BALANCING GROWTH AND WOOD QUALITY OF <em>INTSIA</em> <em>BIJUGA</em> UNDER MANAGEMENT: COMPLEXITY OF SILVICULTURE CONSERVATION DECISIONS

Abstract

Intsia bijuga plants were protected from natural infestations of the native psyllid in Guam, Insnesia glabrascuta, to determine the influence on plant growth and morphological traits. The primary goal was to contrast growth and wood density responses to protection from the ubiquitous arthropod herbivore. Growth increased as a result of protecting the plants with insecticides and the relative increase was greater for plants derived from Philippine seeds than Guam seeds. Wood density decreased with insecticide treatment to 65% (Guam) or 49% (Philippines) of wood density in psyllid-infested trees. Results pointed out complexities in silviculture conservation decisions. Managing I. bijuga in a tree farm as means of conserving the natural forest trees may use protection from psyllid damage to seek a shorter production cycle but a concomitant change in wood quality may be an unavoidable consequence.