A STANDARD PROTOCOL FOR WOODY PLANT INVENTORIES AND SOIL CHARACTERISATION USING TEMPORARY 0.1-HA PLOTS IN TROPICAL FORESTS

Abstract

The use of both uniform woody plant inventories and laboratory soil analysis methods facilitates data sharing and improves the understanding of large-scale biological patterns in tropical forests. Temporary small 0.1-ha plots, fast and cheap to install, are increasingly employed in the tropics. This study presents a standard protocol for woody plant inventories and soil characterisation using 0.1-ha plots. The protocol gives specific recommendations on the size and shape of a 0.1-ha plot, taxa to be included in the inventories, minimum stem diameter cut-offs, evaluation of multiple stems and height estimation. In addition, we present a number of recommendations on soil sampling and analysis, whose standarisation is much required in tropical forest research. We suggest to measure Al and nutrients simultaneously after Mehlich-3 extraction, followed by inductively coupled plasma spectrometry, and to measure C and N through total combustion. The pH, texture and bulk density can be measured with standard manual methods. The study also includes guidelines to create and maintain a standardised database and metadata. All the proposed recommendations are compatible with those already employed in the standardised establishment of large plots. Each recommendation represents a reasonable trade-off between investment and data quality and is oriented to obtain low-cost standardised baseline data, useful to a broad range of studies.