Alien species can be extremely destructive and have had damaging effects in recent years in both the developed and the developing world.
Forest protection is an integral part of sustainable forest management.
Good management including the use of appropriate species and provenances to meet prevailing environmental conditions and end use requirements, and planting materials of optimal physiological and genetic quality, coupled with good silviculture, is thus the key to a healthy forest. The best line of defence in forest protection is prevention through international and national phytosanitary legislation. The purpose of the IPPC is to secure common and effective action to prevent the spread and introduction of pests of plants and plant products, and to promote appropriate measures for their control. Despite phytosanitary measures and information exchange, pests still continue to move between and within countries and given suitable climatic conditions and the absence of indigenous natural enemies, are quick to establish. Health monitoring is thus important to ensure that pest activity is discovered before extensive damage occurs, and to provide data to support decisions on appropriate tactics of control once a problem has been detected.