Relation between nutrient status of rainforest trees and environmental factors

The mineral nutrition of native plant species is still poorly understood. This is particularly true for the various tree species in rain forest ecosystems. In order to evaluate the mineral nutrient status of the dominant tree species and its relation to environmental factors such as elevation, slope, landscape position, and soil nutrient status, Z.S. Chen and co-workers (Wu et al., 2007) collected leaf, stem, and wood samples for nutrient analysis from a total of 636 trees belonging to 20 dominant species from 27 contiguous 20m x 20m quadrants along an altitudinal transect in a subtropical rain forest in southern Taiwan. They also collected composite soil samples from the 0-5 and 5-15 cm depths in each quadrant for chemical analysis.

Their results revealed that leaf concentration was better correlated with the environmental factors than stem and wood nutrient concentrations. This means that leaf analysis is more appropriate than stem and wood analyses to evaluate the nutrient status of native tree species. They also found wide concentration ranges for most mineral nutrients except P and Cu and most tree species were clustered at the lower end of the concentration ranges indicating they have low nutrient status. Among the macronutrients, P had the lowest and narrowest foliar concentration (0.25-2.8 g kg^-1) confirming the results of other studies from other tropical areas that P is the most limiting nutrient in tropical ecosystems. For the micronutrients, the lowest concentration was shown by Cu (3.88-17 mg kg^-1). A few tree species were found to accumulate (called “accumulator species”) nutrients like N, P, K, Ca, Mg, Cu and Zn indicating high absorption capacity for these nutrients. Foliar mineral nutrient concentration of the trees was generally correlated with the environmental factors such as elevation, topographic position, slope, vegetative type and soil nutrient status.

Reference

Wu CC, Tsui CC, Hseih CF, Asio VB and Chen ZS. 2007. Mineral nutrient status of tree species in relation to environmental factors in the subtropical rain forest of Taiwan. Forest Ecology and Management 239: 81-91.