Variation of nutrients in forest tree foliage : a review

Abstract

Variation in nutrient content of forest trees is discussed using the data from literature plus data collected by the authors. Sections are included on sampling and methods of expression of nutrient content. The emphasis is on possible causes of variation, which involves nutrient variation between years, within the year, and during the day, as well as effect of tree age and of foliage age. The effect of variation between tree species, crown classes, position on the tree, branch aspect, foliage exposure, presence of fruit, presence of pathogens, nutrient variability, geographical location, soils differences, and management practice are also discussed. Not all of the literature found is included in the discussions but all items are given in the References and Reading List.