In recent years, the tropical coastal forest of the Siangjiaowan Ecological Reserve has
been severely invaded by shade-intolerant species and Leucaena leucocephala due to
road construction which created adverse edge effects along the forest. In addition, many
valuable tree species lack new recruits. The composition and structure of this forest are
dramatically altered compared to those 40 yr ago. To understand the current status of
this coastal forest, we established a 1.55- ha sampling plot (300 m long, 40~60 m wide)
in the forest in January 2012. Each individual of a woody species was identified and
tagged, and its height, diameter at breast height (DBH), and location were recorded.
In total, 1765 trees ha-1 belonging to 58 species with a DBH of ≥ 1 cm were recorded;
among them, Aglaia formosana and Macaranga tanarius had the highest species
abundances.  For trees with a DBH of < 1 cm, a total of 3023 stems ha-1 belonging to
53 woody species was recorded, with 934 stems belonging to Agl. formosana. Among
the 58 species with individuals with a DBH of ≥ 1 cm, e.g., Hernandia nymphiifolia and
Barringtonia asiatica, most of them appeared to have a fluctuating diameter structure,
indicating that many disturbance events had occurred during their regeneration process.
Sorted by the Importance Value Index (IVI) of this stand, Bar. asiatica and Her.
nymphiifolia were listed as nos. 1 and 3. However, Mac. tanarius and Melanolepis
multiglandulosa, both very shade-intolerant species, were nos. 2 and 6 in the IVI.
Furthermore, Mac. tanarius and Leu. leucocephala rapidly occupy tree-fall gaps created
by disturbances from typhoons. From 1974 to 2012, species abundances of Her.
nymphiifolia and Bar. asiatica were respectively reduced by 31 and 21%, and those of
Murraya paniculata and Morinda citrifolia were reduced 51 and 55%, while those of Mac.
tanarius and Mel. multiglandulosa increased 56-and-4 fold. The leaf area index of this
tropical forest decreased from 3.96 to 1.73 after 2 typhoons hit in August 2012, but had
rebounded to 3.02 in only 75 d after the second typhoon. Preliminary ecological
restoration efforts of this forest were initiated in July 2012. We reduced the density of 3
invasive shade-intolerant species in a wind-disturbed site and planted Bar. asiatica and
other native species of this coastal forest, in an effort to improve the stand structure of
this tropical coastal forest.