OUR PLANTATIONS: CANARIES IN A MINE
Our Sentinel trials are based on similar principles. The rapid increase in pests and diseases entering South Africa is a major challenge to the long-term sustainability of Sappi’s plantations. Furthermore, with rapidly changing environments, we have seen previously productive and healthy varieties succumb rapidly to either new pests or even pests that in themselves are adapting and evolving. Accordingly, we continuously monitor our land base by establishing test plots that include a large diversity of our varieties across a range of environments and at different ages. This is because different pests and diseases attack trees at different stages of growth.
Sentinel trials in high risk areas such as Zululand are established with all varieties, developed by our inhouse breeding programme, and are monitored for pest and disease symptoms on a continual basis (every six months). These trials are replicated four times and, at regular intervals, one replication is felled and allowed to coppice. These coppiced trees are physiologically young and will thus be exposed to a different set of pest/disease than the more adult trees. The result is that at any one time, all varieties are present on the same site at different physiological ages. These trials thus provide excellent monitoring plots for changes in the pest and disease populations over time, site and age.