## 1 Introduction  
Amazonia plays a major and yet poorly understood function in the global carbon cycle. The Amazonian tropical forest holds about 120 \(\pm\) 30 Pg of carbon in biomass [1] with an approximate spatial distribution of above ground live biomass ranging from 300 Mg\(\cdot\)ha\({}^{-1}\) in Central Amazonia and in regions to the east and north, to 100-200 Mg\(\cdot\)ha\({}^{-1}\) in the transitional and seasonal forests at the southern and north-western edges of the basin [2]. In addition, it contributes approximately 10% (4-6 Pg\(\cdot\)C) of the world's terrestrial annual net primary productivity (NPP, the net amount of carbon that is fixed from the atmosphere into new organic matter per unit time) [3, 4].  
The carbon cycle has been receiving increased attention, not only from environmental scientists but also from the public and media. It has become part of the political agenda because 60% of observed global warming is attributable to the increase in carbon dioxide concentration in the atmosphere [5]. The idea that terrestrial vegetation may significantly influence the climate at regional to global scales has advanced mainly in the past three decades. Progress in technology and an increase in scientific multinational and trans-disciplinary integrative collaborations have enabled vegetation feedbacks on atmospheric and climatic processes to be studied over a wide range of scales [6, 7]. For example, evaporation, condensation, cloud formation and cloud condensation nuclei particles over Amazonia have been found to play a significant role on the global circulation, affecting not only South American rainfall but also the climate of the North Atlantic and Western Europe [8, 9, 10]. On the other hand, regional patterns of rainfall, radiation and temperature act on the physiological functioning, species composition and spatial distribution of plants in the Amazon region. Studies have shown that length of the dry season in Amazonia has a significant correlation with the above ground live biomass distribution [2] and also has a major effect on geographical variation in tree community composition [11]. Water availability may also exert a yet unrecognized selective pressure on leaf shape of rainforest trees [12], and if the environmental contribution is removed (e.g., site growing conditions, soil fertility and temperature), the total annual rainfall was found to positively influence the _per area_ leaf mass and some leaf nutrient concentrations [13]. Photosynthesis and productivity are stimulated by diffuse radiation, which can penetrate deeper than direct radiation into closed canopies [14]. Recent results have shown that increased diffuse radiation, caused by the increase of aerosols in the Amazon atmosphere during the dry season, increases forest CO\({}_{2}\) uptake [15].  
Despite these studies, Amazon ecosystem processes cannot be understood in terms of climate alone. It has become clear that Amazon forest structure and dynamics are strongly related to physical and chemical graphic conditions [16]. However, elevated logistic and research costs and the high heterogeneity of these forests make a detailed understanding of these ecological observations very challenging.  
Therefore, in this paper I explore the recent findings on the large-scale patterns of the forest ecosystems properties in Amazonia. First, I focus on forest biophysical properties that directlyinfluence the carbon dynamics across the Amazon (wood density, above ground biomass, tree height, crown size and wood productivity). Then, I explore the macro-scale phenological patterns of these forests, and bring into discussion the recent findings derived from remote sensing dataset. Finally, I present the most recent findings on the effects of droughts in Amazonia. A review of climate change effects on tropical forests have been explored elsewhere [17].