Vegetation and environmental change in the early-Middle holocene at a tropical peat swamp forest, Central Kalimantan, Indonesia

Abstract

A pollen and charcoal record from a 153 cm peat swamp forest core in Central Kalimantan provides a picture of environmental change and fire history from 8440 yr BP to 6540 yr BP. The existence of charcoal in all sample layers indicates that fire occurred in the tropical peat swamp forest throughout the period. In the earliest period, from ca. 8440 to 8000 yr BP, there was a Camnosperm comp.-Cratoxylum forest. Palaquium comp. and Sandoricum comp. were also important constituents in this forest. Subsequently, dry climatic conditions prevailed between 7240∼8000 yr BP. These climatic conditions increased the fire frequency and intensity causing vegetation change, i.e. the encroachment of Palaquium comp. and the replacement of the Camnosperma comp.-Cratoxylum forest with a Palaquium comp.-Cratoxylum forest. A Camnosperma comp.-Cratoxylum forest with more prominent representation of Elaeocarpus, Ilex, Randia, Rubiaceae and Sterculiaceae returned to the site when wet climatic conditions prevailed again at ca. 7240-6540 yrs BP. Returning wet climatic conditions reduced fire frequency, prevented intensive fires and allowed for more extensive growth of Camnosperma comp., Elaeocarpus and Ilex, but limited the growth of Palaquium comp. and Sandoricum comp.