There is no generally accepted definition of urban sustainability. A recent report issued by the National Academies of Sciences, Engineering, and Medicine defines it as “the process by which the measurable improvement of near- and long-term human well-being can be achieved” in three areas: environmental, economic, and social. These three areas constitute the “triple bottom line” we hear so much about these days. The report conceptualizes them as combining to represent urban sustainability as illustrated in Figure 1 at right. By mentioning “near- and long-term” welfare, the report points to a popular conceptualization of sustainability: not compromising future welfare in the pursuit of short-term goals.
This blog typically focuses on the environmental part of sustainability. Research consistently indicates that, while a large majority of Americans favor protecting our environment, they consistently rank its importance below other national priorities. For instance, Figure 2 shows the results of Pew Research Center polls asking Americans to rate which issues should be top policy priorities. The chart shows that out of 20, protecting the environment ranks 14th, and dealing with global warming ranks 19th. Polls in 2009 and 2013 had similar results. I feel that the capacity of the planet to support life should not be a low priority; I focus on it because it is neglected.
The specific urban processes that might underly urban sustainability are still under conceptual development. The real purpose of the report is to review that work. It looks at 4 sustainability rating systems that have been developed: the American Green City Index (EIU, 2011), the Urban Sustainability Indicators (Mega and Pedersen, 1998), The Sustainable Cities Index (Arcadis, 2015), the Sustainability Urban Development Indicators (Lynch et al., 2011). In addition, the report develops its own rating metrics by looking at 9 North American urban centers, plus the United States itself, to see what systems are being monitored, and which specific indicators are being used to monitor those systems. The 9 cities are Cedar Rapids, Chattanooga, Flint, Grand Rapids, Los Angeles, New York, Philadelphia, Pittsburgh, and Vancouver.
Table 1 at right shows the results of the review. I have adapted the table to focus only on the environmental indicators, and to eliminate the scholarly references.
If you are interested in this conceptual work, then the report would make important reading. I suspect than many readers of this blog, however, want to know what the results are: which cities rate as sustainable, and which don’t. As I said, the metrics are still under conceptual development, and I could find only one rating system that has actually been applied to cities in the United States: the US and Canada Green City Index. They rate 27 North American cities using their system. They provide separate ratings on policies related to CO2 emissions, energy mix and consumption, land use, green buildings, green transportation, water consumption and purity, waste management, air quality, and environmental governance. They also combine it all into an overall index.
Figure 3 shows the results for the overall index. St. Louis is the only urban area in Missouri represented, and it comes in 26th out of 27; only Detroit ranks lower.
The index values have no specific meaning other than as a score on this particular index. Thus, absolute values probably have no interpretable meaning. They probably do have relative meaning, however, in comparison to each other. What disturbs me is not that St. Louis is low on the scale, anybody familiar with the city would suspect as much, but with how far behind the city is.
In considering this chart, please be aware that the index was not constructed by an academic or governmental body. It was developed by the Economist Intelligence Unit (a part of The Economist Media Group) in cooperation with Siemans AG (a German corporation). This does not mean its conclusions are invalid, but it may mean that their work hasn’t undergone the review processes that academic and governmental publications do.
Arcadis. 2015. Sustainable Cities Index 2015: Balancing the Economic, Social and Environmental Needs of the World’s Leading Cities. Available at https://s3.amazonaws.com/arcadis-whitepaper/arcadis-sustainable-cities-index-report.pdf.
Economist Intelligence Unit. 2010. US and Canada Green City Index. Munich, Germany: Siemens AG. Downloaded 2/26/17 from http://www.siemens.com/greencityindex.
Lynch, A. J., S. Andreason, T. Eisenman, J. Robinson, K. Steif, and E. L. Birch. 2011. Sustainable Urban Development Indicators for the United States. Report to the Office of International and Philanthropic Innovation, Office of Policy Development and Research, U.S. Department of Housing and Urban Development. Philadelphia: Penn Institute for Urban Research. Online. Available at http://penniur.upenn.edu/ uploads/media/sustainable-urban-development-indicators-for-the-united-states.pdf.
Mega, V., and J. Pedersen. 1998. Urban sustainability indicators. Dublin, Ireland: European Foundation for the Improvement of Living and Working Conditions. Online. Available at http://www.eurofound.europa.eu/sites/default/files/ef_files/pubdocs/1998/07/en/1/ef9807en. pdf.
National Academies of Sciences, Engineering, and Medicine. 2016. Pathways to Urban Sustainability: Challenges and Opportunities for the United States. Washington, DC: The National Academies Press. doi: 10.17226/23551. Downloaded 1/12/2017 from http://www.nap.edu/23551.
During the last decade, a huge increase in the number of earthquakes striking the Midwest has been reported, especially in Oklahoma. Despite the presence of the New Madrid Fault, historically this part of the country has not been known to produce large numbers of earthquakes. There has also been an uptick in earthquakes in Arkansas, and I have been tracking the yearly number of earthquakes in Missouri.
The last time I looked (here), I looked at data through 2014. This post updates the data through 2016. The U.S. Geological Survey database is not categorized by state, so I have been following earthquakes of magnitude 2.0 or greater in a rectangle that approximates Missouri. The precise boundaries are given in the Sources list.
The data are in Figure 1. It shows that the number of earthquakes continued to increase through 2015. The chart forms a rather dramatic spike, with the number of earthquakes in 2015 being more than 5 times as many as the number in 2012. The number was somewhat smaller in 2016.
The vast majority of these earthquakes are small. In 2016, only 2 were larger than magnitude 3.0, and none were larger than magnitude 3.5. In 2015, 5 were larger than magnitude 3.0, and one was larger than magnitude 3.5. It occurred on April 2, 2015, and was measured at magnitude 3.6.
The felt intensity of an earthquake depends on several factors, including the type of soil, the distance from your location to the epicenter, the type of ground movement that occurred, and the depth underground at which the earthquake happened. Still, in general, earthquakes below magnitude 2.0 are not commonly felt by people. Earthquakes above magnitude 3.0 are often felt by people, but rarely cause damage. Earthquakes above magnitude 4.0 may cause minor damage. Earthquakes above magnitude 5.0 typically cause moderate damage to vulnerable buildings. It is the earthquakes of magnitude 6.0 and greater that cause severe damage. The Richter Scale is logarithmic; that means that every 1.0 increase represents a 10-fold increase in the energy released by the quake. The earthquakes that caused the tsunamis in Indonesia in 2004 and in Japan in 2011 were magnitude 9.1-9.3 and 6.6, respectively.
According to the Missouri Department of Natural Resources, the famous New Madrid Earthquake was actually a series of 3-5 major quakes of magnitude 7.0 or larger, and several thousand smaller ones. Major earthquakes are also believed to have occurred in southeastern Missouri around the years 300, 900, and 1400 C.E.
Figure 2 is a map showing the location of the earthquakes counted above in 2015-2016. It is easy to see that they cluster along the New Madrid Fault in southeast Missouri. The second largest group extends across northern Arkansas.
I don’t know why Missouri is experiencing this increase in small earthquakes, or whether 2016 signals that the increase is ending, and the numbers will return to those typical of the years before 2012. The swarm of earthquakes in Oklahoma has been attributed to the deep well injection of wastewater from fracking, but there is virtually no fracking in Missouri, and Missouri has no deep well waste injection sites. There are fracking operations in Arkansas, but they run through the center of the state from Conway west to Oklahoma. They are not particularly close to the New Madrid area.
United States Geological Survey. Search Earthquake Catalog. Data and map retrieved 2/16/2017 from http://earthquake.usgs.gov/earthquakes/search. I searched for minimum magnitude 2.0, no maximum magnitude, starting date 1980-01-01 and ending date 2016-12-31. I searched for earthquakes in a rectangle defined by the following decimal degree coordinates: 40.964 on the north, 35.729 on the south, -95.999 on the west, and -89.099 on the east.
Wikipedia. April 2011 Fukushima Earthquake. Viewed online 2/16/2017 at https://en.wikipedia.org/wiki/April_2011_Fukushima_earthquake.
Wikipedia. Richter Magnitude Scale. Viewed online 2/16/2017 at https://en.wikipedia.org/wiki/Richter_magnitude_scale.
Missouri Department of Natural Resources. History of Earthquakes in Missouri. Viewed online 2/26/2017 at https://dnr.mo.gov/geology/geosrv/geores/historymoeqs.htm.
Wikipedia. 2004 Indian Ocean Earthquake and Tsunami. Viewed online 2/16/2017 at https://en.wikipedia.org/wiki/2004_Indian_Ocean_earthquake_and_tsunami.
Climate change has more than doubled the yearly area burned by wildfire in the United States.
In the decade from 1985-1994, wildfire burned 3,041,549 square miles in the USA. In the decade from 2006-2015 it burned 6,991,669 square miles – more than twice as much (see Wildfires Growing in Size, Not Number). But the number of fires has not greatly changed, rather the size of individual fires has grown. My findings parallel the results of several scientific studies and also field reports from the fire fighters themselves: wildfires, especially in southern and western mountain regions, have grown larger and more fierce. Why?
Using data to explore the change is complicated by the fact that the human response to wildfire has changed: instead of suppressing every fire as rapidly as possible, some are allowed to burn to fulfill their natural role in the forest ecosystem. It was during the 1960s that evidence of the beneficial role of fire began to accumulate, and it was during the 1970s when a change in policy began to be discussed. Yellowstone was the test site for the new policy, and it was phased in during the early 1980s. The terrible fires of 1988 changed all that, and the policy was suspended for review. It was reinstated during the early 1990s, and then it spread to other regions of the country The result was that the change occurred gradually, and not everywhere at the same time. The mid-1980s through 1990s are precisely the time of greatest increase in wildfire size. Thus, it is possible that part of the reason relates to the change in fire suppression policy. I know of no way to untangle that possibility from the data.
The change in policy notwithstanding, two other explanations are generally put forward to explain the increase: a build-up in fuel load due to the nearly century-long policy of suppressing wildfire, and climate change. The most recent studies suggest both play a role.
In Renewal by Fire I described how lodgepole pine forests age and become unhealthy if all fires are suppressed. To release their seeds, they require fire to melt the resin sealing their pine cones shut. In the absence of fire, little grows on the forest floor. Instead, downed timber builds up, forming conditions that are ripe for a large, destructive fire. Other western forests, dominated by species such as ponderosa pine or piñon pine, have different dynamics, but the effect is much the same: in the total absence of fire, fuel builds up, making conditions ripe for a severe, destructive fire.
I could find no studies that compare the fuel loads in America’s western forests over time. I did find one study that suggested that across 15 western states there were 6.9 billion bone dry tons of fuel in the forests, of which 2.2 billion (32%) should be removed. This assessment counted not only debris on the forest floor, but also trees that should be thinned. Figure 1 shows the data.
(Click on chart for larger view.)
There may be questions about this explanation, however. The near-century of fire suppression would lead to a gradual build-up in fuel load over the entire period, rather than a sudden spike in the 15 years from 1985-2000. In addition, in recent years some fires have burned through areas burned in previous fires. For instance, this year’s Maple Fire in Yellowstone National Park partially burned through areas that burned in the North Fork Fire of 2008. Until recently, fires had difficulty burning through areas that had burned previously, there just wasn’t enough fuel. Not so in recent years. Thus, a build-up of fuel load due to fire suppression doesn’t fit the shape of the data well, and it doesn’t account for some recent fire behavior.
Weather (short-term) and climate (long-term) are typically thought to be the most significant controls over the number, size, and ferocity of wildfires. As noted in Smokers, Smolders, and Big Blowups, it is when fuel becomes very, very dry that the fire danger becomes most extreme. Fires start more easily, and they wait only for a windy day to become raging infernos.
Climate change can dry the fuel in forests three ways: it can result in less precipitation, it can cause the snowpack to melt earlier, leading to a longer dry season, and it can raise the temperature, causing the moisture in the forest to evaporate faster. All 3 seem to be occurring.
There are no data regions that correspond precisely with the areas of Wyoming and Montana that include Glacier, Yellowstone, and Grand Teton National Parks. Instead, I will share data from sub-regions and/or specific locations that we can take as representative of the whole area.
Scientific studies of the snowpack sometimes look at the flow of rivers that depend on snowmelt for their water. They use the date of maximum flow as a proxy for the date of the snowmelt. They typically show that maximum flow is occurring earlier in the year than it used to, suggesting the snowpack is melting earlier than it used to. (Westerling et al, 2006)
I am not interested in when the snow is melting the most, however. I’m interested in the date at which snow no longer covers the ground, and thus, is no longer available to moisten the ground. I know of no data set that reports this information. Instead, I have selected a date late in the season – April 15 – and looked at the snowpack on that date over time. If there is less snow on the ground late in the season, it probably indicates an earlier date when the snowpack is gone and the dry season begins.
Figure 2 shows the data. Because the amount of snow can vary greatly according to local variables, I have taken measurements from the SNOTEL stations at Grassy Lake in Grand Teton National Park, Beartooth Lake in Yellowstone National Park, Emery Creek in the lowlands of Glacier National Park, and Flattop Mountain in the highlands of Glacier National Park. I have averaged the readings from 1981-2016, 1981 being the earliest measurement at two of these locations. The blue columns represent the actual data, and the black line represents the trend. You can see that since 1981 the average snowpack at these locations has declined, but the change is very small: -0.02 inches per year. Since the chart covers 36 years, that represents a change of -0.72 inches, or 3%. It suggests that the snow free date may have shifted a few days earlier, but by itself it is probably not a large enough change to account for the increase in fire.
Figure 3 shows the annual average winter temperature in Western Montana from 1981 to 2016. Figure 4 shows similar data for summer. The purple lines show the actual readings, the blue lines show the trends. You can see that the winter temperature has increased significantly, at a rate of 0.4°F per decade. You can also see that the summer temperature has increased even more, at a rate of 0.7°F per decade. That is a very large change for such a fundamental climate variable.
Figure 5 shows the total winter precipitation in Western Montana from 1981 to 2016. Figure 6 shows similar data for summer. The green lines show the actual measurements, the blue lines show the trends. During winter, precipitation has increased marginally, at a rate of 0.10 inches per decade. However, during summer, precipitation has declined at a much higher rate: -0.65 inches per decade, about 6.5 times larger than the winter increase.
The data suggest that precipitation in the region may have increased slightly during the winter, but it has decreased significantly during the summer. During both periods, the temperature has increased significantly, with the larger increase occurring during summer. The effect would be that reduced summer precipitation and increased temperature would result in significantly drier conditions during the summer. In addition, the higher temperature would affect fire conditions by raising the ambient temperature. This is probably a less important factor than dryness, but it is significant nonetheless. Thus, we would expect fire season to begin earlier, as the forest dries earlier in the year, and we would expect that as the fire season goes on, fires behavior would become extreme, as the forest becomes extremely dry and hot. And this seems to be what has happened.
As noted in the previous post, data suggests that wildfire acreage burned in Missouri may not have increased in the same way it has in the western forests. Some data suggests that there has been an increase, but other data suggests that the increase comes from an increase in prescribed burns, not from nature-caused fires. In general, Missouri wildfire requires a human cause and human intervention to spread. Thus, it is unlikely to be affected by climate change in the same way as is fire in the western forests.
A recent research paper confirms the analysis here: fuel in the western forests has, indeed, become significantly drier in recent decades, and human-caused climate change is responsible for more than half of the increase. The increased dryness has more than doubled the area burned by forest fires from what would be expected without climate change. (Abatzoglou and Williams, 2016.)
Abatzoglou, John, and A. Park Williams. 2016. “Impact of Anthropogenic Climate Change on Wildfire Across Western US Forests.” Proceedings of the National Academy of Sciences. Downloaded online 10/17/2016 from www.pnas.org/cgi/doi/10.1073/pnas.1607171113.
National Interagency Fire Center. 2016. Total Wildland Fires and Acres. Data downloaded 10/3/2016 from https://www.nifc.gov/fireInfo/fireInfo_stats_totalFires.html.
Rummer, Bob, Jeff Prestemon, Dennis May, Pat Miles, John Vissage, Ron McRoberts, Greg Liknes, Wayne Shepperd, Dennis Ferguson, William Elliot, Sue Miller, Steve Reutebuch, Jamie Barbour, Jeremy Fried, Bryce Stokes, Edward Bilek, and Ken Skog. 2003. A Strategic Assessment of Forest Biomass and Fuel Reduction Treatments in Western States. U.S. Forest Service. Downloaded 10/15/2016 from http://www.fs.fed.us/research/pdf/Western_final.pdf.
Vautard, Robert, Julien Cattiaux, Pascal Yiou, Jean-Noel Thepaut, and Philippe Ciais. 2010.”Northern Hemisphere Atmospheric Stilling Partly Attributed to an Increase in Surface Roughness.” Nature Geoscience, 10/17/2010. DOI: 10.1038/NGE0979. Macmillan Publishers. Accessed online 10/14/16 from http://www.nature.com/articles/ngeo979.epdf?referrer_access_token=swKTAeDzYW4Kl15-TdbsINRgN0jAjWel9jnR3ZoTv0P_XZlZh9_0kSsrMp3iDVwubdoqNb5x1ysMj6Pi8WEDIGybf8d5YnWrK_K0z-rv-P5kg3zf4Xp2N303GmtI-sb1Pqxj-EgEPD2e8yP4zFLMB7MsVO75vxb45IdLL-6IGgaNxzUO-R2JVCJEQqMBo_ss1gYX8sILyKMpm8pnuA4OUXwG6FbEqe3OWYcb0RYdRPU%3D&tracking_referrer=www.nature.com.
Westerling, A.L., H.G. Hidalgo, D.R. Cayan, and T.W. Swetnam. 2006. “Warming and Earlier Spring Increase Western U.S. Forest Wildfire Activity.” Science, 313:5789, pp. 940-943, 7/18/2006. Downloaded 10/17/2016 from http://science.sciencemag.org/content/313/5789/940.full.pdf+html.
Wildfire statistics for Missouri confirm how different wildfire is here compared to wildfire in the national parks and forests of the Northern Rockies.
Wildfire statistics for Missouri are kept by two agencies: the National Interagency Fire Center (NIFC), and the Missouri Department of Conservation (MDC). Let’s look at the NIFC data first.
Most wildland fire in Missouri is either started by humans or requires human intervention to spread significantly (see previous post). The NIFC data calls fires that were not prescribed “wildland.” Figure 1 shows the number of square miles burned by wildland fire (blue) and prescribed fire (red). I have dropped linear regression trend lines on the data (the dashed lines).
You can see that the number of acres burned in wildland fires has varied widely, from a minimum of 1,660 in 2013 to a maximum of 55,395 in 2011. The number of acres burned in prescribed fires has also varied widely, from a minimum of 6 in 2003 to a maximum of 95,268 in 2009. In contrast to much of the rest of the country, Missouri does not appear to be experiencing an increase over time in the number of acres that were burned in wildland fires – the trend is basically flat. For acres burned in prescribed fires, however, there was a significant increase until 2011, and since then the number of acres has slowly decreased. Over the 13 years with data, wildland fires burned an average of 24,209 acres per year, and prescribed fires burned an average of 38,078 acres per year. Thus, for every 2 acres burned by wildland fires, more than 3 were burned by prescribed fires.
The number of acres burned by wildfire in Missouri is somewhat lower than in many western states. This year, 4 wildfires burning in Wyoming each burned more than 20,000 acres, and the Maple Fire by itself burned 45,425 acres. In California this year, the Soberanes Fire burned 132,127 acres.
The fire data from the NIFC includes fires managed by federal agencies (in Missouri principally the National Park Service, the U.S. Fish and Wildlife Service, and the U.S.Forest Service). It also includes a subset of fires managed by state agencies, although what is included in the subset is not clear. MDC’s data seems to come from fire reports by local and regional fire departments. Those reports appear to be voluntary, and I couldn’t find any guidance about what the local departments file reports on. I did notice that the data included reports from departments that were the primary responders to fires, and from departments that were assisting responders to fires. Thus, there could be duplication in the data, as well as inconsistencies from year-to-year in the participating departments. It is also unclear what lands are included (state lands? private lands? developed lands? undeveloped lands?). For these reasons, I can’t use MDC’s data to indicate either the absolute number of fires in Missouri, nor their trend over time in acreage burned. The data do indicate the cause of the fires. Despite the possible inconsistencies in the data, it seems to me that they can be used to give a rough indication of the causes of fire in Missouri, especially if summed over a number of years.
Figure 2 shows the percentage of Missouri fire from each cause from 2006-2015. The largest category is Unknown. After that, however, the largest category is Debris. This is where somebody burns something – a pile of brush they cleared from their land, some construction waste, etc. – and the fire escapes. The next largest category is Arson. Lightning accounts for only 1% of the fires counted by MDC. Dry lightning is common in the West (lightning from a thunderstorm that drops no rain), and it accounts for about 2/3 of western wildfires. It is rare in Missouri, however. In addition, Missouri’s overall climate is wetter and more humid. A lightning strike may cause a single tree to burn, but it rarely spreads into a significant fire.
I wish that the Missouri Department of Conservation’s data included a description of what the data counts. Despite repeated attempts, the director of their fire program and I have been unable to connect with each other, so I haven’t been able to clarify it.
The next post will explore why western wildfires have become larger and fiercer in recent years.
InciWeb Incident Information System. This is a data portal. To find wildfires in Wyoming, I selected “Wyoming” in the “Select a State” data field, and clicked “Go.” Data viewed 10/31/2016 at http://inciweb.nwcg.gov.
Missouri Department of Conservation. Wildfire Data Search. Data downloaded 10/31/2016 from http://mdc7.mdc.mo.gov/applications/FireReporting/Report.aspx.
National Interagency Fire Center. Statistics > Historical Year-End Fire Statistics by State. Data downloaded 10/31/2016 from https://www.nifc.gov/fireInfo/fireInfo_statistics.html.
Fire helped create Missouri’s forests, then helped destroy them. Can it be used again to rebuild them?
When it comes to wildfire, Missouri is very different from Montana and Wyoming, just as our forests are very different. Figure 1, reprinted from a previous post, shows the forest surrounding Lower Two Medicine Lake in Glacier National Park. It is 80% lodgepole pine. Figure 2 shows the forest at Hemmed-In Hollow in the Buffalo National River. It is in Arkansas, but the forest is an Ozark Highland forest, as is the forest in southern Missouri. You can see that there are a few pines scattered here and there throughout the forest, but it is mostly deciduous hardwoods, predominantly oak.
Much of the state has been cleared for agriculture or for cities. The remaining forest occupies primarily the Ozark Highlands. The bluffs, streams, and narrow ravines tend to fragment fire. (In previous posts I have discussed how this geographic fragmentation also leads to the diversity of species in Missouri.)
In addition, most forest is privately held in Missouri (see here). Yellowstone and Grand Teton National Parks are surrounded by national forests. The combined land totals 22,481 square miles. That is approximately 1/3 of the entire state of Missouri. The largest forest landholder in Missouri is Mark Twain National Forest, and it contains only 2,331 square miles (see Figure 3). Not only that, but Mark Twain National Forest is broken into 9 non-contiguous tracts, the largest of which is something like 585 square miles. Thus, we are talking about contiguous tracts of public land out west that are more than 30 times the size of their Missouri counterparts.
The Ozarks are not prime agricultural land. Sources suggest that the edge of the ancient Mississipian civilization encroached on the Ozarks, which were occupied for hunting and foraging during the warm months of the year. Evidence suggests that the Mississipians used fire to manage the forest. It wasn’t until the Cherokee migration in the 19th Century, however, that the Ozarks became permanently occupied. The Cherokee used fire to burn the understory, improving their hunting, forest farming, and foraging. The first white explorers and settlers wrote of Missouri as a region of open woods, large areas being almost treeless. This was true for both bottoms and high ground, and the open character was due to the burning regime.
When the white settlers moved into the Ozarks, they established permanent residences and an economy based on herding, hunting, and gardening. They let their animals roam the woods freely, a practice that endured into the 20th Century. The settlers used fire for similar reasons: to clear the understory, to improve forage for their animals, to make hunting easier, and to suppress the pests, such as snakes and insects. However, they burned more frequently than did the Cherokee. Burning was so rampant that settlers would set fires to create a fire break around their holdings to protect them against the fires set by other settlers. Over time, too much clear-cut logging, too much burning, and burning that was too intense degraded the land. By the early 20th Century, Missouri forests were among the least productive in the country.
The Ozarks constitute a distinctive landscape for fire. The bluffs, the streams, and the ravines fragment fire. The climate is more humid, and we get approximately double the annual precipitation of Yellowstone. Most importantly, about 2/3 of wildfires in the Northern Rockies are caused by lightning strikes. Fires caused by lightning are rare in Missouri. Lightning may strike the ground and cause something to burn, but because of the moisture and fragmentation, it doesn’t burn vigorously, and it goes out without spreading. In Missouri, fire requires human intervention to spread widely; almost all wildfire in Missouri is human caused.
Thus, by the time white settlers moved into Missouri, and certainly by the time conservationists and foresters began studying Missouri’s forests, the ecosystem was already controlled by human-caused fire. If by “natural” one means land without human influences, then there is almost no such thing as natural forest in Missouri.
In previous blogs I discussed the importance of fire in the lodgepole pine forest. Those trees have serotinous cones that will not release their seeds without fire. The cones are coated in a resinous substance, and only fire is hot enough to melt it, allowing the cones to open. None of Missouri’s large forest trees are serotinous in that sense. We do have some species that respond favorably to fire. For instance, about 1/3 of tallgrass prairie species germinate more vigorously if their seeds are exposed to smoke (e.g. coneflowers). But perhaps more significantly, Missouri has rare natural habitats that depend on fire: upland glades and prairies – open places dotted throughout the forest (Figure 4). Without fire, cedar and other tree species would colonize and close these open spaces.
The first aim of forest conservation in Missouri has been to try to eliminate the burning that has been too frequent and too intense. Progress has been slow, as some backwoods settlers regarded foresters as something akin to “revenooers,” and fire towers as something akin to prison guard towers. They wanted to continue to free range their animals on public land, and to continue to burn to promote that practice. It took many years to convince the legislature to make arson in the forest on public lands, a crime. Though slow, progress has occurred.
As was discovered out west, however, total suppression of fire did not lead to a healthy forest. It led to a tangled mess of unhealthy plants, many of which were invasive. Gradually, as it was understood that the forest in Missouri could not be “natural” in the sense described above – uninfluenced by humans – prescriptive fire has come into use in an attempt to return Missouri’s forests to the condition they were in when white settlers first arrived. In essence, this involves an attempt to return to a fire regime that is similar to the one to which the forest had adapted prior to the arrival of the white settlers. Figure 5 shows a prescribed burn. Note the low intensity of the fire. Because Missouri’s forests are 80% privately held, the program requires the education and participation of many private landholders.
The attempt has been largely successful in some areas – Ha Ha Tonka State Park is often touted as a notable success – and less successful in others. Using fire in this way depends on the forest’s ability to heal itself. Unfortunately, a significant chunk of Missouri’s forest may be too far gone to heal itself. Time will have to tell.
In the next post, I will look at some fire statistics for Missouri.
Flader, Susan. 2004. History of Missouri Forests and Forest Conservation. In North Central Research Station. 2004. Toward Sustainability for Missouri Forests. General Technical Report NC-239. North Centeral Research Station: St. Paul, MN. Downloaded 10/5/2016 from http://www.nrs.fs.fed.us/pubs/gtr/gtr_nc239.pdf.
Journet, Alan, and Christine Logan. 2004. Ecological Sustainability. In North Central Research Station. 2004. Toward Sustainability for Missouri Forests. General Technical Report NC-239. North Centeral Research Station: St. Paul, MN. Downloaded 10/5/2016 from http://www.nrs.fs.fed.us/pubs/gtr/gtr_nc239.pdf.
Ladd, Doug. Ecologically Appropriate Fire in the Missouri Landscape: A 35 Year Reflection. Missouri Department of Conservation 2014.Missouri Natural Areas Newsletter. 14(1). Downloaded 10/5/2016 from https://mdc.mo.gov/sites/default/files/resources/2014/12/mnawinter14.pdf.
Mark Twain National Forest. Glade Top Trail. Downloaded 10/10/2016 from http://www.fs.fed.us/wildflowers/regions/eastern/GladeTopTrail.
Nigh, Tim. 2004. Missouri’s Forests: An Ecological Perspective. In North Central Research Station. 2004. Toward Sustainability for Missouri Forests. General Technical Report NC-239. North Centeral Research Station: St. Paul, MN. Downloaded 10/5/2016 from http://www.nrs.fs.fed.us/pubs/gtr/gtr_nc239.pdf.
Pennacchio, Marcello, Lara Jefferson, and Kayri Havens. 2014. Smokin’ Prairies. Missouri Department of Conservation 2014.Missouri Natural Areas Newsletter. 14(1). Downloaded 10/5/2016 from https://mdc.mo.gov/sites/default/files/resources/2014/12/mnawinter14.pdf.
Pyne, Stephen. 2009. Missouri Compromise. Essay downloaded 10/5/2016 from http://static1.squarespace.com/static/552bfa74e4b0dcf927eb50b8/t/55311efee4b0363f6e869d8d/1429282558398/missouri_comp2.pdf.
Shifley, Stephen. 2004. Missouri’s Timber Resources: Finding a Sustainable Balance Among Growth, Harvest and Consumption. In North Central Research Station. 2004. Toward Sustainability for Missouri Forests. General Technical Report NC-239. North Centeral Research Station: St. Paul, MN. Downloaded 10/5/2016 from http://www.nrs.fs.fed.us/pubs/gtr/gtr_nc239.pdf.
Thomas, Justin. 2014. Smoldering Questions and the Opinion Factory. Missouri Department of Conservation 2014.Missouri Natural Areas Newsletter. 14(1). Downloaded 10/5/2016 from https://mdc.mo.gov/sites/default/files/resources/2014/12/mnawinter14.pdf.
Vaughn, Allison. 2014. Prescribed Fire in Missouri: Editor’s Note. Missouri Department of Conservation 2014.Missouri Natural Areas Newsletter. 14(1). Downloaded 10/5/2016 from https://mdc.mo.gov/sites/default/files/resources/2014/12/mnawinter14.pdf.
Walter, W. Dustin, and Paul Johnson. 2004. Sustainable Silviculture for Missouri’s Oak Forests. In North Central Research Station. 2004. Toward Sustainability for Missouri Forests. General Technical Report NC-239. North Centeral Research Station: St. Paul, MN. Downloaded 10/5/2016 from http://www.nrs.fs.fed.us/pubs/gtr/gtr_nc239.pdf.
White, Cliff. Prescribed Fire in Missouri. Missouri Department of Conservation. Downloaded 10/10/2016 from http://mdc.mo.gov/property/fire/prescribed-fire.
Yellowstone National Park. The Greater Yellowstone Ecosystem. Downloaded 10/10/2016 from https://www.nps.gov/yell/learn/nature/greateryellowstonemap.htm.
Since 1984, the size of wildfires seems to have grown, though the number of fires does not.
In previous posts I have looked at wildfire in the national parks and the role it has in promoting a healthy forest ecosystem. How is wildfire changing over time? Is it increasing? I can address that question two ways: with maps and with statistics. Maps first.
Figure 1 is the top half of a map that shows the history of wildfires in Glacier National Park and the surrounding area from 1984-2015. On the map, the park is shown in pale yellow. Flathead National Forest is shown in pale green. The line at the top represents the border with Canada. The fires are mapped, and the year they occurred is color coded. Bright red represents fires that occurred in 2015, orange represents fires that occurred in 2003, and dark green those that occurred in 2001. In the previous post, I gave you photos of forest recovery in 3 of these fire areas: the Reynolds Creek Fire, the Red Eagle Fire, and the Moose Fire.
Looking at the map, you can see that over the last 22 years, a significant fraction of the area has burned in one fire or another. Orange is the color most represented on the map, and 2003 was, indeed, a very active fire year in this region.
(Click on graphic for larger view.)
Figure 2 shows the fire history of Yellowstone National Park from 1988-2013. The park is outlined with a black line. As in the previous figure, fires are colored according to the year in which they occurred. If you recall, 1988 was the year of the terrible fires in Yellowstone. Those fires are shown in pale yellow. Approximately 1/3 of the park burned that year. (The map shows the final fire boundaries – not every acre within the boundary burned. Wildfire is very fickle regarding what it burns and doesn’t burn.) Since 1988, fires have been much smaller, and have consumed much less acreage.
What I want you to take away from these maps is that fire is anything but rare in these national parks. It is a yearly occurrence. Over time, significant portions of the park burn – in Yellowstone most of the park has burned in the last 28 years. This is a natural pattern, and evidence from burn scars and layers of ash in the soil suggest it has been this way for thousands of years.
Fire experts estimate that healthy lodgepole pine forests burn about every 90 years on average. Now, that’s an average, so it means that some areas burn more frequently, and some less. About 2/3 of western fires are started by lightening, and nobody knows where lightning will strike.
Tens of thousands of wildfires are reported every year. Figure 3 shows the number of wildfires reported in the USA from 1960-2015. These statistics are compiled by the National Interagency Fire Center from situation reports on individual fires that come in from many sources. Situation reports have been in use for several decades. Prior to 1983 the source of the data is not known, and the data for 1983 and 1984 seem to have been affected by the phasing in of situation reports. Thus, data up to 1984 should not be compared to data after 1984.
Because of variability in the data, I have dropped a 5-year moving average on it for the period after 1984. The trend in the data is not strong, however it may be toward a slightly decreasing number of fires. The years from 2010-2015 all saw a below average number of fires, although in some cases barely.
Figure 4 shows the total number of acres burned by wildfire each year. As in Figure 3, data before and after 1984 should not be compared. That said, this data is less ambiguous: there has been an increase in the number of acres burned in both active and inactive fire years.
Figure 5 shows the annual number of acres burned per fire – it is just a graph of the number of acres divided by the number of fires. Again, don’t compare data from before and after 1984 . The first thing I notice is how small the average number of acres is – somewhere between 15 and 150. Given the results of the two previous charts, it is inevitable that the number of acres burned per fire has increased in recent years, and the chart confirms the change. The size of the change is astounding, however. The number of acres per fire in 2012 and 2015 is about double the highest number in the 10 years after 1984.
The data seem clear: the number of fires each year has not increased, but the number of acres burned per fire has, leading to an increase in total acres burned. This goes along with the statement from the U.S. Forest Service that I quoted in the lead post of this series: the size and ferocity of fires has increased in recent years.
I will try to bring the data home to Missouri in the next post.
Flathead National Forest. 2015. Current Fires and Fire History 1984-2015: Flathead National Forest & Clacier National Park. August 21, 2015. Downloaded 10/3/16 from http://www.fs.usda.gov/Internet/FSE_DOCUMENTS/stelprd3851454.pdf.
National Interagency Fire Center. 2016. Total Wildland Fires and Acres. Data downloaded 10/3/2016 from https://www.nifc.gov/fireInfo/fireInfo_stats_totalFires.html.
Yellowstone National Park. 2014. Yellowstone Fires: 1988-2013. Downloaded 10/3/16 from https://www.nps.gov/yell/learn/nature/upload/Fires_88_2013.pdf.
Most forest fires have beneficial effects on a wide variety of animals and plants, and are necessary for the long-term health of the forest.
In August 1910, hot dry winds caused fires burning in Montana, Idaho, and Washington to blow up into the worst wildfire event in this country’s history: 3 million acres were burned in 2 days, and 87 people were killed. That event caused people throughout the country to view wildfire as a monstrous evil, to be fought with every resource available. To the full extent possible, every wildfire was extinguished – the official policy called for fires to be suppressed by 10 a.m. on the day after the fire was first reported.
During the 1960s, however, research began to show that fire played a positive role in forest ecology. How could such a destructive force play a positive role? This post will look into some of the answers to that question.
Figure 1, repeated from the previous post, shows the understory of a mature stand of lodgepole pines along the Avalanche Lake Trail in Glacier National Park. Even a casual glance shows how densely the trees are packed together. You can notice that there is very little growing on the forest floor – no grasses, flowers, bushes, and no baby pine trees. Instead, downed wood litters the forest floor. This is unhealthy. No plants on the forest floor means that there is little for animals to eat. No baby pine trees means the forest can’t renew itself. And the build-up of dead wood makes the forest ripe for an extreme and destructive fire.
(Click on graphic for larger view.)
Figure 2 shows Lower Two Medicine Lake in Glacier National Park, but I want you to look at the pine trees on the slope to the left of the lake. These are also lodgepole pines. You can get a sense of how thousands of acres are covered with these densely packed trees. In fact, 80% of Glacier Park is forest, and 80% of that is lodgepole pine. Lodgepole pines are also the dominant trees in Yellowstone and Grand Teton National Park.
You can also see that all the lodgepole pines are roughly the same height. That’s because they are all the same age. “How can that be?” you may ask.
Like all pine trees, lodgepole pines bear their seeds in cones. Figure 3 shows the cone of a lodgepole pine in Grand Teton National Park. Figure 4 shows some cones in the top of a white pine in St. Louis. Contrast the two: the white pine cones have opened while still on the tree. The seeds have been discharged to germinate and make little white pines. On the other hand, the lodgepole cone has not opened. It is sealed shut with a resinous substance. To release its seeds, something has to melt that resinous substance. Only fire is hot enough. These kinds of cones are called “serotinous cones.” Not all lodgepole pines have serotinous cones, but the ones in the Rocky Mountains mostly do.
Serotinous cones mean that lodgepole pines can’t disperse their seeds unless there is a fire. When there is a fire, the cones open and disperse their seeds. The seeds fall on ground that has been cleared by the fire, and which has been fertilized by chemicals from the ashes of the burned trees. They sprout and grow in thick stands, which mature into the dense forests shown in Figures 1 and 2. Thus, fire is not only beneficial for healthy forests of lodgepole pine, it is required.
Aspen trees also benefit from fire. If you look at stands of aspen trees, often they too are all roughly the same age. Aspens don’t sprout from seeds, however. They send runners underground, and then suckers sprout up from the runners. In a grove of aspens, every tree may be genetically identical, having suckered from one parent tree. Aspens are not as long-lived. Though originally dense, after several decades they tend to decay and rot, and other species can invade and take over. Without fire, the entire stand may vanish. With fire, however, the land is cleared, but the runners underneath the ground survive. They sprout again, and the stand, still genetically identical, renews itself. The genetic material in some aspen stands is thought to have derived from a single parent aspen thousands of years ago.
Many animals also benefit from fire. In the first year after a fire, animal populations may crash, due to lack of food. But the first colonizers of a burn area are flowers and berry-producing bushes that are much better food sources than are mature stands of lodgepole pine. They grow luxuriantly in the sun and fertilized soil, without competition from taller trees. Feeding on this rich forage, animal populations quickly recover.
Which animals benefit from fire? Elk, deer, and bear all do. Rodents experience the highest fire-related mortality of any animals, but because they reproduce so abundantly, their populations quickly rebound. Most bird species are not directly harmed, and a few benefit, such as species that live in holes in dead trees. Moose is one species that does seem to have declined in Yellowstone as a result of the 1988 fires.
The process of recovery takes many years. Mature stands of lodgepole pine may be 90-300 years old. What follows is a series of photos showing some early stages in the forest’s recovery after a fire. They were all taken in August-September 2016.
Figure 5 shows a burn area from the Berry Fire (2016) near the northern boundary of Grand Teton National Park. This area burned about 2-3 weeks before this photo was taken. Everything is dead, nothing is growing.
Figure 6 shows the burn area of the Reynolds Creek Fire (2015) in Glacier National Park. The regrowth is about 1 year old. Notice the growth of grasses and flowering plants, many of which provide good forage for animals. The pink flower is fireweed, a common colonizer of burned areas.
Figure 7 shows regrowth from the West Thumb Fire (2009) in Yellowstone National Park. September is late in the season for Yellowstone, so the flower- and berry-producing plants have all finished. Though it has turned brown, you can see that there is grass among the burned trees, while there was no grass under the trees of the mature lodgepole forest. You can see the 7-year old lodgepole pine sprouts.
Figure 8 shows regrowth following the Red Eagle Fire (2006) in Glacier National Park. Notice how a whole new forest of lodgepole pines has sprouted and is growing healthily. They are interspersed with grasses and other plants. You can see how densely they have sprouted – in time, they will form a dense forest. These trees are 10 years old; you can see that full recovery takes a bit of time.
Figure 9 shows regrowth following the Moose Fire (2001) in Glacier National Park. At bottom are willows along a riverbed. In the middle are 15-year-old lodgepole pines in the burn area. On the ridge at left are mature lodgepole pines that were left unburned by the fire. This is a common story. Wildfire is very fickle about what it burns and doesn’t burn. This photo gives some idea of how, when left to its own devices, fire creates a patchwork landscape consisting of various types of trees in various stages of development. This sort of patchwork is very healthy for the forest. You wouldn’t want a city where everybody was 65-years-old, you would want a city composed of people of every age. Similarly, the healthiest kind of forest is one consisting of a variety of habitats in all stages of development.
Figure 10, the final photo for this post, shows the Upper Geyser Basin in Yellowstone, home to Old Faithful. While the photo is intended to be about the steamy geysers, it also shows the forested hills behind the basin. This is the same part of the park shown in the dramatic photo of a wall of flame bearing down on the Old Faithful Photo Shop that was included in previous posts (North Fork Fire, 1988). You can see that the forest is still in a process of regrowth, especially along the top of the ridge. But the predictions that Yellowstone had been devastated were wrong: Yellowstone is well along the process of recovery, even from the terrible fires of 1988. Trees are abundant, forests are healthy, and, at least during my visit, wildlife was everywhere.
A raging crown fire can be a destructive force that achieves none of these beneficial effects. But most forest fires have beneficial effects on a wide variety of animals and plants, and are necessary for the long-term health of the forest.
In the next post, I’ll look at some data to address the question of whether wildfire behavior is changing over time.
Forest History Society. 2016. U.S. Forest Service Fire Suppression. Downloaded 9/30/2016 from http://www.foresthistory.org/ASPNET/Policy/Fire/Suppression/Suppression.aspx.
Johnsgard, Paul. 2013. Yellowstone Wildlife: Ecology and Natural History of the Greater Yellowstone Ecosystem. Boulder, CO: University Press of Colorado.
Reinhart, Karen. 2008. Yellowstone’s Rebirth by Fire: Rising from the Ashes of the 1988 Wildfires. Helena, MT: Farcountry Press.
Rockwell, David. 2007. Glacier: A Natural History Guide. Second Edition. Guilford, CT: Falcon Guides.
Yellowstone National Park. 2016. Fire. Downloaded 10/1/16 from https://www.nps.gov/hell/learn/nature/fire.htm.
Yellowstone National Park. 2016. Yellowstone Resources and Issues Handbook. National Park Service. Downloaded 9/28/2016 from https://www.nps.gov/yell/learn/resources-and-issues.htm.
Most wildfires smoke or smolder and don’t amount to much. But some blowup, and then they are dangerous and destructive.
When we think of wildfire, we tend to imagine a raging crown fire, like the one in Figure 1, repeated from the last post. Such fires make for dramatic photos and stories in the media. But raging crown fires are not typical. Lightning ignites hundreds of wildfires every summer, and most go out naturally after burning less than half an acre. Others consume isolated or small groups of trees and eventually go out on their own. In Yellowstone National Park, 72% of fires consume less than 0.2 acres, and 84% consume less than 10 acres. Figure 2 shows the Buffalo Fire burning in Yellowstone National Park on 9/3/2016 – a far cry from the huge wall of fire that threatened Old Faithful in 1988!
Figure 3 shows the forest floor along the Avalanche Lake Trail in Glacier National Park. An old forest can get positively junky as downed wood accumulates on the forest floor. Fire won’t typically jump too far from log-to-log, it more easily spreads to something nearby. The more downed wood, the better the fire spreads.
Similarly, fire doesn’t like to burn in wet wood – anybody who has ever tried starting a fire with wet wood knows what I mean. In the national parks, fires only burn vigorously if fuel moisture levels drop to 13%. How dry is 13%? Well, kiln-dried lumber, like you buy at the lumber yard, is 12%, so, it is pretty dry. In an average year, the moisture content of downed wood in the national parks is 14-18%, too moist to burn ferociously. In really dry years, however, it can get as low as 5%, and then watch out!
Finally, as anybody who has ever tried to start a campfire knows, moving air makes a big difference. If you have a fire started, what do you do to make it grow? You blow on it. Same in the national parks. A raging fire requires wind.
Thus, three factors have to come together to make a raging crown fire: lots of downed fuel so the fire can spread easily, dry conditions so the wood burns readily, and strong winds to whip the fire into an inferno. Only when those three conditions come together does fire behavior become “extreme,” as they say. When these conditions do come together, however, wildfire becomes extremely dangerous, capable of moving fast, even of hurling fireballs up to a mile away. In 1988, Yellowstone experienced the worst wildfire season in its history. The fire started on June 14. By early August, 8 fires were burning. During the 2 weeks from 8/6 to 8/19, the fires in Yellowstone consumed an average of 11,607 acres per day. Now, that’s already pretty active fire behavior. But on 8/20, the fire exploded, consuming 152,959 acres – 13 times as much. And that wasn’t the worst of it. On 9/9 the fire ate 228,137 acres – in a single day!
So, most wildfires are small and go out on their own. But some blow up, and when they do, they become destructive and dangerous.
The worst fire blowup in United States history may have occurred in 1910 (The Big Blowup). Over 2 days in August that year, fire in Washington, Idaho, and Montana consumed 3 million acres and killed 87 people. The U.S. Forest Service was just 5 years old, and that experience was very influential in the development of the ethos that every wildfire must be suppressed as quickly and vigorously as possible, without exception. We know more nowadays, and the ethos has changed, but it held sway for a long time.
One final characteristic must be mentioned here: how you view a fire depends on where it is burning. A fire in your barbecue is one thing, a fire in your bedroom another. The American landscape is a patchwork of different kinds of land. Some is private, but even public lands belong to a variety of agencies: the National Park Service, the U.S. Forest Service, the Bureau of Land Management, state parks, state forests, wildlife refuges, etc. Differing policies regarding wildfire apply in each of these kinds of land.
Generally, the first, overriding policy is to protect life, whether it be that of firefighters or civilians. The second overriding policy is to protect significant assets, such as homes, mine buildings, ranch buildings, and visitor facilities. After that, the policies vary. In the national parks, fire is thought to be an important part of the ecosystem that is necessary for the health of the forest (more on this in the next post). In the national parks, fire is allowed to fulfill its natural role in the ecosystem without interference, unless it is threatening life or significant assets. The national forests, however, harvest their trees. Thus, the trees are themselves an important asset, and wildfire is much less likely to be allowed to burn without a suppression effort of some sort.
In the next post I’ll look at the role that wildfire plays in renewing the forest, and why it is an important part of the natural ecosystem. I had the chance to see this right before my eyes, and it was pretty impressive.
Rothermel, Richard, Roberta Hartford, and Carolyn Chase. 1994. Fire Growth Maps for the 1988 Greater Yellowstone Area Fires. General Technical Report INT-304. Intermountain Research Station, U.S. Forest Service. Downloaded 9/30/2016 from http://www.fs.fed.us/rm/pubs_int/int_gtr304.pdf.
Forest History Society. 2016. U.S. Forest Service Fire Suppression. Downloaded 9/30/2016 from http://www.foresthistory.org/ASPNET/Policy/Fire/Suppression/Suppression.aspx.
Yellowstone National Park. 2008. The Yellowstone Fires of 1988. Downloaded online 9/30/2016 from https://www.nps.gov/yell/learn/nature/upload/firesupplement.pdf.
Yellowstone National Park. 2016. Yellowstone Resources and Issues Handbook. National Park Service. Downloaded 9/28/2016 from https://www.nps.gov/yell/learn/resources-and-issues.htm.
On my vacation, I encountered wildfire in 3 national parks. What does it mean?
In September I returned from a road trip that took me to Glacier National Park, Yellowstone National Park, and Grand Teton National Park. The day I drove to Glacier, my route led through Billings, MT. As I drove in, I found it laying under a thick brown haze, with visibility only about 1 mile, perhaps even less. It made my eyes burn. As I drove out of town, the haze gradually thinned, and disappeared. “What is going on?” I wondered. “This is worse than the air pollution in Los Angeles. Does Billings really have worse air quality than L.A.?”
As I drove north, I encountered another cloud of heavy, brown haze, this one over lightly populated land near Lake Frances. “This can’t be air pollution,” I thought. “It must be smoke from a wildfire somewhere.” And, indeed, it was.
I encountered wildfire and/or its effects in all three national parks. Figures 1, 2, and 3 show smoke near Gardiner, hanging in front of Mt. Moran, and filling the Yellowstone River Valley.
I asked a ranger, and found out about Inciweb, the interagency system for information about many kinds of risk, especially wildfire. I discovered that 8 wildfires were burning in regions of Montana and Idaho just upwind from Glacier National Park, that 5 were burning in Yellowstone National Park itself, and that one was burning in Grand Teton National Park. This last one, the Berry Fire, twice burned across the highway between Yellowstone and Grand Teton, forcing its closure. Fortunately, I was able to sneak through during the brief period between the two closures. I also discovered that none of these were the worst wildfires of the season; those were burning in California.
Wildfire sometimes makes for dramatic news stories with spectacular photographs. Perhaps many readers can recall the wildfires in Yellowstone National Park that made national headlines in 1988 (See Figure 4). Yellowstone was devastated, they said, it would never recover.
Guess again, smoke breath! Raging crown fires like the one in the photo are the exception. Most wildfires present a much more complex story. All three of these national parks have been heavily affected by wildfires, but they are far from dead. In fact, in some ways, they are more healthy now than before the fires. On the other hand, a Forest Service publication notes that in the last 25 years, wildfires have increased in size and ferocity. What’s going on?
In the following posts, I hope to share with you the role that wildfire plays in a forest ecosystem, look at whether wildfires are getting larger, more fierce, or more frequent, and how wildfire has impacted Missouri. I found it a fascinating topic to explore, and the evidence was right in front of me. Hopefully I can share it with you in a way that will interest you, too.
Forest History Society. 2016. “U.S. Forest Service Fire Suppression.” Downloaded 9/30/2016 from http://www.foresthistory.org/ASPNET/Policy/Fire/Suppression/Suppression.aspx.
Photo of fire approaching Old Faithful Photo: “13744.jpg.” Unknown photographer. Wildfire, 1988 – Crown Fire. Yellowstone’s Photo Collection, Yellowstone National Park. Downloaded 9/26/16 from https://www.nps.gov/features/yell/slidefile/fire/wildfire88/crownfire/page-1.htm.
Missouri is loaded with turkeys, and that doesn’t even include the human kind. Turkey hunting is a substantial recreational activity in Missouri, and hunters spend more than 500,000 days afield each year (Missouri Department of Conservation 2013). Consequently, the Missouri Department of Conservation monitors turkey population trends. No way of doing it is perfect, so they do it several different ways.
Turkeys are not really a “canary-in-the-coal-mine” species, and their population levels can change due to how much hunting pressure they experience, as well as for reasons that would be of more interest to this blog, such as habitat destruction and environmental pollutants. Nevertheless, they are a major large species, and provide one bit of information about how well Missouri’s land can support life.
One major way the Department monitors turkey population is to track the number of turkeys killed by hunters each year. The spring season is the largest, and during it Missouri hunters kill lots of turkeys! In 2015 hunters bagged 48,432 wild turkeys during the spring season. In 2013, they bagged 47,601. The harvest hit its highpoint in 2004 at 60,744, then declined by almost 1/3. Since 2011 it has been increasing again. The first chart at right shows the trend. You can see that the number of kills increases rather dramatically from 1960 through 2004, then declines, then increases again (yellow line). Notice that the number of hunting permits (green line) follows a similar trajectory. One might be tempted to attribute the fewer kills to less hunting. Data below does not support that interpretation, however.
(Click on chart for larger view.)
Another way the Department monitors turkey population is through a survey conducted with the voluntary cooperation of bowhunters. Participants report sightings of turkeys to the Department. Because how many turkeys you see may depend on how many hours you spend in the field, the Department constructs an index by dividing the number of sightings by the number of hours in the field. For our purposes, the raw index doesn’t really mean much, so the chart at right shows change in the index for regions in the state over several time periods. The 1-year trend was toward more sightings, but over every other time period the trend was toward fewer sightings, in some places a lot fewer. (See the report for a map of the various regions.)
A third way the Department monitors turkey population is to send its staff into the field to look for turkeys. During this survey, the Department is especially looking to see how many female turkeys have young with them, called poults. The poult-to-hen ratio is considered a marker of whether conditions are favorable for turkey breeding and survival. The third chart at right shows the trend in the poult-to-hen ratio in Missouri from 1950 to 2014. The ratio peaked in during a 20-year period from 1970-1989, and it has declined since then.
Combined, these three reports suggest that there are a lot of turkeys in Missouri. The trends seem to suggest that conservation practices during the 1970s and 1980s led to an increase in breeding success, which then led to an increase in the number of turkeys in Missouri, and the number of turkeys seen and killed by hunters. The bowhunter survey, which only goes back to 1989, suggests that over the last 20 years turkeys have gotten harder to spot. Whether that means they are more wary or that their numbers are declining is not obvious from this data. The decline in the poults-to-hens ratio could have occurred because of environmental problems, or it could simply be a sign that the turkey population reached its saturation point.
The Department is in the midst of a 5-year study to investigate the health and the needs of Missouri’s turkey population.
Missouri Department of Conservation. 2013. 2013 Missouri Wild Turkey Harvest and Population Status Report. Viewed online 10/31/15 at http://mdc.mo.gov/sites/default/files/resources/2014/07/2013wildturkeyreport.pdf.
Missouri Department of Conservation. 2014. 2014 Missouri Wild Turkey Harvest and Population Status Report. Retried online 10/31/15 at http://huntfish.mdc.mo.gov/sites/default/files/downloads/2014TurkeyStatusReport_0.pdf.