Norman Endacott sent in the following comment in response to yesterday’s post on this issue.
I am sure there is another perspective and invite someone (perhaps Steve) to send me a piece that is supportive of the Greenfleet initative that I could post perhaps as ‘Feeling Good About Emmissions (Part 3)’.
I wish to comment on Greenfleet’s naive efforts to compensate for the world’s excessive fossil fuel consumption by landscape-scale tree planting.
They should realize that Nature, in collaboration with Murphy’s Law, is lined up against them.
These are the problematical facts about tree/forest growth and carbon sequestration:
1. Though their life cycle, trees photosynthesize and absorb CO2 , lock up carbon in their tissues and expire oxygen. That is great, but simultaneously they respire and convert some of their carbohydrates back to CO2. It is a balancing act (CO2 versus O2) which fluctuates dramatically daily (night versus day) and more subtly and inscrutably over the decades of the tree’s life.
2. As the tree passes through its juvenile phase and into middle age, its rate of wood increment accelerates, remains at a high level, plateaus out and after maturity (100 years plus) starts to decline, becoming virtually zero when the assault of wood-destroying fungi and insects take their toll, cancelling out the miniscule annual wood accretions of which the veteran tree is capable. Then the inevitable failure of the life processes leads to death and disintegration and reversion of all that sequestered carbon back into CO2. (Refer to the condition and fate of the revered Monarchs of the Forest in Tasmania’s Midlands and Victoria’s Central Highlands, observed over the past 100 years.)
3. The greater the compatibility between soil and climate and the tree species chosen, the greater the success in maximising annual wood increment (carbon sequestration). Impoverished sites and arid or unreliable rainfall profiles lead to poor or mediocre growth and wood increment, and accentuate attacks by insect pests. In those situations, languishing and mere survival are all that may be expected. (I’m sure that Greenfleet’s expectations go beyond this).
4. Insect and fungal attack throughout the life cycle of the forest are an actuarial unknown. So are forest fires. Past successful carbon sequestrations may be wiped out with little or no warning.
5. There is no free lunch in this tree planting caper! If success is achieved, and cleared farmland has been converted to vigorous young forest , the conclusion that may be drawn is that good quality agricultural land in a good climate has been used, and high OPPORTUNITY COST attaches to this operation. (Which prompts me to ask – what land is being used by Greenfleet to create its new forests, and produce the promising young forested landscapes depicted in the photographs on its website?).
6. I gather that Greenfleet occupies the high moral ground, and its plantations will never be used for the sordid business of producing timber crops. Those new forests will remain sacrosanct for ever more. But if such new forests have commercial forestry intent, it’s a different carbon cycle ballgame. The forests will be periodically harvested (20 years or 50 years, depending on management objectives). The carbon sink will be reduced to zero, and replanting or regeneration will take place. One must presume that for practical purposes, the harvested produce will finally revert to CO2, given time. I have no idea how the mathematics of ‘carbon trading’ will handle this puzzle. Possibly somehow the continuum of carbon sequestration figures for an idealistic , high-minded, sacrosanct-in-perpetuity , carbon-dedicated plantation may have to be divided by a factor of two , to cover commercial plantations.
8. Likewise, how will the carbon-trading caper get its head around the question of ‘perpetuity’? If the new forest, planted specifically for creation of a carbon sink, goes through its life cycle of say 200 years, then dies and disintegrates and becomes CO2 again, calling for a regeneration process, how can all that complexity be anticipated in the mathematics of 2005 carbon trading? Or is Greenfleet’s programme entirely pro bono (apart from Premier Beattie’s largesse and the donations of the gullible public)?
9. There is another OPPORTUNITY COST burden. The idealogues have only in recent years discovered that forests consume soil moisture in the course of tree metabolism and physiology. What’s more, the faster the growth and the more carbon sequestration that occurs, the greater the water uptake, and the greater the loss to urban and rural water supplies. This should be factored into Greenfleet’s rosy-tinted view of the situation.
Greenfleet is milking the Queensland Government of large sums of money, and also appealing to the community for financial support.
We are entitled to confront them with the above complexities, and find out how rigorously they have thought through the whole process, its uncertainties, economic and social cost/benefits, growth limits and practicalities. One of the most important things we would wish to know is the foreshadowed end-game. How much non-forested land is available thoughout Australia which is of suitable quality and is available. Then, an idealistic scenario to be set out, covering a reasonably short project period. Then some pretty good mathematics indicating what sort of a dent that effort would put, in the overall (alleged) global warming problem.