In part one of this four-part series, I discussed the colonization of brownfield sites in the UAE’s cities with a range of trees and shrubs – almost all of them “exotic invasive” species. I argued that these could be forming the basis of new, adapted ecologies. To revise those arguments, please the link at the end of this article. The next question is, once we accept this premise, how do we create these new ecologies as a conscious expression of our own adaptation to climate change?
First, let’s understand that we need these landscapes to be unirrigated. Why? Well, in the Middle East especially, water is a precious resource and expensive; the UAE is particularly bad, with a per capita use of 550 litres/day. So with landscaping, let’s keep the irrigation for the urban centres, parks and gardens. If we just focused, for example, on all the miles of roads and interchanges between Dubai, Abu Dhabi and Al Ain that are irrigated, and imagine these replaced with unirrigated greenery, the water saving from this alone would be massive. Yet that is an immense challenge, for as soon as you plant something in a desert, you must water it.
If we want a vibrant plant ecology, then we also need a vibrant soil ecology, something that conventional landscaping ignores completely
I think this is the key, that planting in such a climate rarely establishes without help, whereas seeds can. What we need therefore, is a methodology of establishing and maintaining, seeded landscapes.
It is true that in a scenario where we are consciously creating an unirrigated landscape, we would want to greatly increase the odds of establishment. In this respect, much detailed assessment would need to be given to soil amelioration. If we want a vibrant plant ecology, then we also need a vibrant soil ecology; this is crucial and something that conventional landscaping ignores completely.
Can we create a healthy soil, rich with microbial activity and naturally water retentive in such an arid climate? I think we can, but we must first change our thinking from one of assisting landscapes with external inputs (irrigation) to that of creating self-sufficient ones, with cyclical, living, self-sustaining ecologies. Soil becomes the vital kingpin in all this, not just an anchorage medium for plants.
Native soils need to be worked with, not replaced. They can be moderated, made more moisture retaining, but basics like salinity and pH will always dictate plant choice. First and most important, is to increase the soil’s water retention capacity. There are a number of ways to do this, involving additives which may incorporate clays, granules or other water-holding mediums and we know that when used in irrigated landscapes, they can reduce water demand by up to 50%. Given that an unirrigated landscape might have periods of time when it is extremely dry, we need a medium that doesn’t become hydrophobic if it does dry out and that will react swiftly to absorb water when it does arrive.
We can also inoculate the soil with mycorrhizal fungi cultured from local, healthy environments to enhance soil micro-ecology; there is little point in importing this from another part of the world, as the relevant strains of microbes are likely absent. Microbes and bacteria are the essence of good soil. Many of the plants used will be nitrogen-fixers, and so live in a symbiosis with certain bacteria. They also make nitrogen available to other species, as cycles of life and decay build up.
Organic matter is also essential, but perhaps the most problematic element as it is in short supply. One aspect of the practical usage of such landscapes, and a part of the long-term management, can be the coppicing of trees and shrubs for biomass to make compost. Organic matter tends to oxidise if conditions are not conducive, so we need to get things right, but I’m sure that even desert soils can sequester carbon, given the right conditions.
We would need to mix these various elements into the soil to the appropriate depth, perhaps a metre, probably by air injection, and possibly to different depths for the different mediums. Soil preparation becomes the most major, one-time investment in the land but will pay back endlessly over the lifetime of the landscape.
Once the preparation is done we have to seed the land, when conditions are optimal (not when contract deadlines require); this would have to be timed after rain, if possible. Otherwise, I would give the land a soaking, with our soil amendments helping to retain the moisture, then apply seed, in a variety of ways, possibly by hydra-seeding. Finally, a locally-sourced stone mulch should be placed over all, to again help retain moisture, but not too thick to inhibit germination. This would be the entirety of the preparation and installation work.
Next is the nurturing stage, followed by on-going management and maintenance; this will be very different from a conventional landscape, but no less intensive, at least for the first few years. It may be beneficial to give additional watering to aid plants as they germinate and establish, but this must be done with care, or seedlings could be washed away. We would need to give enough to ensure success, but no more.
Once established, these plants would grow at whatever speed the conditions allowed and a new landscape would emerge over time. Thinning out and reseeding of failed areas would be the main work, acts of stewardship rather than maintenance. Prunings shredded and spread as mulch, soils fit to support life, insects, animals and birds would soon make this place their home. The result would be a slow and genuine landscape uplift into the realms of a new and adapted ecology.
How we design such landscapes, choose which plants to use, obtain the seed and know how to maintain them, is the subject of the next article.
A problem, or an opportunity for a new landscape paradigm?
I was recently working on a tree project in Abu Dhabi when I came across a derelict site which intrigued me with it’s range of exotic self-seeded, non-native plants. The site was next to the Corniche and sandwiched between the Formal Park, my hotel and Capital Gardens. It struck me initially as the perfect basis of a xeriscape, as all the plants (mostly trees) were thriving without irrigation. On closer inspection and identification of the species involved, things got more complex and raised a lot of potentially conflicting thoughts and issues.
A natural Xeriscape
The site was clearly awaiting redevelopment and the plant invasion was opportunistic. Nothing that I could identify was native, yet all seemed happy there. When you see the list, you might understand why. Amongst the plastic and litter I identified:
Of those plants, the P. juliflora was the most robust and when you look at its reputation, that is of no surprise. It was of landscape scale, lush and greener than anything in the adjacent parks. It’s form, leaf, flowers and seeds are attractive from a landscape perspective. Yet this is undoubtedly the most controversial plant on this list – some would say alarming. A Native of arid zones in central and South America, this was, like so many others, introduced into the UAE in the 70’s as a forestry plant. Lauded as something of a super-crop tree, it is tenacious, vigorous, provides fuelwood and stock-feed in the form of abundant seeds. The latter, it turned out, were a problem in that they are spread by cattle and are extremely aggressive. Plants also regenerate rapidly from the roots when cut back and they reputedly produce biochemical inhibitors to suppress competition (allelopathy). With no natural competitors in the UAE and roots that can descend 50m in search of water, they out-compete native flora, even their cousin, Prosopis cineraria (ghaf tree).
Prosopis juliflora flowers
P. juliflora has a low, mounding habit, attractive from a landscape point of view.
Also on the site were a number of Banyan trees, Ficus benghalensis, which seemed to be growing happily. Another tough survivor, it should be borne in mind that the water table here is likely only a metre or so below ground, although it will have a high saline content.
Then there was Eucalyptus camaldulensis , another forestry/amenity introduction of the 70’s, also known and now generally avoided for its aggressive roots, yet here looking beautiful with its grey, lanceolate foliage. This was the tallest tree on site.
Eucalyptus camaldulensis , showing adult foliage
Of course, there was the ubiquitous Conocarpus lancifolius, widely planted still yet also recognised and a danger to any nearby drains, and on it’s way out in popular use. Except it does make such a good tall hedge, and it has a much nearer native origin, coming from Somalia, Djibouti and Yemen. I’m not sure that the UAE landscape industry is ready to ditch it just yet.
There was even a palm, Washingtonia robusta, self-seeded around the place. Much of it was to be found growing underneath the canopy of the P. juliflora, so that at least is not put off by any allelopathic biochemicals from the Prosopis.
I believe this legume is Sesbania sesban, more commonly seen with yellow flowers. Rose-ringed Parakeet
Inhabiting, or at least visiting the site, was a Rose-winged Parakeet. Another exotic invasive with beautiful form but aggressive tendencies; it seemed appropriate to the moment, somehow.
What does this mean for future landscapes and ecology?
From a conventional ecology point of view, these plants are all threats, and the threats probably outweigh their usefulness. So why am I even talking about this? Clearly, the move towards more naturalistic landscapes draws heavily on native species and would shun all of these species.
Except we have climate change.
Climate change is the elephant in the room, when it comes to ecology, in fact when it comes to sustainability generally and a livable planet overall. That we have already moved beyond vital tipping points is highly likely; that climate zones are moving away from the equator at a rate too fast for nature to adapt is a fact. Flora and even some fauna just can’t move regions that quickly. They will adapt, eventually; but those that are rare, specialist and struggle with change, will die. The tougher generalists will adapt and survive. Nature will build a new ecology to reflect the new reality, and it doesn’t mind if it takes a few thousand years to do so. Only we humans mind and so, if we are to survive, we must adapt our environments to fit the new reality. It is a sad fact that many cherished plants will eventually die out or move zones. In the UK, I dread losing our native oaks (I view these as our ghaf tree equivalent), yet we may get Mediterranean species to replace them, such as holm and cork oak.
If you are already positioned in the arid equatorial zones then you have precious few plants that will form your new ecologies and landscapes. Perhaps the plants I have described above will be UAE naturalized-natives in 100 years’ time and the ghaf and sidr may be gone, or diminished, or moved north. I hope not, but before we spend vast fortunes on eradication and control of non-natives, we should look to the future. These aggressive invaders may just form the landscape of our children; I know I’d rather live with a landscape, than none at all. If there is no landscape, there is no life. They may, in fact, be here to save us.
Once we grasp this fact, we can look at building new landscapes to suit our changing environments. I’ve written about this before and you can read the articles listed below. We must be vastly more holistic in our thinking in order to do this and broaden our horizons to understand the new future. Technology will help us to monitor, collect data and produce working strategies. Robotics and drones will help manage and control plant communities. Alongside that, we need a vastly better understanding of soils, microflora and fauna, for the bit of nature that we see is just, literally, the tip of the iceberg. The selection of tree and shrub species for adaptation is easy, we get this wrong when we don’t deal in whole context thinking eg. only thinking of forestry or ornamental benefits.
The challenge ahead is huge but in a weird way, exciting; it will challenge the human race to grow. There’s a whole new science to develop and we’d best get on with it.
According to Google, the site has been cleared some time in 2019:
In my previous post I talked about a regenerative planting methodology for urban landscapes, in which I suggested you would manage, rather than maintain your planting areas. So how exactly do you you do this? Both involve work and the difference is a subtle but important one, in both attitude and application. Think urban forester rather than garden pruner. The picture above illustrates this perfectly, so let me explain.
It shows two hazels in my garden, both planted as young bare-root trees in the winter of 07/08. The one on the left was coppiced down to the ground in the winter of 12/13, the other has been pruned to keep a structure of older wood, with all suckering growth removed annually. What is the difference? The coppiced hazel has been less work overall and has not been touched since it was coppiced, the pruned tree has been pruned annually, which was not great amount of work but this is just one tree. If there were a hundred, it would be a different matter. The main difference is that the pruned tree has catkins, the coppiced tree does not, but I think this is a difference of genetics, rather than pruning technique, as they have always been like that. The shape of the pruned tree is also wider in its spread and will become gnarled as it gets older.
So in terms of management, if you go the coppice route you do nothing much to the trees except coppice them every 4-5 years. I would suggest that 50% of the trees are coppiced so that not all structure is removed at once. Notice that the growth of the coppiced hazel is straighter, making for a productive yield of canes and poles that can be used in the local community. Other trees that can be coppiced include sweet chestnut, lime, alder, ash, willow and hornbeam. Birch and oak will coppice, but from young trees only. Willows and dogwoods grown as bushes for their winter colour can be coppiced or “copparded” (inbetween coppice and pollard) to around 300-600mm every two years to keep the winter stem colours strong.
Salix elaeagnos (foreground)
By adopting such techniques in our larger masses of urban street planting and parks, we would deliver a more biodiverse, beautiful and biophilic interaction for all concerned. It would also cost less both to establish and possibly to maintain, than traditional planting. The above willow is beautiful and graceful, yet I have seen it all too often used in municipal car-parks and reduced to a-n-other shrub that is caressed all to frequently with the indifference of a hedgetrimmer.
Time to re-wild our inner selves, and our urban landscapes. We can do so much better than the average landscape we see in our towns and cities.
Almost all urban landscapes are contrived and designed, due to their artificial nature and short timescales of development and use. We see increasing use of mature rootballed trees and extensive hard landscape and this is normal for intense inner urban areas; I do get concerned that the increasing complexity of urban planting systems divorce trees particularly from their natural functions and prevent the occurrence of the biological interactions/communities that go to make up an ecosystem. For example, I have seen trees planted whose surface levels are around a metre below the surrounding paving level. No matter how well designed, this seems fundamentally wrong to me.
So I’m thinking that there must be a way of dealing with the majority of less intense landscape zones (especially where there isn’t the financial budget that a high-end development attracts) to provide urban regeneration, ecological restoration and biophilic connection, all on a modest budget. This would create a new method to allow for wide-spread adoption in urban and suburban zones. I think the solution comes from Nature’s own process of natural regeneration and a developed philosophy of minimal (but specific) preparation.
silver birch are pioneering species for natural regeneration
Starting from the observation that Nature is very efficient at regenerating itself, what can we do? Too often, I have seen unnecessary interference in this process. I still recall that a few years after the great storm of 1987, I walked through some nearby National Trust woodland of pines and birch. A great deal of damage had been done with many trees blown over. Birch had however, regrown abundantly from dormant seed and was already three or four foot tall. The NT then sent in the bulldozers to clear out the fallen wood so the area could be – replanted. I watched them tracking over all the natural regeneration. Why didn’t they just leave well alone? The restoration of the woodland was only slowed down by such clumsy interference and this was not even a productive forest.
If we simply broke up paving in our urban centres and loosened up the sub-base, what would happen? Nature would soon find a footing and things would start to grow; however, that process would be too slow and unpredictable for human sensibilities. So what if we did a little more, adding a small amount of topsoil to the rubble, planting small (1+1 year transplants) bare root trees and shrubs, with plugs of understory forbs, ferns and grasses. Starting so young, we’d generate a successful community in no time. These could be designed as narrow ribbons – two to four metres wide, inserted into suitable wider areas of paving.
An urban area suitable for natural regeneration
The above area was one I thought would be suitable for such an approach; there are many such areas throughout all urban spaces. They cry out for regeneration, yet seldom can this be done for lack of adequate finance. Below is a quick sketch showing how it might look.
Sketch showing regenerative planting
The benefits of such an approach would be huge. It would cost far less than using a traditional approach to landscaping such an area, maybe half (I haven’t costed it!). The care would move from maintenance to management, using a rotational coppice methodology, rather than trim and tidy (which always ruins a plants natural habit. Biodiversity would be hugely enhanced, air pollution mitigation would increase, wind buffering, urban heat island reduction, stormwater runoff (they would act as rain gardens) and of course, our biophilic needs, our connection to nature.
I have been lucky enough to have designed and built a lot of water gardens in my time; I’ve been looking back over some of my pictures, and thought I’d share them here. Working with water is like nothing else; it is enigmatic, frustrating, contrary, exciting and absolutely rewarding in a way that few other mediums can be.
A Naturalistic pond with simulated wetlands and planting
Pond bio-filters clean the water, naturally
A stream runs down to the pond
A stream runs through a gravel-garden
A bridge of sleepers over the stream
A gentle waterfall emerges from within willow bushes
I was chatting to the local farm manager the other day, out on the snow-lined track. “There’s nothing in the hedgerows for the birds” he told me. It made me glad that there was in my garden, which borders the track and fields. It also brought home such a startling truth: the birds need us and we need to garden for them, and that means for the whole food-chain.
A Robin sits on one of our Wayfaring Trees – Guelder Rose, or Viburnum opulus.
The picture shows a Robin; but they don’t eat the berries; Blackbirds and Thrushes do, at least around here. I’ve been wondering why, since the berries were first produced in Autumn, they hadn’t been eaten; perhaps they were saving them for harder times, maybe it is not their favourite, but it is there, they are eating them and so surviving. I’m so glad that a planting choice I have made has made a tangible difference to the birds. Although native, Guelder Rose does not naturally grow on the south coast, so perhaps they simply hadn’t discovered the fruit – but they have now and the bushes are almost bare. To me, this is the best reason to garden for wildlife; the simple rewards are better than almost anything I can think of…
I’ve been doing a lot of research since writing my blog post on trans-migrational landscapes, my theory on how we have to adapt our natural environments – or rather, help them adapt – to combat the rapidly increasing effects of climate change. It’s not going to be easy; right now I’m not sure if we can do it without making a complete fudge of things, or if we would simply be making matters worse. I’ve just read this article in the Telegraph, which would seem to agree with my idea, but as some of the comments after point out, it’s the insect and microbial ecologies that count; many of our native population just can’t live on non-native plants.
I’m also reading a book by ecologist Douglas Tallamy, called Bringing Nature Home; in which he talks eloquently about these problems, about the environmental collateral-damage caused by horticulture and agriculture. That plants, insect and fungi go rogue is understood; that they might only do so after 80+ years of benign cultivation and growth in a new continent is astonishing. Alien plants displace more fragile natives and they can rampage, simply because they are not subject to the checks and balances caused by a predatory ecology. What we, as gardeners, admire about an introduced plant – that it doesn’t get eaten by “pests” – shows that it is ecologically barren, is not taking part in the local micro-ecology and so is not being transformed into higher trophic levels of being, ie. into the higher food chain of insects, birds and mammals.
So if, as Tony Russell suggests in his Telegraph article, we were to plant non-native woodlands, they would become ecologically less diverse as a result, even if the trees were better able to grow in an altered climate. So should we then introduce all or some of the microbes and insects that naturally live in such trees? That could be very dangerous, with results that are entirely unforeseeable. Of course, we might have to gamble as the climate gets more and more extreme and moving Mediterranean ecologies to Southern England might save them as they die out in the place where they have evolved to live in.
My fear is that we are not smart enough to understand and control (as if we ever could) such a process, my hope is that we could take the issue seriously enough to learn how to do this successfully. We will need it, if we are to retain useful and beautiful ecologies on which we depend for our survival. Nature doesn’t need it, because she won’t mind taking a long, LONG, time to rebuild things…
With the climate shifting now so rapidly that we cannot foresee what the future may bring – or rather, with an ever increasing certainty of life as we know it struggling to survive – do we need a new approach to our understanding and management of our natural landscapes? I think this will become inevitable and that this idea needs to become a proactive rather than reactive measure.
A quick look around the globe shows Arctic ice melting at unprecedented rates, massive flooding events (in Bangladesh recently 20m people were displaced), increased hurricanes (h. Sandy), both in frequency and strength, desertification through deforestation and inappropriate agriculture and relentlessly increasing global temperatures, to name just a few that come to mind. And we can see effects much closer to home. The UK is likely to lose most or all of its ash trees due to the fungus Chalara fraxinea, which has mutated and migrated from Japan, where it is a balanced part of its ecosystem. Ash trees make up 40% of the UK landscape canopy. This follow from our lose of elms, but oaks have their problems too, as do horse chestnut and and larch, which although not native, are under attack from imported diseases. We have everywhere, a landscape under stress, that cannot adapt to the rapidly changing environments we humans have imposed upon the planet, either from our living patterns or from pollution. Our landscapes are under duress as never before. Vast and rapid change is inevitable and cannot now be stopped. But there is possibly something we can do, and that is learn to help speed up Nature’s adaptations. This would involve actively changing the flora and fauna of our native landscapes, an approach that would not be without risk, but might mean that some kind of meaningful ecology can adapt and survive.
It is clear that to do nothing is to watch our beloved regional and continental. landscapes change beyond recognition. But this would require a sea-change in thinking and current practices. Ecologists naturally resist the introduction of new species, with good cause; the aforementioned tree diseases are with us at least partly because of imported plants or timber. Lists of invasive species and control advice is provided in the UK by the Non native Species Secretariat; but I now think that we are beyond preventing the influx of invasive species and that we must look ahead and ask ourselves: do we want an ecology and landscape in 50 or 100 years time? Of course the answer is yes; we depend on our landscape, body and soul, and we may regret that we were forgetful of that for so long. But we cannot preserve what was, into the future.
My previous post was a review of a book by Bill McKibben, a leading environmental thinker, who says that we now live on a different planet, that it’s future will never be as its past was; he renames the planet Eaarth. We have caused this; if we are to adapt to our future, we have to re-think our attitudes and expectations. We cannot conserve England’s green and pleasant land; it is gone, or going. We must adapt it to suit its future, to build new ecologies, with new species or variants of existing species that are better able to cope. Ironically, trans-migrating species from one continent to another may save them from extinction in their original habitat.
This would be a big challenge; it is easy to introduce a new tree species, but it is the microflora and fauna that come with them that is important, for both the good and the bad. Sycamores are a now familiar part of the British landscape but are non-native and considered invasive. Whilst they are robust and may be well suited to our warmer climate, they are ecologically barren in the UK landscape, when compared to our oaks, which support some 300 + species of life. And this is the crucial bit; nature builds up complex and diverse ecosystems, of which we are still largely ignorant. Thus if we are to be able to do this with any success, we need to learn a new discipline, that of building micro and macro ecologies to suit our new future. If we put the same energy into this as we do GM research, it would be far more productive and useful – but it can’t be funded by private companies; this is our future, not a potential for financial gain.
And whilst we are at it, let’s build a new agriculture, based on perennial crops and trees, all as part of our ecological future. A diverse polyculture of trees, shrubs and herbs which provide a diversity of food, fuel and resources, including wildlife. Such an agriculture (or agroforestry, forest gardens, permaculture) will not be dependant upon fossil fuels, chemical fertilisers or pesticides as it’s perennial; harvesting can be done by hand or machine, and methane from cellulose digestion can provide the fuel for tractors where they are used. Nuts replace wheat and we move to a far more resilient and varied diet, which will make us healthier and give us food security, both of which are in rapid decline. Such annual crops as we do grow will be the domain more of the market-garden, a philosophy which we must revive to give us local food. Who knows, such balanced, wholesome and resilient landscapes might even be good for our soul’s too; certainly peace of mind relies on having a secure life, and we are rapidly losing that, far more than we realise.
So we need to build a new philosophy and practice of trans-migrating landscapes from areas of stress to areas of comfort, to match the shifting of climates zones around the world. It’s quite a challenge but we might just learn some humility and a far deeper appreciation of nature. In fact, we might just finally discover that we are inseparable…