But, the environmental scene has turned out to be a Hydra, with three other infestations reported as the battle to bring the Cypress aphid one rages. Attention is now turned to the leucaena psyllid infestation and the African Pencil Cedar's reported die-back but, just as the ink dries on the proposals for funding projects to help deal with these two, another infestation was reported in August 1995. The tree is Casuarina equisetifolia which grows on the Kenya Coast. Casuarina is native to New South Wales, Queensland and Northern Australia but is widely planted throughout the tropics. It grows fast on low nutrient, saline, sandy soils and is often used as a sand dune stabiliser and as an ornamental shade tree.
Casuarina wood makes good building poles.
The tree is also ideal for rehabilitating areas such as quarries and other degraded and denuded surfaces. The tree has been relatively free of pest problems in Kenya but, in the recent past, there have been a number of reports on its mortality and the plantation failure associated with its specimens following which, the Forest Health Management Centre made an evaluation to identify causal factors associated with the accelerated mortality. It was discovered that death of affected trees is rapid and is characterised by an initial yellowing of foliage followed by browning and drying. There are no stem cankers or any evidence of foliar diseases on the affected trees. Examination of a tree with fading or yellowing of foliage indicated that the cambium layer in the stem and branches was still green but an area of discoloured, necrotic tissue was found at the root collar.