Tuesday, January 18, 2011

Robbo Holleran: The Biomass Controversy from a Forester's Perspective

Biomass Controversy from a Forester's Perspective

By Robbo Holleran
(Mass Forestry lic# 397)

Robbo Holleran
There are quite a few proposals for new biomass facilities around New England, and of course, they all come with some controversy. The main opposition comes in three categories: Forestry practices/sustainability, emissions such as particulates and carbon dioxide, and the efficiency of producing electricity from wood.

The forestry issues are most dear to my heart. I am a proponent of active forest management, and believe that the benefits of harvesting trees sustainably, outweighs any real or perceived problems. Most people ignore the growth of the forest. Change happens slowly. Harvesting seems messy, wasteful and destructive. But trees are growing faster than they are being harvested in every state. In Massachusetts, we harvest about 20% of the annual growth, and in Vermont it is far less than half. I think it is appropriate to harvest near the growth rate, especially since we are starting with middle-aged to mature, generally overstocked stands.

Grapple skidder pulls low grade hemlock polewood.
Mike Leonard
Crowding is the largest, and often overlooked, threat to the health of forest trees. Trees use sunlight energy to create sugar; they use sugar for the energy of life and the building block for cellulose. A tree with a large crown in the main canopy has an ample supply of sugar, and is healthy. Trees that are overtopped are weak, suppressed and unhealthy. Most of these will eventually die. Harvesting trees is an important part of maintaining appropriate stocking levels to reduce mortality, maintain forest health, and influence species composition, quality and other forest objectives. Since harvesting in Massachusetts has been well below growth levels for a hundred years, many forests have become overstocked; growth rates have been slowing and mortality rates increasing over the last 30 years. Over a million tons of trees die in Massachusetts each year from crowding and other natural causes.

Biomass markets have given landowners the option of removing low-grade material: cull trees, tops and branches, and pulp logs without better market options. This allows landowners to implement their management plans, especially to improve the proportion of high-quality growing stock, which increases the value of the subsequent growth. Having the occasional income from periodic harvesting allows the ordinary citizen the extraordinary opportunity to own forestland, improve wildlife habitat, and hopefully, to pass this on to their heirs. Massachusetts is a mosaic of forest types, agriculture, harvesting practices and landownership. We have tremendous diversity. That diversity is maintained by a full range of forest practices, which are highly controlled by the Forest Practices Act, chapter 61 forest management plans, and licensing of foresters and timber harvesters.
After a biomass cutting with "slash" left for nutrients.
Mike Leonard 

The investors in biomass plants count on the fact that wood chips are cheap and plentiful. They have done the math. There is a bountiful supply of low-grade, low value wood all through our region. Landowners are glad to get rid of this for a low price that barely covers the efficient harvesting cost. If there was any risk of “over-harvesting”, wood chips would become too expensive to burn. Wood supply and alternative demands have been carefully considered in each of these proposals, and they are completely sustainable.

Burning wood for energy creates emissions, such as particles, steam and carbon dioxide. Federal and state emissions standards are tough, and in fact have already driven much of our industries to other countries. So the new technology for biomass is pretty clean. In fact, it produces about 99% less particulates than if the wood were burned in a conventional woodstove. The carbon emissions are part of the controversy. Since wood chips have high moisture content, some of the energy is used to drive off the moisture. There is an argument that says, since coal or natural gas is more efficient to burn, wood emits more carbon per kilowatt; and since tree growth is slow, it may take 10-50 years for forest growth to “reclaim” the excess carbon. We have been spoiled to burn concentrated fuels like coal or natural gas. Efficiency of wood burning has greatly increased, but the moisture content is a limiting factor. Using spent steam for some type of heating increases the efficiency, but is not always practical. Since the carbon in wood was all in the atmosphere, and since every tree eventually dies and releases its carbon, we might as well salvage the energy that we can.

Small group selection regeneration (G40) DCR Quabbin
The real nugget on carbon management in forests is that tree growth is enhanced by thinning, or even clearcutting forests. In an overmature forest, tree growth and mortality are equal, and there is no net growth of wood, net release of oxygen, or net storage of carbon. Those who would like to stop all logging on public forests are advocating for ‘old growth’. While these forests can be beautiful, they tend to be crowded with unhealthy trees, and net growth is zero. If we were to emphasize carbon management for energy in our forests, we would be clearcutting, spraying with herbicides, and planting genetically engineered ‘super trees’ to harvest just after the growth rate peaks. I think the correct balance is to manage our existing natural forest to increase its growth rate, storing more carbon and releasing more oxygen, and producing the full range of products, wildlife habitat and recreational opportunity we all enjoy.

It is easy to look at any proposal and point out problems. Solutions are found by looking at the big picture, and accepting the least amount of harm. It is not practical to think that we could produce all of our electricity with solar, wind or hydro power. Each of these has its own controversies, such as the ecological impacts of solar cell production in China, the impact of wind turbines on view-sheds and bird populations, and fish and water management issues for hydropower. We need to utilize a wider range of power sources, especially since the solutions to our economic and ecological problems are found in technology. By burning some woodchips, we provide a reliable, renewable, homegrown source of power without adding fossilized carbon to the atmosphere. We keep energy dollars in the community, with hundreds of family wage jobs. We assist landowners with a substantial tool for forest management, which encourages investment in growing forests for higher value products and keeping the land in forest use for another generation.

Robbo Holleran (Mass Forestry lic# 397) is a private consulting forester helping landowners meet their goals in Vermont and adjacent areas. His work has him outdoors about 150 days each year, plus play time. He and his wife home-school their children. They have a home office, a big garden and a large bonsai collection.

Mike Leonard is a consulting forester (Mass Forester License #145) 
Website: http://northquabbinforestry.com/

1 comment:

  1. Morris Housen (Erving Paper Mills) likes this.