With warming summer temperatures across Alaska, white spruce tree growth in Interior Alaska has declined to record low levels, while the same species in Western Alaska is growing better than ever measured before.
The findings are the result of a study led by University of Alaska Fairbanks School of Natural Resources and Extension researcher Glenn Juday, Claire Alix of the University of Paris 1 Pantheon-Sorbonne, and Tom Grant, formerly an adjunct faculty member at UAF. Their findings were recently published online by the journal Forest Ecology and Management.
'For the first time across a major forest region, we have real data showing that biome shift has started,' Juday said. 'This is not a scenario model, or a might, or a maybe. The boreal forest in Interior Alaska is very near dying from unsuitably warm temperatures. The area in Western Alaska where the forest transitions to tundra is now the productive heart of the boreal forest.'
The paper is the result of 10 years of research. Juday and Alix gathered white spruce tree cores and disks from 540 trees in 36 stands along the Yukon, Tanana and Kuskokwim rivers. They started in easternmost Alaska and sampled downriver to the western edge of the boreal forest near the Bering Sea. The research required the team to travel hundreds of miles down some of the most pristine large rivers left on Earth. Sam Demientieff, a longtime Interior river traveler and Alaska Native leader, provided much of the river transportation and expertise required to navigate the silt-filled water and constantly shifting channels.
The researchers took two measurements from each annual growth ring of the 100 to 250-year-old trees, then analyzed the nearly quarter-million measurements to determine how much the trees grew each year. They then compared that growth to temperature data from eastern, Interior and Western Alaska historical records and weather stations. In addition, they drew on previous scientists' work chronicling tree growth and temperature back more than two centuries.
They found that in Interior Alaska, as summer temperatures rose, the growth of the trees slowed. Meanwhile, in Western Alaska, which is also warming, the trees are growing more rapidly.
White spruce trees thrive within an optimal temperature range. The long-term average temperature in Interior Alaska used to be at the high end of that optimum. In Western Alaska, the average temperature was below or at the low end of the optimal temperature range.
In the mid-1970s, temperatures suddenly increased and have cycled around a higher average since. Interior Alaska's average temperature became warmer than the trees' ideal range, and growth slowed. Meanwhile, the average temperature in Western Alaska increased to more closely match optimal conditions, which increased growth.
'One aspect of the study that makes the results especially clear is that the trees were all growing in the same environment along the big rivers,' Juday said. 'In many transect studies, lots of variables change across the area studied. In ours, the main thing that changed was the climate, from the hot, dry summers of the Interior, to the cooler, wetter climate near the coast.'
Juday notes that their findings don't mean the boreal forest is going away. It's simply shifting away from lowlands in Interior Alaska to higher elevations and the western part of the state, he said. 'The movement of an entire biome is often hypothesized in models of probable future climate, but the Alaska boreal forest is actually shifting today, and the process is well underway.'
Note to editors: downloadable photos are available online at http://news.
Marmian Grimes | EurekAlert!
Cryo-electron microscopy achieves unprecedented resolution using new computational methods
24.03.2017 | DOE/Lawrence Berkeley National Laboratory
How cheetahs stay fit and healthy
24.03.2017 | Forschungsverbund Berlin e.V.
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
24.03.2017 | Materials Sciences
24.03.2017 | Physics and Astronomy
24.03.2017 | Physics and Astronomy