Abstract Understanding the factors influencing agricultural productivity is vital to food security, especially for food insecure smallholder farmers. Within agricultural landscape mosaics, the arrangement of tree cover such as forests, trees, and hedgerows can positively or negatively impact agricultural productivity in fields. In such settings, forest restoration has the potential to impact food security goals in addition to the typical restoration goals of reversing land degradation and supporting carbon storage. Here, we compare and contrast forest restoration scenarios in order to explore whether there are ideal amounts and configurations of forests that optimize benefits for food production. To do so, we explored forest restoration scenarios in an agricultural-forest landscape in southern Ethiopia where previous research showed increased wheat productivity in sections of fields adjacent to forests. We used hypothetical historically-relevant and plausible future scenarios to examine the landscape-level implications of forest restoration on total wheat production. To accomplish this, we first characterized contemporary forest cover as well as long-term trends using remote sensing. Then, trends in forests and hedgerows were used to create a series of hypothetical yet realistic scenarios to explore trade-offs among total forest cover, its configuration, and total wheat production. From 1967–2013, analysis of historical aerial photography and Landsat imagery showed a general trend of reforestation (an 8% increase in forest cover). While the abundance of primary forests remained constant from 1986–2013, mixed vegetation expanded from 16 % to occupy 26 % of the landscape, generally in the form of small forest fragments with sparse tree cover. Our hypothetical reforestation and hedgerow planting scenarios found that field productivity increases near forest edges resulted in non-linear food production benefits with hedgerow expansion. Benefits to total landscape-level wheat production were almost twice as great when transitioning from low to medium tree cover than when transitioning from medium-high to high tree cover. Furthermore, the benefits of hedgerows on agricultural production were asymptotic; productivity gains eventually levelled off with increasing hedgerows. Our results highlight potential benefits of a landscape approach for enhancing smallholder agricultural productivity in southern Ethiopia and beyond. We argue that considering a landscape perspective can help support food security goals particularly within the context of climate change and should play a more prominent role in forest conservation and restoration.

中文翻译：

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森林恢复情景对埃塞俄比亚南部的农业生产产生协同作用

摘要 了解影响农业生产力的因素对粮食安全至关重要，尤其是对粮食不安全的小农而言。在农业景观马赛克中，森林、树木和树篱等树木覆盖的布置可以对田间的农业生产力产生积极或消极的影响。在这种情况下，除了扭转土地退化和支持碳储存的典型恢复目标之外，森林恢复还有可能影响粮食安全目标。在这里，我们比较和对比森林恢复情景，以探索是否存在优化粮食生产效益的理想森林数量和配置。为此，我们探索了埃塞俄比亚南部农林景观中的森林恢复情景，此前的研究表明，与森林相邻的部分农田的小麦生产力有所提高。我们使用假设的历史相关和似是而非的未来情景来检验森林恢复对小麦总产量的景观影响。为了实现这一目标，我们首先使用遥感对当代森林覆盖率和长期趋势进行了表征。然后，森林和树篱的趋势被用来创建一系列假设但现实的场景，以探索森林总覆盖、其配置和小麦总产量之间的权衡。从 1967 年到 2013 年，对历史航拍和 Landsat 图像的分析显示了重新造林的总体趋势（森林覆盖率增加了 8%）。虽然原始森林的丰度在 1986-2013 年保持不变，但混合植被从 16% 扩大到占据景观的 26%，通常以树木稀疏的小森林碎片的形式出现。我们假设的重新造林和绿篱种植场景发现，森林边缘附近的田间生产力增加导致绿篱扩张带来非线性粮食生产效益。从低到中等树木覆盖度过渡时，对景观水平小麦总产量的收益几乎是从中高到高树木覆盖度过渡时的两倍。此外，树篱对农业生产的好处是渐进的；随着树篱的增加，生产力的提高最终趋于平稳。我们的结果突出了景观方法在提高埃塞俄比亚南部及其他地区小农农业生产力方面的潜在好处。我们认为，从景观角度考虑可以帮助支持粮食安全目标，尤其是在气候变化的背景下，并且应该在森林保护和恢复中发挥更突出的作用。