In response to the unsustainable practices and negative externalities of the modern industrial monocrop agriculture complex, there has been growing interest in permaculture and food forests as a sustainable way to produce food. Permaculture is a philosophy and set of practices that aims to create regenerative ecosystems that are self-sufficient and promote biodiversity. Food forests, also known as forest gardens, are an example of a permaculture design that mimics the structure and function of a natural forest ecosystem.
So, what exactly is a food forest? Essentially, it is a type of agroforestry system that combines fruit and nut trees, shrubs, herbs, and perennial vegetables to create a diverse, low-maintenance food production system. The idea is to mimic the layers of a natural forest, with a canopy layer of tall trees, an understory layer of shorter trees and shrubs, a herbaceous layer of groundcovers and herbaceous plants, and a root layer of bulbs, tubers, and other perennial vegetables.
The goal of a food forest is not just to produce food, but to create a self-sustaining ecosystem that benefits both humans and the environment. By using permaculture principles like companion planting, nutrient cycling, and species symbiosis, a food forest can increase productivity and resilience while reducing the need for external inputs like pesticides and fertilizers.
One key aspect of food forests is the use of species symbiosis, or the interdependent relationships between different species in an ecosystem. In a food forest, each plant plays a specific role in the ecosystem, whether it is fixing nitrogen, providing shade, attracting pollinators, or repelling pests. By selecting plants that complement each other and create mutually beneficial relationships, a food forest can become a thriving, diverse ecosystem that supports a wide range of species.
Another key principle of permaculture and food forests is the idea of “stacking functions.” In other words, each element in the ecosystem should serve multiple functions to maximize productivity and efficiency. For example, a fruit tree can provide shade for an understory crop like berries, while also producing food and providing habitat for birds and insects. These species may act as predators to crop destroying pests.
Here are a few examples different species relationships that can be used in a permaculture food forest:
Nitrogen-Fixing Plants and Fruit Trees: Nitrogen-fixing plants like legumes capture nitrogen from the air and convert it into a form that other plants can use. By planting nitrogen-fixing plants in and around fruit trees, the trees can benefit from this natural source of fertilizer. In return, the trees can provide shade and support for the legumes, creating a mutually beneficial relationship.
Pollinator Plants and Fruit Trees: Most fruit trees require pollinators to produce fruit. By planting a diverse mix of pollinator-friendly plants like clover, borage, and comfrey around fruit trees, the food forest can attract bees and other beneficial insects that will help pollinate the trees. At the same time, these plants can provide habitat and food for a wide range of other beneficial insects and birds.
Pest-Repelling Plants and Companion Plants: Some plants have natural pest-repelling properties that can help protect other plants in the food forest. For example, marigolds are known to repel pests like nematodes, while garlic and onions can help repel pests like aphids and spider mites. By planting these plants in and around other plants that are susceptible to pests, the food forest can reduce the need for synthetic pesticides.
Groundcover Plants and Trees: Groundcover Plants: Strawberries, clover, and mint can help prevent soil erosion and retain moisture in the soil. By planting these plants around fruit trees and other tall plants, the food forest can create a natural mulch layer that will help retain water and nutrients in the soil. At the same time, the groundcover plants can provide food and habitat for a range of beneficial insects.
Food forests are also designed to be low-maintenance and require minimal inputs once established. By using perennial plants that come back year after year, a food forest can reduce the need for tillage and other soil-disturbing practices that can damage the ecosystem. And by mimicking the structure of a natural forest, a food forest can take advantage of natural processes like nutrient cycling and water retention.
Food forests are a promising example of how permaculture principles can be applied to agriculture to create sustainable, diverse ecosystems that benefit both humans and the environment. By using species symbiosis, stacking functions, and other permaculture techniques, food forests can increase productivity and resilience while reducing the need for external inputs and minimizing negative impacts on the environment. As we continue to face growing challenges in food production, food forests offer a promising alternative that can help us build a more sustainable future.
If you are interested in developing a food forest on your property, call Tannenbaum Design Group today and let’s start planning your garden and dinner table today!
Jacke, D., & Toensmeier, E. (2008). Edible forest gardens. Chelsea Green.
“Like extracting bread from air.” In 1908, Fritz Haber’s invention of synthesized fertilizer revolutionized the agriculture industry. Through a process of extracting ammonia for fertilizer use from the air, annual global crop yields doubled overnight. His invention is credited with our ability today to feed billions of people. But new problems are catching up to us.
Here in the United States, we are extremely reliant on international imports to meet our produce needs. Coupled with the challenges of affordability and accessibility of labor, much of the country is also incapable of producing outside for the colder half of the year. Specifically, as of 2020, 53% of all the fresh fruit and 32% of all the fresh vegetables consumed in this country are imported.[i] Comparatively, increasingly unpredictable weather patterns are only making the challenges of conventional domestic farming more difficult. Globally, we are still struggling to meet demand for produce. In fact, a 2015 World Health Organization study found that only 36% of the global population has adequate availability of fruits and vegetables to meet minimum nutrition targets.[ii]
Controlled Environment Agriculture
Fortunately, a new wave of technology categorized as controlled environment agriculture (CEA) has the potential to revolutionize America’s food production system once again and help alleviate the greater global deficit of high quality, affordable produce. CEA is proven to increase yields per acre by a magnitude of over 10 times that of conventional agriculture through curation of year-round, ideal conditions and symbiotic micro-ecosystems.[iii] Conventionally, these facilities use hydroponic, aeroponic and aquaponic systems to grow vegetables without soil. This technology allows growers to use exponentially less water and fertilizer than conventional field agriculture. With new innovations in digital monitoring, robotic harvesting, and automated sorting and packaging, the challenges of finding labor are also alleviated. Equally important, CEA avoids the externalities of environmental degradation, systemic in conventional agriculture.
Through CEA we are able to produce higher quality crops without damaging the ecosystem. The controlled environment facilitates the elimination of toxic chemicals in exchange for biological pesticides (predators for parasites). Additionally, as facilities move closer to market in response to demand for local produce and rising shipping prices, breeding programs are able to pivot away from a focus on shelf life (for long-haul shipping) towards flavor, texture, and nutritional value. Changes in consumer demand for healthier local food is creating growing demand for CEA and ultimately opportunities for investment in the asset class.
Over the last century, conventional industrial farming has had catastrophic effects on the environment. Chemical pesticide use has decimated insect pollinator populations. Monoculture farming, erosion from tilling, herbicides, and fungicides have polluted, depleted, and sterilized our soils. Excessive fertilizing has polluted our water. It is not an exaggeration to say that the choices we make today will have cascading effects for centuries. The United Nations Food and Agriculture Organization estimates that 33% of the world’s soil is moderately to highly degraded through erosion, salinization, compaction, acidification, chemical pollution and nutrient depletion.
These degradations hamper the soils’ ecological functionality affecting its food production capabilities.[iv] Insect populations have also declined by 75% over the past three decades, largely due to agricultural practices, hampering natural breeding and fruiting processes.[v] The cataclysmic loss of biodiversity is reaching a breaking point that will not be easy to reverse. Therefore, it is critical that we reinvent the way in which we produce our food. Controlled environmental agriculture addresses all of these environmental concerns by creating a closed loop system.
CEA can be classified into three main structures: high tunnels, greenhouses and plant factories. Each has their own benefits and limitations.
High Tunnels are the least expensive and most common solution in the market today. At as low as $3 per square foot in construction cost, they require very little capital to get started. While they are a great improvement over conventional agriculture, they have a short life span, are very susceptible to environmental damages, are less light and heat efficient, and are uninsurable.
Greenhouses average $35 per square foot at commercial scale and are the most energy efficient form of CEA.
Indoor Plant Factories — typically what people think of when they think of vertical farming — are highly variable in price (generally between $100 and $200 per square foot for new construction), but can essentially be established in any reclaimed building or container. They are very high in climate control efficiency and yields per acre possible (by growing vertically) but are more limited in what crops they can grow efficiently. (Some crops demand more light than the LEDs can provide.) Plant factories also require extreme electricity consumption. For example, lettuce crops grown by CEA consume upwards of 350kWh per square foot per year compared to a typical greenhouse’s 25kWh per square foot.
Choosing the Right Asset Type
The costliest aspect of running any CEA facility is electricity consumption. Not accounting for transportation or increased quality’s value proposition, electricity consumption is the biggest barrier today to achieving production cost parity with conventional agriculture. The key to understanding which structure type is optimal for a given location is through understanding the supplemental lighting efficiency, the cost of electricity, and local conditions. Consider this: In New York state, at current electricity prices, even if LED technology was perfected to translate 100% of input energy to light, a greenhouse’s use of the sun and supplemental light, instead of 100% artificial lighting, is still more efficient than the benefits of a plant factory’s more insulative qualities.
For this reason, choosing the right asset type to invest in for a given location is critical. Are you near the Arctic Circle where natural sunlight is very limited for half the year and temperature lows are extreme? Then a plant factory is likely the correct option. Are you in a generally mild climate state with high electricity costs? Then a greenhouse may be right for you.
CEA is a better impact solution than many other popular alternatives. It is often carbon negative. It requires limited use of rare earth metal materials whose mining undermines the true environmental values of many energy oriented ESGs. CEA very poignantly addresses the problems of biodiversity and habitat loss. Additionally, it decreases agricultural water usage by over 95% and fertilizer usage by 60%. It dramatically reduces the waste of shipping. And socially, it has the potential to solve global food crises.
As of today, investment in CEA has reached just over $2 billion across North America and Europe. The compound annual growth rate for the North American vegetable greenhouse market since 2007 is greater than 20%. In a $20 billion market, crops from CEA facilities only account for 1.3% of the annual produce consumed in the US. With total food demand expected to increase between 59% to 98% by 2050, CEA’s growth potential is exponential.[vi] Moreover, this does not even account for the opportunity of increased produce demand facilitated by improved accessibility; research shows an increase of up to 32% in produce consumption for each additional supermarket in a census tract.[vii]
The barrier for some, and therefore the opportunity, is that these facilities require high upfront costs. In addition to the structures themselves, the intricate hydroponic irrigation systems, robotic equipment and sensory equipment can carry a large price tag. As a plethora of start-up companies race to compete and establish market dominance, they are hungry for capital. As such, many forego ownership of their facilities, instead focusing on their core expertise and leveraging capital towards opening more facilities.
Several developers and investors are capitalizing on this opportunity in a number of ways. The most common is a sale-leaseback. As examples: Equilibrium Capital acquired and leased two greenhouse facilities to indoor agriculture company Revel Green for $11.3 million and plans to finance at least three more greenhouse facilities. Another firm, Green Acreage provides sale-leaseback and construction financing to companies operating in the cannabis industry. Green Acreage invested $77.3 million with Acreage Holdings that entered into long-term, triple-net lease agreements with Green Acreage for properties in California. Other players in the market executing similar strategies include Power REIT, which owns six CEA properties in southern Colorado and Maine with a total of approximately 131,000 square feet of greenhouse and processing space; and Innovative Industrial Properties who focuses on the acquisition, disposition, construction, development and management of CEA facilities across the country.
To better understand the lucrativeness of the opportunity, Innovative Industrial Properties states that their typical absolute net lease terms are 10 to 20 years with base rents at 10% to 16% of total investment and 3% to 4.5% annual rent escalations. Typical deals range from $5 million to $30 million and carry security deposits and corporate guarantees. This compares quite favorably to conventional farmland sale-leasebacks that often have 5-year terms and net around 5% of the purchase price as base rent and escalate 7.5% to 12.5% every term.
Other growers have opted for mixed-use facilities where they can rent roof top greenhouse space. This allows growers to be in deep urban locations and virtually eliminate shipping expenses. For example, Gotham Greens recently purchased and built a 15,000 square foot greenhouse on a vacant Brooklyn rooftop. Others have chosen to take the concept directly to the literal market. BrightFarms has, to date, signed up eight supermarket chains around the country (including three of the largest national chains) to build these rooftop farms for about $2 million per acre. The facilities are expected generate $1 million to $1.5 million in annual revenue.
International investment continues to be an important funding source for controlled environment agriculture as countries like Saudi Arabia and the UAE look to establish sustainable domestic food systems through the furtherance of the technology. Correspondingly, many CEA growers have gotten their start through partnerships with sovereign wealth funds.
The opportunity is clear; how real estate investors choose to enter the space is up for debate. Funded by $82 million from Equilibrium Capital, AppHarvest, a 3-year-old start-up, has purchased 366 acres in eastern Kentucky with the goal of leveraging economies of scale. With plans to develop a 2.76-million-square-foot greenhouse for $97 million, AppHarvest will be one of the largest greenhouses in the world, supplying much of the Eastern seaboard within one day’s drive.
Although CEA has existed for the past decade, technological development and botanical research have greatly reduced the risk and challenges of the business. Digital monitoring and control technologies have simplified running a controlled environment agriculture facility. Concurrently, consumer demand for high quality organics has risen dramatically, creating a bigger market.
As we stand today, the climate crisis has reached boiling point and habitat degradation has pushed biodiversity to the brink. CEA stands as a profitable, sustainable, lower-risk alternative to conventional agriculture, whose biggest challenge is simply the upfront costs of developing the facilities.
Fresh Alternative Farms:
If you are interested in starting a controlled environment agriculture facility of your own, send us a message and check out our partner organization: FreshAF
[i] Center for Food Safety and Applied Nutrition. “FDA Strategy for the Safety of Imported Food.” U.S. Food and Drug Administration, FDA, www.fda.gov/food/importing-food-products-united-states/fda-strategy-safety-imported-food.
[ii] FAO, IFAD, UNICEF, WFP and WHO, The State of Food Security and Nutrition in the World 2020: Transforming food systems for affordable healthy diets, 2020. https://www.unicef.org/reports/state-of-food-security-and-nutrition-2020
[iii] GL Barbosa, FD Gadelha, N Kublik, et al., Comparison of Land, Water, and Energy Requirements of Lettuce Grown Using Hydroponic vs. Conventional Agricultural Methods, International Journal of Environmental Research and Public Health, 2015, 12(6), 6879-6891. https://doi.org/10.3390/ijerph120606879
[iv] FAO, Polluting Our Soils Is Polluting Our Future, May 2, 2018. www.fao.org/fao-stories/article/en/c/1126974/.
[v] Euan McKirdy, New Study Suggests Insect Populations Have Declined by 75% over 3 Decades, CNN, October 20, 2017. www.cnn.com/2017/10/19/europe/insect-decline-germany/index.html.
[vi] Maarten Elferink and Florian Schierhorn, Global Demand for Food Is Rising. Can We Meet It?, Harvard Business Review, April 26, 2019. hbr.org/2016/04/global-demand-for-food-is-rising-can-we-meet-it.
Agroforestry is an agricultural methodology that optimizes production by exploiting the benefits of interspecies interactions. By deliberately combining trees, shrubs, perennials, annuals, or livestock, a grower can enhance their farm economically, ecologically, and environmentally. In juxtaposition to popular monocultural farming practices, agroforestry reestablishes the complexity of time, place, and biodiversity that plants experience in the wild. From a sustainability perspective, it can serve as a bridge between natural resource management and agriculture, in a world that is in dire need of a better relationship between the two.
Agroforestry can be divided into several categories: Riparian Vegetative Buffer Strips, Intercropping, Sivopastoral, Windbreaks, and Forest Farming. Each represents a different circumstance in which agroforestry can provide benefit, ultimately with the same symbiosis methods at their core.
Riparian Vegetative Buffer Strip Systems are the establishment of agroforestry plantings along stream and riverbanks to protect aquatic habitats and reduce nonpoint source pollution in waterways.
Intercropping Systems are the planting of widely spaced trees with conventional crop rows in between allowing for diversified farm income, the abatement of soil erosion, mitigation of nutrient loading, and the protection of watersheds.
Silvopastoral Systems are the combination of trees and livestock as a means of maximizing the land for economic, wildlife habitat, fire protection, and forest management benefits.
Windbreak Systems are the simple and more commonly seen practices of today. Windbreaks are plantings around the perimeter of a field used to protect and enhance the production of crops and animals while creating environmentally more stable microclimates.
Forest Farming is the development of microenvironments resembling natural forest stands that look to mimic nature throughout a farm. Forest Farming develops suitable environments for growing specialty crops within its shaded settings.
Agroforestry offers a wide variety of both localized and macro benefits for the farm and the greater landscape. On a macro level, Agroforestry practices can increase productivity during successional changes, decrease weed competition, increase internal regulation, increase biological regulation of insect pest, increase solar radiation usage efficiency, increase soil organic matter, increase biodiversity, decrease agriculturally derived contaminants in riparian zones, decrease wind and water erosion, increase the uptake and fixation of carbon dioxide from the atmosphere, and increase the retention of nutrients in soils.
For the farmer, Agroforestry offers a variety of crop production benefits. Foremost are the benefits of wind damage protection. The creation of woody corridors traps windborne particles and slows windspeeds across sites. Small seeded, shallow sown, and newly emergent crops are particularly susceptible to wind and sandblast damage. Additionally, orchard fruit crops are often compromised from wind as well – which can cause the desiccation of petals and pollen loss as well as fruit drop, bruising, and scaring. Further, research indicates that livestock also benefit from the wind protection, with studies indicating that feed needs are decreased by up to 20% by offsetting the cold wind temperatures. Similar studies indicate benefits to livestock such as decreased newborn losses, increased cattle weight gain, and increased milk production as well.
Agroforestry offers erosion mitigation benefits as well in the form of wind and water erosion protection. It is estimated that conventional monocultural farming practices can result in the loss of five tons of soil per year per acre. A problem that agroforestry practices greatly eliminate. By retaining soil organic matter, farmers can greatly reduce or even eliminate their need for commercial fertilizer.
When using commercial fertilizers, Agroforestry practices can greatly resolve the problems of nutrient runoff. Riparian Vegetative Buffer Strips were found to greatly decrease negative externalities from farms, in particular. Forested Vegetative Buffer Strips 90 to 150 feet wide were found to reduce ground water nitrogen content by 68% to 100% and surface water runoff nitrogen by 78% to 98%. Further, Forested Vegetative Buffer Strips are able to reduce phosphorous concentrations in surface water by 50% to 85%. This runoff, when allowed to reach water bodies can have devastating ecological effects, causing life choking algae blooms in its extreme circumstances. Further, the preservation of soil health improves the quantity and quality of the soil microbiome. These resident bacterial and fungi are critical for making nutrients available to plants.
Agroforestry offers other water benefits as well. Locally, Agroforestry practices can increase soil porosity, reduce runoff loss, and increase soil coverage, which leads to higher water infiltration and retention in the soils. This is of particular benefit in drier climates and drought conditions for reducing soil moisture stress on crops. Further, through a process called hydraulic lift, trees with deep roots redistribute deep soil water supplies to higher strata, where other crop root zones can have access during drought.
Agroforestry practices reduce sedimentation in reservoirs as well. Conventional farming results in unnaturally high sedimentation. By mitigating this, reservoir life spans can be extended at a national savings of $200 million.
Additionally, woody corridors have the added benefit, in winter, of increasing water availability through snow capture. This snow capture is also important as insulation preventing winter kill of more sensitive perennial crops.
Agroforestry practices overall act as valuable climate modulators. These forested settings better moderate against extreme temperature fluctuations that can be very destructive to crops. Agroforestry farms have higher humidity, soil moisture, nighttime CO2 levels, and lower nighttime air temperatures compared to their conventional monoculture counterparts. These regulatory effects were found to increase crop productivity 10% to 25% in dry climates.
It is estimated that 18% of all crop loss is the world is due to insect pests. As global warming progresses, this problem is likely only to get worse. Agroforestry practices can impact the pest mitigation aspects of farming in a variety of ways. Through the creation of woody habitat for birds and bats, these spaces can increase the presence of the predators that prey on insect pest in the fields. Though this won’t eliminate pests in their entirety, it helps to keep populations under control.
Additionally, these wooded spaces provide the habitat needed for beneficial insects as well such as arthropod predators and parasitoids who further suppress pest insect populations. These spaces offer stable habitats for reproduction, overwintering, and refuge free from the from perturbations of conventional farming practices. Additionally, reducing wind through farms can also significantly help beneficial insects find and consuming pests. It is estimated that the wind barriers that agroforestry practices provide can improve crop pest reduction by beneficial insects up to 40%. Lastly, Agroforestry practices reduce visibility for pests, decreasing the chances of epidemic by making pests that target a single species less prolific. Overall, these predatory species serve a critical ecological role in the farm. It is estimated that these insects provide ecosystem services worth $4.5 billion per year.
Agroforestry practices can play a critical role in the protection and creation of critically endangered habitats for both aquatic and terrestrial species. In sensitive aquatic areas, the forested zones shade and stabilize stream banks. This reduces erosion while improving aquatic insect habitat, raising dissolved oxygen levels, reducing denitrification, reducing evaporation, and ultimately raising fish population levels. Further, these buffers play an important role in bioremediation, breaking down and capturing chemicals that drift from the farmland, decreasing their ecological destruction effects.
Over 30% of the crops we cultivate for food rely on insect pollinators. These pollinators largely come as wild native bees and European honeybees. Over the last century, due largely to the chemical and habitat destruction practices of industrial farming, populations of these bees have been significantly reduced. The practices involved in conventional monocultural farms are largely incompatible with the needs of many of the 4000 species of North American bees.
Approximately 30% of our native bees are wood nesters that require trees and shrubs for nesting. About 70% create nests underground requiring undisturbed soil away from the tilling of conventional farm practices. Agroforestry is a poignant way to address the habitat needs of both species. Bumble bees for instance, were found to be twice the density in wooded habitats as compared to grassland habitats. By bringing the habitats of these species closer to the crops by better interspersing woodland, fields can experience greater pollination levels and ultimately better crop production.
The many pest reduction benefits of Agroforestry decrease the need for chemical pesticides, commonly used in conventional farming. These chemicals wreak havoc on bees through direct contact and inadvertent spray drift. With the ecological service value of these bees over $3 billion, farming faces a critical need for solutions like agroforestry that can help bring the bee species back from the brink.
Agroforestry offers significant values in regard to air quality improvement as well. In addition to reducing chemical spray drifts up to 90% through woody buffers, Agroforestry farms serve a valuable role as greenhouse gas reducers, smog reducers, particulate catchers, and odor reducers in livestock areas where this can be a major concern.
Beyond the role that Agroforestry plays productively, it also can play a valuable role for the farmer themselves and the local community. First, from a biophilia perspective, agroforestry natural mimicry creates aesthetically pleasing spaces that are psychologically inviting for people. From a real estate perspective, greenspaces are among the top 5 things people seek when choosing a place to live. Greenspaces are proven to raise property values up to 32%. This land value is not shared by spaces juxtaposed to monoculture farms. These agroforestry spaces can play a valuable social role as leisure spaces for walkers, joggers, birdwatchers, and wildlife spectators – improving the quality of life. They also can serve as grounds for hunters as a secondary value.
From a practical perspective, agroforestry systems reduce the need for building snow fences, saving the farmer capital costs. Additionally, the microclimate affects reduce utility costs for dwelling units on site. Lastly, by better holding water on site, overall usage can be decreased. These effects cumulatively, ultimately, lower overall farm expenses.
On a broader scale, agroforestry serves as a means of increasing domestic food security – enabling the production of diverse products locally. Further, research suggests that, if utilized at scale, agroforestry systems could help mitigate climate change through significant carbon sequestration. And lastly, increased forest covering in watersheds can reduce the total amount of runoff from storms and mitigate flooding risks during peak stormflows. In these many ways, agroforestry offers environmental services values that are difficult to quantify.
Though many of the different agroforestry benefits are externalities outside the direct capture of the farmer, many are still measurable as the relate to the economics of the farm. From the broad perspective the values vary greatly as the mixture and effectiveness of agroforestry can vary greatly between different crops’ symbiosis and settings. However, as a mean, agroforestry has been proven to increase overall yields on the average between 6% and 56% – overall, increasing IRR to the farmer 4% to 11%.
However, the landscape of farming is changing. Agroforestry offers several other valuable properties as well. In an increasing labor challenged industry, agroforestry offers flexibility to the farmer that monocropping does not, as all crops do not need harvesting in mass at one time. Further, Agroforestry reduces risk by offering multiple harvest timings and products for sale rather than risking a year on a single yield. This also allows many fixed costs to be spread across a variety of products rather than laying idle for long periods of time.
From a startup perspective, Agroforestry offers a means of creating revenue sooner, rather than waiting years for the first crop as is seen in a conventional orchard. Additionally, it allows for the phasing out of equipment as it depreciates and succession to other crops becomes necessary.
Lastly, from a land scarcity perspective, agroforestry offers better overall utilization of land. This is particularly valuable for islands, for example, that are running up against a delicate balance of natural resource conservation and food security.
Agroforestry faces a number of unique challenges to wide adoption still today. Although there is becoming an ever-vaster databank of resource for learning best practices for agroforestry, there still limited research conducted in the field. Overall, there is little graduate study emphasizing agroforestry. This stems from overall limited employment opportunities in the field and as such limited funding. Given the breadth of the field and its variability across locales, there is a need for more localized testing of the practices.
Public perception holds agroforestry back from wide adoption as well. Generally, people believe that high establishment costs and high management expertise is needed. Many seem to believe that the economic gain would be lower than traditional farming. Others are disinterested in adopting systems whose rotational length may exceed the landowner’s life expectancy. Much of this is misconception only exacerbated by the public sectors disinvolvement, assuming that landowners would be unwilling to follow the land management prescriptions necessary for developing and maintaining agroforestry systems properly.
Public policy overall has a way to go in catching up with the needs of agroforestry becoming the norm. Currently some states offer extensions to the conservation reserve program to compensate farmers for the differences in payments they would have received from non-agroforestry practices. This is neither across the board nor a full compensation for the externalities that agroforestry provides. Currently, agroforesters are excluded from certain programs that are based on tree planting density. Considerations are being made through regarding valuing agroforestry for its carbon sequestration value. The challenge has largely been from organized commodity groups who feel that subsidizing producers entering the market through federally funded programs would give them and “unfair advantage”.
Lastly, agroforestry faces physical challenges as well. Overall, scale and time are necessary for realizing many of the benefits of agroforestry. Additionally, there can be added expenses to undergoing the practice. Sivopastoral systems, for instance, add additional costs for fencing and risk of tree damage from the livestock. Further, in some circumstances, agroforestry practices have been found to exacerbate pest problems by protecting insect pests with alternative hosts, allowing them to rebuild populations and reinvade crop areas the next season.
In 1935, the Dustbowl showed us the consequences of not having any agroforestry practices across the Midwest. In its wake, the Prairie States Forestry Program planted more than 200 million trees as shelterbelts, to reclaim the land ravaged by the Dust Bowl. To a great extent, agroforestry is a return to the old way of farming of ancient times – but this time with more information.
Agroforestry offers a solution to many of traditional farming’s biggest issues today. It can address the climate crisis, the biodiversity crisis, soil depletion, air and water quality, and the struggles of smaller scale farms trying to stay in business. The evidence posits that agroforestry can sustainably increase production per unit of land area while enhancing economic, social, and environmental services. While demand for local and organic specialty crops continues to grow exponentially to support the market, the time for shift has never been better or more necessary. What we need now is a policy environment that recognizes the valuable macro externalities of agroforestry better and compensates farmers for the transition in a manner more appropriate to its true value.
Patel-Weynand, T., Bentrup, G., & Schoeneberger, M. M. (2017). Agroforestry: enhancing resiliency in U.S. agricultural landscapes under changing conditions. Washington, DC: U.S. Department of Agriculture, Forest Service. Retrieved from https://purl.fdlp.gov/GPO/gpo90991
National Agroforestry Center. (2008). Agroforestry: working trees for agriculture. (Sixth edition, 2008.). Lincoln, NE: National Agroforestry Center, USDA. Retrieved from https://purl.fdlp.gov/GPO/FDLP639
Doddabasawa, Chittapur, B. M., & Mahadeva Murthy, M. (2020). Economics and energy potential of traditional agroforestry systems under contrasting ecosystems in semi arid tropics. Agroforestry Systems: An International Journal Incorporating Agroforestry Forum, 94(6), 2237. https://doi-org.proxy.library.cornell.edu/10.1007/s10457-020-00545-y
Obviously as designers of green roofs, we are very happy about the Green Roof Initiative being passed this week. But more so, the environmental and energy efficiency benefits of green roofs make for a no-brainer. For those who do not know, the Green Roof Initiative (Ordinance 300) mandates, “every building, building addition, and any roof replacement of a building, with a gross floor area of 25,000 square feet or greater, constructed after January 1, 2018, shall include a green roof or combination of green roof and solar energy collection.” Specifically, the total coverage of rooftop requirements increases 10 percent every 50,000 square feet. This eventually caps at buildings of 200,000 square feet or more with 60 percent of the roof requiring coverage by gardens or solar panels.
So, let’s discuss the benefits of green roofs, first, from an environmental perspective. Green roofs provide air quality benefits to the city by filtering particulates from the air in the same manner all green space does. They help to mitigate the effects of urbanization on water quality, often dramatically. Green roofs can do this by filtering, absorbing and retaining rainfall. And ultimately, from a nonhuman-centric mindset, the green roofs restore biodiversity to the urban environment. This is done by returning green space habitats to the local ecosystem.
So now let’s discuss the benefits from an economic perspective. Denver’s status, noted in a 2014 study by Climate Central, found the city has the third-greatest urban heat island effect of any American city. An effect partially produced by the radiating of heat off rooftops and pavements. The only American cities that ranked higher are Las Vegas, Nevada and Albuquerque, New Mexico. (The urban heat island effect is the raising of the temperature in the urban environment in comparison to the surrounding areas).
Impacts on Energy Consumption
In the summers, by implementing green roofs on the macro level, we can significantly reduce the overall heat index and our energy consumption used to cool buildings. Urban heat islands are also affected by the reflection of the sun’s rays off the sides of buildings, particularly glass buildings. The effect can be so intense that it can actually scorch trees and grass. A problem ultimately, solvable with more use of green walls. But we’ll leave that initiative for another day, as we wait for green wall innovation to catch up and make more economic sense.
On the micro, per building level, green roofs also work to insulate structures. They’re able to do so by reducing the amount of heat entering a structure in the summers. They can then hold on to artificial heat from the inside in the winters. In addition, the green roof protects the top of the structure from hail damage and wear from the intensity of the sun. This ultimately reduces repair and maintenance costs of the roof when compared to a standard roof. From an energy perspective alone, green roofs have been found to provide a return on investment. Usually within five or six years in many cases.
And finally, from a social and psychological level, green roofs and green spaces in general, provide a mental health benefit. This is called Biophillia. Those who get to enjoy the new view of nature have been shown to experience therapeutic benefits.
A green roof has a vast range of functional opportunity as well though. Green roofs can be made into community gardens, social spaces, recreational areas, and even meeting spaces in an outdoor setting. The initiative doesn’t have to be looked at solely as a dysfunctional space at higher cost. But rather an opportunity, with the required addition of the structural integrity, to turn the roof into a usable space.
Unlike many environmental initiatives, this benefit doesn’t come from taxes at all. This is because the cost is up to the building owner who, in the end, is saved money by energy savings. The only people who don’t benefit from this proposal are large scale developers who simply want to build as much, as quickly, and as cheaply as possible to sell. That’s a mindset that hardly represents the best interest of the people of Denver, the ultimate consumer.