THE ROLE OF ZINC IN FORESTRY .1. ZINC IN FOREST ENVIRONMENTS, ECOSYSTEMS AND TREE NUTRITION

The role of zinc and its importance in forestry is reviewed. The distribution of Zn in soils, rocks, the atmosphere and wastes from Society and the exposure of tree species and forests to Zn are summarized. Zinc is the 'heavy metal' found to occur in the greatest concentration in the majority of wastes arising in modern, industrialized communities. Chemical factors influencing the availability of zinc in the forest environment are related to forestry sites. The biological role of Zn in forest tree species and the biochemistry of zinc deficiency and toxicity are examined. The significance of Zn in plantations and natural ecosystems is discussed. Zinc features strongly in the enhanced levels of pollutants and the wastes being distributed in the environment. There is a growing incidence of plantation forests found in close proximity to urban and metropolitan areas as these spread into the countryside. Recent developments have renewed interest in the management of Zn (and other heavy metals) through forestry and arboriculture. Forests and plantations under intensive management probably will be regarded as having relatively little 'nature conservation' value but be suitable places for the disposal of Zn-enriched noxious wastes and sludges in rural locations. Effective management of these developments will require further research into the Zn economy of forest ecosystems. © 1990.