Pest and pathogens threaten the sustainability of plantation forestry: Global research collaboration will define the future
Global plantation forestry is dominated by intensively managed stands of Pinus, Populus, Acacia and Eucalyptus species. The greater proportion of these plantations has been established in areas where the trees are non-native and have thus been separated from their natural enemies. In all documented cases, these plantations have initially been free of serious pest and disease problems. But as time has passed, their health has been increasingly damaged by such agents. In some cases, disease and pest problems have led entire plantation failure, the closure of major business ventures and timber shortages.
Pest and disease problems affecting planation forestry can have one of two conceptually different origins. They are either accidentally introduced into the areas where the non-native trees have been established or they are themselves native to these plantation areas.
In the former case, the pests and pathogens arise through breaches in plant quarantine. They have become uncomfortably common and are closely linked to global trade in wood and plant products. The adaptation of native insect pests and pathogens to feed on non-native trees is complex and includes opportunistic organisms typically with wide host ranges as well as highly specialized, host specific insects and pathogens. The latter group have typically undergone host shifts to infect/ infest trees on which they would not naturally occur. The genetic basis of these changes in poorly understood and deserves more intensive study.
Looking to the future, all indications are that pest and disease problems will increasingly affect the health and sustainability of plantation forestry. This will be driven by increased movement of people and products globally as well as growing complexity to control the movement of small and difficult to detect organisms that move in concert with trade and travel. While quarantine efforts must be encouraged and reinforced, the likely future of plantation forestry will lie squarely in innovative research that will make it possible to grow healthy trees. Tools relating to the genetic improvement of trees and those linked to computerization and information technologies will increasingly be required to enable sustainable forestry. In this regard, there is an urgent need for education and support of researchers able to meet the challenges posed by forest pests and diseases. Global collaboration, particularly including research across scientific disciplines will define successful and sustainable forest industries. International research networks such as the International Union of Forest Research Organisations (IUFRO; www.iufro.org) will surely play an important role in reaching the challenges posed by the ever increasing threats to forests due to pests and diseases.
Keywords: pests, pathogens, plantation forestry
Conference: 18-04-29/05-03 Johannesburg, South Africa