Rocky slope forest
This characteristic forest occurred in a narrow belt centred on 170 m on the northern side of the Irawan valley (fig. 6, locality 4) . Exposed rock formed 25 - 50% of the forest floor and many dry stream-beds were encountered. Leaf litter was sparse, though depressions had several centimetre deep accumulations.
The forest was open and had a high percentage of large diameter trees. Dipterocarpus gracilis was the largest of the nine emergents. Mangifera altissima was an important discovery as it is a new record for Palawan. Alstonia angustifolia grew to a considerable size here, as did Palaquium dubardii. The ebony Diospyros pilosanthera grew as a large emergent while D. cf. cauliflora and D. discolor occurred as smaller trees. Albizia pedicellata was another emergent of note. Ficus sundaica also grew here.
Epiphyte growth was poor and the herb-scrub layer sparse. Artabotrys vidaliana and Securidaca sp. were common large lianas. Further details are given in table 4.
