Landscapes are all about creating micro-climate, or would be, if designed for that goal. Why is this important and what do I mean?
Almost all life is contained in a thin crust of soil, a wedge of atmospheric gases, and water. Plants are the principal medium that interacts with and regulates all three. Absolutely nothing else does this as well, or at all; think about it.
The way we organise our plants in our urban landscape will determine how well this interaction occurs, how successful it is. Yet I have never heard of a single project that has been developed with this understanding and this goal in mind. With climate change, we urgently need to re-think the way we design our landscapes, and why we design them. Whilst all the human-centric design reasons will always hold true, we need to layer into our thinking this new understanding of how plants interact. To build new ecologies, new ecosystems, we have to design for plants to actually function, rather than just look nice. For when they do this, our environment literally comes alive. More importantly, they might just, if done on sufficient scale, save us from ourselves.
When I use the word treescapes, I don’t just mean trees and grass; we’ve had that for years in the form of parks, and in their traditional form, they’ve done little for us. No, our designs need to build up layers of living material – biomass, for with biomass comes moisture entrapment, shade, food for insects, etc. Think of it in terms of height and depth of microclimate. How much depth is there in a stretch of irrigated grass, maybe 50mm above ground, 200mm below? No species variation, so what we have is little more than a green desert, albeit one that can hold bit a of moisture.
Trees in paved streets are also less able to generate micro-climate, but they are a bit of an exception, as they provide shade for people to walk under. Where width allows, even here we should layer our planting.
If we replace that grass with a range of groundcover plants – not a monoculture – you begin to get a little more variation; different root structures and depth, different foliage shapes, height, form and flower. More variety, more microclimate, more food source, more ecology. Looks good too.
Next we add shrubs and suddenly we are into an new realm, that of woody plants (I’m being simplistic here, many groundcovers are of course woody). Shrubs create three-dimensional space with their frameworks, within which micro-worlds reside. Deciduous plants shed their leaves, as do evergreens, and this begins to build leaf litter – mulch. Don’t tidy it up! We need ecologies in that soil, and microbes need food. Our obsession with tidyness has a lot to answer for. Suddenly, we have height in our micro-climate, three-dimensional form. We humans (for we scale everything according to our own height and perception) can walk amongst these plants, take part, interact. Our microclimate is now two metres high, maybe more. But something is missing and it’s still too hot…
Trees! Now we have a game changer and our micro-environment just became vast, in relative terms, maybe up to 30 metres, though 10-20m may be more average. We now have true diversity of shape, height, leaf, flower and roots. We have shade! Under trees it may be 10°C cooler and we love it. Plants love it too. Moisture now gets retained within the human habitable zone, fungi and microbes thrive in soils, insects and birds abound. This is our urban jungle and we need it. The planet needs it. This tiny sliver of crust we live on can be rich, abundant, in every climate and every place, if we put our minds to it, if we have the will. And when the planet becomes searing, creating livable environments with trees of any type, may be the only thing that keeps us alive, unless we become troglodytes.
This is the next level of landscape design, the new challenge; creating future ecologies and environments that matter, that keep us cool, that give us resources and soothe our souls. We will create new (novel) ecologies that fit the changing environment, trans-migrating parts of ecologies that once lived elswhere. In that place they may be dying out, as might your local ecology. If they now fit where you live, that’s where they need to be. In turn, that place of origin may itself need to adapt and change. In all things and all places, we need microclimate, shade and soil.
The other side of work I undertake in the Middle-East region (other than tree consultancy) is planting design, for creating new landscapes always brings me a special joy. When they are in public spaces, I love the chance it gives to interact (albeit remotely) with many people in place, over time and hopefully, enhance their enjoyment of that place. In the public realm, what that place is, is being questioned and challenged in the light of urbanisation and climate change. Ecology and environment are driving design as never before.
I am about to start working on a collaborative project in Saudi Arabia. It will involve the specification of many trees, shrubs and groundcovers and I get to find out just how many locally-sourced big specimens I can find that are of acceptable quality. Much of this will come down to the application of formative pruning in the nursery and I’ll be on the lookout for the best available in the region. I suspect I’ll be sourcing a lot from neigbouring UAE, simply because of familiarity of sources. Quality remains a challenge, though.
My most pressing concern I have is how to improve on irrigation techniques, which are traditionally massed surface drip lines onto marginally improved sand. This is inefficient and wasteful and I shall be looking at the use of moisture retention mediums and sub-surface irrigation. I believe most watering of landscapes in arid climates could be cut by half, just by more efficient application and retention, in the right place. The picture above shows typical wastage in a Dubai suburban landscape.
Whilst urban planting requires urban plants, I will also be looking at the use of more climate-adaptive species, which I think is important in an era of climate crisis; the Middle-East is going to struggle to cope with every degree of temperature increase. The use of more desert-adapted planting is not new, and not applicable everywhere but I believe there is much scope for experimentation and new thinking.
For me, planting design is about building communities, layering types of plants together in harmonious associations that fit. I don’t mind grouping plants together that come from different geographical regions, but they have to come from a similar ecological niche. Such design is so much more than just nice foliage contrasts and I believe the results can be subtle, but profound.
Landscape must, of course, fit our purpose but I believe we tend to pursue this end to the exclusion of everything else. Nature is the basis of landscape, and so too is ecology, ecosystem and planet. We should not divorce our landscapes from this reality; rather, they should always seek to remind us of these connections. So yes, in town centres and urban streets, we have our eco-bling landscapes; vibrant places, exotic, heady, purfumed, exciting. Nature at it’s most unbelievably flamboyant (cue pic: delonix, the flamboyant tree). Elsewhere, we need more grounded landscapes, more real, more connected to place.
I love this tree, it is everything I have described above, pure eco-bling. Yet it is not appropriate everywhere and because it has become a part of the standard landscape palette, I belive it is overused, and used in places where other species would be more appropriate. I think there are many trees and shrubs that could be used in the region that haven’t been tried yet, from East Africa, for example. The climate there may be more equatorial and more varied but it is not so remote or different as that of some exotics imported from sub-tropical climates (the Delonix mentioned above is from Madagascar, again not too dissimilar).
I think planting design in the Middle-East faces a whole new range of
challenges and opportunities. The changing climate will force new
thinking, to match the new development and the new understanding that is
emerging of our intimate relationship with nature. I’m hoping to
contribute towards that new expression and understanding.
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:
I’m pleased to have launched a new website and blog dedicated to this aspect of my work. Over time the blog will become a useful resource to all those interested in the care of trees in the Middle-East. My focus and experience has so far been within the UAE but the tree range is similar in most GCC countries. treecare UAE
On my most recent trip to Dubai, I enjoyed walking through some of the new landscapes that emerge as projects are completed. The UAE, along with most regions of the Middle-east has a rather limited palette of plants to work with (although that is growing as new plants are tried). What struck me, however, was how poor the quality of nursery stock was in some cases and what problems are being created for later, especially with regards trees.
This is not new, nor confined to this part of the world but it bothers me that new areas of urban green are sometimes given a poor start with sub-standard nursery stock, often flown in from other parts of the world.
Simple pruning at an early stage would have improved this tree’s framework, removing crossing and rubbing branches.
Wandering around a residential area in Jumeirah, I came across some newly planted Delonix regia, one of my favourite exotic trees. At first glance it looked nice, a simple planting of trees and groundcover but on closer inspection I was somewhat dismayed at the condition of the them. The problems of poor framework were caused by their time in the nursery, not due to planting, although some of them could have been rectified by a vigilant planting crew.
This tree tie – complete with post – must have been like this from the nursery. The post did not reach the ground.
Many of the dozen or so trees had ties left on which the tree had grown around completely, making them impossible to remove. As the planting is only around two years old (by my estimation), these may have been on the trees from their time in the nursery. Possibly the planting was older and pre-dated the building they were attached to and the trees then grew around the ties after planting. Either way, it’s a strong indication of neglect or lack of care. In the picture below, all the bark ridge above the tie may indicate “included bark” – bark sandwiched against bark, preventing live tissue growth and a strong branch collar formation.
The tree tie is trapped with “included bark” at the branch collar, which indicates a potentially weak branch join.
Several problems are arising here: pre-planting care in the form of correct formative pruning (five minutes with a pair of secateurs) and Post-planting care in terms of releasing planting ties – if they were not simply left over from the nursery days. If there is no way to go back and release the ties, a bio-degradable tie should have been used.
This Ficus nigra was most likely damaged long before it was planted in this location.
Damage to the main trunk or structural framework of a tree might go unnoticed when the trees are small but cause major problems as the tree gets older and puts on size and weight. This can range from the cosmetic to the potentially dangerous in a large tree and at this stage the remedy is costly and the expertise hard to find.
As fast-growing cities like Dubai mature, the needs of landscape shift from creation (in a hurry) to maintenance (at a constant pace). Skills, awareness of the need for – and absence – of skills, will become more and more urgent. If Dubai wants to keep it’s beautiful, green mantle, then there is a whole new phase of arboricultural care awaiting to be discovered and initiated. I have carried out trees assesments and given basic training of correct pruning methods in the UAE, but that has hardly scratched the surface; there is a lot more to be done.
Trees are the urban, biophilic, blanket that clothe and surround the concrete mountains we build. Trees make hot places not just bearable, but unbelievably beautiful. Trees absorb dust, cool the air, add moisture and oxygen and enrich our Souls. We need to honour and look after them, so that they can look after us.
This article first appeared in Pro Landscaper Gulf – a .PDF copy can be seen here on page 12. It is based on tree consultancy work I have undertaken in Abu Dhabi in recent years.
Irrigation is taken as a necessity when landscaping in arid climates. It is a view that I wouldn’t like to completely contradict, yet I have seen a fair bit of evidence that tells me many plantings, and trees especially, are over-watered. Of equal importance is the fact that many of the irrigation methods are wasteful of water and sometimes damaging to the trees themselves.
Lawn Watering with sprinklers is damaging the trunk of this Millingtonia
We have to discern the different needs of trees and understand that what is necessary for one species is overkill for another. I particularly speak of natives verses exotics. Ghaf and Sidr you will see growing wild and without irrigation but imported exotics need a regular supply. I have seen Ghaf blown over in irrigated plantings, caused by shallow rooting from an easy water supply.
Bacterial wetwood in Delonix regia caused by overwatering. It also reduces the flowering, for which these trees are famous.
How the water is put on is just as important; pop-up sprinklers in lawns can damage the trunks of trees, causing aerial rooting in species like palm or fig, discolouring bark and causing stress-induced rots to occur in others. Exotics like the Flame tree (Delonix regia) get over-watered, causing a reduction in flowering and a susceptibility to bacterial wetwood (slime flux). Even drip irrigation is not ideal, as it applies the water at the surface and promotes shallow rooting. Trees with shallow roots are vulnerable to drought and so dependent upon the irrigation supply – a vicious circle.
Excess surface irrigation is wasteful.
In the UK, we are used to putting in a subterranean irrigation ring around trees, which gets water to the tree roots at a deeper level. For watering established trees, perforated tubes can be utilised, inserted vertically throughout the root zone and either manually watered, or connected to standard irrigation systems. Supplying water at a slightly deeper level means less water used and wasted. A word of warning though – most feeding roots occur in the top 300 – 500mm of soil, so watering too deeply can also be wasteful.
Tree roots growing along the line of surface irrigation pipes
In coastal cities, problems can arise from a naturally high-level, saline water table. Halophytes (salt tolerant plants) have evolved to cope with this, but for some imported species, salinity can be a problem. You also have to be aware of the quality of the irrigation water itself, which if drawn from the ground, may have a high saline content. Get your water supply tested if you are unsure.
Ultimately, I believe that planting styles and expectations of “landscape” must change. A more natural style, with more xeriscaping and use of natives or other arid loving plants from different parts of the world (but from similar conditions), will emerge. More important, in my view, than using strictly native species, is building plant communities that function and thrive in place without much human care or maintenance. As climate zones shift rapidly around the world, nature cannot keep up and it will be down to us to create landscapes that sit well in their altered environments, whether native or not. I believe we can do this with considerably less use of irrigation. The water we do use should then be grey water (from taps and sinks), which is a much better way to conserve processed water use.
Canopy of Delonix regia
The goal has to be minimal water use, natural, ecologically benign planting and urban environments which feed our biophilic needs for connection to nature.
Zizyphus spina-christi, crown of thorns tree. A native of the UAE
Last winter I did some interesting work in Abu Dhabi, concerning the care of trees. I can’t name one of the projects (a royal palace), but one was Mushrif Central Park undergoing a major redevelopment (and now reopened – March 2015). In both places I undertook a survey of 100+ broadleaf trees (as opposed to palms), assessed their condition and trained staff in basic arboricultural pruning techniques. Such information is lacking out there as most such trees, with the exception of things like ghaf (Proposis cineraria) and acacia (A. tortilis) are imported from abroad, so knowledge of the necessary arboricultural techniques of pruning, especially of broadleaf trees, is generally absent (palms they are well used to dealing with).
As you can see in the pics, the trees in the park had been “salvaged”, which is perhaps not a good word. A specialist tree-lifting company from the US had been engaged to train ground staff in the techniques of boxing and lifting the trees, no easy task in a pure sand soil and 35-40degC – and that’s the winter temperatures. I then had to attend to the care and aesthetics of the tree. My assessment was that most of the trees had been badly pruned in the past, causing poor crown developments and in some cases allowing disease to enter.
Not surprisingly, some of the trees suffered severe shock in being lifted, but most survived, with varying degrees of die-back and then regrowth. Much of the work was simply about deadwooding and the teaching of correct pruning cuts and methods. Access is always the main issue and there was no way to teach the guys how to climb – that is a job for a specialist training school, so we were restricted to a cherry-picker and for the most part, hand tools.
Many trees suffer, surprisingly perhaps, from over-irrigation. This causes surface rooting which makes trees dependent upon continued irrigation, plus natives like ghaf become prone to wind-throw from lack of deep anchor roots. Exotic trees such as Delonix (below), grown for their beautiful red or yellow flowers, bloom less well when over-watered and become prone to bacterial wetwood infection.
Places like Dubai and Abu Dhabi are developing at an astonishing speed and their landscapes are growing at a similar rate. Knowledge is the thing that lags behind, and it will take some time for this to catch up. I’m sure it will; there is something alluring about creating beautiful landscapes in a naturally hostile climate. This becomes a critical issue in the light of climate change and global urbanization, which is happening fastest in the hotter regions of the world; landscapes moderate climate and make such places livable, whilst biophilia demands that we need close contact with greenery in this urbanised world.
More needs to be done to increase the knowledge and care of trees, including species selection and nursery practice, reducing over-irrigation and teaching good pruning methods, but it can be done. I’m looking forward to the next phase.
I am working as a consulting arborist in the UAE for a couple of large projects. Whilst there, I have been observing the broad state of the art and there is a long way to go in bringing across current best practice to the Middle-East, and I suspect that is so for many parts of the Middle-East and Asia. Even in my village in Sussex, in the last month tree butchery has occurred, so the UK still doesn’t always get it right, despite a long tradition of arboriculture.
I have always worked in accordance with the advise given by Dr. Alex Shigo, of the US Forest Service. His investigations revolutionised our understanding of the way trees react to injury, and this should inform the inquiring arborist. Sadly not everyone inquires.
Delonix trees in a public park in Dubai – note the split branch over a footpath!
Back to trees in the UAE. What I am seeing is a gradual awakening of interest in the care of trees, and the acknowledgement of the skills needed to carry out that work. It seems that as more emphasis is put on landscape and more trees are planted, there comes a point when caring for them becomes a higher priority. This needs to go right across the board, to include the correct pruning in the nursery, this can save many years of bad growth habit, which is not always correctable later. Prevention is always better than cure. Perhaps the UAE, and especially Dubai, is maturing to the point of switching from development to maintenance. That’s as true for arboriculture as it is for plumbing and building maintenance.
A part of my contracted work is to train local teams in the correct methods of pruning. Basic techniques can be taught, but in the UK it takes three years to train an arborist, so we have to be realistic in what we can achieve. I think it won’t be long before I have UK based arborists over there caring for trees. With the 2020 World Expo now secured, the demand for trees can only grow, whilst in Abu Dhabi a new law requires 25% of all ground space on a development to be landscaped – the demand for beautiful trees has never been greater, nor the need of skilled care more evident.
I’ve been reading several websites by visionary developers in Azerbaijan, who are proposing some massive Dubai-style developments to the Bay area of Baku, the country’s capital. One, the http://khazarislands.com/ seems like an ambitious Dubai-competitor, an ultra-sleek development on up to 30 artificial islands (think the Palm Jumeirah), the other is based on an existing island and whilst just as pretentious, http://www.ziraisland.com/ at least aims to generate all its own energy from renewables, and to be carbon-neutral.
The buildings are all based on the forms of nine iconic mountains in the Caucasus Range. Actually, not a bad idea from the point of view of seismic safety and thermal efficiency etc. Serious plans to make a huge modern metropolis that is self-sufficient are rare, with perhaps only the Chinese actually trying this with some of their Eco-Cities.
What is needed is to develop a coherent urban greening policy to integrate technologies like living walls and urban tree planting and care, with a carefully thought out irrigation policy. People still don’t see how essential green walls will be in integrating ecosystem services into a buildings basic functionality, but it will come. Let’s watch with interest.
I’ve just come back from Dubai again, following up on the Biowall green wall installer, Acacia LLC. Indoors it is much the same conditions as anywhere in the world, but outdoors is a challenge. Temperatures in the hot summer months can reach 50°C (in the oasis town of Al Ain, it can get to 62°C, with low humidity). Finding plants that will cope with these levels of heat is not easy. We’ve had test walls going for nearly a year now, so about to have a second summer test.
Biowall at Acacia (photo taken September 2013)
Indoor walls growing in Acacia’s nursery
I have just set up a stage two trial, to run from September, testing an expanded range of 50 outdoor species, mostly plants used there as groundcover. This will be divided into sun and shade walls, for obvious reasons, and have a rigorous testing regime.
A Biowall outdoor wall with shade canopy
There are, of course, other people trying green walls. Both of the ones I have seen (outdoors) I fear are likely to fail. This is not good news, because UK experience tells us that a major public failure can set the whole industry back considerably, as it takes a lot of proving then to show that it can be done.
This is a brand-new wall on a new hotel using a compost pot system on the Sheikh Zayed Road. Plants are looking very poor already… since recovered but not that great.
So walls like this one cause a lot of problems, which of course, will be corrected with time; the momentum out there for vertical greening is becoming unstoppable. Systems like the one above that use individual pots to hold compost, mean the root zone is exposed on all sides to heat and wind; keeping such a plant well watered will be a tough call, especially when there is no drainage fitted and it just drips onto the building façade.
Never mind. Pioneering always carries risks and at least they have been bold enough to try. But the wall should look like this…
Biowall system outdoor living wall at Acacia’s garden centre.