A new study from the University of Northern Arizona shows that rising temperatures are shifting the coldest forests on Earth to the north, raising concerns about biodiversity, increasing the risk of forest fires and increasing the impact of climate change on northern communities.
Logan Berner, Associate Professor of the School of Informatics, Computing and Cyber Systems (SICCS) and Scott Goetz, Professor Regent and Director of the GEODE Laboratory, wrote: “Satellite observations document trends that are consistent. boreal forest biome shift ”, which was published on Thursday Biology of global change. The boreal forest is a belt of cold-resistant conifers that stretches for nearly 9,000 miles through northern North America and Eurasia; it accounts for almost a quarter of the Earth’s forest area and is the coldest – albeit mostly rapidly warming – forest biome.
For this study, researchers used 40-year-old satellite observations with moderately high (30-meter) resolution and various sets of geospatial climate data on boreal forests and assessed where and why vegetation has turned green and brown in recent decades. “Greening” indicates higher vegetation growth rates, which can occur when global warming promotes the growth of trees and shrubs, as has been observed in Arctic and alpine tree lines. “Destruction” indicates lower vegetation growth rates and potential vegetation loss, for example, when hotter and drier conditions stifle tree growth and kill trees.
“There is evidence that climate change is causing boreal trees and shrubs to spread to the Arctic and alpine tundra, while causing increased stress and dying trees along the warm southern edges of the boreal forests,” Berner said. “This dynamic may lead to a gradual shift to the north of the geographical volume of the boreal forest biome, but the extent to which such changes are already occurring remains unclear.”
What they found was no surprise. Vegetation has become greener on most of the cold northern edges of the boreal forests; warmer conditions led to increased vegetation growth and allowed trees and shrubs to expand into the Arctic and alpine tundra. On the contrary, vegetation has become more brown along parts of the warm southern fringes of this biome as a result of hotter and drier conditions that have increased stress and tree death. Interestingly, Berner said vegetation is likely to become greener in areas with high soil nitrogen, indicating that the soil availability of nutrients is an important constraint on the response of boreal vegetation to climate change.
“The boreal forest ecosystem has changed a lot in recent decades, and these changes are often associated with increasing fires,” Goetz said. “Here we have deliberately focused on areas that have not been recently affected by the fire so we can highlight the impact of climate change. Our hypotheses about what will happen have been confirmed by this analysis – forests are becoming more productive in cooler northern areas and at higher altitudes. and they are becoming less productive as a result of hot air masses and drying up in warmer and southern areas. We fully expect this to continue and are likely to intensify in the coming years. ”
Which means a changing biome for the forest
Changes in vegetation can affect both plant and animal biodiversity, especially species such as caribou and elk, which have specific benefits in forages (eg deciduous shrubs and trees). These wildlife species are the most important sources of food for natural communities in the boreal-tundra ecotone. Changes in vegetation on both the northern and southern edges of the Baral forests will affect forest fire regimes, which is likely to increase the risk of new and strong fires. Changes in vegetation also affect the resilience of carbon-rich permafrost soils and the absorption of solar energy by the land surface in a way that can accelerate global warming. Moreover, increasing tree mortality can have far-reaching implications for forest products and also lead to further degradation of semi-solid and sporadic permafrost.
These future effects are not limited to the geographical area around the forest.
“Basically, greenhouse gas emissions from human activities cause global warming, which, in turn, leads in boreal forest move north as well as affect other ecosystems around the planet, “Berner said.” To minimize the adverse effects climate change, efforts are needed to drastically reduce greenhouse gas emissions, especially those related to fossil fuel consumption and deforestation. In addition, northern communities need to plan for potential changes in vegetation that could affect the availability of resources (such as wildlife, timber) and the risk of forest fires. ”
This study is part of a broader initiative that is funded NASA’s Arctic-Boreal Vulnerability Experiment (ABOVE) that will include further efforts to understand the extent, nature, causes, and consequences of emerging shifts in the boreal biome. Goetz is the research supervisor of ABoVE.
Logan T. Berner et al., Satellite observations document trends consistent with shifts in the biology of baral forests, Biology of global change (2022). DOI: 10.1111 / gcb.16121
Northern Arizona University
Citation: A new study shows that the coldest forests on Earth are shifting north with climate change (2022, February 24), obtained February 24, 2022 from https://phys.org/news/2022-02-earth-coldest- forests-shifting-northward.html
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