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monitoring period. The trees mapped in the 40 vegetation plots that have now been 
handed over to NParks, will provide baseline data for future monitoring; establishing 
more plots would increase the probability of sampling future fluctuating hydrological 
conditions. 
Furthermore, the plant species that were found to be rare or restricted to the Nee 
Soon freshwater swamp forest should be targeted for propagation. These propagules 
can then be transplanted elsewhere. For example, they can be used for restoring other 
potential freshwater swamp sites, and hence the dilution of conservation threats. 
The community assembly patterns within the Nee Soon freshwater swamp forest 
may provide further insight on restoration strategies. For example, species such as 
Gynotroches axillaris Blume and Pellacalyx axillaris Korth. are commonly found 
in other swampy areas in the Central Catchment Nature Reserve, but these sites 
seldom have other swamp indicator species such as Baccaurea bracteata Mull.Arg., 
Lophopetalum multinervium Ridl., Mussaendopsis beccariana Baill., Palaquium 
xanthochymum (de Vriese) Pierre ex Burck, Pometia pinnata J.R.Forst. & G.Forst., 
etc. and almost never have the rarer swamp Syzygium R.Br. ex Gaertn. spp. or nutmegs 
(Myristicaceae family). Two main reasons can be suggested: (1) these species are 
dispersal-limited from establishing populations in other swampy sites beyond the Nee 
Soon catchment; (2) specific soil or biotic conditions are limiting the establishment of 
these species. The first reason can be overcome by transplanting propagules obtained 
from the Nee Soon freshwater swamp forest. The second reason would require more 
detailed studies and experimentation that involve swampy sites outside of the Nee 
Soon catchment. 
Regarding concerns about increasing tree falls and diebacks, the vegetation 
ecology team considered that these are more likely to occur (1) for large trees (2) 
of species with weaker wood, and more often observed (3) along forest edges, such 
as around the firing ranges and along the pipeline. Only systematic monitoring and 
dedicated data collection can test these hypotheses, and determine the extent of the 
issue, together with possible solutions. This could begin with large trees, e.g. >10- 
cm DBH, within visual range of the forest edge. These should be measured, mapped, 
identified, tagged, and checked for liana infestation of the crown that may cause it to 
be at risk of being pulled down by other falling trees. Whenever researchers, ground 
staff, or members of the public report that a tree fall has occurred, the manager in 
charge of the area could visit the affected site and (1) determine if any of the mapped 
trees have been affected, (2) salvage any crown epiphytes and rare climbers that may 
have been brought down by the tree fall, (3) log the exact locality, spatial extent of the 
affected area, and the estimated time of occurrence of the event for future analyses. The 
40 vegetation plots established during this study, and the tree plots set up within the 
Central Catchment Nature Reserve previously, can be used as baselines for monitoring 
tree fall, dieback, growth and regeneration. These can be supplemented by regular 
(e.g. bimonthly to half-yearly) surveys along the forest edges to check the status of 
these trees. The field guides being published as a result of this study, in addition to the 
voucher specimens that were collected and that will be deposited in the two Singapore 
herbaria, should help future researchers and staff to identify most of the large trees. 
