Overall, we classify Tournefortia as a shrub (Stoddart & 

 Gibbs, 1975). However, following Mueller-Dombois et al. 

 ( 1 98 1 , p. 58), we also distinguish between its shrub (scrub) and 

 tree communities. Because they intergrade. sometimes we 

 lump them together ( vegetation maps and schematic profiles of 

 the motus) and at other times treat them separately 

 (Tables 2.5, 1 and ecological discussions |: 

 /. Tournefortia Scrub: <5 m high (x = 2 m). <60% canopy 

 coverage (Pis. 20,30,33,47 (.This open scrub growth is typically 

 confined to islet perimeters or emergent reef channels and 

 covers much of the vegetated rubble on smaller islets. Its 

 species composition is similar to that of the taller forest, except 

 that herbs are more prominent. 



2. Tournefortia Forest: >5 m high ("x = 8 m), >6C7f canopy 

 coverage (PI. 48). This taller, closed forest, with maximum 

 height 1 5 m. develops as a second belt of woody vegetation 

 approaching the interior of the larger islets. Figure 34 depicts 

 a schematic profile through pure Tournefortia scrub and forest, 

 while Fig. 35 diagrams a profile of a larger islet where 

 Tournefortia is represented only on its periphery. 



Species Diversity in Tournefortia Woodlands : The 

 following species occur in both scrub and forest. Those marked 

 "*" occur primarily in the scrubland (Table 2). 

 Trees: Pisonia grandis, Morinda citrifolia, Pandanus 

 tectorius. Cocas nucifera, Cordia subcordata; 

 Shrubs: Suriana maritima, Tournefortia argentea, Scaevola 

 sericea. Species A; 



Herbs: *Heliotropium anomalum, *Boerhavia repens, 

 *Portulaca lutea, *Lepturus repens, *Laportea ruderalis, 

 *Achyranthes canescens, Phymatosorus scolopendria, 

 Ipomoea macrantha. 



Caroline's tallest Tournefortia stands (12-15 m) occur on 

 Nake. On all other windward motus, the Tournefortia canopies 

 vary between 6 and 9 m tall, shorter than expected if their 

 forests were virgin. This has historical significance: we do not 

 know the extent of forest felling (if any ) on the Windward Islets 

 (Crescent through Tridacna) during the guano era, but we do 

 know that 4.587 coconut palms were planted during 1 9 1 9-20, 

 and that "misses" (dead seedlings) were fastidiously replaced 

 over the following 2 years (Young, ca. 1922). Thus, their 

 forests, though weed-free today, comprise secondary growth 

 around 60 years old. It is not surprising that Achyranthei 

 canescens and Lepturus repens, both weedy (though 

 indigenous), are particularly common inland on some windward 

 motus (Figs. 13.16). Tournefortia' s rapid recovery illustrates 

 that ecosystems in the pioneer stage generally recover their 

 original condition rapidly when left alone (Fosberg. 19S3). 



Stature and Area Coverage : Forming an umbrellalike 

 canopy, a typical Tournefortia forest is very simple. Its twisted 

 branches ami gnarled trunks stretch about untidily over an open 

 understory. The lower branches die off as the trees increase in 

 stature. Sometimes a scant coverofherbs develops in restricted 

 pockets of better soil, such as a clearing where a dead tree fell, 

 a semishaded spot beneath a colony of seabirds, or a site where 

 a storm deposited a leu dead fish. 



Tournefortia is abundant throughout the atoll. Areas with 

 90-10095 canopy cover were found on Nake (Tr. 4). Long 

 (Trs. B.C.4.6. 1 0. 1 2 ). North Pig, Pig. North Brothers, Brothers. 



Crescent, Arundel (Fig. 34). Tridacna (Trs. 1.2). South 

 (Trs. 1,4), all 5 Southern Leeward Islets, all Central Leewards 

 over 0.5 ha, and Pandanus Islet. Tournefortia is present across 

 the entire width of some small motus — for example. Fishball 

 (144 in wide). Even on larger motus such as Mannikiba 

 (280 m wide). Tournefortia blankets nearly all the land ( PI. 70). 

 Long (75.98 ha) is a composite motu: long, narrow, and 

 derived from the coalescence of at least five former islets. 

 Because 7barn€/brria encircled the perimeters of these ancient 

 islets, it is now present in five sets of concentric circles. 

 connected by herb mats, down the length of the island ( Fig. 39). 



In the herb mats, Tournefortia is small (x = 1.4 m) and 

 widely scattered (Table 10). It may be of typical hemispherical 

 shape or irregularly windshorn (Pis. 13.45). On windward 

 coasts they typically form a tight wind barrier one or two trees 

 thick. Moving inshore from the seaward fringe, the trees 

 become progressively taller ( x = 6 m) with a more open 

 understory. Cordia often mixes with Tournefortia, either as 

 scattered individuals in the understory or canopy, or as small 

 groves. On the Southern Leeward Islets, such belts border the 

 seaward scrublands. 



Though still widespread in the Pacific. Tournefortia is far 

 less abundant than formerly. On inhabited islands it exists 

 primarily in relict patches or as edging around anthropogenic 

 forests. It rarely covers most of the land area of islets: two 

 exceptions are TaongK Marshall Islands) and GaferuK Caroline 

 Islands), both in Micronesia (Fosberg. 1956: Wiens. 1962). 

 The finest quality Tournefortia forests on Caroline Atoll (15m, 

 80% cover) occupy central and northern Nake (Fig. 37); given 

 Caroline's history of occupation, these could well be virgin. 

 These 15-m Tournefortia compare favorably with 18-m 

 specimens found at Jemo Island by Fosberg ( 1956). Perhaps 

 Jemo's trees are at the upper size limit for the species, as 

 Tournefortia is generally recorded as 3 to 6 m tall (Wiens. 

 1962). 



Ecology : Tournefortia is an integral part of the atoll's 

 evolution and ecology. Bearing seeds capable of floating for at 

 least 4 months in the sea (Guppy, 1906), it is the first woody 

 plant to establish on tiny motus (<0. 1 ha), appearing immediately 

 after the native herbs have begun to germinate in the coarse 

 coral rubble. Requiring little or no soil and adequate rainfall, 

 it can grow up to 2 m a year (Fosberg. 1959). Tournefortia' s 

 leaves contribute to soil development, paving the way for plant 

 succession from Stages I through IV. for it only persists in soils 

 that are conducive to the growth of its mesophytic competitors 

 (Fosberg. 1953). The most mature trees (x = 9.5 m) occur at the 

 Tournefortia— Pisonia interface, but die off as Pisonia expands. 

 When Tournefortia has reached its maximum height, most of 

 its lower branches have fallen, leafage is reduced, and flowers 

 and fruits are few. Tournefortia usually drops out after one 

 generation. Seedlings are rarely seen in heavy shade, and fallen 

 trees are fairly common on the edge of the interior forests where 

 Pisonia replaces it. 



An example of complete replacement of Tournefortia by 

 Pisonia is illustrated by nearby Vostok. It has heretofore been 

 assumed that Vostok's sole tree species was Pisonia grandis 

 (Fosberg. 1936: Bryan. 1942: Clapp& Sibley, 1971b; Garnett, 

 1983). However, Young (ca. 1922) stated that when Captain. I. 



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