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 24th, 2020 by Mark Laurence

This is the third in a four-part series. In previous articles (links at bottom) I talked about the spontaneous regeneration on brownfield sites in the UAE and the utilisation of seeded landscapes to create semi-natural ecosystems without irrigation. Another factor of these landscapes would be to make them productive in a way that would enrich the soils of not just that landscape but, by the production of useful products, returning fertility to the soil for both the site concerned and also urban landscapes and gardens elsewhere.

Sesbania sesban, a nitrogen-fixing shrub or small tree

Coppice woodland is not a term that you normally associate with the Middle East, yet there are many trees, both native and introduced, that would work in this manner. So what would be the point? Well, we have become used to landscapes being either for agriculture, or for ornament, yet this simplification overlooks the fact that we can have landscapes that are multi-functional and that they can also be productive in other ways.

To understand this concept, we should look to agroforestry, or forest gardens, where multi-functionalism is the order of the day. We think of these systems as being in tropical or temperate regions, yet there are many plants that can be organised and used in this fashion in arid lands. I want to focus this article on one aspect only, the production of biomass. Biomass has multiple functions: the production of poles for building and firewood, compost, and when shredded, mulch. We can produce biochar, which is seen as an increasingly important part of long-term soil enrichment and carbon sequestration. There are also food and fodder crops which would be a valuable product, dependent upon species. And of course, verdant biomass supports verdant wildlife.

Eucalyptus street tree, Abu Dhabi. Note the epicormic growth from the base

Many of these plants are also nitrogen-fixers and these are especially valuable for building fertility and assisting the development of other species. Whilst some may have allelopathic properties, which inhibit the germination of other seedlings within the root zone, my general observation is that this is not particularly effective, nor a problem.

So a list of trees that would grow in the Middle East unirrigated, can be coppiced and are nitrogen fixers, would include:

  • Acacia saligna
  • Acacia (Senegalia) senegal
  • Acacia tortilis
  • Albizia lebbeck
  • Leucaena leucocephala
  • Pithocellobium dulce
  • Prosopis cineraria (possibly)
  • Prosopis juliflora
  • Sesbania sesban
Strong epicormic growth is ideal for coppice. Prosopis juliflora

Other species, coppicable but non-nitrogen fixing, would include:

  • Azadirachta indica (assumed from observed regrowth)
  • Conocarpus lancifolius (assumed from observed regrowth)
  • Eucalyptus sp.
  • Ficus sp.
  • Moringa oleifera
  • Tamarix sp.
  • Ziziphus spina-christi
Regrowth from cut branch of Tamarix aphylla
Ziziphus spina-christi, showing classic epicormic growth

There will be many other species that could fit these lists, but it’s a start. Many ornamental trees, such as Millingtonia and even Delonix show tendencies to throw up epicormic growth from wounds and therefore, in theory might coppice, but I am concentrating on trees which can do this without irrigation.

It’s important to say right here that this shouldn’t ever be designed as a monoculture; there is sound ecological reasons to to maximise the diversity of a planting. Naturally, you wouldn’t use everything, for conditions will suit some better than others for any given site. Nor would you coppice everything all at the same time. Staggering the harvest evens out the work-flow but more importantly, creates communities of plants at different stages of growth. The “edge zones” are always where the greatest biodiversity occurs, for you get the overlap of differing ecologies. Whilst each species will have it’s own regrowth rate and optimum cutting cycle, this can also be varied, according to the use of the product.

Of course, there is a problem, for many of these species are incredibly thorny, which is a real issue for those carrying out the coppice-work. Young vigorous growth also tends to have the most vicious thorns! On a larger scale, it may be possible to use forestry-style Forwarder tractor-trailer units to collect the brush and load it directly into the chipping machine hopper, without human intervention. Someone’s still got to cut it and do initial handling though.

Ziziphus stump, showing strong epicormic regrowth

So how do we express this idea, of coppiced woodlands, arid-land style? it would depend on context but there are several approaches we could take. On a large scale, machine operated (as mentioned above), we would have to do traditional layouts with alleys or rows, firebreaks etc. Mixed planting though, would be preferable although strips of one species are possible. If kept narrow, with different species to either side, the effect ecologically would be similar to mixed planting.

In smaller areas, or where human interaction is intended, then these could take the form of the mixed, seeded landscapes that I discussed in my previous article. In other words, we can combine the function with the elements of aesthetics and ecological diversity. Not to mention desert reclamation. Remember, all this is proposed as unirrigated land. The verges along main roads are a prime candidate, instead of over-manicured lawns and hedges that you see at many junctions.

My next article will discuss design, the knowledge and training needed for the creation of such landscapes. I believe we could transform the landscapes of the Middle East, without the intensive irrigation that is required by conventional approach.

First and second articles in this series:

Posted in Abu Dhabi, Adaptive Planting, Agroforestry, Brownfield regeneration, Climate Change, Coppice, Ecosystem Services, Environment, landscapes, Middle-East, Natural Landscapes, Regenerative Planting, Sustainability, Trees, Treescapes, Uncategorized, woodland Tagged with: , , , , , , , , , ,

Trees add height and microclimate
December 9th, 2019 by Mark Laurence

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.

Trees in grass lose most of their microclimate
Trees in grass lose most of their microclimate and ecology. Traditional design fails us here.

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…

Here we have (in Umm al Emarat park, Abu Dhabi) the beginings of an true microclimate. This is a treescape.
Here we have (in Umm al Emarat park, Abu Dhabi) the beginings of a true microclimate. This is a treescape.

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.

Are you up for it? I am!

Posted in Adaptive Planting, Arboriculture, Biophilia, Climate Change, Design, design principles, Dubai, UAE, Ecosystem Services, Environment, Garden Design, Landscape Futurism, landscapes, Middle-East, Planting Design, Sustainability, Trees, Treescapes, Urban Landscapes Tagged with: , , , , , , , , , , ,