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Tropical forests hold 30% of Earth’s terrestrial carbon and at least 60% of its terrestrial biodiversity, but forest loss and degradation are jeopardizing these ecosystems. Although the regrowth of secondary forests has the potential to offset some of the losses of carbon and biodiversity, it remains unclear if secondary regeneration will be affected by climate changes such as higher temperatures and more frequent extreme droughts. We used a data set of 10 repeated forest inventories spanning two decades (1999–2017) to investigate carbon and tree species recovery and how climate and landscape context influence carbon dynamics in an older secondary forest located in one of the oldest post‐Columbian agricultural frontiers in the Brazilian Amazon. Carbon accumulation averaged 1.08 Mg·ha−1·yr−1, and species richness was effectively constant over the studied period. Moreover, we provide evidence that secondary forests are vulnerable to drought stress: Carbon balance and growth rates were lower in drier periods. This contrasts with drought responses in primary forests, where changes in carbon dynamics are driven by increased stem mortality. These results highlight an important climate change–vegetation feedback, whereby the increasing dry‐season lengths being observed across parts of Amazonia may reduce the effectiveness of secondary forests in sequestering carbon and mitigating climate change. In addition, the current rate of forest regrowth in this region was low compared with previous pan‐tropical and Amazonian assessments—our secondary forests reached just 41.1% of the average carbon and 56% of the tree diversity in the nearest primary forests—suggesting that these areas are unlikely to return to their original levels on politically meaningful time scales.

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ResumoNeste artigo é apresentada a fitossociologia de um fragmento de Floresta Ombrófila Densa de 84 ha no nordeste do estado do Pará, com árvores de DAP ≥ 20 cm. As espécies foram classificadas em grupos ecológicos em função das exigências de luz e quanto ao uso comercial. Os dados foram coletados em 12 parcelas de 1 ha aleatorizadas e subdivididas em 100 subparcelas de 10×10 m. Foram registrados 2.326 indivíduos distribuídos em 158 espécies, 107 gêneros e 43 famílias. As famílias Fabaceae e Lecythidaceae tiveram a maior riqueza e densidade na composição florística da área. A primeira apresentou o maior número de espécies (41), a segunda, o maior número de indivíduos (609), e ambas apresentaram alta dominância e freqüência. Quanto aos grupos ecológicos, as espécies tolerantes foram maioria (63,29 %); quando considerada a classificação quanto ao uso econômico, as espécies comerciais predominaram (41,15 %). Sugere-se que espécies com alta importância ecológica e interesse comercial sejam utilizadas para a recuperação de áreas alteradas. Entres as espécies encontradas, destacaram-se Pouteria heterosepala, Eschweilera amazonica, Eschweilera blanchetiana, Protium apiculatum, Guatteria poeppigiana, Sterculia pilosa, Inga brevialata e Licania heteromorpha. Entretanto, antes de qualquer ação empreendedora, devemse obter informações seguras sobre a ecologia e a silvicultura dessas espécies. Palavras-chave: Composição florística; estrutura de floresta; grupos ecológicos; riqueza de espécies; mata ciliar. Abstract Phytosociology of a permanent preservation area in east ofAmazon: indication of species for recovering altered areas. This paper presents the phytosociology of a fragment of a dense ombrophilic forest with 84ha in Northeastern Pará state in trees with DBH ≥ 20cm. The species were classified in ecological groups in function of light demand and commercial use. The sampling was composed by 12 random 1ha plots and divided in 100 subplots of 10m × 10m. It was recorded 2,326 individuals in 158 species, 107 genera and, 43 families. The families Fabaceae and Lecythidaceae had the highest richness and density in the floristic composition of the area. The first family presents the highest number of species (41) and the second, the highest number of individuals (609), and both of them present high dominance and frequency. As regards to the ecological groups, the species shade tolerant were majority (63.29 %) while in the economic use, the commercial species predominated (41.15 %). It suggests that species with high ecological importance and commercial interest be used for altered area recovering. Around sampled species, some of them are most important such as Pouteria heterosepala, Eschweilera amazonica, Eschweilera blanchetiana, Protium apiculatum, Guatteria poeppigiana, Sterculia pilosa, Inga brevialata and Licania heteromorpha. However, before any kind of investment it must get safe informations about ecology and silviculture of these species. Keywords: Floristic composition; forest structure; ecological groups; species...

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Forest restoration is a strategy to reverse forest loss and degradation. We overviewed deforestation in the period 1975-2018 in the Brazilian Amazon and the projects, techniques, and scientific publications conducted to recover forest in the area by 2019. We used GIS to assess forest loss and a systematic data collection gathered from 12 universities, five major environmental agencies, and an ad-hoc bibliographic survey that rendered information from 405 restoration projects and 152 published studies. The Brazilian Amazon has undergone an accelerated deforestation in the last 43 years, resulting in 20% (788,353 km 2) of its territory deforested