Restoration pathways for rain forest in southwest Sri Lanka: a review of concepts and models Mark S. Ashton a,* , C.V.S. Gunatilleke b , B.M.P. Singhakumara c , I.A.U.N. Gunatilleke b a School of Forestry and Environmental Studies, Yale University, 360 Prospects St., New haven, CT 06511, USA b Botany Department, University of Peradeniya, Peradeniya, Sri Lanka c Department of Forestry and Environmental Science, University of Sri Jayawardenapura, Nugegoda, Sri Lanka Abstract In the last 10 years the Sri Lankan government has changed its policy regarding its remaining rain forest from one that promoted commercial exploitation to one of conservation. The growing importance of uplands as catchments for water production,biodiversityconservationandotherdownstreamserviceshasbeenrecognizedbytheSriLankangovernment.Itis therefore timely that we review 15 years of research investigating rain forest dynamics of southwest Sri Lanka with the objective of using this knowledge for forest restoration. We provide six common principles for understanding the integrity of rain forest dynamics in southwest Sri Lanka. The principles are: i) disturbances provide the simultaneous initiation and/or releaseofanewforeststand;ii)thatdisturbancesaregenerallynon-lethaltothegroundstoryvegetation;iii)disturbancesare variable in severity, type and extent across rain forest topography; iv) guild diversity habitat diversity) is dependent upon ``advance regeneration''; v) tree canopy strati®cation is based on both ``static'' and ``dynamic'' processes; and vi) canopy dominant late-successional tree species are site specialists restricted to particular topographic positions of the rain forest. These principles are applied to determine effects of two rain forest degradation processes that have been characterized as chronic continuous detrimental impacts) and acute one-time detrimental impacts). Restoration pathways are suggested that range from: i) the simple prevention of disturbance to promote release of rain forest succession; ii) site-speci®c enrichment plantingprotocolsforcanopytrees;iii)sequentialameliorationofarrestedfernandgrasslandsbyuseofplantationanalogsof old ®eld pine to facilitate secondary succession of rain forest, and plantings of late-seral rain forest tree species; and iv) establishment and release of successionally compatible mixed-species plantations. We summarize with a synthesis of the restoration techniques proposed for reforestation using native vegetation on cleared conservation areas and parks, and for the stabilization of eroded upland watersheds. We conclude with a comparative analysis with restoration work done in other tropical forest regions. # 2001 Elsevier Science B.V. All rights reserved. Keywords: Buried seed; Clidemia hirta; Dicranopteris linearis; Dipterocarps; Disturbance; Plantations; Secondary forest; Selective logging; Shorea spp.; Swidden; Tea cultivation 1. Introduction Mixed dipterocarp forests comprise an important forest type that covers much of the upland hill, and lowland regions of southeast Asia Whitmore, 1990). Thisforesttype,andthedipterocarpsinparticular,has providedmuchoftheregion'stimberforbothlocaluse andexporttoEurope,JapanandNorthAmerica.After logging, many of the more accessible regions have eitherbeenconvertedtolargescalerubberandoilpalm plantation, or to small-holder subsistence gardens. Forest Ecology and Management 154 2001) 409±430 * Corresponding author. E-mail address: mark.ashton@yale.edu M.S. Ashton). 0378-1127/01/$ ± see front matter # 2001 Elsevier Science B.V. All rights reserved. PII:S0378-112701)00512-6