North American Agroforestry. Группа авторов

regional overviews along with overviews for Canada and Mexico (Schoeneberger et al., 2017).

      The challenges to generating practical, broadly useful knowledge about agroforestry are well documented (Sanchez, 1995), revolving around the comparative complexity and site specificity of various applications and thus the difficulty of generalizing from studies of particular practices. Each practice involves multiple components and processes, the dynamics of which change with time as the perennial components mature and assume different ecological and biological roles. Similarly, profitability, social acceptability, and regulatory incentives for practicing agroforestry vary and change as a function of complex interactions among a host of intended and unintended socioeconomic and policy factors (Van Vooren et al., 2016). These are exceptionally complex to untangle (Buck, 1995), but in recent years researchers have been working on new tools to deal with this complexity. For example, Hi‐sAFe is a novel tool for exploring agroforestry designs, management strategies, and responses to environmental variation (Dupraz, Wolz, et al., 2019). Added to this are the institutional problems of dispersed, often uncoordinated resources that combine to influence the generation and use of new knowledge—mainly researchers, information, infrastructure, and financial support. Relevant and broadly encompassing scientific research in this context becomes prohibitively expensive—particularly in the current economic climate of the United States where agricultural research resources are increasingly scarce and often monopolized by “big business” interests whose central focus is on generating profitable products. Although there is some dedicated funding for integrated research on sustainable agriculture through the Sustainable Agriculture Research and Education (SARE) program of the USDA, and a variety of related funding opportunities through the USDA National Institute of Food and Agriculture (NIFA), funding is limited, extremely competitive, and relatively short term. Concerns about integrating conservation and sustainable development goals through agroforestry are likely to continue to receive limited priority.

      We propose a complementary strategy for advancing understanding of the conditions under which the desired attributes of agroforestry practice may be achieved and how well various systems can be expected to perform. This involves harnessing the experience and learning processes of numerous, dispersed agroforestry practitioners into purposive knowledge networks. During the past decade, a series of regional agroforestry networks have been established (e.g., Mid‐American Agroforestry Working Group [MAAWG], Northeast/Mid‐Atlantic Working Group [NEMA], Pacific Northwest Agroforestry Working Group [PNAWG], Southwest Agroforestry Action Network [SWAAN], etc.). In addition, a number of regional specialty crop cooperatives have formed (e.g., Midwest Elderberry Cooperative, multiple chestnut cooperatives, etc.). What is still needed is to challenge these regional working groups to share and evaluate their experience with others about specific activities along integrative themes. Facilitators, who might come from universities, federal agencies such as the National Agroforestry Center, and/or NGOs including the Savanna Institute, would help to link landowners with one another and with other key actors from production, trade, NGOs, professional associations, land‐grant universities, national agency research laboratories, the markets that are essential for viable systems, and various policy units. They would document individual and collective learning processes with an aim to move knowledge from the particular, context‐specific state to a more global and predictive one integrating knowledge across landscapes.

      Workshops and study tours designed to help participants recognize and evaluate the informal experimental design and evaluation processes in which landowners engage, and how they inform these processes through their respective learning networks, would serve to sharpen and focus the collective expert judgment that develops. In recent years, many such workshops have been established. For example, in 2013, the Center for Agroforestry, in conjunction with MAAWG and via initial funding from SARE, established an annual Agroforestry Academy to help address this need. As of 2019, 175 individuals (farmers and educators alike) have been trained across seven academies, and a longitudinal study is ongoing to extract lessons learned and to create a learning network among the trainees (Gold et al., 2019). The Savanna Institute is also very active in hosting workshops and study tours and linking farmers together in networks. These activities overlap with conventional extension roles in agriculture and forestry, helping to provide a dual purpose and justification for funding.

Numerous trainings, workshops, and study tours have been very successful in attracting agroforestry practitioners. These individuals, varying widely in age from their 20s to their 60s, are typically curious, open‐minded landowners, many of whom come from an understanding of permaculture, who believe there may be a better or different way to manage agricultural and forestry resources than conventional land use approaches. They are also likely to have a multigenerational vision for the development of their production system, while at the same time adopting a willingness to compromise it in practical terms to the realities of today’s transient society. Agroforestry attracts individuals who value hard work and understand the critical role of management in generating multiple outputs in as complementary and noncompetitive a manner as possible. They are likely to experiment with various components of their evolving production system and to have created a diverse network of information resources to assist their efforts to design new systems and informally test new hypotheses. Such people can be found in the membership of numerous organizations throughout the United States and Canada (e.g., the Association for Temperate Agroforestry [AFTA], the Appalachian Beginning Forest Farmer Coalition [ABFFC], etc.) that are concerned with the development and marketing of alternative crops and enterprises or the management of natural resources. In a highly connected world of social media, they can easily reach out to existing organizations, anticipating their role in satisfying their needs for learning, improving their practices, and addressing important social issues. Once they are part of such networks, they attract others to join.

      Implementation of the proposed strategy is well underway, and critical perceptual and institutional barriers to improving the capacity for knowledge and information generation about agroforestry are being addressed. Scientific knowledge about agroforestry is rapidly being integrated into practice via the host of organizations previously mentioned (Gold, 2019).

      The important implication is that landowners have now become an integral part of the knowledge generation process. This requires careful examination of the processes they use, the products they develop, and the various learning groups with whom they interact. In doing so, the research and development community now acknowledges and participates in the dense networks of informal learning about agroforestry that they understand and appreciate. As stated, numerous organizations are now playing important roles in developing generalizable knowledge if adequately recognized and organized to do so. Actions are being taken to link them. In this way, agroforestry now offers important opportunities fostering innovation in land use management.

Progress to Date and Challenges Ahead

      The potential for domestic agroforestry and the constraints to its development that were first identified in 1989 (Lassoie et al., 1991) and then reexamined 2 yr later (Lassoie & Buck, 1991) are dramatically different from those facing us today (Gold, 2019). Agroforestry practices are becoming part of the repertoire of management strategies that are emerging from the research and development community to address complex land use sustainability issues within interdisciplinary forums.

      As mentioned above, however, agroforestry is a hybrid of the established fields of agriculture and forestry, closely aligned with the science of agroecology and regenerative agriculture. Therefore, each new approach will face its own set of challenges as it moves from theory into practice. Practical application of these approaches also will face different challenges and offer different opportunities to the research and development community. These challenges and progress to date in meeting them are discussed here as well as specific recommendations to further advance agroforestry research, development, and practice in the United States.

      Basic Challenges and Progress

      Agroforestry in the United States has faced some unique challenges as an emerging land use strategy, many of which are being overcome. First, concepts and methodologies were originally obtained from international experiences primarily in developing, tropical countries with very different ecological and socioeconomic contexts.