If you need help or advice with your trees, I will be visiting Dubai for the week of February 23rd, advising on trees for private and commercial clients. If you have a tree you need help with, or a developments project with trees involved, I have a few appointments available.
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 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 experience 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 less harsh 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.
I recently supervised a major crown reduction on an over-mature Eucalyptus on an historic site in Abu Dhabi.
I had surveyed the tree last year and made a recommendation to carry out a substantial crown reduction, due to the declining vigour of the tree and the close proximity to people and buildings.
We used a MEWP (mobile elevating work platform) to access the tree and do works to the lower areas of the crown. The top branches were removed by use of the site crane, which could lift substantial sections of the tree and bring them safely to the ground. I have some great video’s which I may post at a later time.
Needless to say, this type of work needs a skilled arborist and crew to carry out, which we used. If you have complicated tree works that need carrying out, do get in touch…
On my last few trips to Dubai, I have been noticing a lot of trees with lighting installed in them. Whilst these can create stunning effects at night, the correct methods of installation and maintenance are essential for the long-term well-being of the tree. We have to put the needs of the tree first – if the light effects are more important, then just don’t use a tree! Much of what I have seen – and this applies world-wide, not just in the UAE (I have seen equally bad wiring in the UK, Chicago, etc.) – is messy and very likely to cause long-term damage to the tree, if it doesn’t kill it entirely.
We have to reconcile the fact that trees expand in girth year on year (including palms, though in a different way) through what is termed secondary growth. All this growth happens in the region just under the bark in the cambial layers and produces new meristematic tissue. Damage or restrict this layer and it effects the whole health of the tree. Cable ties are like a choke collar to a tree; as it grows it gets choked. Many trees will solve this by growing over such a restriction but this can leave the wood vulnerable to infection and mechanical stress. Likewise, light mounting brackets screwed directly onto a tree become overgrown and are again a source of potential infection.
If the aim of lighting is to create an aesthetic effect, it should not be at the expense of the trees aesthetic, nor of it’s health. I can’t imagine that the lights above look very good at night, although i wasn’t there to see them on.
There is a correct way to do all this and keep the tree in good health (as far as any interference can be healthy). If you have such a project, either existing or potential, please contact me to discuss assistance in achieving best practice.
I have said elsewhere that the landscapes of Dubai and Abu Dhabi are growing (no pun intended) at an extraordinary rate and that the knowledge and skills needed to care for the landscapes as they mature are not keeping pace. This is especially true when it comes to trees.
Palm trees are familiar to the region as a crop tree; they are tough, easy to move without too much worry and of simple form which does not necessitate any complex pruning. Broadleaf trees however, demand more than the crude lopping they are so often subject to, especially in urban spaces where there are issues of health and safety. Bad pruning, but also lack of pruning can lead to dangerous conditions.
The following two pictures show dangers from no pruning care taken:
Often a tree’s lifespan and health are determined even before they are planted on a site. Many problems come from lack of formative pruning right at the nursery stage and roots may be damaged during lifting or potting on.
So many trees are off to a poor start before they are even planted but once they are, environmental factors will kick in. How well they are planted and irrigated will effect their health. Assuming they survive and grow (and the average life-span of a UK planted urban tree is less than 10 years) then they have to cope with the occasional pruning that they are given and the damage that this may cause.
We have to understand that trees never heal. They survive damage by a process of isolation, or compartmentalisation, whereby cells surrounding damage isolate this area from the remaining areas of the tree. Unfortunately, bad pruning tends to rip right through these natural defenses, opening up the tree to infection and decay. Key to this is understanding the correctand way to place cuts. Here’s how you DON’T do it:
All these abuses and bad practices can be seen anywhere in the world, even in the UK which has a thriving profession of arboriculture. Trees in hot climates are critical, however, to the health of people and the city overall. As the landscapes of our modern cities and mega-cities continue to grow, and the effects of climate change become more severe, we need to look after our trees – everywhere – to a much higher standard than our current levels.
Trees deserve our respect – and our thoughtful care. More, they deserve active and knowledgeable management and the correct level of arboricultural skill and care to ensure they thrive and serve us, and our built environments, as best they can. The more we give, the more we get back.
On my latest visit to the UAE I had a number of tree-related experiences.
In Dubai, I met with James Palmer from WT Burden, to view the Baobab trees they import from Australia. These trees are succulents, so don’t possess the usual vascular system. As such, they are huge water storage tanks and can live uprooted for two years (I believe the biggest weighed 11 tonnes)! The trees in the picture were planted in January and are just now coming into leaf, as the season warms up. I will follow these closely as I’m intrigued about how well they will re-form a good crown shape.
I also got to have a fabulous green tea in the Four Season’s hotel, which was nearby. The landscaping there is sublime, with beautifully terraced stone walls and planters to the roadside boundary and a form of living wall with horizontal planters built into a curved wall.
In Abu Dhabi, I was commissioned to carry out a survey on a large tree, which is located on a site I cannot name. The tree itself is large and in gradual decline, so needs some help. Following a thorough inspection from the ground and also using a MEWP, I will return in the Autumn/Winter to oversee a crown reduction. It’s great to see such care and concern being placed on trees, they are the stuff of life!
I also got a chance to visit Umm Al Emarat Park (formerly Mushrif Central Park), to see it finished and to look for the trees I surveyed and made pruning recommendations on, back in 20 14. It is obviously now completely different, the trees I worked with had all been lifted and containerised for re-use in many different areas of the park. Saw some I could recognise though, like seeing old friends!
This shows a few of the trees in 2014 which had been lifted from the old park and saved for re-use. I surveyed each tree and made recommendations for pruning works, then trained the landscape crew in the correct pruning methods to carry out the works.
One of those trees (Ficus nitida) in its new home and looking happy.
I would like to have had more time there, and will visit again. I note an on-going need for aboricultural advice there to maintain the trees in the best of conditions…
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. 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