July 1st, 2020 by Mark Laurence

This is last in a four-part series of articles on this subject, somewhat separated from the other three by time, because of COVID. Links to the first parts are at the bottom.

In searching for a new way of creating natural, non-irrigated landscapes in the Middle East, I have already shared how certain species, often non-native, will regenerate on abandoned brown-field sites across the Middle East; my personal experience is from observations in the UAE but I suspect this holds true across most of the region. I have suggested that to recreate such unirrigated landscapes (xeriscapes), designed with conscious intent, we must seed them, rather than plant. That sounds simple, but is actually quite complex and reveals yawning gaps in design and horticultural knowledge, as well as seed supply. So how could we rectify that?

The beauty of native desert plants is often overlooked

I think the UAE in particular needs a place of horticultural learning, but I don’t mean just a conventional horticultural college (though it needs that too), but a place to test and learn new things. Perhaps that would be a botanic garden, but one focused on future adaptation rather than what is or was; seed collection is generally part of the remit of such places. There was one being designed in Sharjah, but I understand that is not going ahead, which is a great shame. Such knowledge is desperately lacking in the region. It is also true that the UAE needs much greater horticultural and arboricultural knowledge and practice, to advance all standards and methods of care. However, to achieve what I propose, such a place would have to first study, trial and learn, then disseminate new techniques.

There is a huge volume of knowledge needed, of soils, species, of seed gathering and storage, seeding trials and combinations and of how to design, create and then manage such landscapes. The one thing we have to realise, is that this approach is contrary to pretty much all conventional landscape and horticulture conventions and practice. In fact, the best place we can look for inspiration and instruction is in permaculture (see Greening the Desert) and regenerative agroforestry. Such practices are gradually moving from the fringe into mainstream thinking, for one simple reason: they deliver results with relatively low inputs. The principle difference here is that we are focussed upon novel ecology building, rather than food production. That doesn’t mean there wouldn’t be food produced, or other useful products.

The “dream team” that might be assembled to carry out such work, might include:

  • Soil scientist/microbiologist
  • Hydrologist
  • Botanist
  • Permaculturalist/regenerative agroforester
  • Ecological landscape designer

To me this is exciting and a combination all these elements would emerge as a new land-management practice that could be utilised in many parts of the world. It is the Middle East and other arid regions who need this the most; if through the effects of climate change the native flora should fail as the environment becomes ever more hostile, what will replace them? We need to tip the balance towards resilience first, then regenerative ecosystems. As wet-bulb temperatures threaten to reach the 35°C and make the Middle east uninhabitable, we need to employ the benefits of evaporative cooling on a massive scale.

So how do we design such landscapes? First, we should see this as the creation of novel ecosystems: new, functioning ecologies that serve the needs of the moment and are adapted and will continue to adapt, to changing climatic conditions. As such, they will be a mix of natives and non-natives, even some plants labelled “invasive”. The key to this system is long-term development and management as a resource. In my last article (third in this series) I looked at the effects and benefits of coppicing as a system of management, a source of mulch materials and so the generation of fertile and water-retentive soils. Such landscapes, created en masse (think of green corridors surrounding cites for hundreds of miles) would have a major beneficial effect in mitigating the heating effects of climate change, moderating dust storms and absorbing the occasional but problematic flooding from rainstorms.

Next, we have to understand the nature and habit of the particular piece of land we are dealing with. Key to success is the capturing of whatever rainfall there is (as mentioned above, even Dubai has rain – and occasional floods). We need to encourage and enhance the capture and retention of this rainfall with the use of contoured swales, heavily mulched. Even small changes in elevation create micro-climate and a plant’s success may be favoured by a few inches of contour. We also need to maximise the soil’s ability to retain that water with the addition of soil ameliorants and organic matter (the aforementioned mulch). We might band the planting into ribbons that follow these swale contours, and choose different plants in different bands. It is at the transition between different eco-zones that we get the greatest diversity of species, both flora and fauna. It is possible that if carried out on a large enough scale, such landscapes might have a benign effect on the local hydrology, even inducing rainfall. Whatever the potential, this needs serious effort and resources to implement and that implies government backing. Pilot schemes could be carried out though, on a small scale, with the backing of ecologically aware business and/or philanthropists. I’d love to have some conversations!


This concludes my series and my thoughts so far. As an observer and some-time participant in aspects of landscapes of the Middle East (particularly trees). I may be very wide of the mark here, or I may just have spotted something that hasn’t yet been thought about. What I do know is that the ME region will desperately need to create ecological resilience and buffers if it is to remain habitable over the next 100 years.

The first three articles in this series are below:

Posted in Abu Dhabi, Adaptive Planting, Agroforestry, Arboriculture, Brownfield regeneration, Climate Change, Coppice, Dry Garden, Dubai, UAE, Ecosystem design, Ecosystem Services, Environment, landscapes, Middle-East, Natural Landscapes, Novel ecologies, Sustainability, Trees, woodland, Xeriscapes Tagged with: , , , , , , , , , , , , , ,

March 13th, 2020 by Mark Laurence

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?

A self-seeded landscape, Abu Dhabi

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.

Flowers of Prosopis juliflora attracts bees and insects

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. A large part of this would be creating contour swales across the site to capture whatever rain falls and to ensure it soaks into the soil. Even a small change of elevation can change the conditions and so the ecology that can grow there.

Once we’ve created swales, can we build 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.

Sesbania sesban, a nitrogen-fixing shrub

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 essential and the best innoculator of bacteria and fungi, but it can be 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.

Black Carpenter bees on Leucaena leucocephala

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.

The first article of this four part series is:

Posted in Abu Dhabi, Adaptive Planting, Brownfield regeneration, Climate Change, Dry Garden, Dubai, UAE, Landscape Futurism, landscapes, Middle-East, Natural Landscapes, Planting Design, Regenerative Planting, Sustainability, Trees Tagged with: , , , , , , , , , , ,

Natural regeneration on a brownfield site Dubai
March 8th, 2020 by Mark Laurence

This is the first of a four-part article, links to the others are at the end.

These articles are all a part of the same thought progress, which has been brewing for some time and started with an article I wrote two years ago, in March 2018.  I think this is an important subject, and hope that you’ll agree and read them…

Whenever I am in the UAE, I find time to visit various parks and gardens; on my latest trip to Dubai (February 2020), I went to see Al Ittihad park, a well-kept secret in the spine of the Palm Jumeirah, underneath the monorail, which was designed using native and naturalized plants of the UAE.  It also, the blurb said, promised everything was labeled, so ideal for a crash course in local flora.  The park was interesting but unfortunately all the labels had gone, and it was being maintained in the manner of all landscapes; incorrectly, especially so for native planting.

Of equal or greater value, however, are simple walks around the back-streets and suburbs of a city and I find empty brownfield sites, awaiting development, often offer the best insights as to what will actually grow in an arid region, if things are left to their own devices.  It’s more than you’d think, and it’s not all native.  I’ve written about this before, in this article and I’m building here on my earlier observations.

Video of brownfiled site in Dubai showing natural regeneration

The world is gripped in fear of biological invasion, currently of Coronovirus but I’m talking here of the floral kind.  Globally, there is a growing passion for conservation, restoration of what was, of what we think of as native and right.  We seem to think that in taking this approach, we are setting right the wrongs we have done; nothing could be further from the truth. Fortunately, Nature doesn’t share that passion and is busy dispersing its flora and fauna around the place, wherever and however it can.  That it uses humans as vectors for that dispersal, is obvious, if you just look upon it from a wider perspective.  Perhaps Nature knows something that we humans are trying hard to ignore; that the climate is changing, the rules of life are shifting, that ecologies need to adapt to the new conditions. 

Leucaena leucocephala

I think we humans are both arrogant and ignorant when we say, “that plant doesn’t belong here, we must get rid of it”.  Plants that arrive and succeed are the pioneers of a new, adapting ecology; yes, they are aggressive, yes, they grow without restraint and colonize -usually – disturbed ground, yes, some make monocultures.  Like all pioneer species they are fast, competitive and relatively short-lived.  But they establish life and the conditions for the next species of successional plants to come along.  All parts of the world are, or soon will be, under such huge environmental stress that we must actively embrace change and nurture these new ecologies. We cannot live in a world without complex ecology, nor can we hold back the change, so we have to go with it.

Prosopis juliflora

To come back to my brownfield sites, on my previous article, linked above, I encountered the following trees growing on a brownfield site in Abu Dhabi:

  • Prosopis juliflora
  • Ficus benghalensis
  • Eucalyptus camaldulensis
  • Conocarpus lancifolius
  • Washingtonia robusta

From recent observations in Dubai I can add the following trees:

  • Azadirachta indica
  • Leucaena leucocephala
  • Plus the Prosopis and Ficus from the above list.
Azadirachta indica

From the looks of it, this site was more recently cleared than the Abu Dhabi one, and trees appeared to be no more than 2-3 years old.

There were also a range of groundcovers and grasses growing; I haven’t been able to ID them all, but some I saw included:

  • Aizoon canariense
  • Heliotropium bacciferum
  • Salsola collina
  • Tribulus terrestris
  • Chloris virgata
  • Panicum turgidum
Tribulus terrestris

Such plants are equally important in building new ecologies, and a big part of the whole.  There are of course, a huge range of native or adaptive plants not represented here, which would nonetheless grow, given the chance.

These observations might be interesting, but how useful are they? If we think of conventional, irrigated landscapes, perhaps not very useful at all; we know and use many of the trees already.  Where this becomes interesting, is in that they self-seed and establish without any human intervention.  If we could master the art of this, then such landscapes we would nurture and manage, with occasional thinning, removals, perhaps some sucessional seeding or planting. Imagine this on a large scale, in peri-urban locations, alongside roads, at intersections, instead of the over-watered ornamentation we see now throughout the UAE.  We then save the ornate for the urban parks, streets and gardens.

Aizoon canariense

Could this be the basis for a new approach to creating landscapes and if so, how would we do it?

This is the subject of the next article:

Posted in Abu Dhabi, Adaptive Planting, Brownfield regeneration, Climate Change, Dubai, UAE, Environment, landscapes, Middle-East, Natural Landscapes, Regenerative Planting, Sustainability, Trees, Treescapes Tagged with: , , , , , , , , , , ,

Grassess in Abu Dhabi
November 29th, 2019 by Mark Laurence

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.


Excess Irrigation in a Dubai housing area

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.

The power and the beauty

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.


Delonix regia, the flamboyant tree

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.

Posted in Adaptive Planting, Biophilia, Climate Change, Design, Dry Garden, Dubai, UAE, Environment, Garden Design, Middle-East, Natural Landscapes, Planting Design, Regenerative Planting, Sustainability, Trees, Urban Landscapes Tagged with: , , , , , , , ,

A natural Xeriscape
March 23rd, 2018 by Mark Laurence

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

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:

  • Prosopis juliflora
  • Ficus benghalensis
  • Eucalyptus camaldulensis
  • Conocarpus lancifolius
  • Washingtonia robusta

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

Prosopis juliflora flowers

P. juliflora has a low, mounding habit, attractive from a landscape point of view.

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.

Ficus benghalensis

Ficus benghalensis

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 glaucescens, showing adult foliage

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.

Conocarpus lancifolius

Conocarpus lancifolius

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.

Washingtonia robusta

Washingtonia robusta

Unknown Legume

I believe this legume is Sesbania sesban, more commonly seen with yellow flowers.Rose-ringed Parakeet 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.

Update

According to Google, the site has been cleared some time in 2019:

Site cleared of vegetation in 2019

But seeds will be waiting for future opportunity!

Other articles by ML that relate to this topic:

Brownfield site natural regeneration in the UAE

Creating climate-adapted landscapes in the Middle East

Coppiced treescapes for the Middle East

Older articles:

https://www.marklaurence.com/wp/trans-migrational-landscapes-a-survival-strategy-for-the-world/

https://www.marklaurence.com/wp/why-we-can-and-must-create-new-adaptive-ecologies/

https://www.marklaurence.com/wp/trees-climate-change-our-landscapes/

Posted in Arboriculture, Climate Change, Dubai, UAE, Ecosystem Services, Environment, landscapes, Middle-East, Natural Landscapes, Regenerative Planting, Sustainability, Trees Tagged with: , , , , , , , , , , , , , ,

March 6th, 2017 by Mark Laurence

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

Posted in Arboriculture, Climate Change, Dubai, UAE, Environment, Middle-East, Trees, Urban Landscapes Tagged with: , , , , , ,

December 7th, 2014 by Mark Laurence

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.

Containerised Trees in the nursery area

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.

Pruning

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.

wetwood

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.

Posted in Arboriculture, Dubai, UAE, Environment, landscapes, Middle-East, Trees Tagged with: , , , , , , , , , ,