New Forests 27: 89–100, 2004.  2004 Kluwer Academic Publishers. Printed in the Netherlands. Genetic diversity of Castanopsis acuminatissima (Bl.) A. DC. in northern Thailand and the selection of seed trees for forest restoration 1, 2 1 * DAVID BLAKESLEY , GREUK PAKKAD , CELIA JAMES , FRANCK 1 2 TORRE and STEPHEN ELLIOTT 1 2 Horticulture Research International, East Malling, West Malling, Kent ME19 6BJ, UK; Forest Restoration Research Unit, Biology Department, Science Faculty, Chiang Mai University, 50200, * Thailand; Author for correspondence (e-mail: david.blakesley@hri.ac.uk; phone: 144 1732 843833; fax: 144 1732 849067) Received 18 July 2002; accepted in revised form 19 March 2003 Key words: Castanopsis acuminatissima, Forest restoration, Genetic diversity, Microsatellites, Tropical trees Abstract. Castanopsis acuminatissima (Bl.) A. DC. is one of a number of ‘framework species’ which are being planted to restore seasonally dry tropical forests in northern Thailand. This study describes the level of microsatellite variation within and among three populations of this species in three National Parks in northern Thailand: Doi Suthep-Pui, Doi Inthanon and Jae Sawn, using published primers developed for Castanopsis cuspidata var. sieboldii Nakai. The five microsatellite loci employed in this study detected a total of 54 alleles (n 5 72). The informativeness of the microsatellite loci varied from six to 18 alleles, with an average of 10.8 alleles found over all loci. The mean observed heterozygosities in the three populations showed no significant deviations from Hardy-Weinberg expectations. The vast majority of genetic diversity was contained within the populations, with no significant differentiation between them (F 5 0.006). Algorithms were designed to capture microsatellite diversity, and the rationale for using ST microsatellite markers to inform genetic conservation is discussed. The implications for seed collection of C. acuminatissima for forest restoration are also discussed. Introduction Forest restoration measures are necessary to counter the continued disappearance of forests in tropical Asia, which is estimated at 1.1% annually (1990–95) (FAO 1997). The ‘Framework Species Method’ was developed within the Queensland Wet Tropics World Heritage Site (Goosem and Tucker 1995; Lamb et al. 1997; Tucker and Murphy 1997), and has since been applied to the seasonally dry forests of northern Thailand (Blakesley et al. 2002; Kerby et al. 2000). This method involves planting mixtures of 20–30 native tree species to provide a framework for re- establishing biodiversity. Tree species are selected for their fast growth, spreading canopy (for suppression of weed growth), ease of propagation and provision of resources for wildlife (particularly fruit) at an early age. The planted trees re- establish basic forest structure and functioning, and frugivores attracted by such resources disperse the seeds of additional non-planted tree species into the planted sites, thus accelerating the return of biodiversity.