Thinning studies in plantation-grown Queensland maple (Flindersia brayleyana F. Muell.) in north-east Queensland

Abstract

Queensland maple (Flindersia brayleyana F. Muell.) is one of Australia's most highly-regarded native rainforest cabinet timber species. This study analysed historical thinning trials at four sites on the Atherton Tableland to assess long-term performance of maple in plantations and to quantify diameter growth responses to stand density. Basal area in unthinned stands at age 22 ranged from 34.0 to 41.9 m² ha⁻¹. Highest basal area at this age was achieved on basalt-derived soils at with a precipitation of 2,000 mm. Poorest growth was on the lowest rainfall site with coarse-textured granite soils. A maximum value of Reineke's stand density index (SDI) of 900 was achieved on an unthinned 22 year old plot. Mean diameter increment to age 22 was greater than 1.0 cm y⁻¹ on all thinned plots, with the largest mean diameters (about 27 cm) on metamorphic soils in plots that had been thinned twice to relatively low levels (40-45% of maximum SDI). Maple generally responded well to thinning, particularly early thinning. Mean diameter increment declined relatively quickly once stand density rose above 35% of maximum SDI, especially in older stands. The implications of these results for density management are discussed.