Abstract: The aim of this study was to examine the dynamics of functional composition of a non flooded Amazonian forest in response to drought stress in terms of diameter growth, recruitment and mortality. The survey was carried out in the continuous forest of the Biological dynamics of forest fragments project 90 km outside the city of Manaus, state of Amazonas Brazil. All stems >10 cm dbh where identified to species level and monitored in 18 one hectare permanent sample plots from 1981 to 2004.For statistical analysis all species where aggregated in three ecological guilds. Two distinct drought events occurred in 1983 and 1997. Results showed that more early successional species performed better than later successional ones. Response was significant for both events but for the 1997 event this was more pronounced possibly because of the fact that the event was in the middle of the dry rather than the wet period as was the 1983 one.
Abstract: The aim of the work presented here was to either use
existing forest dynamic simulation models or calibrate a new one
both within the SYMFOR framework with the purpose of examining
changes in stand level basal area and functional composition in
response to selective logging considering trees > 10 cm d.b.h for two
areas of undisturbed Amazonian non flooded tropical forest in Brazil
and one in Peru. Model biological realism was evaluated for forest in
the undisturbed and selectively logged state and it was concluded that
forest dynamics were realistically represented. Results of the logging
simulation experiments showed that in relation to undisturbed forest
simulation subject to no form of harvesting intervention there was a
significant amount of change over a 90 year simulation period that
was positively proportional to the intensity of logging. Areas which
had in the dynamic equilibrium of undisturbed forest a greater
proportion of a specific ecological guild of trees known as the light
hardwoods (LHW’s) seemed to respond more favorably in terms of
less deviation but only within a specific range of baseline forest
composition beyond which compositional diversity became more
important. These finds are in line partially with practical management
experience and partiality basic systematics theory respectively.