Sea Ice Reductions In Arctic Help White Spruce Trees Move North, Up Mountainsides

Experts found out that sea ice reductions in the Arctic could help white spruce trees to move north and up in the mountainsides.

Warming Arctic Region

The study pointed out that the Arctic is warming multiple times faster than the global average, and the resulting loss of albedo from melting ice and increasing tree cover is further increasing global climate change.

Experts noted that boreal forest is predicted to shift into the tundra zone as the climate warms, but thus far tree lines have moved northward slowly or not at all. They have linked tree line advance to declines in Arctic Ocean sea ice.

Through combining field and remotely sensed measurements from northern Alaska with published data from 60 other Arctic sites, the authors then found out that distance to sea ice predicted tree growth and recruitment, as well as the probability of forest advance.

The study explained that climate-induced northward advance of boreal forest is expected to lessen albedo, alter carbon stocks, and replace tundra, but where and when this advance will occur remains largely unknown.

Through the use of data from 19 sites across 22 degrees of longitude along the tree line of northern Alaska, researchers have shown a stronger temporal correlation of tree ring growth with open water uncovered by retreating Arctic sea ice than with air temperature.

Spatially, our results suggest that tree growth, recruitment, and range expansion are causally linked to open water through associated warmer temperatures, deeper snowpacks, and improved nutrient availability,'' the experts said.

They also applied a meta-analysis to 82 circumarctic sites, finding out that proportionally more tree lines have advanced where proximal to ongoing sea ice loss.

Taken together, these findings of the study have underpin how and where changing sea ice conditions facilitate high-latitude forest advance.

Authors of the study further gathered data from 19 field sites over four years, hiking 1,500 miles.

They had discovered a pattern in which tree lines were encroaching near places where the sea ice has been retreating but not in other areas.

Read Also: Fossil Forests Found In Arctic Circle; Drastic Climate Shifts 380 Million Years Ago

Increased Snow Land

Further, the researchers also found out the increased snow land near places where the sea ice has been retreating serves as a blanket on the ground.

They pointed out that everything below the blanket stays warmer through the long winter than it does in places with a thinner blanket.

Due to this, microbes are allowed to decompose organic matter in the topsoil all winter long. And that in turn releases nutrients that feed seedlings, which will further help them survive the winter.

The team concludes that as tree lines encroach, they cover more land with greenery, which absorbs heat.

This will then push the Arctic to grow warmer at an even faster phase.

Previous studies indicated that when large bodies of water grow warmer during the summer, they tend to experience more evaporation as the winter months arrive.

The endgame would be more snow falling on nearby land. 

Related Article: Scientists Shed 'Light' on Arctic Tree Divergence Problem