Sustainable forest management is more than limiting harvesting volume of timber in tall forest areas. Reclamation and restoration of depleted forest areas is gaining importance as areas of remaining tall forest are diminishing. Irrespective of the causal factors be it unsustainable logging, mining or forest fires, secondary forest resulting from these activities deserve special attention. In East Kalimantan a wide variety of trees has been used for reforestation of areas affected by the devastating fires of 1982- 1983. These attempts involved exotic as well as indigenous species, and results varied considerably. The 1998 fires that raged through the area sadly destroyed most of the successful trials. Gradually emphasis of reforestation has shifted towards the use of indigenous species, which are obviously well adapted to the often very harsh conditions of secondary scrub vegetation. The problem is to find and identify these good alternatives. Identifying seedlings is often very difficult, as they may differ conspicuously in their general morphology from the adult stages and many distinguishing characters are often not yet present (e.g. characters of flowers and fruits). In this manual a selection of the secondary forest tree species as encountered in various areas of East Kalimantan is presented. Circumstances resulting from the 1998 forest fires prevented a traditional approach of collecting seed from mother trees and raising seedlings under nursery conditions. Instead wildings were collected in various secondary habitats. Fruiting trees were relatively rare at the time of this study, which explains the absence of certain, less regularly fruiting, species in the book. However, this may well be considered a first selection concerning availability of planting material for reforestation purposes. Information on habitat and ecology is briefly mentioned, to give a first indication of suitability in reforestation. In December 1999 I had the opportunity to very quickly test the manual in the field in East Kalimantan. Grabbing seedlings along a roadside in badly depleted forest resulted in successful identification of the plants in over 90 percent of the material. Whereas the manual is intended for seedlings up to 6 months, identification of older plants worked remarkably well.