SUCCESSIONAL PATTERN AND PROCESS IN SECONDARY FORESTS OF DIFFERENT AGES IN THE EASTERN AMAZON

A maioria dos estudos de sucess\ue3o em florestas secund\ue1rias na Amaz\uf4nia avalia s\uedtios de diferentes idades, que representam uma cronoseq\ufc\ueancia sucessional, em vez de monitorar um \ufanico s\uedtio por v\ue1rios anos pelo invent\ue1rio cont\uednuo. Este estudo comparou a composi\ue7\ue3o e estrutura flor\uedsticas de esp\ue9cies arb\uf3reas com di\ue2metro a 1,3 m de altura (DAP) 65 1 cm, em s\uedtios com 4 e 12 anos na Amaz\uf4nia Oriental, e avaliou a mortalidade e o recrutamento em ambos os s\uedtios baseados em dados de invent\ue1rio cont\uednuo durante 4 anos de estudo. As \ue1reas de estudo foram abandonadas ap\uf3s m\ufaltiplos ciclos de uso agr\uedcola de 7 a 10 anos, desde ~1940. Ambos os s\uedtios s\ue3o dominados pelas esp\ue9cies arb\uf3reas Lacistema pubescens e Vismia guianensis , com densidade de indiv\uedduos, di\ue2metro, altura, \ue1rea basal e riqueza de esp\ue9cies significativamente maiores no s\uedtio de 12 anos. A densidade de indiv\uedduos, ao longo do tempo, foi crescente no s\uedtio de 4 anos e decrescente no de 12 anos; o di\ue2metro, a altura e a \ue1rea basal aumentaram nos dois s\uedtios. No s\uedtio de 4 anos, foi constatada uma taxa de recrutamento l\uedquido crescente entre 2000-2001 e 2001-2002, que diminuiu entre 2002-2003, indicando redu\ue7\ue3o gradual na coloniza\ue7\ue3o. No s\uedtio de 12 anos, foi observada alta mortalidade l\uedquida (13 e 11%), sobretudo nas duas primeiras avalia\ue7\uf5es, indicando o processo de autodesbaste. A combina\ue7\ue3o dos m\ue9todos de cronoseq\ufc\ueancia e invent\ue1rio cont\uednuo aumenta substancialmente o entendimento do desenvolvimento sucessional.Most published studies of secondary forest succession in the Amazon examine stands of different ages that represent a successional chronosequence, rather than monitoring a single stand over the long-term. This study compares floristic composition and structure of tree species with diameter at 1.3 m height (DBH) 65 1 cm in a 4-year-old and a 12-year-old re-growth stand in the Eastern Amazon, and examines mortality and recruitment occurring within both stands based on repeated sampling carried out annually for four years. The study areas were abandoned after multiple agricultural cicles that lasted 7 to 10 years, beginning in ~1940. Both stands are largely dominated by the same tree species Lacistema pubescens and Vismia guianensis , with significantly higher stem density, diameter, height, basal area and species richness in the 12-year-old stand. In the 4-year-old stand there were measured an increase in annual net recruitment during the first two data collection periods but relatively lower net recruitment during the last evaluation period, indicating on-going but gradually weakening colonization. There were registered a high net mortality during the first two data collection periods in the 12-years-old stand with a relatively lower net mortality during the last evaluation indicating rapid self thinning. When used in combination, the chronosequence and the longitudinal approaches significantly strengthen the understanding of successional development