Regreening the Earth

A fortuitous but unintended consequence of increased atmospheric CO2 levels has been carbon accumulation and increased fertilisation in plants leading to regreening in some regions. As discussed in the last IPCC report these effects include increased forest cover at the expense of savannah and grasslands, migration of tree-lines to higher latitudes and elevations, and increased crop yields. These  impacts can be seen most clearly in dryland areas, increasing vegetation cover as well as available soil water (Lu et al 2016). The CO2 fertilisation effect has been significant enough to slow the growth rate of atmospheric CO2 since 2002 (Keenan et al 2016).

CO2 fertilisation will only be a net benefit up to a certain point, but changes in land use over the past century have also lead to significant re-greening in much of Europe and North America, as shown by dramatic graphics produced by Ralph Fuchs of the University of Wageningen.  Europe now has a third more forest area compared to 100 years ago, due to vigorous post-war re-afforestation schemes, a shift to much more energy dense fossil fuel sources (Perlin 1989), and agricultural intensification leading to abandonment of  large areas of marginal farmland as they become unprofitable (Macdonald et al 2000; Renwick 2012).  This pattern of change has been accompanied and reinforced by urbanisation and other broad socio-economic changes as people leave the land (Keenleyside and Tucker 2010).

In the UK, land abandonment  has been largely stemmed so far by CAP farming subsidies (Chesterton 2009; Ceaușu et al 2015), and the apparent profitability of grouse moors across much of Scotland, meaning that practically the entire countryside is managed. Post-BREXIT, this may change if farming subsidies are dropped. In Europe however, the process is well-advanced and covers significant areas of land. Some 20 million ha. of land is expected to have fallen out of production from 2000 and 2030 (Navarro and Pereira 2015). Much of this will regenerate to scrub and forest- a kind of “passive rewilding”.

This process has been observed worldwide and is understood to follow both “economic development paths” and “forest scarcity” paths towards a forest transition (Rudel et al 2016).

In her 2012 book Nature Next Door: Cities and trees in the American North East Ellen Stroud gives a detailed account of this process happening in New England, which has seen a truly dramatic return of forests since their near-decimation at the hands of the early settlers. New York state went from just 25% forestation in the late 19th century to 61% a hundred years later; Vermont increased from 35 to 76%; New Hampshire from 50% to 86%. “Today,” writes Stroud, “the northeastern United States is almost 75 percent forested.”

This remarkable come-back was not a purely passive process that just happened as farmers left the land. Rather, it depended on a number of factors that contributed to reforestation, not least a conscious and deliberate effort by key individuals and institutions to recreate protected forests by buying land and putting it under protection.

The return of forest to former farmland and other cutover tracts is not merely the result of benign neglect, allowing forests to establish themselves wherever they were no longer beaten back to make space for fields. Trees came back because time and ecology gave them favor, but they were also encouraged and protected by choice.

A major driver was the arrival of railroads from the mid-west where large-scale farming on the prairies had taken off by the middle of the 19th century and was able to out- compete  the hilly and poorer soils in the north east. These began to be bought up by the Forestry Commission, who had been given the charge to protect water supplies form the rapidly growing cities of New York and Pennsylvania. It was the growth of these cities, and the recognition that extensive areas of forests would be needed upstate to ensure clean water supplies- what we would now call “eco-system services” -that provided the impulse for the rapid re-afforestation on much of the upland areas.

At the same time, a new class of wealthy urbanites wanted somewhere cool and tranquil to escape the city, and they preferred a “natural” forested setting for their summer houses over any signs of industrial farming. Some smaller farms were able to survive, particularly in Vermont, by diversifying into providing summer accommodation for those keen to escape the city heat, but many farms that were abandoned were bought up and converted to summer homes- a policy deliberately encouraged in some states by the Board of Agriculture. The tourists and summer visitors in turn helped support the remaining small farm enterprises.

Stroud describes how the railroads were also big consumers of timber themselves in their construction, and also brought timber markets closer to the forests: however, the tourists and summer visitors preferred trees to forestry operations, and in many places this is what tended to win out, with extensive areas of new forest placed under protection from logging- although in some states, perhaps ironically, some restricted judicious logging was permitted to preserve favoured views. People like trees, but not always dense dark closed forest.

So the return of the north eastern forests was not an accident, but intimately tied up with wider social changes, growing up alongside the growth of the cities:

Drinking water, industry, and even electric lights owed their security to the trees of New Hampshire. The city and the mountains, Ayres understood, were part of a single, interdependent landscape. The state’s seemingly pristine environment is a metropolitan nature, the result of new urban and rural interactions.

 

The story of the forest in the NE US is highly relevant to current debates about land sparing and the prospect of “peak farmland”. FAO data suggests the total area worldwide used for farmland may have been declining since 1998, even as production has increased along with calories-per-capita. Stroud warns however that land-sparing through agricultural intensification comes at the price of dependency on foreign or distant farmland:

Such extensive woods are only possible because of the region’s connections with and dependence on agricultural and industrial landscapes in distant places. If it were not for grain from the Midwest, fruit from the West and the South, meat from around the world, and lumber from distant woods, these trees would long ago have been felled for timber, cleared for other uses of land, or both.

However, as Phalan et al (2016) show, access to fertilisers, machinery and improved seeds can dramatically increase yields and secure farmer livelihoods, obviating the need for them to clear more forest for farming. This needs to be coupled with appropriate conservation policies and programs to ensure inclusion for all farmers in the locality.

Significant re-greening of the earth is possible given the right conditions and regulatory regimes, and the history of the past century in the US and Europe shows that this can happen rapidly on significant areas of land. As agricultural intensification, along with expanding conservation movements continue apace, watching the continued reforestation of areas cleared in the recent past for agriculture and fuel as developing nations go onto experience their own forest transitions will be an exciting prospect.

Source: World bank; cited in humanprogress.org

References

Ceaușu et al 2015 Mapping opportunities and challenges for rewilding in Europe Conservation Biology, Volume 29, No. 4, 1017–1027

Chesterton, C. 2009 Environmental impacts of land management Natural England Research Report NERR030

Keenan, T. F., Prentice, I. C., Canadell, J. G., Williams, C. A., Wang, H., Raupach, M., & Collatz, G. J. (2016). Recent pause in the growth rate of atmospheric CO 2 due to enhanced terrestrial carbon uptake. Nature Publishing Group, 7, 1–9. https://doi.org/10.1038/ncomms13428

Lu, X., Wang, L., McCabe, M. F., D’Odorico, P., Bhattachan, A., Davis, K., … Poulter, B. (2016). Elevated CO2 as a driver of global dryland greening. Scientific Reports, 6(February), 20716. https://doi.org/10.1038/srep20716

Macdonald, D.V.et al 2000 Agricultural abandonment in mountain areas of Europe: environmental consequences and policy response Journal of Environmental Management, 47–69.

Navarro, L.M. and Pereira, H. M.2012 Rewilding Abandoned landscapes in Europe  Ecosystems (2012) 15: 900–912

Phalan, B., Green, R. E., Dicks, L. V., Dotta, G., Feniuk, C., Lamb, A., Balmford, A. (2016). How can higher-yield farming help to spare nature? Science, 351(6272), 450–451. https://doi.org/10.1126/science.aad0055

Perlin, J. 2005 A Forest Journey: The Story of Wood and Civilization
Countryman Press

Renwick, A. et al 2012 Policy reform and agricultural land abandonment in the EU Land Use Policy 30 (2013) 446– 457

Rudel, T.K. et al 2016 The drivers of tree cover expansion: Global, temperate, and tropical zone analyses Land Use Policy 58 (2016) 502-513

Stroud, E. 2012 Nature Next Door: Cities and trees in the American North East Washington University Press

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Rewilding Discourses

Here is my dissertation submitted for the MSc in Agroforestry, Bangor University, September 2016.

Evaluating different discourses of rewilding amongst land-use           stakeholders in the UK

Abstract

Rewilding- the restoration of natural processes, sometimes including animal reintroductions – is drawing increasing popular and academic interest as a radical approach to conservation and land management, but is a plastic term with contested and sometimes conflicting definitions. Popular polemical presentations of rewilding have contributed to raising awareness of issues in current conservation policy, which focusses on maintaining specific habitats in a steady-state. At the same time, conflict and controversy has been created as existing land users perceive themselves to be under threat from a new movement to rewild the landscape.

A series of 18 semi-structured interviews were conducted with a range of stakeholders from Wales and Scotland including members of rewilding NGOs, the farming community, and professional ecologists, to answer the question:

“What are the discourses of nature and the environment that both inform and challenge rewilding projects in the UK?” and the subsidiary question:

“Why do people associate with and reproduce these different discourses?”

Significant differences, as well as agreements, were discovered between respondents. Reintroduction of carnivores such as wolves and lynx to Britain was generally deemed unrealistic in the short term. There was also broad support for the role farmers are playing to increase biodiversity and habitat under existing agri-environment schemes, and general agreement that such schemes need revising to facilitate greater integration of food production and conservation.

Divergent perceptions of current land management were expressed, a key difference lying between the value ascribed to culturally and naturally produced landscapes. Amongst rewilding advocates there was a lack of distinction made between romantic desires to return to a pristine “wilderness” and the move towards “wildness” as a process.

To move forward, the rewilding movement needs to clarify its goals of restoring natural processes rather than attempting to return to a historical baseline. Greater mediation and bridge-building is required between all stakeholders.

Carrifran Wildwood, Moffat, Dumfries and Galloway

Introduction

Rewilding has been defined as a process

“to restore self-regulating ecosystems, with a strong emphasis on the role of top-down control of ecosystems by large predators.”

(Soule and Noss 1998).

A discourse has been defined as “groups of statements that structure the way a thing is thought, and the way we act on the basis of that thinking” (Rose 2001 p.136).

Public and academic interest in rewilding has increased rapidly in recent years, with multiple discourses emerging around the term in both academic and public forums (Lorimer et al 2015; Svenning et al 2015). In the US, public interest has been galvanized by the relatively high-profile reintroduction of wolves to Yellowstone national park (Ripple and Beschta 2004). In Europe, the NGO Rewilding Europe, initiated in 2011, now has 43 member projects from 18 countries, covering 3.7million hectares of land at some stage of the process of rewilding (Rewilding Europe 2015). The charity Rewilding Britain, inspired by George Monbiot’s book Feral (Monbiot 2014), was established in 2015, with the stated aim of establishing three core areas of rewilded land of 100,000ha each by 2030 (Rewilding Britain 2015).

Romantic ideals and the appeal of a novel form of radical conservation has so far left collation of a strong scientific evidence base lagging behind (Corlett 2016). This has lead to diverse definitions of rewilding which has become a plastic term, with multiple interpretations (Jørgensen 2014).

Rewilding has been as a holistic process for ecological restoration and resilience (Monbiot, 2013, Jepson and Shepers 2016) and a tool for delivering ecosystem services as part of a suite of technologies for land management (Navarro and Pereira 2015). Other researchers have cautioned about unintended consequences and over-reach from expectations about what rewilding can achieve (Nogués-Bravo et al 2016), while more traditional land users may see their more conservative values threatened by land-use changes demanded by rewilding (Schnitzler 2014, Rebanks 2015).

Beyond its role in conservation, rewilding is also proposed as a remedy for social and psychological problems considered to be part of a “modern malaise” brought on through industrialization, consumerism and loss of contact with the natural world (Taylor 2004). By contrast, ecomodernists, while acknowledging the therapeutic benefits of contact with nature, see rewilding as something that is facilitated by more modernization, with increasingly intensive and efficient energy and food-production technologies potentially freeing up more land for wild nature (Lewis 2015).

There is an increasing recognition by ecologists and conservationists that habitat and biodiversity protection are as much social issues as ecological ones, which is reflected in the rise in popularity of inter-disciplinary research (Moon and Blackman 2014). Different groups such as farmers, hillwalkers and conservationists may hold very different values concerning how they feel the countryside should be used. Within rewilding itself, differing interpretations could lead to widely differing policy outcomes. Following this understanding, this dissertation sets out to address the research question:

“What are the discourses of nature and the environment that both inform and challenge rewilding projects in the UK?”

and the subsidiary question:

“Why do people associate with and reproduce these different discourses?”

Related concepts such as “nature” (Proctor 1998), and “wilderness” (Oelschlaeger, M. 1991, Cronon 1996), as well as environmental issues such as climate change (Nisbet 2014) and wind farm development (Woods 2003) have been subjected to similar analysis to reveal the sometimes hidden or unconscious meanings underpinning such terms, including deep-rooted historical and cultural associations. To apply a similar analysis for “rewilding”, the method of semi-structured interviews was chosen to attempt to uncover and understand meanings which otherwise may not be directly observable or identifiable through more quantitative methods such as formal surveys (Moon and Blackman 2014).

Rewilding strategies have implications for a whole range of public policy issues, in particular the future of farming and conservation policy post-Brexit, and with debates becoming potentially more fractious between competing interests, it is becoming increasingly important to find forums in which different perspectives are voiced and listened to.

The complete dissertation can be downloaded here:
strouts-g-2016-rewilding-discourses

What would Eat a Badger? Rewilding at the Hay Festival

I took a trip last week to the Hay Festival with my supervisor Dr. Sophie Wynne-Jones of Bangor University, and trustee of the Cambrian Wildwood group,  who was participating in a panel debate on rewwilding, along with Minette Batters,  deputy president of the NFU, and Julia Aglionby, Executive Director of the Foundation for Common land.

Left to Right: Julia Aglionby, Sophie Wynne-Jones, Minette Batters, Rob Yorke

Chaired by independent rural commentator Rob Yorke, about 100 people turned up to listen and ask questions. In his introduction, Rob showed he has an in-depth understanding of the topic, and began by proposing two variants of rewilding- passive, as in taking a step back and letting nature run its course, and active, including such things as herbivore and carnivore re-introductions, and asked the panelists how important they felt it is to have an agreed definition. Sophie felt it was not so important and the greater issue currently was to build bridges and make connections with all stakeholders; Julia felt that however it was defined, rewilding would need management in some shape or form: farming is a long-term activity and land cannot just be abandoned. One problem already occurring in some areas is the rapid spread of bracken, a result of reduced sheep grazing and milder winters. Minette later argued this is bad for climate change since the build-up and subsequent rotting of such vegetation releases a lot of methane. Is this what we mean- or wish for- when we say “rewilding” ?

Rob suggested that we might conceive of scales or degrees of rewilding- with something akin to Yosemite in its early days- when all the native peoples were forcibly removed in order to make room for “wild nature”- at one end of the spectrum, and something much more managed perhaps at the other, though it was not made clear what this might be, though Juila did make the comment that “wilderness is in the eye of the beholder”.

Rob briskly moved the discussion on, asking whether rewilding had been used at times more as a weapon against existing land use and users than as a tool- at this point, a farmer in the audience piped up to assert that as farmers “we love our farm and we love the countryside”. Rob again pointed out that the fault line in these discussions is often drawn between those for whom the “wild place” is seen for leisure and those for whom it is their place of work and source of livelihood.

Should production landscapes be focussed in the fertile lowlands, thus allowing the uplands to be for culture, heritage and nature? It was here that clear differences between the panelists emerged: Minette was adamant that it would be disastrous to take stock off the uplands. Farmers are the custodians of the land and we must not allow their skills to be lost by such drastic changes in land use. There is a danger that all this talk of rewilding will alienate farmers and put them off from improving biodiversity on their own farms. James Rebanks’ 2015 book The Shepherd’s Life was referenced, perhaps to provide balance with the bad press brought upon sheep farmers by Monbiot’s laying the blame on them for what he sees as the current “sheepwrecked” state of Britain’s uplands.

It was when the discussion moved onto animal reintroductions that positions became even more entrenched: I was somewhat taken aback by the stridency with which Minette dismissed the idea of carnivore reintroductions: lynx are a danger to man and our animals, she argued, and there is a very good reason they were got rid of. It would be disastrous to bring them back. She had to back-track a bit and extol the virtues of the fine animal that is a lynx when challenged by a member of the audience who asked if, then, it was a generally good policy to deliberately cause the extinctions of animals we don’t like, but I felt she then contradicted her own position by saying, “look what has happened with the badger- their numbers are out of control because they have no predator.”

Isn’t this one of the main arguments for rewilding, I asked? Badgers are not top predators in the same way a lynx would be, and are generally classed as mesopredators, generalists and omnivores which prey on smaller animals like hedgehogs- and are blamed for drastic impacts on the numbers of the latter and other small animals.

Badgers are the center of a long-standing controversy over culling and TB which I have not really looked into and shall not get into here- but this has nothing to do with the issues of threats to sheep and people by the lynx. However, Minette’s response to me was, “What would eat a badger?” which did give me pause for thought and became something of a joke between myself and Sophie on the way home. Further research later that night suggests that  badgers do not in fact have many natural predators, being well-adapted for their own defense, and probably would not be the first choice of a lynx looking for its lunch, although badger cubs might be taken by various predators including lynx and eagle. Mesopredator release – the rapid increase in numbers of mesopredators as a result of the elimination of higher carnivores- is a real thing (Prugh et al 2009), but it is unclear that there are good documented examples of this happening with badgers, apart from a controlled experiment in Texas when Cayotes were removed. In this case however “the increase in mesopredators did not lead to the decreased rodent numbers that classic trophic cascade theory would predict”  I don’t know why, or if, then, badger populations have increased relative to historical levels.

Much more worrying was Minette’s concern about the danger of lynx to humans or stock: Lynx are a shy animal and pose no real threat to humans, and any increase in sheep take would barely register against the several hundred attacks by domestic dogs each year. These arguments against carnivore re-introductions are common and understandable, and should not be dismissed, but seem to me to be the weakest, and such fears should not be fueled by representatives of the NFU . Far more serious are the concerns raised by Rob about our own duty of care to such animals, which may not survive in any case, or be vulnerable to being hit by traffic.

Another application of rewilding is flood mitigation, through riparian plantings (trees can increase infiltration rates) and re-meandering of rivers as we saw at Pickering on the Study Tour. Minette was also completely opposed to this, arguing that the most fertile land is generally the flood-plains and should be kept for farming; the water should not be “slowed” but sped up through the towns to be got rid of as soon as possible. If only it were so simple…

Sophie was keen to focus on practical examples such as the Pontbren in mid-Wales, which is cited as a a successful case of using trees to help in flood mitigation- however she cautioned against extrapolation from relatively little data and experience which might lead to over-stating the case for what trees in the landscape can achieve, and also made the important point that this was a farmer-lead project not originally connected with flood mitigation at all, but originally driven by using trees and hedgerows to shelter livestock.

An hour was far too short and the conversations continued over drinks afterwards, when I had some interesting discussions with countryside blogger Ben Eagle who also has a nice write-up of the event.  Ben had also pointed to the recent policy briefing by Paul Jepson which disentangles some of these debates and shows the way forward for a possible policy framework for rewilding.

A local farmer who was present, a neighbour of Rob’s in the surrounding Black Mountains,  also emphasised the crucial importance to farmers of maintaining their role of food producers. Why? Going back to Rob’s question earlier, could not the less fertile upland areas be rewilded, and food produced where more intensive methods can be implemented? Earlier Minette had explained to me that lambs do not stay long in the upland areas, being soon sold to lowland farmers, and sheep farming is highly integrated across the landscape; I am not sure if this really makes the case though. The conversation turned to policy- would farmers not simply do what they are paid to do? Would they not be just as happy to be paid for conservation as to produce food? For me it was something of a revelatory moment when the table went quiet as it seemed all parties present agreed on one thing at least: noone was really sure what the current farming payments are actually supposed to be for.

I have a lot to learn about farming and farming policy in the UK, as well as about rewilding in its various ramifications, but the diverse opinions I heard at Hay have provided plenty of fodder for this week at least. I shall  post more findings and insights as I continue my research through the summer.

References

Prugh, L.R. et al 2009 The Rise of the Mesopredator BioScience 59: 779–791

Feedback on the Forest Garden

My last post dealt with the permaculture edible forest garden, and it received some commentary on a couple of Facebook groups and permaculture forums. A lot of the responses were, predictably, from permaculture advocates who took umbrage at my having deigned to critique their philosophy at all, but there was one very valid criticism concerning yields: while I had compared weights of different crops per acre, a more useful approach would be to compare calorific yield. Doing this for the crops I listed gives a result looking something like this:

Crop                         tonnes/ha                 Cal/100g              m cal/ha

potatoes                           40                                  70                        27

wheat                                 8                                  333                        26.6

hazelnuts                       3.5-4                             646                       25.8

Sweet chestnuts             4.75                             200                        9.5

Corn (US)                          10.5                               360                       37.8

apples                                  44                                50                           22

As you can see, hazelnuts do perform extremely well on this score, having a very high calorific value, but as explained in the article, in a forest garden, the trees would be at wider spacing and the yield per hectare would be lower as a result.

As was pointed out to me by one commentator, apples score very high, comparable to wheat and potatoes and coming in behind only US corn (maize). Can apples substitute for those foods as a staple crop? For a food to be classified a staple it requires not just calories but high levels of macronutrients including proteins and oils; so I do not think we would thrive on a diet of mainly apples, although the person who pointed this out to me was adamant that we could and indeed should, precisely because they are a tree crop. An original argument for sure, and not one I have heard before in any of the forest gardening literature. Once again, though, the yields cited are from conventional apple orchards, not forest gardens.

Most of the other critiques were based on misunderstanding the article (aka not reading it properly!). The whole issue of yields was questioned- why am I comparing yields from tree crop monocultures- we know that forest gardens produce far more than they would, even though there is no data! This is of course the whole point: unless anyone has any better ideas, the use of tree crops as a proxy makes perfect sense, as they will almost certainly be producing the staple crops with the highest yields (and the most calories)- but they will not be achieving such yields in forest gardens, and indeed one of the best known forest gardeners, Martin Crawford, grows his nuts in a separate orchard, with nothing but mown grass beneath the trees.

Not everyone on the permaculture forum took the same defensive line- one commentator asked “So who ever said it was a good idea to grow vegetables under trees anyway?” implying my whole article was a straw man, apparently missing that I had carefully quoted directly from the principle authors in Britain and America who  advocate this kind of system. Again, the question of yields is important since these authors- Jacke, Whitefield, Hart, and the UK Permaculture Magazine, really do position forest gardening- including growing vegetables under the trees in a multi-storey system- as a sustainable and viable alternative to modern industrial agriculture.

Another recent permaculture author who makes similar claims- not specifically for forest gardens but for general systems based on perennial woody agriculture- is Mark Shepard. There is an interesting review of his book here, coming to similar conclusions to myself, and further commentary here on the issues of perennials vs. annual crops.

Another commentator seemed indignant that I was not only critiquing Hart’s invocation of a new “Age of Gaia” but also, apparently, that I completely discredit ecology aswell. They did not say exactly where I do this, but I guess it might be in the section on systems and complexity, where I cite to Gleason’s 1926 paper The Individualistic Concept of the Plant Association. Far from  dismissing ecology as a science, I am here quoting one of the most fascinating chapters in the history of this young science, the famous Clements-Gleason debate. The earlier view- originally from Tansley who coined the word “ecosystem”- saw nature as best represented on the community level, with more or less fixed boundaries around ecosystems and communities of plants and animals who had co-evolved over long periods of time. This was promoted by Clements and became the dominant paradigm, but later gave way to  Gleason’s view of nature more as a continuum, in constant flux, with no fixed boundaries around communities.

I suggested by the response above, the permaculture community has not moved on with the new paradigm. It is certainly this old conception of nature being in a state of balance on which the whole philosophy of permaculture rests- which is precisely why forest gardens, based as they are on the adage of “copy nature”, are still considered so important. Hart explicitly takes this further almost into the realms of religion with his Gaia quote, but so do many others in the permaculture community-  as indeed I did once myself. Even Clements probably never saw natural systems in this way. Forest gardens are however largely entirely novel systems, resembling nature only in structure and function and relying on previously untried assemblies, mixing wild, “native”, exotic and domesticated species together, so it is questionable to what degree they could be said to be “mimicing nature” in any case.

The Clements-Gleason debate is still ongoing, and demands an essay in its own right- perhaps I shall return to it as some point.

Finally, some conspiracy theories were spun around my essay, with comments along the lines that my real intention was to make a hatchet job on permaculture in an attempt to justify modern industrial farming. I have no hidden intentions, but simply wanted to explore the origins of the forest gardening idea and consider theoretical reasons why it is unlikely to meet the claims being made for it from within the permaculture community. Certainly, if it really held the promise being made for it, everyone would be doing it, but as I point out at the outset, despite some 30 years of promotion, the concept has failed in any way to capture the interest of more than a handful of farmers. The undeniable fact that there are costs and externalities for industrial agriculture does not mean that forest gardens- or even agroforestry- are necessarily a viable alternative solution.

More interestingly from a sociological point of view is the question as to why they are still so popular (within the permaculture fraternity) as an idea, with so much being claimed for them, when for the most part what are actually planted as forest gardens here are little more than orchards with a few herbs and soft fruit bushes, with even the most enthusiastic advocates getting most of their produce from more conventional annual vegetable beds. It is relatively easy to create wildlife gardens, or low-intensity food gardens that are also great habitat, and require few inputs, but for the time being at least it seems that the low-input high-output garden remains an appealing but unattainable dream.

 

 

 

Permaculture and the Edible Forest Garden: a Critical Analysis

I’ve been interested in the edible forest garden idea for over twenty years and have planted and designed several myself in Ireland in that time, and visited several others. But they have never lived up to my expectations and were largely unproductive, despite sourcing as many perennial vegetables and other interesting edible plants as I could. Here I review the claims made for them and what evidence there is to support the idea- and conclude that, as Permaculture founder Bill Mollison said in the first place, in temperate regions you are far better growing your fruit trees and vegetables separately.

Temperate permaculture– is this a passing fad, an idealist’s hobby or is there a case for wider promotion of the practice?

• Introduction- Design By Nature: Permaculture and the Forest Garden Concept

 “Permaculture” – derived from permanent agriculture – is a concept of sustainable land use and design coined and developed by Bill Mollison and David Holmgren in 1974. Mollison defined the concept as:

The conscious design and maintenance of agriculturally productive ecosystems which have the diversity, stability, and resilience of natural ecosystems

 (Mollison 1988).

 Since then, permaculture has grown into a worldwide movement of activists and designers applying permaculture principles to the whole of society (Holmgren 2002). Permaculture is more an approach or philosophy than any specific technology, but where it has come under academic scrutiny, many of the kinds of practices frequently advocated have been found lacking in supporting evidence (Chalker-Scott 2010).

In this essay we shall focus on one of the best-known expressions of permaculture design, the edible forest garden or food forest for temperate regions, which are designed with the intention of mimicking the structure and functions of natural woodlands. Successful integration of trees with agriculture for multiple environmental and crop protection functions, nitrogen fixation and fodder is well established in traditional systems in many parts of Europe (Rigueiro-Rodriguez et al 2009), and is gaining renewed interest today as an essential part of agricultural sustainability. It is worth examining why, then, while forest gardens continue to be popular amongst the permaculture fraternity and the sustainable food movement, they have attracted little academic research, and very little uptake by farmers, orchardists or market gardeners. As we shall see, evidence to support the claims that forest gardens achieve both low inputs and high yields is lacking, and there are good theoretical reasons why the concept is unlikely to succeed in temperate zones.

2. Definitions, Origins and extent of current practice

 Edible forest gardens –also known as forest gardens, woodland gardens, food forests or analog forests have been defined as “a perennial polyculture of multi-purpose plants” (Jacke 2005) and are comparable to the multistory agroforestry systems common across the tropics known as homegardens (Kumar and Nairn 2006). Robert de J. Hart is generally credited with being the first to bring the concept to Europe in the 1980s when he started the UK’s first forest garden in Shropshire (Hart 1996). He cites as his influences Smith (1950), Yeoman (1971) and Sholto Douglas (1985), and his work in turn went on to influence Patrick Whitefield (1996) and Martin Crawford (2014) in the UK and Jacke and Toensmeier (2005) in the US.

Based on the definitions used by the authors cited above, for this essay we will define edible forest gardens as:

Gardens which are primarily or entirely perennial polycultures, containing at least three identifiable vertical layers of food-bearing plants including trees, shrubs and perennial herbaceous understory.

 This definition differentiates them from both annual vegetable gardens as well as other well-established agroforestry systems such as broad-scale silvoarable systems, which generally include only one or two annual crops in between rows of trees (Rigueiro-Rodriguez et al 2009).

Crawford (2014) estimates there are some 800 hectares of forest gardens in the UK and lists approximately 160 forest gardens in his Forest Garden Network, including 9 in Ireland, 30 in Europe and a handful in the US. They range in size from small gardens of as little as 50 square meters to smallholdings of up to about 5 hectares, with the smallest area for a “fully functional” forest garden estimated at around 1000 square meters.

Perhaps ironically given their continued popularity in permaculture, Mollison did not himself advocate perennial edible forest gardens for temperate regions. He was well aware that temperate gardening was characterized by annual or biennial seed crops and tubers and by the need to store root vegetables over the winter, and that tree crops are more likely to be for fruit than for staples (Mollison 1988). The academic literature also indicates that temperate gardens have traditionally tended to be based on annual vegetables, often arranged in relatively formal beds and generally requiring full sunshine (Ninez 1987; Vogl and Vogl-Lukasser 2003).

Despite this, Jacke and Toensmeier (2005) cite the ancient practice of coppicing of woodlots for firewood and poles as an example of traditional forest garden practice. However, coppice woodlands are not primarily food gardens, and generally only involve one or two layers, the coppiced hazel and sometimes a standard timber crop. In the UK, orchard trees were commonly grown with an intercrop of soft fruit—blackcurrants or gooseberries—prior to 1955; less commonly some (mainly annual) vegetable crops were included, and there are examples of intercropping between trees with annual vegetables (Kumar and Nairn 2006). One of the few examples that do meet the definition of a three-layered system included asparagus as a perennial vegetable (Newman 1986, citing Fekete 1958), but apart from these cases it seems unlikely there was any widespread traditional practice of genuine three-story perennial edible homegardens in Europe or the US.

In a recent effort to correct the dearth of research on edible forest gardens, the UK Permaculture Association began a 10-year forest garden trial in 2009, publishing a baseline survey of 117 forest gardens in the Europe and the US in 2013 (Remiarz 2013, 2014). The oldest sites were started in the 1980s, with the majority starting since 2000. Nearly half reported that “food self-reliance” was their main objective, with the majority saying this has been largely achieved, though what proportion of each gardener’s food requirements was met is not quantified. In fact, the species lists suggest that in reality the crops grown in most of these forest gardens differ little from the fruit and green vegetables typically grown in traditional home gardens from the 1950s (Ninez 1987).

This apparent mismatch between aspirations and practice requires some explanation: why are forest gardens still believed in and promoted—at least within the permaculture fraternity—if the practice falls so far short of expectations? To answer this we now consider the philosophy of copying nature underpinning the forest garden concept.

3. Philosophy: Return to the Garden?

 Along with other more recent influential permaculture writers (Crawford 2005, Jacke 2010), Hart (1996) saw planting forest gardens as not only a practical way of growing food but also about ushering in new ways of living and seeing the world:

My mini-forest is the culmination of many years’ study and practice of the system that has come to be known as Agroforestry or Permaculture, and which many people, including myself, believe has a major role to play in the evolution of an ‘alternative’, holistic world order. A Green World. The World of Gaia.

– Robert Hart (1996)

The belief underpinning permaculture that “nature knows best” and agricultural systems are best shaped in the image of the natural world stems from the “organismal metaphor” proposed in the early 20^th Century (Clements 1916), seeing ecosystems as behaving like a “super-organism,” and on Odum’s cybernetics, seeing ecosystems as analogous to machines (Odum 1981, cf. Holmgren 2001). Conservationists such as John Muir then popularized these ideas of an ideal state of “natural balance” for both nature and man (Marris 2011), but while still a dominant idea in both popular culture and much environmental policy (Botkin 2012), most ecologists today see natural systems as being characterized by continual change and adaptation rather than any ideal state of stability, and some suggest that the ecosystem concept itself may have outlived its usefulness (O’Neill 2001).

Permaculture and other alternative approaches to farming are rooted in the post-1960s counter-culture’s beliefs about the need to prepare for an inevitable collapse of industrial society and a consequent return to subsistence farming (Gold and Hanover 1987). Botkin (2012) traces this idea of a “Fall” and “Return to Eden” back to the roots of Judeo-Christianity, a powerful metaphor that also helped shape early ecology and environmentalism. Perhaps these deeply held cultural beliefs help explain the ongoing interest in close-to-nature approaches to farming such as forest gardens, which are seen as a way of restoring a presumed ideal state of natural balance that humans have disrupted by clearing the forests and tilling the land.

4. Design Principles: Diversity, Complexity and Balance

There is a common-sense appeal to the permaculture concept of mimicking nature. Unlike a conventional annual vegetable garden with its ongoing needs of digging, weeding and applications of fertilisers, forest gardens are intended to be self-maintaining, with minimum inputs or labour, and to function with the diversity, complexity and the perceived “balance” of a natural woodland while conveying the following advantages (Hart, 1996; Jacke 2005; Crawford 2010):

• the trees make use of vertical space which in principle would allow more food to be grown in the same area;
• perennial plants don’t require annual tilling of the soil and planting of new seeds;
• the diversity of polycultures should reduce problems with species-specific pathogens;
• mulches and nitrogen fixing plants, common to other agroforestry practices obviate or reduce the need for fertilizer applications;
• diverse systems are more resilient due to greater complexity;
• forest gardens have multiple functions and yields including therapeutic and environmental benefits.

Taking each in turn we can establish theoretical explanations for why these principles in themselves are insufficient to make forest gardens viable as alternative food production systems.

Vertical space

 Yields from tree crops are limited by a trade-off between yield produced and the energy used by the tree itself in maintaining its woody structure. In addition, while yields increase over time as the trees grow larger, they will also produce more shade and roots (which will extend at least as far as the leaves), both of which are likely to reduce the yield of understory plants via competition for light, water, and nutrients. Crawford recommends up to 50% wider spacing than in conventional orchards to allow enough light through to the lower layers, and so most of the advantages of the vertical space are lost. We will compare figures for yields of tree crops and arable crops below.

 Annuals vs Perennials

 Perennials have the advantage of not requiring annual cultivation and planting, and often emerge earlier in the spring than their annual counterparts, but have the disadvantage of being static and not easily changed in response to changing conditions. By contrast, annual crops can reach optimal yields within just one or two seasons, and an annual system is much more flexible in that a different variety or crop can easily be switched to in the event of disease, climate change or even nutrient depletion. Annual grains were the first plants to be domesticated for the very reason that, in setting seed each year, they have lent themselves to dramatic improvements for yield and other traits through plant breeding (Kingsbury 2009).

Monocultures vs polycultures: Diversity and Intercropping

 Diversity is one of the “principles of permaculture” (Holmgren 2002) providing the notional underpinning for forest gardens, yet this diversity may compromise yields. The competition between species has already been noted. Also, polycultures lend themselves less to mechanization of cultivation and harvest, and nuts that fall from trees are likely to be lost in any groundcover vegetation. However, some researchers have pointed to the work already done on intercropping—traditionally practiced around the world—as a basis for promoting more complex polycultures such as forest gardens (Gowland 1996; Watson 1998). Resource partitioning (soil and light), the ability of combinations of crops to access more soil nutrients than monocrops, and modification of the microclimate, have been shown to increase yields compared to the individual crops grown alone. (Vandermeer 1989, Innis 1996).

While intercropping has also been shown to increase yields in relatively simple silvoarable systems such as vegetables between fruit trees (Newman 1986), Vandemeer also found cases where yields were lower if inappropriate crops were chosen. Whitefield (2013) was also aware of this, pointing out that the largest gain from intercropping is gained from the first crop addition and is likely to decline with the addition of each subsequent crop. In a review, Denison (2012) found that achieving optimum spacing in intercropped systems was difficult, and that while intercropping increased yields compared to the average of the two crops, they were often still less than the best crop grown as a monocrop. Thus, for many farmers the pragmatic choice was to grow the single best yielding crop alone.

The apparent lack of variety in the crops we eat is also cited as a reason to prefer forest gardens over conventional agriculture, but there are good reasons why only some crops have been adopted apart from ease of improvement breeding mentioned above. Being readily storable and transportable, corn, rice and wheat alone account for nearly half of humankind’s calorific intake. Another reason is pollination- a crop suitable for agriculture requires reliable methods of pollination to produce good yields, and so these grains tend to be either self-fertile, pollinated by many different insects, or wind pollinated, in contrast to many other plants that have co-evolved with specialist pollinators (Warren 2015).

Efficiency: inputs and outputs

Along with Jacke, Crawford (2014) argues that it is the efficiency of the system that acts of a measure of sustainability, not the total yield. He claims that modern agriculture often achieves an energy return of 5:1, and sometimes less than 1, with more energy going into the system than coming out, while forest gardens can achieve as much as 40:1. Even if this were true in terms of absolute physical energy- it is not explained how these figures are arrived at- fertilizer accounts for only about 2% of global energy consumption and farming without it would be far more labour-intensive and require up to four times the land to grow the same amount of food (Smil 2011). Thus, while low-input systems may be less dependent on fossil fuels overall, this advantage is vastly outweighed by the land-sparing benefits of continued increases in production from modern agriculture.

Systems, resilience and complexity

 Permaculture advocates the importance of the number of connections between elements in a design, arguing that such diversity of interactions leads to greater resilience: if one synergistic relationship breaks down, plenty of others are there to pick up the slack and prevent system failure. Natural systems are presumed to be in a natural “balance” which can easily be disrupted, with a change to one part unbalancing the whole system

Yet according to Denison (2012), an evolutionary perspective applied to agriculture reveals that natural systems have evolved more by chance than by any design (Gleason 1926) and that the defining unit in terms of function, adaptability and resilience is the individual species and not the system as a whole. Plant assemblies in nature may be as malleable as in a designed garden, readily incorporating newcomers in the form of aliens, invasive or naturalized plants and often continuing to function well even after the loss of many native species (Wilkinson 2004).

Multiple functions- habitat and therapy

Other kinds of “yields”, such as the aesthetic and therapeutic value of gardening and working close to nature, are often cited as highly valued reasons for promoting forest gardens (Hart 1996; Jacke 2005). There is no question that these are important aspects of gardening, but may be served as well if not better in other ways. Urban gardens, though not primarily for food, already provide habitat for a wealth of biodiversity (Goddard et al 2010). Equally, there is good evidence that gardening and gardens have great therapeutic value (Haith 2015) but again, there is no reason to suppose edible forest gardens will significantly add value to this.

5. Yields- Land Sharing or Land Sparing?

 Despite absence of data, claims for high yields produced in such temperate permaculture systems can be extravagant (Sustainability Centre 2015). Hart (1996) for example states that “the forest garden is the most productive of all forms of land use”, supporting some of the most densely populated countries on earth. This might be plausible in tropical climates, at least in terms of total biomass production if not food yields, but the limitations of light and the relatively narrow range of productive tree crops available in temperate zones make this an unlikely scenario for the UK.

Comparative yields of staple crops

In the UK, most food produced in forest gardens is fruit or leafy green vegetables. Yet for forest gardens to prove their worth in production terms, they need to compete with other staple crops with high value of protein and carbohydrates. The main option for tree crops here is nuts.

Cobnuts (hazelnuts) can achieve yields of 3.5-4 tonnes/hectare 8-10 years after planting (CALU 2006), walnuts potentially 1tonne/hectare and sweet chestnuts up to 4.75 t/ha (Crawford and Newman 2006). This is still a long way from typical UK yields for barley and oats of 5-6 t/ha or wheat over 8 t/ha (DEFRA 2014). Potatoes can yield over 40 t/ha  (FAOSTAT 2013) -assuming 80% water content, this would equate to 8 t/ha in dry weight.  These best-case values for nut trees in the UK are not found in forest gardens with a complex understory, but generally in monocultures. Additionally, nut yields in the UK vary from year to year and are vulnerable to poor weather during pollination or early wind-fall (Crossland 2013) and hence are unlikely to grow much beyond their current niche market.

Discussion of yields is important because the driving rationale of the forest garden is that modern agriculture is unsustainable, laying the blame at the feet of monocultural systems based on annual grains and pulses. However, despite often well-founded fears of soil erosion and nutrient depletion, global yields of these crops continue to increase through improved varieties and technology (Ausubel et al 2012; Grau et al 2013). Indeed, total land used for agriculture may have already peaked (Our World in Data 2015) as a result of ongoing improvements in efficiency, and substantial area of land has been “spared” for nature as a result (Stevenson et al 2010). This dramatic and sustained increase in agricultural productivity over the past century has resulted in only 2% of the population in the U.S. being required to farm (AFBF 2015). In these respects then, modern farming is arguably more resilient because of its continual innovation and adaptability.

 6. Conclusions

 The three—or more—layered perennial edible food forest we have examined here is an attempt to improve agriculture and food production by mimicking nature. What works well in the tropics however does not seem to work well in cooler climes. While interest and research into sourcing promising novel crops and new cultivars from around the world continues, most temperate forest gardens seem little different from the fruit gardens and orchards commonly found in Britain prior to the 1950s.

Temperate forest gardens do offer great potential for further research on plant interactions within multi-strata perennial systems, and there is great scope for improvements in cultivars of many tree crops. A warming climate may offer a greater range of possibilities for novel crops to be grown in the UK, as is being tried, for example, by Otter Farm in Devon where they are now growing olives and almonds, but it is as yet unclear whether multi-tiered systems will provide any significant advantage.

Despite the lack of promise forest gardens show in becoming a viable alternative to industrial farming, the ongoing interest in permaculture philosophy together with public concern about sustainability will ensure that they continue to be experimented with by enthusiasts. The myth of the need to return to a “balance with nature” remains a powerful influence in many areas of public policy well beyond the permaculture movement and will continue to shape ideas about food, farming and conservation for a long time to come.

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