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Ba Na Nature Reserve 1996
5.0 VEGETATION SURVEYS
5.1 Aims and Methods
The aim of the vegetation survey was to describe the major vegetation types found in Ba Na. As
the reserve is largely forested, only forest areas were studied in any detail, although other
vegetation types are represented in the reserve, and these are described in section 5.3.
After extensive exploration in and around the reserve area, five sites were chosen to represent the
various forest types present. No untouched primary forest was apparent either within the reserve
or in its immediate vicinity, so all the sites chosen were secondary, differing mainly in the level
of disturbance. All sites except FT3 were Tropical Lowland Evergreen Rain Forest (Whitmore,
1985). The five sites chosen (with altitude in brackets) were;
• FT1 - Secondary Tropical Lowland Rain Forest (430m) - heavily disturbed
• FT2 - Secondary Tropical Lowland Rain Forest (380m) - less disturbed
• FT3 - Lower Montane Rain Forest (1180m)
• FT4 - Secondary Lowland Rain Forest (380m) - recently logged
• FT5- Secondary Lowland Rain Forest (480m) - least disturbed.
At each study site, the following surveys were carried out;
(1) Forest tree survey (all trees over 6cm DBH or Diameter at Breast Height, 1.3 m)
(2) Sapling survey (trees under 6cm DBH)
For the forest tree survey, the DBH of all trees was measured for all trees of 6cm DBH or more in
a 50m x 40m plot (2000m 2 ). Wherever possible, the species were identified. From these data,
species diversity, tree density, wood basal area (which can be used as an index of biomass), and
dominance of each species/family can be determined for each forest type (see 5.2, below). The
structure of each forest type was measured in a transect 10m x 30m within the larger plot. For this
transect, the top height, base of canopy, extent of canopy, height of lowest branch and DBH were
measured for each tree within the transect, or whose canopies overlapped into the transect area.
Transect diagrams were then drawn to scale from this data and field sketches.
The sapling survey involved sampling 5% of the forest plot area (100m 2 ) with 2m x 2m quadrats,
placed systematically across the diagonals of the plot. All saplings under 6cm DBH were
identified and their abundance and average height measured.
In addition, the herbaceous ground flora and shrub layer species in each forest plot were
identified where possible.
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