PLANTATION-GROWN NEW ZEALAND KAURI: A PRELIMINARY STUDY OF WOOD PROPERTIES

For a preliminary investigation into the solid wood properties of plantation-grown New Zealand kauri (Agathis australis (D.Don) Lindl.), 20 stems were sampled from a 68-year-old planted stand in New Plymouth in the North Island of New Zealand. The stems sampled represented the largest diameters and therefore fastest growing stems (mean diameter 39.4 cm, mean height 20.5 m). Sapwood comprised 80 % of the stem at ground level, increasing to 99 % at 10 m above ground. Basic density decreased with increasing stem height from ground level to 10 m (469 kg/m3 to 435 kg/m3). Density was uniform across the width of the stem at the butt, and was consistent across the sapwood zones at higher points on the stem. Tangential and radial shrinkage across the width of the stem averaged 4.1 % and 2.9 % respectively. Modulus of elasticity (stiffness) averaged 13.6 GPa and was as high as 15.0 GPa, and was uniform across the width of the logs. This study identified homogeneous wood property traits in plantation-grown kauri logs composed mainly of sapwood. The sapwood properties tested were at least similar to those of logs from natural second-growth stands and some were superior to old-growth heartwood. Kauri sapwood logs from plantations have the potential to be a legitimate and valuable resource