In Part 1 we just looked at some current data about supply and consumption of water in Saudi Arabia on a broad scale. In part II we are going to get a little more granular on the data and tie it into the broader picture.
THE COST OF DESALINATION
Desalinated water provides just 7% of the national supply currently, but when it comes to urban water, desalination is supplying 61%, and at massive cost. In 2013, desalination in Saudi Arabia required 1.5 million barrels of oil per day, or approximately 547 million barrels of oil per year. At the current rate of 56$ per barrel, this presents an opportunity cost of 30.6 billion USD.
The projections from the water ministry are that domestic consumption of water & electricity could consume 50% of the country’s oil & gas production by 2030 if there are no changes made in national water policy.
A breakdown of groundwater vs. desal by governorate. Without major changes to policy, by 2030 KSA could be using 50% of all its oil production just to supply water and energy.
The cost of desalination, however, is not just financial. In the UAE, salinity of the persian gulf has increased from 35,000 ppm to as high as 56,000 ppm. As salinity increases in the gulf, it may balance the pH of the acidifying sea, but the sea’s corals and fisheries will be “highly stressed,” which is a sanitized way of saying decimated (link is to pdf). Furthermore, the technical difficulty of removing so much salt will make desalination either technically impossible, (a possibility) or simply much more expensive (guaranteed). That situation is exacerbated by the fact that both the persian gulf and the red sea have very small inlets; both are largely self contained, with water that changes over from the ocean once every 8-9 years. In other words, even with advances in desalination technology, it’s still going to become more expensive to desalinate a liter of water as time goes on.
CONSUMPTION & POPULATION TRENDS
Saudi Arabia’s population is growing at around 2%, but its consumption of water and electricity have been tracking around double that amount.
population growth rates have swung over the decades but currently around 2% Source: World Bank
Meanwhile, water consumption per household is increasing at a rate of 7.5% per year, and demand for electricity is increasing at 8% per year. If both trends continue, demand for water and power per capita will double in a decade, and the number of capitas will increase from 35 million to 45 million.
Over that same decade, conventional agricultures in Saudi Arabia may face a major collapse. With some 100,000 million cubic meters (mcm) of water left in the fossil aquifers (based on National Geographic’s estimate), and an annual withdrawal from those aquifers of 14,500 mcm per year for irrigation (taken from the Water Ministry’s 2025 National Water Strategy), time is short on this front.
A truck hauling imported alfalfa to feed camels & goats. I see these every day on my commute to work.
The pain associated with these collapses will be real, as farming communities abandon their land to the desert. The removal of water subsidies already had some farming communities in Hail turning to other employment in 2012. As subsidies for wheat end, and eventually alfalfa, whole agricultural communities will have to look elsewhere. So while it may seem to someone from outside that growing wheat or alfalfa in the desert is neither environmentally nor financially sound, there are now 40+ years of history in some of these places with wheat as the economic base.
Putting It All Together
Saudi Arabia faces a gordian knot entangling its economy, energy, water, food, & population growth. Its rentier economy continues to depend almost singlehandedly on oil and oil derivatives, which provide 90% of the country’s revenues. But in the coming decades, it faces enormous decisions dealing with water, agriculture, energy, economy, and increasing costs:
- The fossil water will run out eventually, which will lead to a collapse of all KSA’s conventional agricultures, leading to greater food imports (which are currently 80%) and a fragile dependence on global food prices.
- Demand for electricity and urban water are set to double over the next 10 years.
- In that time the population will probably increase by some 10 million people.
These are some of the reasons why Citigroup estimated that Saudi Arabia could become a net oil importer by 2030. Whether or not Saudi Arabia can weather these changes quickly enough and untangle its gordian knot will depend entirely on what actions it takes until then. But it will require nothing less than massive changes in pricing structures, subsidies, gains in efficiency, and the creation of new economies to replace one based almost entirely on oil.
On an ending note, I want to emphasize that I do not have an apocalyptic viewpoint of KSA’s future. It is rarely the case that when trends point to disaster that people in charge don’t take action to avert those disasters, and so trends that seem alarming now rarely play out the way they might appear to. Thus, the purpose of this post is not to spread fear; it is to lay the groundwork for understanding the current situation, so that the critical nature of the solutions’ designs are apparent.
This is part 2 of a series on functions that not many people know trees can perform, and how those functions can be utilized in greening the desert. Part 1 was on hydraulic redistribution, in which trees act like pumps moving water from wet to dry areas, from high in the soil profile to down in the water table, and vice versa. Part 2 is on the chemical role that trees play in cloud formation and precipitation.
First, I have to acknowledge that much of the science in this post i have found thanks to Kevin Franck’s site where he posts relevant articles and resources . The other main source for much of this is Bill Mollison’s Permaculture Designer’s Manual, which I have linked to in the resources part of the website.
Isoprene in a rain forest breaks down to 2-methyltetrol compounds. Source: Max Planck Institute for Chemistry
Trees in large numbers (ie forests!) play a giant role in creating rainfall. You probably already know that trees take in carbon from the air and release oxygen into the atmosphere. This is called evapotranspiration. But oxygen is not the only thing trees are exhaling– they also release volatile organic compounds (VOC’s) such as isoprenes, terpenes, and monoprenes. In 2004 it was discovered that these compounds break down into hygroscopic aerosols. From Rice University’s Office of Earth Science, we learn why that is such an important discovery vis-a-vis the relationship between trees and rainfall.
A greater density of aerosols in clouds leads to greater density of small water drops. In turn, this reflects more of the sun’s heat, leading to longer-lasting clouds and cooler temperatures.
“Aerosols are very important in the formation of clouds. Often aerosols act as Cloud Condensation Nuclei (CCN’s), around which cloud droplets are formed. Without aerosols in the air, there would be far fewer clouds. Aerosols can also affect the properties of existing clouds. Recent studies have found that in the presence of high amounts of aerosols, clouds will have more droplets than normal, with droplets tending to be smaller than usual. Because the droplets are smaller and more numerous, the clouds last longer and are reflect sunlight better than before. This effect could have significant implications on the climate. As the clouds reflect more sunlight, less of the sun’s energy reaches the surface of the earth, which then cools. This means that by putting more aerosols in the atmosphere, humans have the potential to alter the world’s climate and cause global cooling.”
In other words, forests emit compounds that provide significant amounts of cloud condensing nuclei. In a study from Berkeley (links to pdf), they found that the 36% of all aerosols in the atmosphere came from tree-emitted terpenes and isoprenes.
These are just the microscopic particles emitted by trees. Trees also give off larger particles from debris that also make up a large amount of ice nuclei, as I mentioned in the post about Kenya’s tea region and hail storms. Remember the 3 main conditions driving the cycle of desertification and preventing more rain from falling in the Arabian Peninsula? One of them was the lack of particles that make up cloud-condensing and ice nuclei in the atmosphere.
It seems that almost everything that trees push up into the atmosphere plays a major role in modifying precipitation–and most of it in the area of increasing cloud formation and rainfall. And that brings us to the real punch in the gut:
According to Bill Mollison, Forests are the sources of up to 60% of all clouds and 40% of all rainfall–and from above we know that part of that is due to the VOC’s and dander emitted by forests and breaking down into aerosols that become nuclei for clouds, water drops, and ice.
This should make one thing very clear: To green the Arabian Peninsula, we need to plant forests. If only for their role in creating clouds and increasing precipitation, planting forests would be reason enough. However in the next post we will see how afforestation won’t just increase cloud cover and rain–it will ameliorate every major element that is currently preventing greater precipitation.
In my last post, I talked about how the water cycle in the Hijaz is disrupted, or sick. Accurately diagnosing the causes of that disrupted functioning gives us a good idea of how to go about healing the water cycle, and also points to the resources available to us to do that in a sustainable, or even regenerative way.
That post was the last in explaining the environmental and climatic sources of the problem facing the Arabian Peninsula vis-a-vis the lack of rainfall and increasing desertification, as well as some of the political complications involved. Here is a summary:
The collapse of traditional rangeland practices in the 1950s lead to a tragedy of the commons and a self-replicating cycle of desertification that increased dust in the atmosphere, increased surface and atmospheric temperatures, and eliminated many of the organisms that were producing nuclei required for rainfall. Due to overgrazing and woodcutting, and as the cycle of desertification takes hold, vast swaths of once-lush valleys and mountains are becoming nearly devoid of life, leading to a dramatic loss of productivity and a disrupted water cycle that causes the only renewable source of freshwater to be lost in dramatic flooding events. As this cycle continues, more and more water will be lost, less and less rain will fall, temperatures will increase, and the productivity of the land will approach 0.
At this time, I am not going to go into the political, social, or economic implications of these facts. Instead, from this post on, I’m going to be explaining what I believe to be the only sustainable solution that has a chance at saving Saudi Arabia’s and the Arabian Peninsula’s water and food security issues.
The most valuable resources in the current water cycle are the floods that periodically rush through the wadi systems of Saudi Arabia’s west coast. These floods (and other rains) constitute the only sustainable source of water in the entire Kingdom. Fortunatey, these floods can be used to establish systems that will make the water cycle more regular, that will increase its cyclical frequency, as well as amplify the total amount of rain that falls. In short, we have to use the floods to bring the rain back, and it can be done in such a way that the total precipitation increases, and the frequency of rain events increases.
The first part of this series will be all about trees and the wondrous effect they can have on the water cycle. Here is the map, tho not a table of contents:
TREES & CLIMATE
Moderating Rainfall, Surface Water Flow & Water retention.
1: Clay pan penetration
2: Erosion reduction, soft rain catching
3: Hydraulic redistribution
4: Soil moderation–increasing carbon & soil life increases water retention
Tackling the Problems of Dust, High Surface Temperatures, & Lack of Raindrop Nuclei
5: Evapotranspiration–VOC’s, vapor, & litter
6: Moderating hot, dry winds
7: Extending evaporation periods while reducing evaporation from bare soils
8: Shade, specific heat, and lower soil temperatures
9; Wind & dust break
Providing Additional Sources of Precipitation
10: Increased condensation
This is going to get sciencey, but I promise that it will be awesome. Here’s the first taste of awesome: Did you know that trees can store water in the soil near their taproots during wet times and then pump it back up to their shallow roots when the soil is dry? This is called hydraulic redistribution and will be the topic of the next post.
In the last post, I wrote about how the cycle of desertification in the Hijaz and much of rural Saudi Arabia was started through the unintended consequence of a Saudi national policy in 1954, after a sustainable, traditional land management system called the hima was abolished. We’ve also seen how desertification is a self-reinforcing feedback loop that builds on itself and makes it more and more difficult to turn back the desert and bring life and productivity back to the land. In this post you will learn one of the fundamental methods for understanding your climate and diagnosing the causes of problems to be addressed, as opposed to the symptoms, which is the following:
1: You cannot bring a desert back to life unless you understand how the water and nutrient cycles are functioning.
The various parts and functions of a healthy water cycle.
How nutrients and minerals cycle through plant and animal and soil life.
2: You must cooperate with the existing function of those cycles to begin mimicking a healthy water/nutrient cycle and then healing them on a small scale. That means you cannot start in the middle of the desert. You have to start on an edge, where these cycles are functioning at least a little.
3: Healing the water and nutrient cycles on a small scale will kickstart a cycle of life that counters the cycle of desertification. Once that cycle reaches a certain tipping point, the system will take on a healthy function and become resilient, regenerative, and irreversible (disregarding shocks to the system such as warfare, major natural disasters, or sudden shifts in the larger weather patterns).
Those are the principles and theory. Here is the application for one of the main edges that must be tackled to afforest/asavannahize the Arabian Peninsula: The hijaz.
The hijaz is characterised by large wadi systems that flood when it rains. These floods cause major destruction when they hit cities, as well as more ruralized devastation outside. One of my worker’s uncles and 4 of his cousins died in a flood in Al Baydha 6 years ago, leaving a widow and two young children to be cared for by his extended family. I am going to pick one watershed characteristic of the rest, and use that as our case study. The watershed we will look at in this post is Al Lith, which is a 90 minute drive south of Jeddah.
As is typical of other hijazi watersheds, Al Lith has an extensive mountain watershed draining into a very short flood plain before it hits the red sea.
Picture a flood the way you would a tree. The way a tree’s leaves and branches collect sunshine, the mountains in Al Lith collect water. There are main branches, small branches, eventually a trunk (where all the water collects and runs as a flood). Then before it hits the red sea, it spreads out in an alluvial fan and then in the hijaz, runs into the red sea. In Al Lith, the catchment area (in the mountains) is approximately 35 x 55 kilometres. If a rainfall of 25 mm (one inch) hits this whole watershed, that means there are 1,925,000 cubic meters of water (the equivalent of 1560 acre feet) hitting that watershed at one time. Because these mountains are largely devoid of plant life, less than 10% of that water will soak into the shallow aquifers, and the rest will run into the red sea. You can se in the picture the two alluvial fans that were created in the last floods from the watershed within the blue polygon. But you can also see 4 other alluvial fans from other floods, and other watersheds just north and south of Al Lith.
Looking at the water cycle above, there are some parts of that cycle that are severely hampered or stunted in the Al Lith watershed.
- The condensation of water droplets to create clouds (listed just as CONDENSATION in the graph above) is severely restricted by high surface temperatures relevant to the dew point, by dust in the atmosphere, and by the lack of potential water drop nuclei that would be produced by a less desertified environment. This means that rainfall, rather than being a regular occurrence, only happens once a year, or sometimes once every two or three years.
- Surface Runoff is the overwhelmingly dominant way water makes it to the ocean.
- Infiltration of water into the soil is severely restricted by a few factors:
- Topography (where most of the watershed is in the catchment and the available space for the trunk of the tree is very small)
- The lack of plants and plant roots in the watershed, which facilitate infiltration, slow water flow, reduce erosion, and reduce the impact of falling water on bare soil
- The inability of the soil to hold and retain moisture due to its sandy makeup and the lack of carbon and organic material.
The best analogy for this kind of water cycle is diarrhea. The hijaz has diarrhea. Within 24 hours of a rainfall event, 90% of that water is already lost to the sea, and only 10% is left to nourish all the plant life in the watershed until the next rainfall (which may not occur for another 1000 days!)
So let’s talk about the actual results of the Hijaz’s ailment. A person with diarrhea is significantly less productive than he would be healthy. The hijaz is no different:
A 1 inch rainfall in Al Lith results in an estimated 1,733,000 Cubic meters of water run into the red sea in the Al Lith watershed above. Let’s put this in a more meaningful perspective since most people don’t intuitively think in acre feet or cubic meters of water. That lost water from a one inch event in Al Lith is enough to irrigate 118,698 mature date palms for one year. Assuming a low average of 70 kilos of dates per tree, that’s the equivalent of just over 8,300,000 kilos of dates per year, from one watershed.
The lost water from the flash floods is an enormous loss of potential, measured solely in the amount of dates you could produce if you were to only plant date palms. That doesn’t account for any other ecological services or potential products provided by these imagined palm trees–fiber for traditional crafts, a reduction in dust, mitigating wind and dust storms, lowering ambient temperatures, shading the riparian areas, and providing more habitat for wildlife. Aside from the lost water, which is the source of all life, Saudi Arabia is losing out on money, employment, higher public health (dust and fine particulate matter has been proven to increase the amount of asthma, respiratory diseases, and heart disease), and just a nicer, greener landscape.
There’s some green in that watershed! What if my 10% estimate is off?
Now, I can hear you critics saying, “What if your 10% number is off? After all, Al Lith does have some greenery in that watershed, and it does have a small strip of running water most of the year. Or what if your calculations on the size of the watershed are off?” The size of the watershed doesn’t matter–the principles are accurate, and being off by a few square kilometres doesn’t change the numbers much. But what if my estimate on the water absorption is off? Let’s assume it’s off by a factor of 5, and 50% of the water is absorbed into the water cycle.
Well, that would mean that the amount of lost water is only 1,000,000 cubic meters in a one inch rainfall. But guess what? The average amount of rain in a year is not 1 inch. It’s 70mm, or just under 3 inches. Which means that even if 50% of the water is being retained, there are still 3,000,000 cubic meters of lost water per year, or the equivalent of 205,500 date palms irrigated per year–slightly less than double my original estimate. And if my estimate of 10% water retention (which is based on studies done in the mountainous deserts of the SW United States) is accurate, then the lost water per year is equal to 5,199,000 cubic meters of water a year, or 25,000,000 kilograms of dates per year (by the way, I am not suggesting that hundreds of thousands of dates should be planted in Al Lith. I am simply trying to give a measurement of the lost water that is meaningful beyond acre/feet or cubic meters of water).
This is only one watershed. There are at least 20 other watersheds up and down the west coast of Saudi Arabia that have diarrhea–some are bigger and some are smaller. The lost production, lost employment, and lost water is worth billions per year in lost productivity, and this is in a country where 70% of all the consumed water is sourced from desalination plants. This is in a country with no recognised rivers or lakes. This is in a country where water and food security are so paramount that they are leasing hundreds of thousands of acres of land in Ethiopia, a land so famous for its food production that it has its own Wikipedia page on famine.
Clearly, if we could heal the Hijaz’s diarrhea it would be of enormous benefit to the county’s economy, food security, and water security. This can only be done by understanding the water cycle and then working to get it regular. In the next post, we will talk about the cure: roughage.
In the last post I discussed the cycle of desertification and its effect on weather patterns, and how dust, high temperatures relative to dew point, and the lack of suitable ice nuclei for cloud formation prevent more rainfall from occurring in the Arabian Peninsula. The next few posts are going to focus on the Hijaz–the strip of land on the west coast of the Arabian Peninsula between the red sea and the mountains. In this post you will learn how the cycle of desertification was set off in the Hijaz in the recent past, as well as how it has been a recurring event in human history.
The hijaz has sustained nomadic pastoral tribes for thousands of years, and over that time, a land management system known as Hima was brought into practice. This system predates Islam, and has been amended over the years to constitute a reserve or protected area, managed by the local tribe, to maintain rangelands and grazing. Shortly after the advent of Islam, the Hima became recognised as a place to provide for the general welfare of the people, particularly the poor.
The caliph Omar ibn al-Khattāb (reigned 634-644 CE) instructed the manager of Rabadhah himā by saying: “Lift your wing from the people! Heed the complaint of the oppressed for it will be heard by God. Let enter those who are dependent on their camels and sheep; and turn away the livestock of Ibn ‘Awf and Ibn ‘Affān (two rich Companions of the Prophet), for they can fall back to their palms and fields if their livestock should perish. Whereas the needy ones, if their livestock perish, will come to me crying (i.e. asking for financial help). (from O. A. Llewellyn, “The Basis for a Discipline”, p. 213)
In the middle ages, Himas were given as waqf surrounding the cities. In the rural areas, local inhabitants established environmental planning and management strategies which balanced the settlements’ growth and natural resources uses according to Islamic laws and the tribal self-government. Tribes were given the authority by the Prophet, PBUH, to be the custodians of their himā-s, and to control them on behalf of the central government. (S. al-‘Ali, “The himā in the first hegira century (7th century CE)” (in Arabic), al-‘Arab (Riyadh), 7 April 1969: pp. 577-95. Also see here) Violators of the rules of the hima–those who brought unpermitted animals in, were either beaten, or had some of their animals confiscated as punishment.
Thus we have a very brief overview of a political system that sustainably managed lands teetering on the desert for thousands of years, and which, contrary to many other human societies, maintained the relative health of their land while caring for the poor.
Hunting was another activity managed through the Hima to maintain stocks and prevent extermination.
This system thrived throughout the Arabian Peninsula and the Levant until very recently. In Saudi Arabia, as in so many other cases throughout history, unintended consequences of policies led to severe deforestation. Here I quote directly from Lutfallah Gari:
In Saudi Arabia the government wanted the tribes to be unified under one umbrella; hence it took the responsibility of management and security of the rural lands through governmental agencies. In 1954 a decree was issued designating the Ministry of Agriculture and Water as the custodian of the rural lands in this country. This created a new statute for the himā-s that became public lands. There was no immediate alternative conservation system. The first national park in the country (i.e. ‘Asīr National Park) was established in 1980. The National Commission for Wildlife Conservation and Development (NCWCD) was established in 1986. The period between the banning of the himī system and the start of constructing national parks and protected areas was a period characterized by severe destruction of the plant cover through overgrazing and felling of trees as well as over-hunting of wild animals… An estimated three thousand himā-s existed in Saudi Arabia in the 1950’s…A report issued by the NCWCD in 2003 mentions only four remaining that are called “old himā-s” that are managed by the Ministry of Agriculture, in addition to a few dozen himā-s that are still managed by local communities in “isolated” rural areas. The NCWCD report says: “Many of the traditional himā s as well as many terraces have been either abandoned or disappeared under fields that are suitable for mechanical cultivation. In some cases, this has replaced sustainable systems of land use with ones that require increasing inputs of water and management to maintain their productivity, but is has also markedly reduced the diversity of habitats” .
The effects of this policy are being felt acutely in the hijaz and many other rural areas of the kingdom. When the Himas were disbanded and tribes lost the legal right to manage their land, A tragedy of the commons took place that resulted in massive deforestation, overgrazing, and environmental destruction that continues today. This is compounded by a surging population (set to double to 50 million by 2035!), and along with it a surging demand for red meat.
The people in Al Baydha, where I work, are the prime subjects of this issue. They have no legal right to manage their land, nor to prevent others from bringing their animals to graze when it rains in Al Baydha. One man I know owns two hotels in Makkah and his hobby (like many of his compatriots) is to keep a large herd of camels, and go out on the weekends to camp, roast a goat, and drink camels milk. When it rains in Al Baydha, he brings some 200 head of camels (worth an estimated 1.2 million USD) into Al Baydha to graze. The people in Al Baydha welcome him because of their sense of hospitality, yet cannot maintain 20 head of goats on their land because of visitors like him. They have no right to forbid others from coming and overgrazing their land, yet bear the full brunt of desertification’s consequences.
Conversely, because they do not own the land, they have disincentives to develop it. There is a real risk that if someone manages land and tries to bring it back to productivity, that it will be seized by the government because that is who owns the land. This scenario is the reality for thousands of rural communities throughout Saudi Arabia–they cannot manage the land, and if they begin to improve it, it could be seized from them. In Al Baydha, they have responded by cutting down trees to be sold as charcoal in Makkah. In turn, the trees’ ecological services are lost, and the cycle of desertification intensifies and progresses more rapidly.
As recently as 40 years ago, this was a forest, with trees so big “you could not reach your arms all the way around them.” as related by Abdul Rizaq al Aduani, pictured above.
Thus we see the interplay of policies, unintended consequences, the collapse of a traditional land management system, and as a result, massive desertification, loss of productivity, and a collapsing way of life for many rural peoples in Saudi Arabia. Without exception, every person I talk to in this country who is older than 50 years old has fond memories of visiting a green, lush wadi, filled with date palms, jujubes, acacias, fish, running water, or forest. When they revisit these areas now, they are dry, dead, treeless, and prone to flooding.
As the land dies, it becomes more and more difficult to bring it back. Soil life dies, erosion increases, and the land’s ability to absorb water ebbs away. As plant life decreases, soil temperatures increase, making it even harder for plants to become established. Finally, the 3 main impediments to rainfall–dust, high temperatures, and the lack of particles that form ice nuclei and clouds, dominate the climatic situation. The water cycle becomes erratic and unhealthy, and the mineral cycle ceases to function as even bacteria cannot decompose plants or animals because of the dryness.
This is the reality for much of the Arabian Peninsula. People have been the catalyst for desertification in many cases throughout history–in the fertile crescent, on Easter Island, in the western United States, China, and much of Africa. This is now the case in the Arabian Peninsula today. In the next few posts, I will go into more detail on the water and mineral cycles, after which we will get into the solutions of these problems–how people can also be the catalyst for regeneration of their land, their environments, and their economies.
On The Hema:
From King Abdulaziz University
A downloadable PDF in Arabic, French, and English
Omar Lutfi’s “Ecology in Muslim Heritage”
Google Books Sources:
A climate analogue is a compendium of plants from all over the globe that adhere to similar climatic qualities and global positions. For Jeddah, similar locations were found in Mexico, Namibia, Mauritania, and India. Thus the following plants are either known to grow in the region, or are likely to grow there, based on similarities in latitute, elevation, soil profile, precipitation, and other factors. There may be other useful plants that would fit in a niche within a food forest or a managed grazeland which I have missed. This does not include plants I would put in a perennial vegetable garden at the moment–in other words these do not include all the zone 1 plants I would use, which would make for a different, more intense, and less drought-tolerant guild. Some plants show up under more than one category.
One of the series I plan to write for the blog is a plants overview–pick one of the species I’m growing and go into detail on it. When I get that started, these will be the first plants I cover, though I may add to or subtract from the guild as experience dictates!
- Chloris gayana Kunth
- Distichlis spicata
- Pennisetum divisum
- lasiurus sindicus
- stipagrostis drarii
- Smilo Grass oryzopsis miliacea
- Harding grass phalaris tuberosa
- Canary Grass phalaris arundinacea
- Hairy Beard Grass andropogon hirtus
- Erhart’s Grass Erharta calycina
- Tall Fescue festuca arundinacea
- Broad Fescue Festuca elatior
- Tall Wheat Grass Agropyrum elongatum
- Mongongo: Schinziophyton rautanenii
- Date Palm Phoenix dactylifera
- Olive Olea europaea
- Pomegranate Punica granatum–Roman
- Fig Ficus carica
- Guava Psidium
- Mulberry Morus
- Citrus glauca
- Citrus medica
- Jujube Ziziphus ziziphus & spinacristi
- Carob Ceratonia siliqua
- Tamarind Tamarindus indica
- Drumstick Tree Moringa oleifera & Moringa Peregrina
- Mango Mangifera indica
- Loquat Eriobotrya japonica
- Pitaya Hylocereus undatus
- Columar Cacti Cereus peruvianus
- bitter melon: momordica charantia
- Passion fruit: passiflora edulis
- Grape: Vitis vinifera
- luffa gourd: luffa aegyptica
(excellent for coppicing, pollarding, firewood, timber, forage, mulch, and nitrogen fixing. I have marked those that are known to perform hydraulic redistribution as HR)
- prosopis juliflora (HR)
- Prosopis Cineraria (HR)
- Leucaena leucocephala
- Sesbania Sesban
- Parkensonia aculeata
- Albizia Lebek
- Casuarina spp (Note as of 2014–all but 3 of the initial 30 casuarinas we planted have died)
- Acacia seyal
- Acacia Senegal
- Acacia Tortilis (HR)
- Ginger Zingiber officinale
- Turmeric Curcuma longa
- Cardamom Elettaria Cardamomum Maton
- hibiscus spp
- Coastal Pigface Carpobrotus virescens
- Baby sun rose Aptenia cordifolia
- Bay Biscayne creeping-oxeye Sphagneticola trilobata
- Lippia Phyla canescen
- Rosemary Rosmarinus officinalis
- Sage Salvia
- Thyme Thymus vulgaris
- Sweet Marjoram Origanum majorana
- Oregano Origanum vulgare
- Felty Germander Teucrium polium
- Jamaica: hibiscus sabdarrifa
- Tagart Bush: Maerua crassifolia
- Horseradish tree Moringa peregrina
- Sanamaki (senna): cassia senna L. (perennial herbaceous in sandy soil)
- Henna lawsonia intermis (perennial fragrant shrub)
- Miswak salvadora persica (tree)
- Neem Azadirachta indica (tree)
Cash Crops (trees):
- Mongongo–staple nut tree/oil tree
- Frankincense: boswellia sacra, boswellia seratta
- Myrrh: commiphora myhrra, balsamodendron myrrha
- Gum Arabic (?): acacia seyal, acacia senegal
- Moringa: oil, compost tea, seeds