Forest Biofibre: To Burn or Not To Burn?
In August of 2008, the Ministry of Natural Resources (MNR) adopted a policy to guide the allocation, pricing and use of forest “biofibre” for energy production and other value-added end uses. It defines biofibre as “forest resources from Crown forests that are not normally being utilized for conventional forest products,” and includes “tree tops, cull trees or portions of trees, individual and stands of unmerchantable and unmarketable trees, and trees that may be salvaged as a result of a natural disturbance.” The main goals of the policy are to reduce Ontario’s dependence on fossil fuels and to diversify and strengthen Ontario’s economy.
The policy states that projects that benefit Aboriginal communities will be given higher priority and that developing technologies may provide new value-added opportunities in the near future. Accordingly, allocation decisions may include reserving some areas or volumes of forest biofibre in order to be able to respond to these priorities. The policy will be reviewed every five years. For a more detailed review of this policy, see Section 4.10 of the Supplement to this Annual Report.
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Implications of the Decision
Climate Change
Upon combustion, fossil fuels release to the atmosphere “old” carbon, which has been stored underground for millions of years; in contrast, the burning of biomass fuels releases “new” carbon, which was only recently absorbed by plants as carbon dioxide (CO2) and will be taken up by plants again as part of the normal carbon cycle as they grow back to their original standing crop. Over the longer term, therefore, burning biomass for energy is superior to burning fossil fuels, as net carbon emissions are nil. This is why biomass combustion for energy is considered “carbon neutral.” In the short-to-medium term, however, the benefits may be less than assumed. Recent research on the net effect of forest harvest on CO2 emissions to the atmosphere indicates that the time-lag involved in the forest’s regeneration and consequent uptake of the CO2 is such that a substantial, short-to-medium term “debit” is incurred.
By providing an economic incentive for forest companies to move into areas that were previously considered uneconomic (those with numerous “unmerchantable and unmarketable” trees), the biofibre policy will almost certainly increase, perhaps substantially, the size of the annual cut. Much of this material will be burned to produce energy, releasing large amounts of CO2 that will not be re-sequestered for decades.
The boreal forest is a fire-adapted ecosystem and it might not seem to matter if the wood is burned in a power-generating facility or in the forest, after all, the CO2 is released to the atmosphere in either case. However, if large volumes of wood are harvested annually for biofuel, the government must successfully increase suppression of forest fires to a corresponding degree, or the total amount of wood burned annually will increase substantially. With climate change impacts potentially increasing forest fire risk, this may not be possible.
Moreover, the climate change benefits could be reduced by another factor: gas release from newly exposed soils. Clear-cutting methods lead to very large releases of nitrous oxide (N2O), a very potent greenhouse gas, from forest soils for a period of several years after harvest; they also reduce the soil’s capacity to absorb and hold methane (CH4), another potent greenhouse gas.
The use of biofibre fuels may approximate carbon neutrality over the long term; however, it will not achieve this goal for several decades. As we approach what many climate scientists feel are crucial “tipping points,” with increasing greenhouse gas emissions threatening major, irreversible change to our climate, these years will be critical.
Forest Sustainability and Biodiversity
The issue of how much wood residual should be left on the forest floor to prevent the depletion of nutrients is usually discussed in the context of harvesting methods. Tree-length logging (TLL) is a system where the slash (branches, tops, etc.) is removed at the stump and left on-site. With full-tree logging (FTL), the entire tree is dragged to the landing, where slash is either burned or left to decay. The percentage of forest lands being harvested using FTL rose to about 90 per cent in the late 1980s. The question is whether the amount of woody material typically left on-site after FTL (the leaves and branches that break off as the tree is hauled to the landing site) is sufficient to ensure sustainable forest regeneration.
MNR is conducting research to try to answer this question. Results to date indicate that for FTL sites, it takes more than 60 years to replace several nutrients in sandy, dry soils through natural processes. The standard rotation time in forest harvesting is 60 to 80 years. The study also indicated that replacement times for calcium (a key nutrient) are greater than 60 years for all soil types, for both FTL and TLL sites.
Timing of nutrient availability is also important, with the first 15 to 20 years after harvest deemed the most sensitive. Nutrient supplies rise after harvest due to residues left on site. As the new trees start to grow, however, nutrient demand increases greatly while supply remains static because of insignificant litter fall from young trees. MNR’s research work on this issue is entering its 15th year and, to date, the studies do not appear to demonstrate any significant differences between growth rates for young trees in FTL sites and TLL sites.
Guidelines based on these preliminary results have been incorporated into the new Stand and Site Guide (see EBR Registry Number 010-5218). The draft Guide, as proposed on the Environmental Registry on Nov. 27, 2008, does not include a separate set of guidelines or standards for biofibre removal. MNR scientists feel that the existing guidelines are sufficient, regardless of what end use is made of the wood. In the case of more sensitive sites (as defined in the Guide), harvesting guidelines are expected to provide adequate protection.
Some scientists, however, have expressed the concern that there is not yet enough information to assess the longer-term impacts of FTL; it has not been practiced long enough to provide evidence beyond a single generation of trees. Recent international studies suggest that the productivity of average forest soils decline over time under intense harvesting similar to the FTL system. Scandinavian studies suggest that FTL can reduce per-tree biomass growth even in the first post-harvest generation.
Another concern is the lack of significant attention being paid by MNR research to the impact of FTL and clear-cutting on soil micro-organisms, in particular mycorrhizal fungi. As soil ecologists continue to learn more about forest soils, they continue to stress the role of mycorrhizae in the health and productivity of virtually all forest plant species. Mycorrhizal fungi form symbiotic associations with plant roots, trading soil nutrients and water for sugars and other products of photosynthesis. They can also stimulate plant growth and help prevent plant diseases. Clear-cutting has been shown to reduce mycorrhizal populations, probably due at least in part to the reduction in organic residue.
The Resource Allocation Process
By making a “new” forest resource available in very large quantities, the ministry hopes to stimulate the development of a number of “green” industries. However, details on the allocation criteria are not provided, and the general policy statements do not reveal the extent of the ministry’s commitment to high-value, environmentally beneficial end uses. If large quantities of forest biomass are committed to combustion for energy there may not be sufficient material available to support higher-value, more innovative, green applications that arise later.
Some of the new technologies being developed seem to offer many advantages over simple combustion of biofibre for heat and power. For example, pyrolysis converts biofibre into three separate products: “bio-oil,” which can be upgraded into fuels, food additives, and pharmaceuticals; “biogas,” which is burned to power the process; and “biochar,” a type of charcoal that makes a good soil enhancement. A promising aspect of this technology is the potential for the use of the biochar to sequester carbon, as it resists degradation in the soil while also enhancing soil fertility. Since up to 50 per cent of the carbon in the original biomass could end up as biochar, the sequestration potential is considerable.
Public Participation & EBR Process
The ministry posted the proposed policy on the Registry on March 27, 2007, and provided the public with 120 days to comment, with the posting closing on July 25, 2007. The decision to proceed was made on August 13, 2008. The ministry received a total of 23 comments. Most of the comments were supportive of the policy in general terms. Many expressed concern that the new allocation processes might not be fair, equitable and inclusive. Many commented that despite the need to nurture a new industry, forest renewal costs must be covered. Two comments indicated that the new policy was too oriented toward economic development and not enough toward environmental sustainability.
ECO Comment
MNR has presented its biofibre policy as if it is a win-only initiative, with little or no downside. The operating assumption is that harvesting additional forest resources under the current management system is without any significant additional environmental costs. The ECO recognizes that, uncertainties regarding long-term sustainability aside, MNR has developed a fairly robust and responsive management system for mitigating the environmental impacts of logging. However, the system is not without environmental cost. It does not eliminate impacts or risk; it mitigates impacts and reduces risk. This raises the question of whether the projected benefits are worth the potential costs.
The main environmental benefit assumed is a reduction in greenhouse gas emissions. The ECO supports the concept of renewable fuels; however, this policy may not provide the climate change benefit advertised, especially in the vital near term. A rigorous scientific assessment of the concept of “climate-neutral” as it applies to biofibre, as well as other forms of biomass, is required to adequately inform future policy decisions.
The ECO is also concerned with the sustainability of our northern forests. The current planning framework was developed in the absence of a demand for forest biofibre as an energy source; therefore, MNR should consult to develop a set of biomass-harvesting guidelines for Ontario’s forests, to complement and enhance the current set of forest guides. MNR should also expand the current research work to include the effects of biomass removal on soil carbon storage and microbial processes (e.g., mycorrhizal fungi).
Finally, the ECO has concerns with the allocation process for biofibre. The policy does not state the criteria to be used in the decision-making processes and how these will be weighted, nor does it make clear who would make that decision and how the public would have input. This process should be part of, or conducted in association with, the development of a long-term biomass energy strategy for Ontario.
MNR’s resource stewardship principles state: “As our understanding of the way the natural world works and how our actions affect it is often incomplete, MNR staff should exercise caution and special concern for natural values in the face of such uncertainty.” Given the many unknowns that arise from a close examination of the biofibre policy, the ECO feels that the application of this fundamental principle is completely appropriate.
| Recommendation 6:
The ECO recommends that MNR lead other ministries (including OMAFRA, MEI, MNDMF and MOE) in developing a biofuels strategy that reflects the full ecological implications of making biomass a major component of Ontario’s energy supply mix. |
| This is an article from the 2008/09 Annual Report to the Legislature from the Environmental Commissioner of Ontario. |
Citing This Article:
Environmental Commissioner of Ontario. 2009. "Forest Biofibre: To Burn or Not To Burn?." Building Resilience, ECO Annual Report, 2008-09. Toronto, ON : Environmental Commissioner of Ontario. 50-54.
