Temperate Agroforester: Volume 26 Number 3

Little is known about the viability of commercial, forest-grown specialty mushroom production in the western Pacific Northwest (PNW) even though the region’s climate provides mild temperatures, ample precipitation, and abundant forests conducive to mushroom growth. This potential is evident in the long-standing and lucrative tradition of selling wild-foraged mushrooms in the PNW (Yoon 1992). Compared to wild foraging, however, cultivation of specialty mushrooms requires minimal acreage, is ecologically low-impact, provides reliable harvests, and holds added market value as an ecologically-appropriate, forest-grown product.

Acorns have long been an appealing food source for humans (Šálková et al. 2012).  The acceptance of acorns as an alternative modern crop is developing (Vinha et al. 2016).  Acorn gathering and processing has provided an exciting opportunity to engage the community and teach food security principles to youth in Northern California (Figure 1).  Perennial cropping presents an opportunity to improve agricultural systems with synchrony between crop nutrient requirements and nutrient supplies (Crews 2005).  Drought poses a major threat to food security (Fàbregas et al. 2018).  These considerations are a sample of the reasons that alternative crops such as nut pines and oak trees were installed in a Northern California food forest to investigate long-term productivity.

Establishing perennial bioenergy crops on marginal lands that do not compete with food crops for land occupation is viewed as an innovative approach to meeting our current and future energy demands while ensuring food security (Norgrove 2010). This is because perennial grasses and short-rotation woody crops such as switchgrass (Panicum virgatum), miscanthus (Miscanthus giganteus), and willow (Salix miyabeana) have high energy potentials and capable of growing on marginal lands with minimal or no external nutrient requirements, alleviating the need to divert agricultural lands and food crops into energy production (Chimento et al. 2016; Searchinger and Heimlich 2015). In addition to rapidly accumulating biomass on marginally productive agricultural lands for energy use, their long-term land occupation helps to regenerate these marginal lands on which they grow (Chimento et al. 2016). As a result, growing perennial bioenergy crops on marginal lands is promoted as a land management strategy, which provides a ‘sustainable’ energy alternative to fossil fuels with climate mitigation benefits (Agostini et al. 2015).

A long-term study conducted at the University of Guelph, Ontario, Canada focused on Carbon (C) sequestration through bioenergy cropping systems in non-agricultural lands (Figure 1) (Bazrgar et al. 2020). These systems sequester atmospheric CO2 in their fibre, as well as in the soil through residue inputs (litterfall, coarse root and fine-root turnover, soil microbial processes, etc. Figures 2 and 3) (Coleman, et al. 2018). In Canada, the current estimate of non-agricultural (marginal) land area that can be brought under biomass crop production is 9.5 million ha (Ashiq et al. 2017). Meanwhile, a significant increase in bioenergy production has also been predicted based on global future energy scenarios. Understanding the system-level C storage potentials in woody and herbaceous cropping systems (long term soil organic carbon (SOC) sequestration, belowground biomass C, annual litter input and fine root turnover associated C), and how these system-level C dynamics will change as systems mature will help biomass growers to comprehend long-term C sinks influenced by biomass crops.

Farmers and agricultural advisors in Wisconsin and surrounding states have shown increased interest in silvopasture in recent years.  Given limited resources for silvopasture research and outreach it is helpful to know what information stakeholders want and how they want to receive it.  From 2014 to 2019 we gathered evaluation data following silvopasture outreach events in Wisconsin and Minnesota and conducted twelve focus group interviews about silvopasture with more than 60 farmers, agricultural advisors, and foresters.  These interviews and evaluation results provide a snapshot of where stakeholders learn about silvopasture, how they prefer to get silvopasture information, and what information they are seeking.  

Agroforestry systems (AFS) are a land-use system that integrates trees and crops or pastures within the same land-use area to improve food production efficiency and ecosystem sustainability, where the latter includes ecological benefits such as carbon (C) sequestration and biodiversity conservation (Albrecht and Kandji 2003, Nair 2011, Schroth and McNeely 2011). A growing number of studies comparing C stocks between AFS and adjacent croplands indicate that AFS sequester more C in both vegetation biomass and soil compared to agricultural land managed using monoculture cropping (Schoeneberger et al. 2012, Shi et al. 2018). Given this, promoting agroforestry regionally and globally may have a high potential to mitigate climate change by increasing C sequestration. However, more detailed and reliable information is needed to increase the effectiveness of AFS use, where such information includes how much C (stock) can be stored as either tree biomass or soil organic C (SOC), and perhaps more importantly, how quickly this biomass C or SOC accumulates and the time period over which this occurs.

Despite significant attention to the benefits of practices along an agroforestry continuum (Fig. 1), disconnects between agroforestry research and practice may limit widespread implementation. Agroforestry research often focuses on a limited number of species and commodity crops (Wolz & DeLucia, 2018). However, many farmers and communities are interested in growing and using other species, especially native plants that produce non-timber forest products, which may have been traditionally managed to increase production but not necessarily planted in agricultural settings.

 The tree crop supply chain may be envisioned as a tree with five branches representing Producer, Gatherer, Processor, Distributor, and Consumer. Each branch can exist independently, but with a connective structure to unite them in an economically-viable system, the potential for a real bioregional tree crops industry increases enormously.  Let’s look at some of the main challenges for each branch.