Biomass and Small-Diameter Wood Utilization

  In many forests regions in the western United States, including the Sierra Nevada, there has been a significant increase in the growth of small-diameter trees and understory vegetation. The reasons for these overly dense forest conditions -- that are not natural -- are complex, but are essentially due to the loss of old forest during the last century and a half of intensive logging, coupled with fire suppression.

The majority of the Sierra's ancient trees, with their huge, fire resistant boles, were logged out over the last century. Along with intensive fire suppression forces, the result has been a profuse buildup of understory trees that are unnaturally crowded in many areas.

Under the conditions of natural forest succession, the regular presence of fire would act to thin out these dense stands of woods. Over time, this natural thinning process resulted in the development of naturally fire resistant stands of massive trees.

Overstocked stands have increased the risk of insect, disease, fire, and drought damage, and they are costly to manage. Finding economical and marketable uses for this material, called biomass, would alleviate these problems and could provide opportunities for local communities to benefit while helping to offset forest management costs.

At the same time, the use of biomass for energy and fuel needs presents a unique set of potential environmental risks. Sierra Forest Legacy is committed to finding the right balance between sustainable uses for forest fiber, and long term protection of the rich natural resources and biological treasures that comprise the Sierra Nevada mountains.

The Forest Guild has developed a biomass policy statement which we support. The policy accurately summarizes the issues we are also concerned about. Here is an excerpt:

Biomass removal and utilization can provide ecosystem benefits by reducing forest fire risk, improving forest stand health and productivity, helping to meet rural community economic development goals as a renewable energy source, and mitigating climate change. Considerable risks are also associated with biomass removal including adverse effects on biodiversity, soil productivity, wildlife habitat, both water and air quality, and reduced carbon storage and sequestration. A finite supply of forest biomass exists that can be produced sustainably, and source forests cannot produce enough wood to meet more than a fraction of aggregate U.S. energy demand. Future demands for both existing and new competitive uses of woody biomass may produce an unsustainable market demand on U.S. forests. Public policy should limit the use of biomass to the amount that can be grown, harvested, and supplied sustainably.

As a precautionary note, it is important to recognize that in the case of private timber industry logging in California, the California Forest Practice Rules are believed by many to be adequate to protect California's natural resources--but unfortunately, this is not the case. Although the language in the Rules is at times exemplary, in actual practice the rules allow sufficient flexibility that conservation goals are rarely achieved. This is why a casual Google Earth search of the Sierra Nevada using the history function will reveal a patchwork of clearcuts on top of clearcuts, leaving little doubt that impacts to biodiversity have been severe--and in fact, on-the-ground assessment reveals a homogenous sea of plantation forests, lacking hundreds of species that should be associated with these forest stands. The agency with jurisdiction for enforcement in California, Cal Fire (California Department of Forestry and Fire Protection) has demonstrated very little ability to enforce the overarching aim of modern improvements to the Rules, such as protection of functional wildlife habitat, and limitations on cumulative impacts to natural resources.

Currently, Cal Fire is in the process of developing new rules or at least a policy in regards to biomass harvests on California's private timber lands. You can check for updates from Cal Fire at this website.

SIerra Forest Legacy is addressing the issue of biomass in a variety of ways, having looked deeply at the issue and determining that there is a level of sustainable biomass removal that we believe is scientifically, and ecologically sustainable and credible. We may not have a lot of choice in the matter now that tree mortality has reached record levels. For a good look at what has happened to the forests in the Southern Sierra Nevada, please review the 2017 report, Tree Mortality--100 Million and Counting. Although some conservationists would argue that the trees should simply be left alone, there are no forest communities and land owners that want to live with the high hazards associated with acres of dead trees, hazards that include increased risk of fire, and the risk of falling trees. It's also important to recognize that the majority of mass die-off has occurred in existing plantations--not exactly biological diversity hot spots.

As a member of the governor's Tree Mortality Task Force, Sierra Forest Legacy is working to ensure that policies meet our science-based sustainability standards. Policy must disclose the full range of possible ecological impacts, including impacts on future fire behavior if reforestation is implemented using business-as-usual methods. Governor Brown's most recent budget amendment for 2018 includes significant new funding that will assist landowners in removing dead trees from their properties, as well as increased funds for prescribed fire. These are policy changes that we consider essential. Learn more about our work to promote prescribed fire on the Fire MOU Partnership page.

In the June issue of The Sierra Voice, we addressed the issue and included a link to a 3-page benefit evaluation guidance document. You can read it here.

If you would like to learn more about Forest Guild's sustainable biomass policy for forestry, you can download the 2010 three page policy here. In 2013, Forest Guild produced a policy guidance for biomass specifically for Pacific Northwest forests. Although not specific for Sierra Nevada forests, much of the guidance easily applies here as well.

Read about some appropriately scaled biomass projects in the links to your left.