CLIMBING BAMBOO (<em>DINOCHLOA</em> SPP.) IN DERAMAKOT FOREST RESERVE, SABAH: BIOMECHANICAL CHARACTERISTICS, MODES OF ASCENT AND ABUNDANCE IN A LOGGED-OVER FOREST

Abstract

Climbing bamboos are extremely abundant in Deramakot Forest Reserve, a lowland dipterocarp forest in central Sabah that was subjected to uncontrolled selective logging in 1975. In 1993, 53% of the trees > 10 cm dbh (diameter at 1.4 m) were bamboo infested and an additional 23% carried vines other than bamboo. The likelihood that a tree supported bamboo in its crown, however, decreased with tree diameter; bamboos were not observed ascending trunks of trees > 41.2 cm dbh (Dinochloa scabrida) or 39.1 cm dbh (D. trichogona). The angle of ascent of twining bamboo stems also decreased with increasing tree diameter, suggesting a biomechanical explanation for their distribution among potential host trees. Most bamboos, reached the crowns of trees > 30 cm dbh by climbing previously established canopy vines or by climbing over from neighbouring trees. Free-standing culms attained heights of up to 3.45 m (D. scabrida) and 2.95 m (D. trichogona); unsupported culms of D. scabrida that twined around one another grew up to 4.68 m tall before toppling over. A partial explanation for the capacity of climbing bamboos to dominate logged-over forests is that they can climb where other vines fail in the absence of external support.