Agroforestry and Climate Change What is the role of trees on farms?

Farm Trees and Climate Change

Whatever your position on the causes of climate change it is impossible to ignore the fact that temperatures have been rising sharply since 1970.  The graph shows the ten year rolling average temperatures over the last 100 years in three major farming regions of Australia (data available from www.bom.gov.au). Both the rate and extent of change in Australia neatly matches the trend in global temperature rises and roughly represents an increase of one degree Celcius over 50 years. The recent drop in temperatures which has occurred within the last ten years (that is getting some of the sceptics so excited) is evident as a tiny dip at the end of the curve.

Whilst there is some uncertainty about the impact of temperature rises on rainfall and wind speeds the fact remains that increasing temperatures will naturally result in increased number and intensity of extreme evaporation events, shifts in the timing and nature of plant growth and changes in pests and disease dynamics. It will also lead to more extreme fire danger events and possibly more intense cyclones.

The temperature increase we have already seen, if permanent, is enough to suggest we need to change the tree species we plant. What worked in the past, including the local indigenous species, may not be right for the future. If the trend continues then who knows what the implications might be for our forests.

Not surprisingly, given the emphasis on reducing CO2, almost all talk surrounding the value of planting trees for climate change has been driven by notions of carbon sequestration and trading.  Unfortunately, this approach overlooks the immediate value of trees on farms and the role they might play in helping farmers remain viable. I accept that it may be true: if enough forest is planted on cleared land around the world the rate at which the temperatures increase may be slowed. That’s fine but the fact is that the climate has already changed so much for most landholders that mitigation of the world’s climate probably comes well behind their immediate concerns about adapting to more difficult and uncertain local weather conditions.

If we, as a community, can support strategic revegetation of farms in ways that help farming businesses survive and adapt to climate change – without forests displacing valuable farmland, increasing the fire hazard, or using up valuable water resources - then the carbon the trees lock-up would be a bonus. I am concerned that under the current and proposed trading rules forests will be established for carbon sequestration alone. This might be the cheapest way to meet our national emission targets but, in the process, it will also introduce new risks and uncertainties – particularly for the landholders involved:

1.  If the carbon in a forest is sold then the value of the land on which it grows must decline because a new owner carries both the cost and the risk: whilst they cannot re-sell the carbon in that forest they take on the previous owner’s commitment to hold that carbon in store for 90 years (or pay a higher cost to buy back the freehold rights).
2. If the carbon is not sold, but is seen as a means of offsetting private emissions (from fossil fuels or agriculture), there will be a need to plant an ever increasing area of land and take on a mounting commitment to protect and maintain all the existing forests.
3. The current rules do not recognise the value of carbon stored in timber products. This means that those who have sold their carbon rights would need to buy them back at the time of harvest (at the full retail price) despite the fact that solid wood can be a long term, and arguably more secure, carbon store.
4. Climate change is reducing forest productivity, and possibly longevity, whilst also increasing the risk of catastrophic losses due to fire, disease and drought. If the trees die, someone needs to replace the carbon that was lost.

To suggest that farmers can “opt-in” to the emerging forest carbon trading scheme ignores the inherent risks of them doing so. Whilst all forests established on cleared farmland contribute to the national carbon emission reduction targets, the costs and risks associated with monitoring, registering and trading the carbon in each and every single forest means that most farmers will not benefit. Planting trees on cleared land for carbon sequestration alone is arguably a form of land degradation. Carbon-only forests will reduce the area of productive land available to sustain a growing population - with expectations or an ever increasing standard of living - during a period of international social and political uncertainty.

With ten to twenty per cent of every farm requiring revegetation in order to control land degradation and protect productive farming systems it is imperative that farmers are seen as the key to increasing forest cover in Australia. Every tree planted for shade, shelter, timber, food, biodiversity, erosion control and aesthetics locks up carbon. If governments and community groups want trees planted on cleared land for carbon sequestration the starting point should not be carbon at all but the other values that making owning these trees worthwhile. The need for climate amelioration and income diversification will drive revegetation on farms – sequestration is what the community gains by helping landholders achieve these goals.

In respect to climate change the priorities for agroforestry research and development should be on the role that trees can play in the:

1. Amelioration of the impact of climatic variability and extreme weather events on agricultural productivity and the resource base on which it depends
2. Diversification of farming enterprises by producing products and services that are independent of traditional agricultural markets, produce fewer emissions and are less susceptible to climatic variability; and, finally,
3. Sequestration of CO² in living biomass, soils and woody products as a means of offsetting agricultural emissions and providing marketing and partnership opportunities.

Governments should not assume that a market based forest carbon trading scheme will, on its own, deliver forests in the location, and of the type we need. A substantial investment, possibly funded by the sale of permits to fossil fuel carbon polluters, is required to pay for the research, development and extension required to underpin the private investment (by both farmers and off-farm partners) in multipurpose forest establishment and management. In addition to storing carbon these living forests deal with the complexity of climate change on multiple fronts by:

• producing carbon-neutral green energy (bio-fuels) and carbon-storing/low energy building material (wood);
• expanding and linking natural habitats to support biodiversity adaptation;
• reducing the impacts of extreme weather events on agricultural production;
• protecting communities from fire and flood;
• trapping sediments and nutrients before they wash into sensitive aquatic habitats or out onto the reefs; and,
• providing real long term locally secure ‘green’ jobs that are not dependent on short term government funding.

Trees on farms are an important part of a low-carbon, sustainable future for rural Australia but they must do more than provide a once-only offset to support our continued reliance on fossil fuels. To pay our debt to future generations we need to be smarter than that.