Selecting species for restoring degraded forests in northern Thailand

ABSTRACT: This paper proposes a system to score the suitability of tree seedling species for planting, to accelerate natural forest regeneration on degraded sites within protected areas in northern Thailand, for biodiversity conservation and watershed protection. The criteria considered are seedling field performance; ease of seedling propagation; ability to shade out weeds; ability to foster regeneration of other tree species; inhibited natural seed dispersal and rarity. Measurement methods and indices are suggested, to quantify each criterion, with minimum values of zero and maximum values of 1. The scores are then weighted, according to the objectives of tree planting activities, and the weighted scores summed, to give an overall suitability index. Questions raised for discussion include: Is this level of quantification justified or practically achievable? Are there alternative, rough "rules of thumb" that could achieve similar results more economically? Are all the criteria discussed really necessary? Should any other criteria be added? Is the scoring system mathematically sound and practically useful?