Abstract：
The Amazonian clearwater igapós are poorly studied floodplain ecosystems that are mainly covered by forests and are undergoing massive threats due to changes in land use and climate. Their hydrochemical characteristics and edaphic conditions fall between those of the eutrophic várzea floodplains on whitewater rivers and those of the oligotrophic igapós on blackwater rivers. Previous studies have indicated the management potential of timber species in the highly dynamic várzea floodplains due to the fast tree growth and high forest productivity. Timber resource management, however, is not recommended for the blackwater ecosystem because of its slow dynamics and high vulnerability to disturbances. For clearwater igapós, information on the potential for sustainable management of timber resources is lacking. In this study, we modeled the growth in diameter, height, and volume to derive species-specific minimum logging diameters (MLD) and felling cycles (FC) for eight merchantable species in the clearwater igapós of the Branco and Tapajós rivers in the northern and southern Amazon Basin, respectively. Diameter growth was modeled by analyzing the tree rings that are annually formed in the Amazonian floodplains as a consequence of the regular and predicable long-term flooding. Growth modeling followed the guidelines of the Growth-Oriented Logging (GOL) concept, with the adjustment of diameter growth improved by applying nonlinear mixed-effects regression. MLDs varied from 36 to 90 cm and FCs ranged from 6 to 21 years, which diverges from the standards of Brazilian logging regulations (MLD: 50 cm; FC: 25-35 years). This indicates the potential for timber resource management, which should be tested and introduced at small scales, integrated in protected areas to stepwise promote the sustainable management of these natural resources by traditional communities to increase their income and the conservation of this ecosystem.
摘要：
亚马逊清水igapós是对洪泛区生态系统的研究很少，这些生态系统主要被森林覆盖，并且由于土地利用和气候变化而受到巨大威胁。它们的水化学特征和土壤条件介于白水河上富营养化的várzea洪泛区和黑水河上的贫营养的igapós之间。先前的研究表明，由于树木的快速生长和高森林生产力，高度动态的várzea洪泛区中木材物种的管理潜力。木材资源管理,然而,不建议用于黑水生态系统，因为其动态缓慢且极易受到干扰。对于clearwaterigapós，缺乏关于木材资源可持续管理潜力的信息。在这项研究中,我们模拟了直径的增长，高度,和体积，以得出亚马逊盆地北部和南部的布兰科河和塔帕霍斯河的清水igapós中八个可销售物种的特定物种最小伐木直径（MLD）和砍伐周期（FC），分别。通过分析由于定期和可预测的长期洪水而在亚马逊洪泛区每年形成的树木年轮，对直径的增长进行了建模。增长建模遵循面向增长的测井(GOL)概念的指导方针，通过应用非线性混合效应回归，改善了直径增长的调整。MLD从36到90厘米不等，FC从6到21年不等，这与巴西伐木法规的标准不同（MLD：50厘米；FC：25-35年）。这表明了木材资源管理的潜力，应该在小范围内进行测试和引入，整合到保护区，逐步促进传统社区对这些自然资源的可持续管理，以增加收入和保护这一生态系统。
