Ecological knowledge of regeneration from seed in neotropical forest trees: Implications for natural forest management

We discuss the main ecological factors that influence tree recruitment in n eotropical moist- and wet forests within the context of timber management b ased on selective logging. We argue that setting aside protection areas in managed forests as a way to preserve ecological processes may not be suffic ient to ensure sustainable levels of tree regeneration, and that a thorough understanding and application of tree seed ecology can help to refine mana gement prescriptions. We review relevant aspects of tree reproductive biolo gy seed production and dispersal, spatial and temporal constraints on seed availability, disperser behavior, and the potential consequences of hunting and forest fragmentation on tree regeneration, and discuss their implicati ons for biological sustainability in managed forests. Tree seed production can be influenced by the selective removal of neighbors of the same species (due to insufficient pollen transfer), flowering asynchrony, and attribute s of the species' sexual system. The extent to which an area is supplied by seed can be affected by dispersal mechanism, spatio-temporal limitations t o seed dispersal, and tree size-dependent levels of seed production at the species level. Studies of vertebrate-disperser behavior and tree seed depos ition in logged forests are scarce and warrant further attention in order t o refine our understanding of the dependency of sustained timber production on vertebrate fauna. Although much remains to be learned about tree seed e cology in neotropical logged forests, the baseline information presented he re may offer a starting point for developing ecological criteria for seed t ree retention. Furthermore, it may contribute in improving ecologically-bas ed management prescriptions in order to enhance or at least maintain suffic ient levels of natural regeneration without the need to rely on artificial regeneration. (C) 1998 Elsevier Science B.V. All rights reserved.