Beneath the Alaskan Tundra

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Photo Essay: Where the Trees Meet the Tundra

Wed, 11/16/2016 - 10:36

Due to warming climate and increasing human exploitation, far northern forests and the tundra beyond are undergoing rapid changes. In northern Alaska, scientists from Columbia University’s Lamont-Doherty Earth Observatory and other institutions are studying trees at the very edge of their range to understand what to expect in coming decades. READ THE FULL SCIENTIFIC STORY  or   SEE A VIDEO

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In northern Alaska, just past the arctic circle, boreal forest begins giving way to tundra. The largest ecological transition zone on earth, the so-called tree line circles the globe for more than 8,300 miles. On a June evening, Lamont-Doherty ecologist Natalie Boelman observes fast-changing weather closing in. This region is reached via the Dalton Highway, one of the few North American roads that reach this far. Built in the 1970s to serve the arctic-coast oil fields, it ends more than 500 miles beyond Fairbanks, the nearest city. The Alaska pipeline, which channels oil southward, parallels the road to the right. Further north, in a valley at the very edge of tree line in the mountains of the Brooks Range, scientists set up a laser-powered LiDAR camera to survey an acre or so. Its highly detailed 3D map of vegetation will provide information on subtle differences in topography and other elements that may allow trees to survive, or not. Lamont-Doherty plant physiologist Kevin Griffin examines a spruce, the only kind of tree capable of growing here. “If temperatures keep warming, species might change, and trees might be able to grow further north,” says Griffin. “If that happens, there will be a whole suite of consequences for ecosystems.” The tree line is altitudinal as well as latitudinal; trees living in valleys can’t survive higher elevations. Here on a windswept mountaintop above one of the team’s study sites, only plants typical of the lowland tundra further north hang on. Lamont-Doherty grad student Johanna Jensen installs a dendrometer, which will record minute changes in this spruce trunk’s diameter over the next three years. The trunk may swell or shrink daily depending on the flow of nutrients and light; if the season is mild, it may even grow a bit. Just beyond the trees, team leader Jan Eitel of the University of Idaho installs a  sensor to record total radiation reaching the plot—a key factor in plant growth. Boelman prepares to test a tree’s capacity to use sunlight for photosynthesis. At the height of summer, intense sun shines 24 hours a day. Remote-sensing specialist Lee Vierling of the University of Idaho takes fluorescence readings from spruce needles. Instruments behind him  automatically record temperature, wind speed, air pressure and humidity. In this environment, everything grows slowly. This seedling only looks like a baby; it is actually 15 or 20 years old.  Boelman and Vierling judged this spruce to be at least 96 years old, meaning it probably took root some time shortly after World War I. University of Idaho grad student Andy Maguire programs the LiDAR. In cooperation with NASA, the scientists will combine their painstaking ground observations with large-scale satellite imagery to paint a picture of how the north is changing. The north is home to a surprising diversity of animals. Here, a year-round forest-dwelling gray jay surveys its domain. In summer, vast numbers of migratory birds also come to nest. Some prefer the trees, while others inhabit only the tundra beyond, so changes in either one will have ecological fallout. The Alaska pipeline has shipped billions of barrels of oil from the oil fields of Prudhoe Bay to the south since the 1970s. The root of global warming is fossil fuel, and this region, the source of so much of it, is warming two to three times faster than the worldwide average. The oil  is starting to run out, but development is proceeding apace. Boelman checks out a fiber-optic cable being laid to Prudhoe Bay. There is now talk of a new pipeline that would carry natural gas instead of the waning oil. The most visible impact of warming climate on northern forests is increasing wildfire; this stretch along the Dalton Highway burned a couple of years ago. Each summer, huge blazes afflict Alaska, Canada and Russia; some even spread into the tundra, where fires had been previously unknown. The researchers stayed each night at the decayed early 1900s gold-mining town of Wiseman (though not at this cabin). Wiseman became reachable by road in the 1990s, and now tourists can drive here—another sign that the far north is opening up. Scott Schoppenhorst, a mechanic, has lived in Wiseman for 30 years. “Call it global warming or what you want--winters are warmer, and everything is growing faster,” he says. Here he is trying to get some grass to grow near his airplane hangar, and he is pretty optimistic it will work.   From the local perspective, the warming trend can be good; the few gardens in Wiseman are certainly benefiting. Oil and mining are pillars of Alaska’s economy, and most residents support more development. One Wiseman doorway is testimony. As human influence grows here, scientists hope to better predict how the environment will affect plants, trees, animals, people. A Wiseman fence made of caribou and moose antlers speaks to the powerful intertwining of man and nature in this region.
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Further north, in a valley at the very edge of tree line in the mountains of the Brooks Range, scientists set up a laser-powered LiDAR camera to survey an acre or so. Its highly detailed 3D map of vegetation will provide information on subtle differences in topography and other elements that may allow trees to survive, or not.

Where Trees Meet Tundra, Decoding Signals of Climate Change

Wed, 11/16/2016 - 10:35

In northern Alaska’s Brooks Range, the earth as most of us know it comes to an end. From Fairbanks, the northernmost city on the North American road grid, drive up the graveled Dalton Highway. Unpeopled boreal forest stretches in all directions. About 200 miles on, you pass the arctic circle, beyond which the sun never sets in midsummer, nor rises in midwinter. Eventually, the trees thin out, and look scrawnier. The rolling landscape rises into big mountains, and you are threading through the bare, razor-edged peaks of the Brooks. Midway through the mountains, scattered spruces cling only to valley bottoms; further upslope is tundra, covered only with low-lying plants. At about 320 miles from Fairbanks, you pass the last little trees. Beyond lie the barren lands of the North Slope, ending at the industrial arctic-coast hamlet of Deadhorse and the oil fields of Prudhoe Bay—the only reason this road is here at all.

 Kevin Krajick) CLICK TO VIEW A SLIDESHOW

Near the arctic circle in northern Alaska, forests begin giving way to tundra. as cold air, frozen soils and lack of sunlight squeeze out trees. Researchers are investigating how warming climate may affect the ecology of this boundary. (All photos: Kevin Krajick) CLICK TO VIEW A SLIDESHOW

The northern tree line, beyond which the climate is too harsh for trees to grow, circles all of earth’s northern landmasses for more than 8,300 miles. It is the largest ecological transition zone on the planet’s surface—a fuzzy boundary that actually loops north and south, and may appear gradual or sharp, depending on locale.

In the far north, climate is warming two to three times faster than the global average. As a result, both tundra and boreal forests are undergoing massive physical and biological shifts. But the details and the outlook remain unclear. Will warming cause forests to advance, pushing out the tundra? If so, how fast? Or will warming reduce the forests—and perhaps also tundra vegetation—by causing more wildfires and insect outbreaks? What will become of the countless birds and animals that depend on one or both environments? And will the huge amounts of carbon stored in the North’s frozen soils and its trees increase, or be released, to cause even more warming?

The tree line is the longest ecological transition zone on earth's surface, circling through the northern landmasses of North America and Eurasia for some 8,300 miles. Here, the tundra beyond the trees is in red. At bottom right is Alaska, where researchers are now working in the area just beyond the arctic circle.

The tree line is the longest ecological transition zone on earth’s surface, circling through the northern landmasses of North America and Eurasia for some 8,300 miles. Here, the region beyond the trees is in red. At bottom right is Alaska, where researchers are now working in the area just beyond the arctic circle. (Map courtesy of U.S. Fish and Wildlife Service)

To  help answer these questions, scientists from Columbia University’s Lamont-Doherty Earth Observatory and other institutions are engaged in a long-term project to sort out what allows trees to survive or not in this borderline environment. They have set up monitoring plots, conveniently located along the highway, at the edge of the trees. Here, instruments will continuously measure air and soil temperature, precipitation, wind speed, humidity and other parameters for the next several years, and compare these with the growth and survival of trees. The fieldwork is part of the larger Arctic Boreal Vulnerability Experiment (ABoVE), a multiyear NASA-sponsored project that seeks to combine large-scale satellite observations of the northern regions with these fine-scale ground studies.

Natalie Boelman, an ecologist at Columbia University’s Lamont-Doherty Earth Observatory, measures the height of trees at one study plot.

Natalie Boelman, an ecologist at Columbia University’s Lamont-Doherty Earth Observatory, measures the height of trees at one study plot.

“There are many conditions that affect whether trees can and cannot grow,” says Lamont-Doherty plant physiologist Kevin Griffin. The main one is heat; trees generally are viable only where the mean growing-season temperature is above about 6.4 degrees C (about 43.5 degrees F). But that is not the whole answer, says Griffin. “We also know it’s things like water, wind, nutrients, how much light is received, whether it’s direct or diffuse light, snow cover in the winter—it’s a complex combination. How that all works, that’s precisely what we’d like to find out.”

Led by Jan Eitel, a forest scientist at the University of Idaho, the scientists arrived by pickup truck in early June to set up the plots. Almost no one lives between Fairbanks and Deadhorse, but they were able to put up at a lodge in the onetime gold-mining settlement of Wiseman, a mostly deserted huddle of cabins (current population about 20) dating from the early 1900s that lies near the highway. From here, the scientists commuted daily to a half-dozen sites, chosen for their sharp ecological edges; at each one, you could walk from the trees right into adjoining tundra, just slightly upslope. The most northerly plot is near a onetime modest landmark, the so-called Last Spruce, a starved-looking tree marked with a metal sign that said “Farthest North Spruce Tree on the Alaskan Pipeline – Do Not Cut.” A year or so ago, someone cut it down.

Trees grow very slowly here; this one that Boelman is examining is about 15 years old.

Trees grow very slowly here; this one that Boelman is examining is about 15 years old.

Part of the project involves mapping the sites with LiDAR, a surveying technology that shoots a pulsing laser to create an exquisitely detailed 3D landscape map. Accurate down to a few centimeters, it maps ground layout, individual tree branches and plant cover. In this environment, where trees are barely hanging on, the tiniest bits of variation in topography or temperature might make a life-or-death difference for a seedling; a bed of deep moss may swaddle it in warmth; a subtle swale, projecting boulder or another tree might protect it from raking winds.

But most far northern soils are permanently frozen just below the surface, and warming climate is not altering the fearfully small amount of light reaching plants much of the year. A neighboring tree might also cast just enough shade so that a seedling cannot get enough light and warmth, and a too-dense stand of trees might reduce the overall soil temperature they themselves need for rooting and uptake of nutrients. The surveys, repeated every few days by automated cameras, are designed to show how the landscape changes over time.

Shrubby deciduous dwarf willows and aspens grow here, but the only real trees this far north are the spruces. Once one takes root, it grows slowly—very slowly. One day University of Idaho remote-sensing specialist Lee Vierling and Lamont ecologist Natalie Boelman aged some smaller ones by counting whorls—the bit of stem that sprouts from the top each growing season. One Christmas-tree size spruce reaching just over their heads turned out to be 96 years old; it had apparently started growing in 1920.

“Woodrow Wilson was president then,” said Vierling. “World War I was just over.” The tallest trees reach 20 to 30 feet, a height that spruces can reach in a decade or two further south; these have probably stood for 200 to 300 years.

Lamont-Doherty plant physiologist Kevin Griffin checks an instrument designed to monitor a spruce tree’s photosynthetic activity.

Lamont-Doherty plant physiologist Kevin Griffin checks an instrument designed to monitor a spruce tree’s photosynthetic activity.

Warmer weather is almost certain to make these trees grow faster, and such weather is already here. With 24-hour daylight, the team worked up to 14 hours a day, much of the time sweating in intense sun. Around this time, the thermometer up at Deadhorse hit an all-time record of 85 degrees F—identical to New York’s Central Park that same day.

“The trees are really booming here,” said the team’s hostess in Wiseman, Heidi Schoppenhorst, who has lived here her whole life. “The climate is warming, and there’s more rain in June, when it really matters.”

There is already evidence from satellite imagery that the tundra beyond is becoming greener and shrubbier. Many scientists expect the tree line to advance eventually, and some studies purport to show that this is already happening. Some models predict that half the current tundra could be converted by 2100, though others say the process would be much slower. On the other hand, some studies assert the trees are actually retreating in areas, as heat dries forests, helping invasive insects and fires to destroy growing areas.

In Alaska, fires are predicted by one study to grow fourfold in coming decades, and it is already being ravaged; on the way up, the scientists passed through several big tracts reduced in the past few years to blackened sticks. This year a fire around Fort McMurray, in northern Alberta, drove out 80,000 residents and leveled part of the city. A few years ago, Boelman was part of a team that studied a 2007 lightning-sparked fire that burned 400 square miles of tundra on the North Slope—the biggest tundra fire ever recorded, in an area where thousands of years may go by without any fire at all.

Team leader Jan Eitel of the University of Idaho sets up a solar-powered radar camera that will scan a study site continuously for years, to capture how trees respond to changing conditions.

Team leader Jan Eitel of the University of Idaho sets up a solar-powered radar camera that will scan a study site continuously for years, to capture how trees respond to changing conditions.

“The differences between tundra and trees are really interesting, especially since one is predicted to start encroaching on the other,” said Boelman, stroking the needles of a nearby spruce about up to her shoulder, but probably much older than she is.

Boelman is part of a separate ABoVE project in which researchers are radiotagging northern animals including caribou, bears, moose, wolves and eagles, to see where they travel in relation to changing fire and weather conditions. Boelman has been working in northern Alberta tagging American robins, which are known to inhabit wide ranges and migrate vast distances. If anecdotal evidence means anything, the trend could be northward; in the last 20 years, some Inuit communities who had never seen robins before have had to invent a name for them: “Koyapigaktoruk.”

On her first trip to the north, Lamont-Doherty graduate student Johanna Jensen takes down data on a wired-up spruce. The study will provide not only long-term information on climate change, but opportunities for young scientists to work directly in the field.

On her first trip to the north, Lamont-Doherty graduate student Johanna Jensen takes down data on a wired-up spruce. The study will provide not only long-term information on climate change, but opportunities for young scientists to work directly in the field.

A few days after installing complex arrays of sensors, cameras and data loggers, along with solar panels and tangles of wires to connect them, the scientists discovered an unexpected wildlife phenomenon: Rabbits, rampant in the forest, loved chewing through the wires, and their equipment was blinking out. The team quickly made repairs and improvised defenses, burying the wires in spongy moss or surrounding them with palisades of sharp, dead sticks. Plans were laid for obtaining chicken wire for a more permanent solution.

Rabbits do not thrive like this in tundra, but if the trees and shrubs move northward, the rabbits will probably move with them. So will other creatures that favor such habitats, such as lynx, moose, black bears and white-crowned sparrows. Those who favor tundra would then have to adapt or get nudged out; these include musk oxen and open-area nesting birds such as Lapland longspurs and ptarmigans. Some animals, including barren-ground caribou and wolves, move seasonally between the two.

Boelman is neutral about the outcome. “People assume that when the ecosystem changes, it’s going to be all bad.” she said. But, she said “with climate change, there are almost always winners and losers. Some species will suffer, but others will benefit.”

Along the Dalton Highway itself, change is happening fast. Near the study sites, workers were digging an endless ditch to lay a fiber-optic line to Deadhorse. Intrepid tourists, encouraged by the mild weather, passed by in heavily laden vehicles and waved. A man pushing a large stroller-type contraption southward was said to be on a mission to walk from Deadhorse to Austin, Tex. Giant trucks raced northward carrying cable, pipes, prefab buildings. Some were carrying gasoline, against the pipeline flow of oil going in the opposite direction. The fossil-fuel circle was being completed; refined energy was heading back to help keep up the production of raw energy.

 

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Water Samples and Wildlife

Thu, 07/05/2012 - 13:56

After a day of coring on Tuesday, we decided to give our arms and backs a rest and collect water and plant samples. We take these samples so that we can characterize the chemical signatures of each plant type, and water from different parts of the system. Then, we can recognize those same signatures in the samples we take from our core. We can use the chemical signatures of the core samples to reconstruct how the vegetation and distribution of moisture has changed in the peatland through time.

While we were collecting our samples, we had a chance to meet some of the characteristic tundra wildlife.

Ptarmigan

Ptarmigan

Phalarope

Red-Throated Phalarope

Long-Tailed Jaeger

Long-Tailed Jaeger

Deepest core yet from Imnavait Creek!

Wed, 07/04/2012 - 03:44

Our first day in the field was a wild success! We visited Imnavait Creek Peatland, named for the small stream that drains out of it into the Kuparuk River. We chose this location because it has the potential to be much older than many other peatland sites. During the last ice age, the area of the creek escaped being scoured away by a glacier, so could have been accumulating sediment during that time. Unfortunately, previous attempts to recover cores that reached these old sediments were hindered by equipment failures. This time, we used an auger specially designed to core permafrost soils, and we were able to core more than two meters of sediment, about a half meter more than had previously been achieved. Hopefully the additional sediment will allow us to understand how peat accumulation differs during ice ages. We won’t know exactly how old the sediments are until we get our cores back to the lab and determine their ages using carbon-14 dating. Stay tuned! See a video of us using the permafrost auger below.

Click here to view the embedded video.

Getting There = 0.5*fun

Tue, 07/03/2012 - 04:31

Hello from the land of the midnight sun! We have just arrived by way of the famous Dalton Highway at Toolik Field Station, a Long Term Ecological Research site of the University of Alaska Fairbanks. We pulled up to the station just in time for dinner, a quick trip to the field station’s wood-fired sauna, and a dunk in Toolik Lake to wash off the dust of the road. Now it’s time to try and block out enough sun to get some shut-eye before a long day of coring tomorrow. Check out some pictures from our 360-mile drive below.

Dalton Highway Sign

The Start of the Dalton Highway

Lupines and The Pipeline

Lupines and The Pipeline

A touristy marker on the Arctic Circle

dirty truck

Who told you our truck was red?

brooks range

High in the Brooks Range