During the last 30 years important methodological questions were not taken into account in the study of plant phenology. The application of different methods for sampling and estimate plant phenology make difficult to interpret and compare phenological studies. We carried out a survey of studies on tropical forest phenology, compiling information about methods applied for sampling individuals and estimate phenology. The methods surveyed were grouped by type and time (decade), and we discuss their proportion of occurrence and applicability. Among the 60 studies analysed, we found the following sampling methods: trails (20%), transects (18%), parcels (15%), and traps (10%). For 37% of the studies the sampling method was not defined. Two methods to estimate plant phenology were surveyed: qualitative or presence/absence of the phenophase (20%), and quantitative, when the intensity of the phenophase is estimated (62%); the combination of both methods occurred on 17% of the studies surveyed. The preoccupation with the application of sampling methods and quantitative estimation of the phenophases has increased over the last 30 years. However, the lack of standardize procedures or the use of some common techniques for sampling and estimate plant phenology persists until today, resulting in the impossibility to perform an adequate comparison among phenological studies. It is necessary and urgent to conduct comparative research of methods to study the phenology of tropical forest trees.
phenology; sampling methods; evaluation methods; tropical forest; forest trees
