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Updated: Nov 21, 2022

Proteins are a building block of life - they are what our muscles are made of, but they are a bit tricky to produce as food and we frequently have a lot of 'leaky' problems where nitrogen - the key element of protein ends up as a water and air pollutant, causing problems for aquatic life or as greenhouse gasses. Tree nuts could be a great part of solving the protein challenge and helping the planet breathe a little more easily.

We need something like 0.75g of protein per kg of body weight - so let's say an average of 50g a day per adult or two palmfuls of fish, meat, nuts or tofu. But they're not completely easy to come by from an agricultural point of view - not if you want to do it sustainably.

The key element of proteins is nitrogen, and whilst 78% of air is benign nitrogen gas - so there is plenty of it you might say, it is difficult to get into a form that we can eat, without using lots of energy and wasting it in quite damaging forms.

Nitrogen, unlike other nutrients, is not found in mineral form and so we pull it out of the air using a lot of energy, producing a lot of greenhouse gas emissions. Then once we have it in a usable form and apply it to soil, it is quick to either form volatile nitrous oxide gasses that go into the atmosphere and act as aggressive greenhouse gasses, or it dissolves in water and washes away, causing problems in aquatic environments. It is so 'slippery' that it is typical to use only 30-50% when it is applied as a fertiliser to crops and the rest is lost. Remarkable when you think how expensive it is too.

When finally nitrogen is available and is used by plants, the high protein plants are not the easiest to grow! Annual proteins - peas and beans for example - require lots of soil preparation and well draining soils, many want fantastic amounts of sun, they don't like saline conditions and can be quite fragile with humidity changes. They really are not well suited to large scale mono cropping - which is pretty much the only way we produce commercially available food. Essentially they are so desirable every pest and problem seems to be after them and yields are highly variable (or the crop is constantly sprayed and treated).

Popular proteins for human consumption are soybean and meat. Both have notable problems - especially meat which anyway almost always uses lot of soybean (perhaps 80% of it) for its production. The particular problem of soybean is the sheer global demand for it as the outstanding 'best' option, so it is produced in massive industrial agricultural systems with no diversity and little care for the soil. Soybean is also grown on deforested rainforest soils - which themselves emit carbon previously stored under the trees aside from the problems of the lost carbon of the trees themselves or the life lost from felling them.

Proteins from meats though - especially beef (this does depend to some degree on the production system) are the worst offenders producing up to 60 times more greenhouse gas than pulses.

All of this to introduce you to the possibility of a tree-nut!

What if you could move from these plants and animals of challenge, to something really totally different? From an annually cultivated uncertain crop that is associated with deforestation and soil degradation; or from an animal that can seem something similar to a greenhouse gas machine, to a perennial crop that literally fixes carbon and hosts biodiversity? The difference is remarkable. In greenhouse gas terms you might say it is up to 400 times better! That is one estimate of the climate impact difference between beef and tree-nut proteins.

This is not a pitch for a shift to only once source of protein. We need diversity. But it is very clear to people who understand agroecology, that we are extremely lacking in trees in our landscape, and we are in urgent need of productive trees. An element of the urgency is simply that it seems with each passing year our climate makes it more difficult even to establish a tree. Trees do need a few particular years of care to establish, during which they are 'not productive'. And hot dry summers present a challenge and a cost in establishing trees. When conversely if we could generate enough woodland cover, we might slow this damaging trend as well as to answer it to some extent as things get worse.

Trees improve water management by slowing rainfall and creating a soft soil surface and deep channels for water to infiltrate quickly, deeply, and to be stored - reducing runoff pollution and drought periods and supporting life. They slow wind speed, provide shade, and moderate temperatures too - all helping to manage water in the soil. They increase organic matter which is a base of biodiversity and life. Their roots reach well beyond the 30cm or so of annual crops to draw on soil fertility and water far beyond that that we usually consider to be agriculturally available. This deep undisturbed constant rooting also enables them to form relationships with beneficial fungus for additional nutrient use efficiency and biodiversity. Trees of course are a good companion of people, offering some stability in a rapidly changing world, they breath our CO2 and offer us back their oxygen. The UK was once of course well over 60% woodland, and I think there are people who have particular need of time in woodland, perhaps from some distant relationship with forest dwelling hidden in their DNA.

We have several wonderful nut species that can reliably produce protein in the UK including Cobb nuts, Walnuts, and Chestnuts.

Let us do ourselves a favour, ignore pay back periods and politics, and risk an act of hope. Let us do something a little bit nutty and plant a tree. You could consider planting one in your garden, or if you would like to plant more than just in your own garden, then you can buy a tree for us to plant and we will care for it and aim to sell its produce in the future which enables it to substitute more ecologically damaging proteins in people's diets. We'll send you 250g of green fresh nuts next season and you can come and visit your tree! And if not... come anyway and enjoy the shade of the trees that we have managed to plant.

Try a meal with raw veg and no boiling, and you’ll save as much energy from greenhouse gas warming as was used to grow it. Make it a locally grown microgreen [ad!], and you’ll do even better!

I spent a little time this evening reading about carbon emissions of UK produced broccoli compared to vs imported, Spanish, broccoli. I love how these studies have a way of throwing up something unexpected – and in this case I think, also something that we can actually do something about.

We do find that in general, fresh UK produced broccoli is better for the environment – not too surprising given that it travels on average 200km rather than 2,600km. What is surprising though, is that the authors calculated that 50% of greenhouse warming potential related to the broccoli life cycle was used in the home - much of this by cooking on the hob!

‘Lifecycle analysis’ are used for these studies and are great for comparisons. They involve looking back at what went before, and before that, and before that, right to the start of the process, and forwards also. For each point then, in this case, calculations are done about what fuels, energy, and materials are used and the impact that these have.

Field grown broccoli is produced by the ploughing of land, usually a few times to get the ground ready, planting of seedlings indoors, transplanting, covering with plastics, spraying for weeds and pest control, harvesting, cooling and packing, transporting (and again, and again), preparing, cooking, eating… lets stop there! Energy is used at each point.

Huge tractors guzzling oil as they turn over heavy soil mile after mile are what come firstly to my mind as big energy users – it turns out that perhaps 30ml of diesel might be used to produce a typical kg of fresh broccoli [2]. This might not sound like much, but burn that amount and watch the smoke go up – not very pleasant. Yet this 300 watts of energy is what you might use for ten minutes of simmering on the hob with a lid on. Use your kg of broccoli on three occasions and you’ve used three times the amount of energy as the tractor that was used in its growing!

Well, raw or juiced broccoli are options, but more realistic might be microgreens! One of our 30g pots will deliver more of some nutrients than a kg of fresh field grown broccoli, and can be readily eaten raw with all its nutrients in place: eliminating that cooking period.

Try a meal or three with raw veg only, and save a little on gas, and its environmental impact.

[1] Depending on farming system, growing conditions, yield and other factors. [2] Some farmers in the study achieved a third of this rate.

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