Acacia heterophylla

Cultivation Details

Acacia heterophylla is a plant of the moist tropics, growing in areas where the annual rainfall should be at least 1,500mm and divided evenly over the year^[1]. The growth rate of seedlings is usually high, in good conditions it can reach about 1 metre per year for the first 5 years after germination^[1]. It is estimated that trees need 100 years to reach a bole diameter of 70cm^[1]. In trials in Madagascar, the tree succeeded only at elevations of 900 metres with an annual rainfall of 1,700 mm^[1]. (Does this mean that the trees succeeded only above 900 metres or only below 900 metres?^[PFAF].) Ten year-old trees had a diameter at breast height of 18cm and were 18 metres tall, but they had a bad shape^[1]. Rooting is superficial, which explains the often severe damage caused to the trees by cyclones^[1]. Natural germination occurs after disturbance of the forest, such as after a fire. Regeneration can be abundant under such circumstances^[1]. In Réunion, clear felling of the natural forest has been practised in order to establish pure, even-aged stands of this species as a result of natural regeneration^[1]. Regular weeding is necessary, twice a year for the first 3 years, to avoid smothering of the seedlings by weedy plants. Thinning is practised when the trees are 6 and 10 years old, to 1,250 stems/ha and 800 stems/ha, respectively. The eventual density to be reached after 50 years is 200 stems/ha^[1]. The yield of timber per tree in natural forest is often comparatively small due to the poor shape and short length of the bole; wood defects such as knots are common. Proper silvicultural practices may improve bole shape and length, and thus timber yield^[1].