Anak Krakatau is the small still active core of the massive Krakatau  volcano which erupted in 1883 creating a tsunami which killed over 36,000 people on the coasts of Java and Sumatra.  Anak Krakatau only emerged above the sea in 1930.

There were severe eruptions in 1952 and 1957 which are said to have sterilized the island of all plant life  so the vegetation on Anak Krakau was approx. 58 years old in 2015 when this photo was taken. The  spit at the bottom of the photo is known as the East Foreland  and the fig population has been well documented. In 1985 the first figs to appear F. septica and F. fulva started fruiting and by 1992  the fig population also  included F. ampelas, F. nervosa, F. hispida, F. variegata and F. fistulosa. Note that all but 2 of the 7 species (F. ampelas and F. nervosa) are primarily bat dispersed.

Sertung (the island in the background)  was part of the original volocanic rim of Krakatau which exploded in 1883, so the vegetation on Sertung was  approximately 132 years old in 2015.

Note the tiny tourist boats  next to the beach on the lower  left. If you  are staying in Jakarta it is possible to visit Anak Krakatau on a (long) day trip. Google Maps

111016 CC Anak_Krakatau by Sammy Sammy
Photos show Anak Krakatau in 2015 before the recent explosions  in 2018.  Since  Anak Krakaktau emerged from the sea in 1930, the  vegetated area  has been frequently modified by lava flows. The photos show areas of  original vegetation which established after 1957 and are therefore c. 58 years old.  The vegetation is primarily Casuarinia equisetifolia  trees which are wind and sea dispersed and only establish in full sun. This means that Casuarina forest is often the pioneer vegetation on newly established sandy beaches  in Borneo
2019-09-20 12_47_11-Thornton (1996) Colonization Krakatau by Ficus.pdf - Adobe Acrobat Reader DC.png
1989 map from Thornton et al (1996) The role of animals in the colonization of the Krakatau Islands by fig trees. Note that  Rakata the biggest island has extensive  areas of Ficus forest . Ficus pubinervis  is a synonym for Ficus nervosa.
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Aerial photo  from Google Maps taken  after the 2018 explosion of Anak Krakatau. Note that the vegetation on Sertung, Panjang and Rakata established in 1883 (136 years ago)  whilst the remnant patches of vegetation on Anak Krakatau established in 1957.
Thornton et al (1996) Ficus list Krakatau.png
By 1996  24 different species of figs had been recorded  on the remnants  of the 1883 Krakatau explosion which effectively sterilized the islands. The majority of figs are growing on Rakata.      F. subulata  which was first recorded  in 1922 had vanished by 1979 and F. heterophylla  was only recorded in 1979 on Rakata.  Note that F. retusa refers to Ficus microcarpa and  F. pubinervis refers to F. nervosa. Data from Thornton et al (1996) The role of animals in the colonization of the Krakatau Islands by fig trees.

Thornton et al. (1969) The role of animals in the colonization of the Krakatau islands

Note that the first 7 fig species  to become established (1896-1908)  were all  small dioecious fig trees of the forest understorey or  secondary forest dispersed primarily by small Cynopterus fruit bats.

Most fig ecologists would have predicted the exact opposite  i.e. that the first figs to establish would be the monoecious canopy level  stranglers  that are common in W. Java such as F. microcarpa, F. drupacea, F. virens and F. benjamina.  In fact it took  nearly 100 years for these monoecius figs to establish. For a possible explanation, see  Are Fig Wasps Hitch-Hikers ?

02 Ficus fulva Java Koorders, S.H., Valeton, T., Atlas der Baumarten von Java, vol. 4 (1918) .jpg
 Ficus fulva from Java, illustrated in  Koorders, S.H., Valeton, T., Atlas der Baumarten von Java, vol. 4 (1918.  Ficus fulva was  the first fig to establish on the bare volcanic rock  3 years after  the islands were sterilized by the 1883 explosion.