GROWTH OF TWO PINUS RADIATA STOCK TYPES ON RIPPED AND RIPPED/BEDDED PLOTS AT KARIOI FOREST

Two site preparation techniques - ripping and ripping plus bedding - were compared with an uncultivated control treatment on compacted, podsolised soils from weathered andesitic tephras at Karioi Forest. Two Pinus radiata D. Eton seedling stock types (1/0 and 1.5/0) were used. Ripping/bedding caused a significant improvement in height and diameter growth between ages 2 and 7 years, but the improvement was not large enough to justify the cost of cultivation on the grounds of improved growth alone. Root form and vertical extension were better in the cultivated plots than in the control, but no significant differences in stability between cultivation treatments were recorded. The 1.5/0 stock was larger at planting time than 1/0 stock, was more difficult to plant properly, and exhibited much poorer root form than 1/0 stock. It toppled almost twice as often as the 1/0 stock, despite slightly deeper planting and a larger mean root: shoot ratio. Growth was not significantly different between stock types by age 7.