What is the appropriate response to large scale, natural disturbance events in New England's forests? I posed this question recently to some ecologically-minded forester friends of mine, and in the course of that discussion we broached the controversial issue of Salvage Logging. This practice received recent exposure last week in the national press, including coverage by National Public Radio and the Christian Science Monitor. An Oregon State study of the short-term effects of timber salvage after a massive western wildfire has found that there is better seedling recruitment and less risk of fire danger in areas that were left alone following the 500,000 acre "Biscuit fire" than in areas where logging operations removed marketable timber.
Although many of the environmental issues in western forests are substantially different than those that apply in New England's Woodlands, such studies deserve our attention since the national debate over salvage logging has heretofore lacked much in the way of objective and verifiable science. Salvage logging is often touted as economically justified and is a centerpiece of President Bush's rather Orwellian-named Healthy Forests Initiative. Bush taunted John Kerry on this subject during the last presidential campaign, quipping: " My opponent says he's in touch with the West, but sometimes I think he means Western Massachusetts." Well, as my old Uncle Archie used to say about sundry sacred cows; "maybe it ain't so."
My western Massachusetts forester friends, either members of The Forest Guild or very familiar with its first principles, felt that salvage logging ought not be categorically rejected in all cases as ecologically unsound. They felt that if done as part of responsible, high quality silviculture, there may be some situations where the negative impacts of salvage logging could be mitigated while benefiting the long-term health of the forest. These are environmentally responsible foresters and I respect their long years of experience in our woodlands, but this practice deserves closer scrutiny in light of the available evidence of its ecological impacts elsewhere, and what we know about our own forest systems, before I am willing to endorse it in New England.
To begin with, the Northeast United states experiences many kinds of large-scale natural disturbance. The Great September Gale of 1815, for example, was the storm of the century, but prior to that nothing like it had been seen in New England for 180 years. In modern memory, only the great Hurricane of 1938 has surpassed it in destructive power. Both storms followed very similar paths as they tore across Long Island and made landfall on the Connecticut Coast. Both brought floods and high winds well inland and ravaged the interior countryside as well as the shore.
There are large forest stands in central New England consisting of trees of a single age class that all spouted following the near total devastation left by the 1938 Hurricane. The southern New England landscape in 1815 was predominantly open agricultural land. Otherwise, the Great September Gale would have wrought destruction in our forests making the blasted woods of 1938 pale in comparison.
Large-scale natural disturbance in New England is not limited to tropical cyclone activity. Microbursts from summer thunderstorms can create localized destruction as severe as tornadoes, which also can affect this region. In 1845, a tornado arose as a waterspout in Lake Ontario, cut a 275 mile long swath through the Adirondacks, and exited as a waterspout in Lake Champlain. Its effects are still discernible on the landscape if one knows how and where to look for them. Ice storms and early fall snowfalls can shatter tree crowns across thousands of acres. Although large scale wildfires are rare except for the pine barren regions of New England, an internal Nature Conservancy assessment of New England forest community types and fire found that nearly 80% of them across the region are fire dependent at some interval.
Natural disturbance can also occur for reasons which are not strictly historical but reflect our changing climate or the impact of introduced forest pests and pathogens such a gypsy moth Caterpillar or the hemlock woolly adelgid, the latter of which may have had an assist in its northern spread across Long Island Sound on the winds of 1991's Hurricane Bob.
Given that large disturbance events can and will continue to affect New England's forests, what are the consequences of salvage logging on forest recovery and long-term viability? There is no question that forests will look like hell after a massive wind event. Even a well managed woodlot can look pretty ugly to some after a sensitively conducted logging job. But human aesthetics need not obscure objective assessment of ecological impacts.
Harvard Forest's Dave Foster has documented different responses following the 1938 hurricane from woodlands where salvage logging occurred and those that were left to regenerate on their own. Fully half of the damaged woodlands across New England experienced timber salvage following this storm. Foster identifies several negative consequences of these logging activities when compared to unsalvaged woodlands. Among these are erosion and sedimentation associated with the logging practices of the time, loss of organic material, and the fact that not all toppled or uprooted trees died and their re-sprouting was an important part of forest recovery in places where they were not removed by logging.
I am willing to concede that the most sterling quality modern day silviculture may be able to address sedimentation, erosion, excessive soil compaction, and needless fragmentation of intact forest stands. Except for a limited number of conscientious foresters, however, mainstream forestry activities and permitted forest cutting practices fall well short of this standard. Salvage work takes place in a heavily disturbed environment, often with piles of downed timber several feet in diameter. Furthermore, there is often a rush to recover as much marketable timber as possible before it rots or the market is glutted with all that salvaged wood. I would like to think that timber salvage could be sensitively done in such conditions, but I fear that it is more likely to compound the disturbance and impact natural recovery more than it would encourage it. As such, I do not believe that timber salvage is ecologically justified in sensitive areas or ecological reserves where commercial forestry is normally excluded, such as is proposed in Massachusetts for some percentage of the Commonwealth's forest land under FSC certification.
Another finding of the Oregon State study was that, contrary to Bush administration claims, the available fuels left behind after the Biscuit fire were large diameter standing snags and not as significant a fire danger. Most of the small diameter fuels that carry an initial ground fire were still in the scorched canopies. In contrast, the timber salvage operations left large amounts of slash and course woody debris on the ground where it would be more available for future ignition.
Wildfires in deciduous, New England forests tend to creep and smolder, although they can persist for weeks and go deep in the duff layer before they are finally extinguished. While most of the nutrients are found in small diameter limbs and the tips of branches, standing snags and large, downed trees play important roles in our forests as nurse logs and microhabitats. They retain a lot of moisture as they decay, nourishing plants, fungi, and amphibians on the forest floor.
A scientist friend of mine with The Nature Conservancy says that the northern hardwood forests of the Northeast should have at least 24 large diameter logs on the ground per acre as part of its optimal complement of course woody debris! Without question, a massive hurricane or microburst will leave plenty of course woody debris in our woodlands, but timber salvage removes nutrients that cannot be readily replaced and diminishes the amount available to the recovering forest in its natural nutrient cycle. As it is, the unsustainable and discredited practice of high-grading, where the large diameter, valuable trees are removed and only low-grade, small diameter trees remain, already compounds this problem in our woodlands. Until mainstream forestry and forest agencies get their houses in order, this problem poses a significant threat to our woodlands with or without salvage logging.
From a practical perspective, there will be plenty of woodlands in New England available for timber salvage after severe wind events that are neither part of ecological reserves nor particularly ecologically sensitive. Private landowners are going to want to clean up their woods regardless of whether it would be environmentally better to leave them a wreck. The big difference between western Massachusetts and the American West is that foresters and loggers here get most of their livelihood from working on private land instead of lands held in public trust by the federal government. I therefore do not think it would represent a significant economic hardship to exclude salvage operations, except where needed to reopen pubic access trails, from public lands with forest reserve and sensitive habitats.
We need more studies from places besides the West and about more recent timber salvage than the 1938 Hurricane to inform responsible forest management decisions on this issue. However, we should not discount what data we have because it is the result of studies that have only been able to assess short-term impacts. Responsible foresters and thoughtful scientists have a tremendous role to play in this debate, and as Aldo Leopold said; "the first rule of intelligent tinkering is to save all the pieces."