United States Agency for International Development - (PDF, 101 mb ...

E.S. Fernando: Vegetation of the Philippine Islands 5
5. Beach forest
This formation forms a narrow strip of woodland along the sandy and gravelly beaches of the
seacoast. Its composition is uniform throughout Malesia and most of the representative
species are pantropical. Many species have fruits and seeds adapted for water dispersal.
'The principal species occuring in the Philippine beach forests are: Terminalia catappa,
Elythrina orientalis, Bam-ngtonia asiatica, Thespesia populnea, Thespesia populneoides,
Hibiscus tiliaceus, Calophyllum inophyllum, Pongamia pinnata, Messerschmidia argentea,
Casuarina equisetifolia and Scaevola frutescens.
Locally one or other species may become dominant, but a mixed association is more usual.
Terminalia catappa may occur in small patches of pure stands in rich river bottoms. On sandy
flood plains near rivers, Casuarina equisetifolia usually forms pure stands.
Desmodium umbellatum and Pandanus tectorius also occur commonly in the beach forest. On
the accreting sand there is usually a narrow strip of herbaceous vegetation dominated by
lpornoea pes-caprae.
6. Mangrove forest
This formation occurs along clayish seashores and in the tidal zones in river estuaries. It can
be bordered at its inland side by old shorelines of low hills, by tidal freshwater swamp or more
or less sandy transition forest. Along its borders on the lateral side, it merges gradually into the
beach fcrmation.
The number of tree species in a mangrove forest is usually limited in the Philippines and
elsewhere in Malesia. By far a total of 39 species have been recorded for the Philippines
(Fernando & Pancho 1980). The number includes inland marg~nal species which are usually
not abundant. Only about 13 species (in 5 genera and 3 families), however, contribute
significantly to the floristic composition of the forest. The following are the more common and
abundant: Rhizophora apiculata, Rhizophora mucronata, Bruguiera cylindrical Bruguiera
gymnorrhiza, Bruguiera parviflora, Bruguiera sexangula, Ceriops decandra, Ceriops tagal,
Avicennia marina, Avicennia officinalis, Sonneratia alba and Sonneratia caseolaris.
Species of Avicennia and Sonneratia occupy the seaward side where the soil is genetally
mixed with sand or coral limestone. Associated with these species is Osbornia octodonta, of
Australian affinity, which forms almost pure thickets. Rhizophora stylosa also invades sandy
shores and coral terraces and does not occur inland.
Species of Bruguiera and Ceriops, as well as Lumnitzera littorea, Lumnitzera racemosa,
Aegiceras corniculatum, Aegiceras floridum, Camptostemon philippinense, Scyphiphora
hydrophyllacea, Excoecaria agallocha, Heritiera littoralis and CenSera manghas are found on
the inner edges of the mangrove formation.
The following species may be rare to frequent and occur along the borders: Glochidion littoralis,
Dolichandrone spathacea, Bam'ngtonia racemosa, Xylocarpus granatum and