Aldrianto Priadjati, Dipterocarpaceae: Forest Fires and Forest Recovery.

Aldrianto Priadjati, Dipterocarpaceae: Forest Fires and Forest Recovery. Tropenbos--Kalimantan Series 2002, ISBN 90-5113-062-7, 214 pp.

Dr. Priadjati carried out studies on the effects of forest fires in Kalimantan as part of his Ph.D. studies--the history of his study plots reflect what was happening in a larger context: his first plots were completely devastated by the fires of 1997-1998, while his second set of plots disappeared during the fires of 2001-2002.

Although the title suggests that the thesis focuses on dipterocarps in general, most of the emphasis is on one key dipterocarp species, namely Shorea leprosula, which occurs from southern Thailand to Sumatra and Borneo. The thesis is divided into seven chapters, along with a comprehensive 23-page reference list and 10 appendices. It is one of the few studies on lowland dipterocarp forests in Borneo that combines field (aut-) ecological studies, trial plantings, and controlled experiments, and therefore presents a very interesting combination of information of interest for specialists (foresters) and more general readers alike.

Chapter 1, the general introduction, provides an overview of the status of forests in Indonesia, forest fires and droughts during 1997 and 1998 and comprehensive information about Shorea leprosula, including its architectural model.

Chapter 2--co-authored with Daniel Cleary--focuses on the development of forest biodiversity after fires, in terms of the natural regeneration of forest and butterfly communities, the dynamics of the natural regeneration of a tree species and the changes in climatic conditions due to forest fires.

Chapter 3 deals with the levels of genetic variation, as related to phenotypic variation and relatedness in Shorea leprosula, which are examined in three representative dipterocarp forest sites in East Kalimantan.

Chapter 4 focuses on the preparation of planting material in nurseries, including the influence of the origin of "wildlings" (i.e. seedlings collected in the wild) and soil, and the influence on Shorea leprosula of soil types, pasteurization of media and mycorrhizae inoculation.

Chapter 5 examines the influence of light and site conditions on the growth of Shorea leprosula and mycorrhizae, and is closely related to the study on shading by the rapidly growing pioneer species Peronema canescens, dealt with in chapter 6 (co-authored with G. W. Tolkamp). Both chapters try to elaborate on the acceleration of succession in mixed plantations composed of pioneer and climax species.

Chapter 7 synthesizes the results presented in chapters 2-6, so as to present an integral overview of forest fires and forest restoration in dipterocarp forests. The application of knowledge obtained by the implementation in silvicultural practice for sustainable forest management in Indonesia is also discussed in this chapter.

According to Priadjati, the outlook for dipterocarp forest regeneration in burnt areas is not good, certainly in the short-term, as the microclimate has changed, and the stress of light, higher soil temperatures and loss of ectomycorrhizae contribute to reduced performance of dipterocarp regeneration in burnt forests. After a light burn, however, quick growth of pioneer species can rapidly improve microclimate conditions and greatly improve the outlook for dipterocarp regeneration. After repeated or severe fires, however, there is no longer a seed source and suitable ecomycorrhizal fungi will have disappeared as well, and eventually repeated fires lead to establishment of Imperata cylindrica (alang-alang) grasslands that readily burn, which kills off any natural regeneration that may have occurred. Less frequent fires lead to woody vegetation types dominated by fire-tolerant and/or rapidly growing species, while areas that are burnt every several hundred years may remain dipterocarp forest, provided that they are still connected to a patchwork of vegetation containing dipterocarps. Fires have a similar effect on other organisms as well, as is demonstrated by the study of butterfly populations--their diversity and genetic variation is also heavily impacted by fires, and they essentially suffer the same fate as dipterocarps.

Practical studies with Shorea leprosula show that although the species is a light-demanding species and can grow well in open sites, it is safer to intersperse the species among earlier established fast-growing species such as Peronema canescens.

In the end we need to save what is left and that involves preventing forest fires as much as possible. This can only be achieved by involving local people and addressing issues such as poverty and illegal activities, and the key may be providing alternatives and education, and enforcing regulations. Priadjati is not overly optimistic and ends with "Let us hope that there still is a future for Dipterocarpaceae in Borneo." (Wim Giesen, ARCADIS Euroconsult, PO Box 441, 6800 AK Amhem, The Netherlands, [e-mail])