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Eyeing soil carbon, ‘small’ tree plantings

Opinion Piece

The recent Tairawhiti rain emphasises the issue of climate change, even though climate has been changing since the beginning of time. Carbon is promoted as the primary driver of current warming and governments have reacted by putting a dollar value on carbon and emissions. The reality of this strategy needs thorough investigation. “Passing the buck” does not resolve the problem.

The carbon credit system endeavours to resolve climate change by connecting carbon and emissions. Unfortunately, it avoids the most significant carbon of all — that which is a vital part of fertile soil. Scientists tell us that one-third of excess atmospheric carbon has come from soils. University of Sydney Professor John Crawford has said that recent projections of topsoil degradation indicate that within the next 45 years, our planet will produce 30 percent less food for a population demanding 50 percent more. (He may be wrong on this in the light of recent plummeting population projections.)

There is urgency to return carbon to the soils for many reasons, including climate change, food productivity, energy and resource production — including biochar and activated carbon, water storage, sustainable agriculture etc.

Carbon in its many forms is, second to water, the most critical factor for land productivity. Soil carbon can store up to 20 times its own weight in water. This has profound implications for irrigation and water requirements in times of increasing climate uncertainty.

Another serious omission from the calculations are “small” plantings of trees which are the most valuable trees we can grow.

Trees should be grown on 20 percent of all land. Every tree canopy metre can be easily measured with modern technology. Selective tree plantings can have extraordinary implications for increasing land productivity, in some situations by more than 60 percent, plus the value of the trees themselves. They have profound implications for diverse and balanced eco-systems and sequester carbon within themselves and into the soil further than 40 metres away.

Trees dramatically reduce wind, which affects evaporation, wind-chill and heat impacts on livestock, wind damage on crops etc. They also provide their own commercial opportunities.

Our “carbon deficit” are calculations summarised for targeted consumption and clearly provide an inaccurate measure of our true carbon position. We are being misled by our own government and not incentivised to plant the trees that have the greatest benefit of all.

Planting large areas of monoculture radiata, at the expense of food production when millions are starving around the planet is, at best, irresponsible. It is also an extraordinary biological, environmental and commercial risk with the likely scenario of when, rather than if, a catastrophe results. A new disease and/or drought could result in a massive conflagration and the release of all that “stored” radiata carbon back into the atmosphere; and leave environmental consequences which will make our East Coast experiences of forest slash seem insignificant.

If politicians are going to prescribe solutions, they need to do so from a perspective of reality rather than political persuasion, convenience and seeking brownie points from targeted audiences.

Nature thrives on diversity and that is urgently needed right now.

Marcus Williams

  1. Ewan McGregor says:

    Totally agree, Marcus. A well informed and thoughtful comment.
    Ewan McGregor, Waipawa

  2. Donald Robson says:

    Well put, Marcus.
    Technology allows us to map soil carbon fairly precisely. And the sooner every landowner is able to understand the importance of soil carbon, and are incentivised to participate in the carbon market, the quicker we’ll get past the tyranny of foreign-owned monoculture pines and angry farmers struggling to see a future beyond government impositions.
    Apart from getting weaned off fossil fuels, mobilisation of the various methods of getting carbon into the ground as fast as we can , especially my own favourite – biochar- is probably our only realistic chance of staying on this wild climate ride we’re about to experience. And as farmers usually have the skills and adaptability to pursue this kind of challenge at the scale required, let’s focus on policies like getting granular mapping of soil carbon for all properties and paying people who build their carbon levels.The additional water and nutrient retaining capacity is also likely to be more productive as well, along with keeping waterways cleaner.

  3. Craig Bauld says:

    Nice, Marcus, thoroughly sensible. I think those population projections are focused on “rich” countries, and have little to do with reality.