Establishment and growth of sandalwood (Santalum spicatum) in south-western Australia: Acacia host trials

Abstract

Summary The influence of four different Acacia species (Acacia acuminata, A. saligna, A. microbotrya and A. hemiteles) on establishment and growth of sandalwood (Santalum spicatum) was examined at two sites in the wheatbelt. The host seedlings were planted in June 1998, and four S. spicatum seeds were planted adjacent to each host at age 1 y (May 1999). Direct seeding S. spicatum near 1-y-old host seedlings again proved to be a successful establishment technique, with 81–91% germination per spot, at both sites. At age 3 y, survival of S. spicatum near A. saligna (94%) and A. acuminata (81%) was significantly greater than near A. hemiteles (45%). At the same age, mean stem diameter of S. spicatum growing near A. saligna was 53 mm, significantly greater than near. A. acuminata (33 mm), A. microbotrya (20 mm) and A. hemiteles (11 mm). Growth was superior at the Dandaragan site, with S. spicatum near A. saligna having a mean stem diameter of 59 mm and a mean height of 2.3 m. At host age 4 y, the mean height of A. microbotrya (4.3 m) was significantly greater than A. saligna (3.3 m), A. acuminata (3.2 m) and A. hemiteles (1.1 m). Between host ages of 1 y and 4 y, mean survival of A. saligna dropped by 27%, significantly more than the other host species (2.5–10%). Mean potassium and phosphorus concentrations in the foliage of S. spicatum were significantly higher near A. saligna than near A. hemiteles. The mean potassiumxalcium ratio was highest near A. microbotrya (2.2–3.7) at both sites. Stem water potentials in S. spicatum were significantly lower near A. microbotrya (-2.9 MPa) than near A. hemiteles (-2.2 MPa) at Dandaragan. There were no significant differences between S. spicatum stem water potentials at Narrogin.