Tropical forests are essential for maintaining biodiversity and play a central role in global climate regulation. Among these forests, the Amazon Rainforest exhibits a diversity of habitats and is characterized by significant topographic and hydrographic variations, ranging from floodplain forests, such as várzea forests, to non-flooded forests, such as terra firme forests. Additionally, a significant portion of the Amazon’s Forest cover consists of secondary forests—areas that naturally regenerate after land use. Understanding the ecological strategies of species in these environments and their capacity for adjustment is crucial for comprehending how these ecosystems respond to climate change, as extreme events such as droughts, heatwaves, and intense rainfall are becoming increasingly frequent. Considering this, the thesis is structured into two chapters. In Chapter 1, we evaluated the hydraulic and anatomical traits of three abundant tree species (Eschweilera coriacea, Licania kunthiana, and Tapirira guianensis) along a secondary forest age gradient in the Eastern Amazon and their relationships with soil characteristics. We observed that individuals adjusted their hydraulic and anatomical traits along the age gradient, with each species exhibiting variation in different attributes. Edaphic factors, particularly potassium (K), influenced plant hydraulic function. Additionally, the relationship between the water potential at which 50% loss of hydraulic conductivity occurs (P50) and anatomical traits related to water transport efficiency (e.g., vessel area, hydraulic diameter) revealed a strong trade-off between hydraulic efficiency and safety. In Chapter 2, we assessed morphological, structural, and hydraulic traits to investigate whether intrageneric variation occurs and how these traits respond along a flood gradient in várzea forests of the Central Amazon. We found no intrageneric variation among congeneric pairs along the gradient. Some traits were more influenced by environmental factors, while others were more strongly associated with taxonomic levels. Certain traits, such as wood density (WD), osmotic potential, and the water potential at which species lose turgor, varied along the elevation gradient, with higher WD and lower osmotic and turgor loss potentials in lower-lying areas, indicating that these traits respond to variations in water availability in the environment. In contrast, other traits remained relatively conserved along the gradient, such as specific leaf area, leaf thickness, Huber value, P50, P88, and maximum vessel length. These findings highlight the complexity of tree species' responses to environmental variations, demonstrating that different ecological and evolutionary processes may shape functional trait variation. Thus, this thesis contributes to understanding the functional dynamics of Amazonian forests in different environmental contexts, providing essential information for the conservation and management of these ecosystems in the face of global change.