Editor's Column

Guest Columns

Notes From All Over

Like all plants this ponderosa pine bud draws life from the free non-polluting energy of the sun.

Editor’s note: Dr. W.R.J. (Wink) Sutton is a botanist of considerable renown. Now a private consultant in New Zealand, his career path included 27 years with the New Zealand Forest Service, 12 years with Tasman Forestry (now Fletcher Challenge Forests) including two years with the Canadian Federal Forest Service in Victoria, BC. He holds degrees in botany, chemistry and forest economics, and is an authority on radiata pine plantations. He is an officer in the New Zealand Order of Merit, a fellow of the New Zealand Institute of Forestry and an honorary member of the Society of American Foresters. He is a frequent contributor and advisor to Evergreen.

Dr. Sutton, what is photosynthesis?
Photosynthesis is the process by which plants, including trees, capture visible light energy and, with the aid of chlorophyll, convert water from the soil and carbon dioxide from the atmosphere into glucose (sugar) and oxygen. Subsequently, glucose is converted into other organic chemicals, the most common being cellulose—a water insoluble polymer containing about 10,000 glucose molecules laid end to end. In trees, these organic chemicals are converted to wood—a very complex cellular structure with a very high strength to weight ratio that makes it ideal for use as a construction material.

Lumber manufacturers tout the “free non-polluting energy of the sun” when describing the environmental advantages of wood over other structural building materials, especially steel. What is the significance of this phrase?
It takes about ten times as much energy to manufacture steel as it does to make the equivalent amount of wood. The smelting process by which iron ore is converted into steel relies heavily on fossil fuels—especially coal—that release carbon dioxide and other gasses into the atmosphere. By contrast, the only energy needed to initiate photosynthesis comes from the sun. We pay nothing for the sun’s energy and it does not pollute the atmosphere. Once the solar-powered wood formation process is completed only a modest amount of additional energy is needed to convert the wood of a tree into finished lumber.

Is the sun our most important renewable energy source?

Dr. W.R.J. “Wink” Sutton holds degrees in botany, chemistry and forest economics and has written widely on the environmental advantages of wood over other, non-renewable structural materials.

Yes. The sun’s energy is vital to all life forms on earth—and of course to photosynthesis. Fossil fuels, which currently power much of the industrialized world, are finite. Someday they will be gone. But as long as the sun continues to rise every morning, it will remain the most important of our known sustainable and renewable sources of energy. Other renewable energy sources include geothermal, tidal and nuclear fission, which is of course, very controversial. Hydro and wind are also important renewable energy sources but they are in fact forms of solar energy—the result of warming by the sun. Sun powered photosynthesis offers civilization a real bonus because it provides not just a way to store solar energy but also a way to create structural building materials and other solid wood products while storing or recycling carbon dioxide, thereby helping to mitigate the environmental impacts of global warming.

What gives wood its high strength to weight ratio?
Cellulose accounts for wood’s great strength. If you look at it with the aid of a powerful microscope you see a honeycomb-like structure which is very strong for its weight. As trees, these complex cellular structures can carry tremendous loads and withstand enormous natural forces. It is thus ideally suited for use in structural applications including floor joists, rafters, framing walls, bridge timbers.

How is it that trees help clean the air?
Once again, we have photosynthesis to thank. As trees grow, they act as carbon sinks, absorbing atmospheric carbon dioxide and converting it to wood. Although both fossil fuels and wood are essentially stored solar energy, their use has a very different effect on the net level of carbon dioxide in the atmosphere. When the carbon from fossil fuel is released into the atmosphere it stays there for millions of years, but as forests grow they re-absorb released carbon dioxide creating new wood. As long as forests are sustainably managed—meaning the wood harvest is no greater than the tree volume increment—our civilization can use as much wood as it wants for as long as it wants, with no permanent increase in atmospheric carbon dioxide. This is why any proposed carbon tax on wood consumption makes absolutely no sense.

You are on record as saying wood may someday replace petroleumbased chemicals.
Yes I am. We have some distance to go in terms of basic research, but the idea intrigues me. I see no reason why a raw material as complex as wood cannot be broken into its molecular components, then reformulated as wood-based chemicals. Biomass fuels, ethanol and methane, are just the beginning. Wood is already used in perhaps 100,000 applications. There is every reason to believe that there are many more potential uses for wood, many of them will be complex organic chemicals and compounds. We could use wood to make all of the petrochemical products that are currently made from fossil fuels.

In the future, will most of the world’s wood come from plantations?
An increasing amount certainly will. I can’t see how else we can meet the needs of a world population that is expected to top ten billion by mid-century. Natural forests currently supply 80 percent of the annual industrial wood harvest, but there is growing political pressure to conserve natural forests. Planted forests have distinct advantages over natural forests: faster growth, trees grown as crops specifically with specified wood properties and the certainty that the fiber will be there when the market demands it. Per capita wood consumption has declined slightly over the last decade in industrialized nations, but it is still increasing in emerging economies. Given rising energy costs and global warming concerns I don’t expect energy intensive wood substitutes, including steel, will take a larger market share than they now have, so it is likely that the worldwide investment in forest plantations will increase dramatically in this and future decades.

What would you say to people who believe that timber harvesting destroys forests?
For millions of years, forests all over the world have demonstrated a remarkable ability to recover from all sorts of catastrophes, including horrific wind storms, massive wildfires, devastating volcanic eruptions and insect and disease infestations. In nature and with harvesting, successful regeneration depends on some of the forest remaining intact. In harvesting, sustainable management is the key. This insures that only a relatively small area of the forest is harvested at any one time, and that the forest as a whole remains intact. I would also ask people to consider the miracle of photosynthesis. Here is a natural process powered by the sun that converts water from the soil and carbon dioxide from the atmosphere into glucose and oxygen. The result is wood, civilization’s most versatile raw material—a material that is environmentally benign, renewable, recyclable and biodegradable. I know of no other earthly process that uses so little energy to create so many life-giving benefits. So long as harvesting is done sustainably in an environmentally responsible manner, there are no downsides to the continuing use of wood. The world should be using more wood, not less.