important resource in need of conservation. Cordia forest 

 occurs primarily on Nake, Windward. Crescent, North Pig, 

 Pig, Danger, Shark, and the Southern Leeward Islets. 



History : Bennett (1840) recorded "two species of 

 Toumefortia" on Caroline, possibly referring to Toumefortia 

 and Cordia. There are no other 19th-century records. From 

 Cordia 's present distribution we can infer that it was formerly 

 more extensive on South and Nake. Scattered trees within and 

 bordering the Coeos plantations suggest that its history is 

 similar to the species on Flint: both Flint and Caroline were 

 worked simultaneously by the same companies for guano 

 ( 1872-1890) and copra (into the 193()'s). Pisonia and Cordia 

 forests were felled to make room for coconuts. Several 

 hundred Cordia logs were exported from Flint to San Francisco 

 to be used for furniture. The last logs were exported in 1896, 

 6 years after the guano supplies were depleted, but coconuts 

 were still being planted (Young, ca. 1922). Today, the belt of 

 indigenous vegetation bordering Flint's coconut plantation 

 still has many large Cordia trees (Kepler, 1990b), unlike 



Caroline, where today Cordia is rare on South Island. However, 

 some of Flint's Cordia trees today may well be those "few tiny, 

 struggling. ..trees. ..recently planted" (St. John & Fosberg, 1937). 



Abundance and Distribution : Cordia seeds are dispersed 

 by ocean currents and can germinate after 40 days in seawater 

 (Guppy. 1906). Requiring the presence of other species 

 (Fosberg, 1953), on Caroline it develops both as an understory 

 shrub and forest emergent (to 15 m high). It typically occupies 

 the woodland periphery, occurring in small circular or linear 

 groves, or mixing with Toumefortia and/or Pisonia (Table 5). 

 On many other Pacific atolls Cordia forms a mixed scrub with 

 Scaevola (Fosberg, 1949). Cordia may form tall, straight- 

 trunked trees (PI. 27) or sprawl like Hibiscus tiliaceus. In dry 

 rubble sites it may become chlorotic ( PI. 79 ) or semideciduous. 

 The tallest groves are on Pig (PI. 27), where six trees averaged 

 12.6 m tall, 1 16 cm circumference at 1.5 m high, and 99.8 cm 

 around the trunk base. Lush Cordia groves sheltered parts of 

 the upper lagoon on Long Island (Tr. 10). 



Flowering times are unpredictable: In November 1989, 

 flowers were abundant, extending through March, yet in 

 November 1990 not one flower was observed (Anne Falconer 

 and AK.K, personal observation). Two flowers were seen in 

 September 1988 (personal observation). 



Associations with Birds : Black and brown noddies, 

 frigatebirds, and white terns nest in Cordia wherever it is a 

 forest component. Great frigatebirds and red-footed boobies 

 favor roosting in the lush, lagoonside forest of Cordia and 

 Pisonia near the south end of Long Island. 



Pisonia Forest (62.17 ha) (Figs. 18,32,33,35,39,41; 

 Pis. 43,52,53; Tables 11-14) 



General Distribution : Although Pisonia grandis is recorded 

 as "present" in the two previous scientific accounts of Caroline 

 (Trelease, 1884; Clapp & Sibley, 197 la), the quality and extent 

 of its forests has not been recognized. Some stands on this atoll 

 are outstanding representatives of a major ecosystem that was 

 formerly far more widespread in the Pacific. 



Common throughout the atoll, Pisonia occurs on 29 motus. 

 Well developed groves, 10-21 m tall and up to 359 cm 

 circumference at 1.5 m, are present on 23 of these (Table 1 1 ). 

 Although present on motus less than one hectare in size 

 (Table 5). it typically occupies interior forests (schematic 

 profile. Fig. 35), with individual trees or groves contributing 

 from 5% to 100% of the canopy. In general, Caroline's 

 windward motus support the lushest forests: the maximum 

 height of windward Pisonia forests is 2 1 m; of leeward forests, 

 15 m. 



Mature Pisonia forests are monocultures of grandeur. The 

 trees bear one to several stout boles of irregular shape, whose 

 rotting cavities often harbor large coconut crabs or miniponds 

 alive with mosquito larvae. Their scraggly branches 

 occasionally bend over and reroot. It is dark and humid after 

 the glare of the beach. Walking is easy because the forest floor 

 is open except for exposed roots and a scattering of broken 

 branches. Few seedlings occur. Overhead, aconstant cacophony 

 of bird calls overwhelms the sound of the trade winds, and 

 guano spills everywhere. Polynesian rats scurry underfoot. It 

 is a curious habitat for a tropical island. 



29 



