Vegetation of Southeast Asia Studies of Forest Types 1963-1965

1 , and around farmyards; the arneci Bambusa arundjnacea
occurs on rich moist soil, such as or. alluvTal stretches along
streams, as well as on poor soil, Rtich as we find in northeastern
Thailand; 0/ylenanthera albo- eillata -rows on low plateaus or hills,
on satvty or lateritic aoilu; l)enar o calamus strictus does well in
Mixed Deciduous forest or in open areas on stony hillsides, extending
into drier conditions nixed with otht..- bamboo species;
Thyrspstachy s sj/imerrGij-': is alfjo frequently planted as live fence
and around farmyards, and is especially common in Thorn forest, on
dry well-drained slopes and in impoverished soils.
Dry bamboo forest is moot extensively developed in the upper
I'eninG'ila and in the west and northwest in the basin of the Maeklon^
river, formed by trie unio.-i of the Khuae Yai and Khwae iloi. These
two tributaries flow southeasterly froi.i the herder cf Burr.a, have a
wide ran.^e of water level, characteristic of rivers influenced by
the monsoon. i)vri;v; the dry season when the water is shallow,
stretches alorv; the banks below the hi.;h water level are covered with
shrubs or low trees, especially "onionoia riparla and Eugenia ripiccla
(ri>*>
!; 3), whiiih are submerged during the rainy season and when the
rivers are flooded. A belt of 'rnai phai 1 (Bambusa arundinacea) marks
the hi^h water level. Its lony. Rracefia c-alns, -KJ to 50 feet (12-16 m.)
Ion-, often extend over the water (Fir;. 101). Scattered among these
bamboo brakes are medium-aized to tall trees normally found in Dry
Evergreen or deciduous forests. The bamboo brakes extend for a considerable
distance from the streams, coveririr; plains of aggradation,
foothills and higher lyin~ flats. Away fror. the rivers, or. dry, infertile
joils, 'nai ruak' (Th.vr son t a c hy s siamensis', oecor.es dominant,
occasionally :n.l::ed v/ith such Dipterojaro trees as I'er'.tacmq siar.ensis
an '* j]]£££ a ££±li£^' ^r' 1Ci ^°^ - n these bamboo brakes is almost bare of
unier ;rc'.t;!, anr! '.luring tlie dry season it is covered with dry bamboo
leaves.
'Mai r.iak 1 (Thyrso.jtach.vs stamen^ia) is also widespread in the Korat
plateau and alon/^ the western margin of the central plain of Thailand,
^roviiv: in small clumps an.i is cfton planted around farmhouses for
windbreak and .live fences (Ki~. 103). In scr.e zones this is replaced
by 'mai pah" (Oxyi-.enanthera ri.i;:rc>-cillata), vhile in parts of northern
Thailand 'mai lai* (pxyter.anthera albo-ciliata) is a dominant species.
Bamboos, especially BtuTi_bus_a arundinacea, Dendrpoalamus str ictus and
T l-.yr s o a t a c hy s sj. amen sis, form extensive brakes in the undergrowth in
outover areas in the Teak forest of northern Thailand. To obtain
natural regeneration o." forest trees it is necessary to cut the bamboo
repeatedly. Frequent .cutting and maintenance of suitable overhead
canopy, particularly on unfavorable soils, causes the bamboo to
deteriorate or leads to its complete eradication. Chemical sprays
have been tested, with-satisfactory Jesuits, to control bamboo under
such conditions.
Clearing of Hain or Moist LVerrjreen forests also creates conditions
'+1