What role does thinning in overstocked and diseased forests play here?
“If we use insect and disease attacks as indicators of genetic simplicity, and resilience to these pests as indicators of genetic robustness, we can use harvesting to assist natural selection to build a more resilient forest ecosystem with a greater ability to survive climate fluctuations and associated perturbations. This may mean changing certain silvicultural paradigms and not selecting for the fastest growing or tallest trees that in species studied also indicated a lack of genetic diversity, often brought on by inbreeding, but intermediate sized trees that use their energy reserves for defense and water conservation as well as growth. It also means removing afflicted trees that create a fuel bed that promotes stand replacing fires that destroy the trees with greater genetic resilience and seed source that insects and diseases just selected for. Rather than “restoration” forestry, we need to practice “assisted adaptation” forestry where we use harvesting to assist nature in selecting for the most ecologically robust and resilient trees for every species across our forested landscapes.”
Peter Kolb, PhD Forest Ecologist
Adjunct Professor – Forest Ecology and Management
University of Montana College of Forestry and Conservation
Peter Kolb is an Associate Professor of Forest Ecology and Management in the University of Montana’s College of Forestry and Conservation in Missoula and an Extension Forestry Specialist for Montana State University Extension in Bozeman. He holds a PhD in Forest and Range Ecophysiology from the University of Idaho, and a Master’s degree in Silviculture and Forest Protection, also from the University of Idaho. He completed his undergraduate studies at Michigan State University in 1983 and in 2008, he was elected to be a Fulbright Scholar at the Bavarian Institute of Applied Forestry, where he lectured on forest ecosystem processes. While at the Institute, he also joined with geneticists and silviculturists in a review of the latest science for advancing forest resilience to climate change. In this interview, he answers questions concerning climate change and forest management in the Inter-mountain West. Dr. Kolb has developed a series of videos explaining the role of climate change in Inter-mountain mixed conifer dry site forests. you can view them here: https://www.facebook.com/swanstudy/videos
Evergreen: Dr. Kolb, you have waded into the climate change debate with both feet. Lots of controversy here. Many people simply don’t believe the climate is changing. What say you?
Kolb: It is definitely changing, and that’s not news. We’ve been going through long periods of warming and cooling, punctuated by mini-cycles that move in the opposite direction, since the last Ice Age ended some 10,000 years ago.
Evergreen: Are we warming or cooling at the moment?
Kolb: We are warming and have been for at least a century, but we experienced a mini-cooling cycle from about 1940 to 1980. Above average amounts of rain and snow that really had a lot to do with the dominance of shade tolerant tree species we have today in western Montana and northern Idaho – the lush Douglas-fir and grand fir forests with which most of us are familiar. The mini-cooling cycle ended in the mid-1980s, perhaps best indicated by the 1988 Yellowstone mega-fire. Over the last 30 years, our climate has warmed again and, as a result, we are in the midst of a major transformation in forest types.
Evergreen: How so?
Kolb: Just the natural order of things. The cooler, wetter period gave most trees species but especially Douglas-fir and grand fir a chance to successfully reproduce and create much denser forests than existed in the previous century, or speculatively even any time since the last ice age. Now we are warming again and we are seeing a major die-off in trees as water is suddenly very limiting due to drought and overly dense forests. Thus, the big buildups in fuel – woody debris – in our forests. Consider that over the past 16 years more than half of the 25 million acres of forest in Montana has been dramatically impacted and potentially altered by wildfires and insects.
Evergreen: Add in our publicly popular policy of purposefully excluding wildfire from forests, and we have a perfect storm in which ever larger amounts of woody debris fuel larger and larger wildfires in forests dominated by shade tolerant, drought stressed tree species that won’t survive our warming climate anyway.
Kolb: You’ve got it.
Evergreen: As a society, we don’t have much use for wildfire, do we?
Kolb: No, we don’t. The past decade people in the NW have gotten tired (and sick) of choking on smoke all summer long. Historically the public horror following the 1910 Fire and earlier fires in Wisconsin and Minnesota turned the whole nation against wildfire. I understand why, but the very useful ecological role fire can play in historically fire influenced ecosystems got lost in our more utilitarian view of forests brought on by the national need for construction wood and paper from these forests as the United States grew from a global backwater to a world leader.
Evergreen: And the result?
Kolb: We have forests in which the historic mosaic that fires created has been lost to more homogenous stocked landscapes that feature significant and uncharacteristic fuel buildups. Such simplified forest ecosystems provide a lesser habitat for the diverse mix of plant and wildlife species that could be there. When these forests burn they are further simplified by wildfires that are uncharacteristically severe and expansive.
Evergreen: And so what we are seeing here in the northern region is – as you say – simply the natural order of things associated with a new warming climate cycle.
Kolb: In a simplistic sense, yes, but to fully understand what’s happening and what it means you must first understand that this region’s forests have a 13,000 year history of boom and bust cycles – periods of flourishing growth and periods punctuated by great upheaval: massive snow packs and floods in some years, huge wildfires in others, cyclone force winds called micro-bursts, bitter cold, searing heat and periods of drought. Add to that a century of wildfire suppression during a cold wet period that promoted great tree regeneration and growth, and the desire for forest managers to create “regulated” forests with faster tree growth and volume production in order to meet national demands for wood.
Evergreen: So the changes we are observing aren’t simply the negative result of European settlement and the developments it brought?
Kolb: They are not. One of the more interesting recent studies examined pollen and charcoal samples taken from the bed of Foy Lake near Kalispell, Montana. These samples are the scientific record of long warming and cooling periods and associated changes in vegetation. Similar studies focused on tree ring and charcoal samples collected across the Northwest that give us pretty good indications that fires along with climatic fluctuations played an important and diverse role, including frequent fire occurrence across the past several centuries in low elevation forests and a variety of mixed severity and stand replacing fires mid and high elevation forests. There is also ample evidence that the northern Rockies original inhabitants played a very active management role by promoting fires to thin forests and provide for better habitat for important food and medicinal sources such as forbs, huckleberries, deer, elk and bighorn sheep.
Evergreen: We’re familiar with numerous of these studies, including Dr. Steve Arno’s Lick Creek studies in the Bitterroot Valley. Is the Foy Lake study you reference the one that traces 13,000 years of warming and cooling climate cycles?
Kolb: : It is among many others– and the Foy Lake study that Kathy Whitlock of MSU conducted shows that during millennia of the past 10,000 years of the Holocene the Flathead Valley was a drier and more open ecosystem of scattered groves of ponderosa pine and sagebrush flats. Douglas-fir either existed as scattered individuals or was restricted to microsites along rivers and north aspect slopes and did not become a dominant species until approximately 2000 years ago. Even then, the much warmer and drier medieval optimum that started about 1100 years ago once again caused significant changes in wildfire occurrence and vegetation. Our modern forests across the northern Rockies truly have only really existed for the past 800 years, developing when the “mini-ice age” started, and depending on which report you read ended somewhere between 1900 and 1980. Thus back to the climate warming phenomenon we have been experiencing.
Evergreen: What’s the take home message here?
Kolb: The baseline data that scientists have gathered suggest the disturbance patterns hold several take home messages. First that leaving forests to nature does not guarantee their perpetuity. Second, that there are limits to what forest “restoration” can do to assure perpetuity as the term “restoration” means to “bring back to a previous state”, even if the conditions of those times no longer exist. Third, that active forest management can be used to accelerate forest adaptation to new climatic paradigms and moderate the many boom and bust cycles that typically are required before vegetation adjusts to the new circumstances.
Evergreen: Why won’t leaving nature to its own devices guarantee forests in perpetuity?
Kolb: If we look at the research that allows us to construct past vegetation patterns across landscapes as well as the ecology of individual species it is obvious that vegetation changes in response to climate trends. Historically forests have disappeared or been diminished over relatively short periods of time because more often than not whole populations get stressed beyond the point of return and fail, not just selected individuals. Think about bark beetles killing 80% of the most maladapted individual trees, only to have the survivors killed by a severe fire that the fuel loading promotes. Forest reestablishment typically takes longer because trees need decades to mature and produce seeds, and the relatively large seeds of conifers do not move great distances quickly.
Evergreen: Which takes us back to forest restoration. What can we do to moderate the transition this warming cycle has forced upon us?
Kolb: Forest restoration should include removing dying and lesser adapted tree species from overstocked forests by a variety of harvesting practices that emulate frequent, mixed severity or even stand replacing wildfires, as well as promote natural regeneration and selection for new generations of trees and genetic diversity. Furthermore implementing continued management practices within “restored forests” including fire to maintain species and structural diversity across landscapes is needed.
Evergreen: We assume the retention of larger and older living trees. Is there more to know?
Kolb: Older and larger trees are an important part of any forest across the northern Rockies which is why it is important to give them the best chances for survival. They are historically and depending on the site also not always prevalent on the landscape as is the case in coastal ecosystems of Washington, Oregon and California. They may be repositories of the past genetic diversity, but they may also have the genetics that were optimal during the time they developed: the mini ace age which makes them maladapted for the environment of today. Luckily most of our native tree species have an enormous stored genetic toolbox hidden within them. This is why it is critical that they are allowed to reproduce which not only preserves their genetic heritage, it allows for a new selection process that furthers new trees that are slightly tweaked to grow best in our new climatic norms. Most trees regenerate best on disturbed soils and in forest openings, which is why a mosaic of disturbances is so essential for northern Rockies forests to build resilience and thereby perpetuate themselves – which includes harvesting units and burned areas.
Evergreen: When you say best chance for survival we assume you mean remove the diseased and dying trees that surround them.
Kolb. As best we can, yes. We need some level of diseased and dying trees as they are important food and denning sources for the myriad of other species that inhabit our forests, but we don’t want big fires to kill trees that display a superior natural immunity to insects and diseases that are so pervasive in northern region forests. This is our future forest.
Evergreen: What role does thinning in overstocked and diseased forests play here?
Kolb: If we use insect and disease attacks as indicators of genetic simplicity, and resilience to these pests as indicators of genetic robustness, we can use harvesting to assist natural selection to build a more resilient forest ecosystem with a greater ability to survive climate fluctuations and associated perturbations. This may mean changing certain silvicultural paradigms and not selecting for the fastest growing or tallest trees that in species studied also indicated a lack of genetic diversity, often brought on by inbreeding, but intermediate sized trees that use their energy reserves for defense and water conservation as well as growth. It also means removing afflicted trees that create a fuel bed that promotes stand replacing fires that destroy the trees with greater genetic resilience and seed source that insects and diseases just selected for. Rather than “restoration” forestry, we need to practice “assisted adaptation” forestry where we use harvesting to assist nature in selecting for the most ecologically robust and resilient trees for every species across our forested landscapes.
Evergreen: So if a tree met your criteria, you would harvest it no matter its size?
Kolb: All trees eventually die. Removing trees solely on the basis of their size or age is the wrong way to go about restoring forests. We first need to identify the tree species mixture that is best suited to the particular site with regard to drought and fire tolerance. Then we need to identify the individuals to leave based on their resilience to insects and diseases that a can be nature’s response to stress brought on by our warming cycle. Based on research on the historical development of Northern Rockies forests, many areas of expansive and dense forests originally developed from small pockets of trees that invaded after the last ice age, which could indicate that our forests consist of a high percentage of inbred trees with limited genetic diversity, and poor adaptability to stress. If a particular stand has an overabundance of big old trees and removing some will help others survive or reproduce, then it would serve the ecosystem well to do so.
Evergreen: Can you cite any examples where the kind of harvesting you describe has protected trees that are more resilient to insects and diseases?
Kolb: One of the best examples is the management on the Confederated Salish Kootenai lands in the Flathead of Montana. Their forest plan incorporates forest science and silviculture as well as historical recollections of forest patterns and densities and thus where appropriate old trees are protected or harvested as well as the diseased and dying. The tribes earn a good income, employ many tribal members and help ensure the survival of the forests and the ecosystem services they provide. I live surrounded by these managed tribal lands and we have moose, bears, bobcats, grouse, wolves and a wide variety of native birds on our 20 acres of forest all the time. In another context such as the most massive mountain pine beetle outbreak on lodgepole pine in recorded history one can look to the Yaak River drainable on the Kootenai National Forest in northwest Montana. It is an impressive mosaic of young and old trees that was left to grow following the mountain pine beetle outbreak and extensive salvage harvesting in the 1970s. Because of the mosaic of young and old, it has not shown the massive impacts of the recent mountain pine beetle outbreak. Unfortunately the harvest units were prepared as squares so the only real negative is the forest appears as a checkerboard, whereas creating irregular clearcuts would have resulted in a more natural looking and functioning forest.
Evergreen: And you believe this same approach is workable elsewhere in Montana today?
Kolb: I know it will for the simple reason that it relies on emulating the same natural disturbance processes at a benign level that created the forests that we have so valued this past century. Humans and our values that include our political system as well as the scientific process do have the great potential of doing great good as well as great harm. Figuring out which is the good versus harm is a messy process but we must remember that protecting landscapes is not exclusive of using them.
Evergreen: And you’ve produced a video series that offers society some alternatives to simply letting nature take its course in our dying forests.
Kolb: Yes, I have spent 30 years studying and trying to figure out the complexities that make the northern Rockies forests unique and functional. Too often NW coastal forest ecology and management are used as the model for the northern Rockies, and they really are not comparable except at very coarse scales. To have an intelligent conversation about what our options are requires that we first understand what our realities are, which hopefully the videos convey. Thus the purpose of the videos is to explain what we know, or should know using terminology and concepts that everybody understands and relates to. The science world tends to revel in their sense of superiority and the use of specialized technical terminology when in reality neither is productive or needed most of the time.
Evergreen: We hear about using management to enhance forest function and resilience discussed frequently among the collaborative groups we’ve interviewed over the last eight months.
Kolb: The collaboratives with which I am familiar have done their homework.
Evergreen: Are you an optimist or a pessimist where collaboration is concerned?
Kolb: When we consider the fact that Europeans and Native Americans have been managing forest landscapes since the last Ice Age ended, I think the answer to your question is that forest collaboration can work if collaboratives are allowed to make decisions based on good information as well as local knowledge, local needs and a commitment to do what is best for both the forest and the community.
Evergreen: How do you think the Forest Service is handling the impacts our warming climate is bringing
Kolb: Where the Forest Service has allowed its District and Supervisor staff to stay in place long enough to acquire local knowledge, it is doing reasonably well. But you can’t bring someone new into the mix and expect them to make decisions until they are well acquainted with local culture, forest conditions and opportunities to initiate forest restoration projects.
Evergreen: For example.
Kolb: I think a lot of young people in the Forest Service in Montana today would like to be as successful as Tim Love, who was the District Ranger at Seeley Lake for 20 years, more or less, before he retired. As you probably know, Tim pioneered the Forest Service’s stewardship contracting program. He was quite knowledgeable with every ecological and practical detail in his district and well respected by nearly everyone in the Swan Valley.
Evergreen: We interviewed Mr. Love twice and found him to be eminently qualified and, frankly, a real pleasure to be around. And he certainly took good advantage of the presence of the Pyramid Lumber Company. Without the log market they provided, his Clearwater Stewardship Project would never have gotten off the ground. But he did it, and he did it very well.
Kolb: Unfortunately, there aren’t enough Tim Love’s to go around, but what he brought to the table in a forestry sense is the same thing that Montana ranchers who own timberland bring to the table. Most of them grew up on the ranches they own. They have a lot of knowledge that you can’t acquire in textbooks. They get their hands dirty every day. You can’t put a price on that.
Evergreen: This reminds us of a man we knew who went to work as the Assistant District Ranger at Prospect, Oregon after he got out of the Army in 1945. We once asked him what his first job was and he said, ‘My first job was to dig a trench from the highway to the office, so we could bury the telephone line.’ I don’t imagine many modern-day District Rangers are given the opportunity to experience a similar story.
Kolb: The application of local knowledge is the key to collaborative success. A PhD with no knowledge of local forest conditions will do a terrible job until he or she acquires sufficient knowledge of local forests and local culture to make good decisions. This is why Montana’s private landowners and tribes are among our best forest managers. Forest management across the northern Rockies must be site specific, because our landscape is so variable and geology, soils, microclimate, hydrology and species mixtures create unique scenarios for every location. Only someone who intimately knows the land they are managing can make quality decisions where timing and cumulative effects are critical.