As one moves up from the plains and foothills to the central highlands, the landscape and vegetation changes noticeably. Heat is rapidly lost after sunset at high altitudes so that in the mountains, temperature ranges between daytime and night—time may differ by as much as 20 degrees centigrade. At the same time, the relative humidity of the air increases as the temperature falls, and at a certain point, condensation will occur causing drops of dew, and even clouds, to form. Much more rain is also likely to fall on the windward slopes of mountains, particularly if the prevailing air currents have passed over seas as is the case for Bali.
Montane Forest Morpology
The vegetation below 1,200 metres is very similar to that of lowland forests, but at higher altitudes, trees become increasingly stunted in height and epiphytes, which include many orchid species, become more common. At the highest altitudes, the trees look gnarledand stunted and there is an abundance of moss and lichens growing both on the ground and on the vegetation itself. Eventually, these montane forests give way to a sub-alpine vegetation with even smaller trees and epiphytic lichens, but very few orchid species. Some alpine plant species are equipped with woolly hairs on their leaves which are thought to protect them against high temperatures during the day, low temperatures at night, and the intense ultraviolet radiation that is the result of the thinner atmosphere at high altitudes.
Monkeys are a common sight at the side of the road in the mountains of Bali. They are usually the long-tailed macaque (Macacafascicularis), who typically travel in groups of 20-30 individuals, consisting of 2-4 adult males and 6-11 adult females, the rest being juvenile or adolescent members of the tribe.The males are considerably heavier in build and larger in stature than the females, weighing between 5 and 7 kilograms. Macacafascicularis are also found in coastal areas, especially mangrove forests, where they dine on crab, hence their alternative title of crab-eating macaque.
Casuarinajunghuhniana is a conspicuous pioneer species on Balinese mountain sides. Like other pioneers, it only grows in extremely light conditions-Casuarinaequisetifoliafavours seashore locations—while its seeds will only germinate on bare soil and not within a forest environment. Unusually for a pioneer, Casuarina is long-lived and can grow to considerable heights of up to 45 metres. Although the Casuarina looks like a pine tree, with cone-like fruit and long feathery branches radiating from a single stem or trunk, its appearance is misleading. Whereas in the case of pine trees, the leaves are compressed into long needle-like cylinders, Casuarina ‘needles’ are actually slender twigs, the leaves themselves being reduced to minute, scale-like protuberances. In both instances, these modifications serve the same purpose, namely to reduce water loss through evaporation to an absolute minimum, which is a useful design feature in exposed situations with poor soils. Like conifers, the Casuarinaalsodrops its leaves in great profusion, and beneath its branches a dry tinder-bed of needles gathers, which readily ignites when occasional fires occur. The thick bark, however, is extremely fire-resistant and mature trees can withstand falls of hot ash during volcanic eruptions to sprout again when the cataclysm has passed. Often Casuarina will be the only tree for miles around, but it is also found in mixed montane forests.