Brantian Association (12)
Note:
All information on soils were from the Land Resource Study 20 series of books
(Volumes 1 to 5), published by the Land Resources Division, Ministry of Overseas
Development , UK.
This
extensive association occurs:
 |
In
valleys on the west coast, |
 |
In
the Tenom, Keningau, Tambunan, Sook and Pedawan Plains, |
 |
On
the northeast coast from the Bengkoka Peninsula to the Sugut estuary, |
 |
In
the Labuk estuary, |
 |
Along
the Kinabatangan downstream from the confluence of the Kuamut and the
Millian, |
 |
Along
the south coast of the Dent Peninsula, |
 |
In
the Semporna Peninsula, and |
 |
Around
Cowie Harbour. |
In
the Segama valley, it is restricted to the Tomanggong Estate. It also occurs
near Sandakan Airport (Eg. Kg. Batu Putih, Kg. Sg.
Kayu, etc.).
The
association occurs on terraces of old alluvium at heights ranging from near sea
level to over 450 m in the inland plains. It reaches 510 m in the Labau valley. The terraces are, in general, flat to
slightly undulating with short steep slopes in dissected parts. The alluvium is
mainly medium- to fine-textured but is occasionally coarse-textured and stony.
The
alluvium is mainly medium, rarely fine, in texture and in places contains
variable amounts of pebbles. Deep pebble deposits also occur. The pebbles are
mainly of quartz and sandstone but in addition are formed of chert in the Kuamut
area, acid igneous rocks and chert at Tomanggong and basalt in the Menanam
Plain.
Lowland
dipterocarp forest covers much of the association and is often rich in Eusideroxylon
zwageri while heath (kerangas) forest occurs sporadically. Sample plots in the Lokan
valley recorded Koompasia malaccensis, Dyera costulata, Shorea exellitica,
Dipterocarpus confertus, Dipterocarpus pachyohyllus and Scaphium
macropodum as large emergent trees up to 54 m in height. Species of the
middle storey included Ganua kingiana, Dacroydes rostrata, Myristica
villosa, Sterculia treubii and the understorey included Mallotus
penangensis, Polyalthia sumatrans, Baccaurea puberla and Parinari
asperula.