Abstract Brazil nut (Bertholletia excelsa Bonpl.) is considered the cornerstone non-timber species of Amazonian conservation. Nuts (or seeds) of this massive tree are harvested by local people living in and near old growth forests, supporting local livelihoods and regional economies. Secondary forests, however, particularly plots previously used for agriculture (swidden fallows), present better B. excelsa seedling and sapling recruitment than mature forest. This study examines the extent to which forest residents could increase nut productivity by allowing their fallows to grow into Brazil nut rich forests. We conducted B. excelsa inventories in the Brazilian state of Acre in abandoned swidden fallows of different ages. We also conducted interviews to determine landowner perspectives on the fallow potential for increasing nut production. An individual-based model, based on in-situ inventories and primary and secondary datasets from prior fieldwork, simulated growth, survivorship and production from the 250 inventoried trees in 18 fallows of varying sizes (from 0.41 to 4.18 ha) and different regrowth stages (12 to 60 years old). These simulation model predictions showed that after 10 years, 2.4% of existing trees would be productive, with an average of 68.6 ± 21.5 fruits per reproductively mature tree in the four fallows that most quickly yielded productive trees. By the final projected time interval (40 years), predictions suggest all fallows will produce fruits with cumulative production averaging 1475 ± 359 fruits ha−1, suggesting an increase in landowner income of US$55.1 ± 13.4 per hectare of fallow. Our simulation model is the first to explore fruit productivity of Brazil nut in secondary forest. It likely underpredicts B. excelsa growth and nut production, considering that swidden fallows provide better resource availability than the forest-derived datasets we used to construct the model equations. In conclusion, our findings support previous research that suggests that higher B. excelsa recruitment rates observed in abandoned swidden fallows could indeed translate into greater adult densities and thus potentially, higher nut production – a conclusion mirrored by most participant landowners.

中文翻译：

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大规模休耕管理以提高巴西坚果的景观水平

摘要 巴西坚果 (Bertholletia excelsa Bonpl.) 被认为是亚马逊河保护的基石非木材物种。这棵大树的坚果（或种子）由居住在古老森林中和附近的当地人收获，为当地生计和区域经济提供支持。然而，次生林，特别是以前用于农业的地块（轮转休耕），比成熟林具有更好的 B. excelsa 幼苗和树苗补充。本研究调查了森林居民通过让他们的休耕地生长到富含巴西坚果的森林中来提高坚果生产力的程度。我们在巴西阿克里州不同年代的废弃荒地中进行了 B. excelsa 清查。我们还进行了访谈，以确定土地所有者对增加坚果产量的休耕潜力的看法。一个基于个体的模型，基于来自先前实地工作的现场清单和初级和次级数据集，模拟生长、存活和生产，来自 18 个不同大小（从 0.41 到 4.18 公顷）和不同再生阶段（从 0.41 到 4.18 公顷的休耕地）的清单中的树木（ 12 至 60 岁）。这些模拟模型预测表明，10 年后，现有树木的 2.4% 将有生产力，在四个休耕中，每棵生殖成熟的树木平均可结出 68.6 ± 21.5 个果实。到最后预计的时间间隔（40 年），预测表明所有休耕地将生产水果，累计产量平均为 1475 ± 359 ha-1，这表明每公顷休耕地土地所有者收入增加 55.1 ± 13.4 美元。我们的模拟模型是第一个探索次生林巴西坚果果实生产力的模型。它可能低估了 B. excelsa 的生长和坚果产量，考虑到与我们用来构建模型方程的森林衍生数据集相比，轮垦休耕提供了更好的资源可用性。总之，我们的研究结果支持先前的研究，该研究表明，在废弃的荒地休耕中观察到的更高的 B. excelsa 招募率确实可以转化为更大的成年密度，从而潜在地提高坚果产量——大多数参与者的土地所有者都反映了这一结论。