Paullinia stellata is found in anthropogenic places and lowland forests, yet little information about their reproductive characteristics is known. This study aimed to determine the physical properties of seeds and the characteristics of their reproductive aspects. Racemes, fruits, and seeds were measured and weighed. The physical properties of the seeds were determined using three-dimensional data. A descriptive statistic was applied for racemes and fruits, and a statistic of small samples was conducted for the physical properties. The results showed low magnitude variations for variables analyzed in both parameters. The physical properties of the seeds are relatively moderate variations from low oscillations. Fruit maturity is detected by the opening of the endocarp exposing the seed, but it presents early and late fruit with asynchronous maturation. This study was conducted only on a single plant and observed asynchronous fruits within the same raceme.

Numerous geometric earthworks have been found in southwestern Amazonia, evidence of a monument-building precolonial civilization ^1–3 . This knowledge has contributed to the discussion about the deep history and the precolonial urbanism of Amazonia, its sociocultural contexts and its environmental legacy ^2,4–8 . Estimates of the geographical extent and population size of the forest civilization have remained weak, because the detection of earthworks has been almost exclusively limited to deforested areas where vegetation does not completely hide the structures. Here we used canopy-penetrating LiDAR data over 4,430 km of flight to define the geographical distribution and quantity of earthworks in this region better. On the basis of both existing data and our LiDAR documentation, we show that this cultural area alone contains as many earthworks as previously estimated for the whole of Amazonia. We also propose that the total human population of the area in 100–300 ad was 1.25–3 million people. If similar results are found elsewhere in Amazonia, the total precolonial population density and its effect on the current Amazonian soil and forest structure, biodiversity and even some modelling of the global climate should be re-evaluated.

Brazil nut (Bertholletia excelsa Bonpl.) is a major non-timber forest product in the Amazon, supporting extractivist communities in Brazil, Bolivia, and Peru and contribute to forest conservation. Unlike other extractive products, Brazil nut production has not declined under commercial use and is recognized for its socioeconomic and environmental importance. Precision agriculture has been transformed by the use of unmanned aerial vehicles (UAVs) and artificial intelligence (AI), which enable monitoring efficiency and yield estimation in several crops, including the Brazil nut. This study assessed the potential of using UAV-based imagery combined with YOLOv8 object detection model to identify and quantify Brazil nut fruits in a native forest fragment in eastern Acre, Brazil. A UAV was used to capture canopy images of 20 trees with varying diameters at breast height. Images were manually annotated and used to train the YOLOv8 with an 80/20 split for training and validation/testing. Model performance was evaluated using precision, recall, F1-score, and mean Average Precision (mAP). The model achieved recall above 90%, with an F1-score of 0.88, despite challenges from canopy complexity and partial occlusion. These results indicate that UAV-based imagery combined with AI detection provides an approach for estimating Brazil nut yield, reducing manual effort and improving market strategies for extractivist communities. This technology supports sustainable forest management and socioeconomic development in the Amazon.

The state of Acre, in the Brazilian Amazon, has 18 forest typologies, eight of which have bamboo (Guadua spp.) as the main or secondary floristic element in their understory. Few studies were able to detail changes in forest typologies in which bamboo is the dominant species, caused by bamboo. The present work evaluated the extent and detailed the types of damage caused by bamboo (Guadua weberbaueri Pilg.) in arboreal individuals found in a fragment of Open Rain Forest with bamboo (G. weberbaueri) dominant in the understory located in the eastern region of Acre and discuss the implications for logging. For this purpose, three plots measuring 50 x 100 m were installed along a 1000 m transect, 300 m apart. Bamboo caused damage in 32% of the individuals evaluated (DBH ≥ 2 cm). The most frequent types of damage were “shoring” (44.74% of the total sampled) and “breakage” (37.55%). The confirmation that the presence of bamboo causes damage to arboreal individuals, compromising the density, volume and quality of their bole, has implications for the sustainable exploitation of wood in forests in which it is present and will demand the development of practices management to mitigate the negative impacts observed.