Until relatively recently the valuable tropical montane cloud forests (hereaf ter usually referred to as TMCFs) of the world had scarcely come under the assaults experienced by the downslope montane and lowland forests. TMCFs are not hospitable environments for human occupation, and their remoteness (except in places near Andean high mountain settlements and in the Ethiopian Highlands) and difficult terrain have given them de facto protection. The ad jacent upper montane rain forests have indeed been under assault for timber, fuelwood, and for conversion to grazing and agriculture for many decades, even centuries in the Andes, but true cloud forest has only come under ex ploitation as these lower elevational resources have disappeared. They have also been "nibbled" at from above where there have been alpine grasslands under grazing pressure. Increasingly now, however, these cloud forest eco systems are being fragmented, reduced, and disturbed at an alarming rate. It is now becoming recognized that steps must be taken rapidly to increase our understanding of TMCF and to achieve their conservation, because: their water-capture function is extremely important to society; • their species endemism is high; they serve as refugia for endangered species being marginalized in these environments by increasingly transformed lower elevation ecosystems; they are relatively little studied; yet, their value to science is extremely high; they have low resilience to disturbance; vii viii Preface and many other reasons, which will be discussed subsequently in this publi cation.

In evolutionary time scales natural disturbances have affected the vegetation on Earth. During the Quaternary the forest biomes of the tropics were subjected to manifold disturbances. Climate changes and climate oscillations were associated with changing precipitation and drought regimes, flooding, siltation, landslides, etc. The prehistorical forest was also influenced by the effects of large wildlife populations. Large-scale catastrophies in the forest biomes were mainly caused by abiotic environmental alterations, the small-scale disturbances were and still are related to both biotic and abiotic processes. Both the large-and the small-scale disturbances have played a significant role in shaping distribution, dynamics, structure and composition of the paleoforest. After the expansion of hominids and early humans, and later, by modern humans, the anthropogenic influences on the tropical forest began to overlap natural disturbances. Today's anthropogenic impacts on the tropical forests differ qualitatively and quanitatively from the natural disturbances. The speed of tropical deforestation and savannization is dramatically increasing. The physical and chemical impacts of forest conversion and biomass burning add to other anthropogenic influences on the atmosphere and climate. The expected anthropogenic climate change will also have considerable impacts on the tropical flora and fauna. The book on "Tropical Forests in Transition" synthesizes information on changing environmental conditions and human impacts on the tropical forest by looking back to the paleoecology, analyzing the impact of modern human populations and modeling the future of the tropical forest in a changing environment. The aim of the book is to strengthen multidisciplinary thinking in disturbance ecology.

Cloud forests are areas of high diversity and endemicity, both plant and animal. This book describes Sri Lanka's cloud forests, now reduced to small island patches dotted across the peaks of the central massif and Knuckles hills.