Abstract This study systematically reviews 146 publications on the socio-economic importance of natural and planted walnut forests in the 15 countries of the Silk Road in order to comprehensively assess the current state of knowledge, identify knowledge gaps and define priorities for further research. Despite widely spreading natural and cultivated walnut forests along the Silk Road, which are intensively utilized and make significant contribution to local livelihoods, we found that existing socio-economic research was still relatively limited and unequally distributed among the Silk Road countries, especially for Central Asia and Iran. As evidenced by the significant decline of walnut forests and their continued degradation, past forest conservation policies and programs were often not effective and, therefore, novel strategies and implementation models are urgently needed to achieve sustainable forest management objectives. Our review has shown that conducive economic policies, well-funded national walnut breeding programs and economic incentive schemes could effectively promote the establishment of walnut plantations, which both considerably contribute to the reclamation and rehabilitation of degraded lands and the diversification of farming systems. At the same time, further efforts are needed in walnut research and practice to improve existing value chain arrangements, develop novel products from J. regia and other underutilized forest species, and to more effectively monitor resources and enforce existing legal frameworks. While country-level research gaps seem often to be driven by national agendas and donor interests, we also identified more general topics that did not have received appropriate attention in the literature across all the investigated countries. This includes research on the impact and effectiveness of walnut plantations in reducing pressure on natural walnut forests under land sparing strategies; investigations on the role alternative forms of tourism can play in walnut forest conservation and development; and consumer studies that can provide useful guidance to enterprises in the food processing, cosmetics, handicraft and other industries to improve the quality, value-added and profitability of products derived from the walnut forests. These points illustrate the need for more systematic studies in the walnut forests of the Silk Road countries.

中文翻译：

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关于丝绸之路国家天然和人工种植胡桃 (Juglans regia L.) 森林的社会经济重要性：系统评价

摘要 本研究系统地回顾了 146 篇关于丝绸之路 15 个国家的天然和人工核桃林的社会经济重要性的出版物，以全面评估当前的知识状况，确定知识差距并确定进一步研究的优先事项。尽管丝绸之路沿线广泛分布的天然和人工培育的核桃林得到了广泛利用，对当地生计做出了重大贡献，但我们发现现有的社会经济研究仍然相对有限，并且在丝绸之路国家之间分布不均，尤其是在中亚地区和伊朗。正如核桃林的显着减少和持续退化所证明的那样，过去的森林保护政策和计划往往无效，因此，迫切需要新的战略和实施模式来实现可持续森林管理目标。我们的审查表明，有利的经济政策、资金充足的国家核桃育种计划和经济激励计划可以有效促进核桃种植园的建立，这两者都对退化土地的开垦和恢复以及农业系统的多样化做出了重大贡献。与此同时，核桃研究和实践需要进一步努力，以改善现有的价值链安排，开发王胡和其他未充分利用的森林物种的新产品，更有效地监测资源并执行现有的法律框架。虽然国家层面的研究差距似乎往往是由国家议程和捐助者利益驱动的，我们还确定了在所有调查国家的文献中没有得到适当关注的更普遍的主题。这包括研究核桃种植园在土地保护策略下减轻天然核桃林压力的影响和有效性；调查替代旅游形式在核桃林保护和发展中的作用；和消费者研究，可为食品加工、化妆品、手工业和其他行业的企业提供有益指导，以提高核桃林产品的质量、附加值和盈利能力。这些观点说明需要对丝绸之路国家的核桃林进行更系统的研究。