Threshold 32°F Art, Poetry & Field Notes

 
Introduction

On a warm September morning in Interior Alaska, an artist, a writer, and an ecologist wander through the boreal forest. As they move among spruce trees, they look to the forest floor, its weave of berries and mosses and fungi and lichens, all well-adapted to extended dark months of cold. The three friends are winter people. The musky scent of autumn lifts their spirits, but signs of warming are clear.

Extended summers and temperature swings above 32°F (0°C) in winter have amplified change in the north. The artist pauses to sketch a tree trunk spilling sap from boreholes left by spruce bark beetles. The ecologist touches a branch full of browned needles and describes the tree’s connection to fungal networks belowground. The writer scans the understory for healthy young spruce.

In the company of fear unspoken, the three forage on an earthen threshold where science meets story, where recipes for resilience might reside. Where 32°F, the tipping point between ice and water, draws them deeper into a high stakes storyline, when temperatures rise in a landscape shaped by cold.

Slumbering queen: The white-backed bumble bee (Bombus jonellus) is an important pollinator of blueberries, cranberries, and willows—key food sources for wildlife and people. During the short summer season, worker bees forage intensely. By vibrating their bodies, they use “buzz pollination” to release pollen from flowers. As winter sets in and temperatures dip below 32°F (0°C), the bumble bee queen finds a place to hibernate belowground, where she lowers her metabolic rate for the winter. Shorter winters could mean that bees extend their active season, while warmer winters could threaten the protection provided by the hibernation burrow; if insulating snows melt or rains infiltrate, the queen’s survival and emergence in spring to lay eggs for the next generation of worker bees will be threatened. Scientists wonder what will happen to the slumbering bumble bee if temperatures warm.

Fireweed the reclaimer: Fireweed (Chamerion angustifolium) is an indicator of disturbance and a symbol of resilience. Its tall spikes of pink flowers and turquoise pollen attract people and bumble bees alike. As a pioneer species, fireweed rapidly establishes after disturbances like wildfire, avalanches, landslides, and logging. Its small, lightweight seeds with fine hairs catch the wind and disperse to new, open spaces. Fireweed also spreads through deep rhizomes—underground stems—that can extend for meters, linking the slender stems seen aboveground. A sprawling patch may actually be an individual or a few plants, connected belowground. These rhizomes are a source of resilience, allowing fireweed to endure disturbances and rapidly regrow by drawing on stored resources. The plant’s tall shoots are food for grazers, and a traditional source of fiber and medicine for people. Over time, if disturbance does not recur, fireweed is replaced by plant species like berry and willow shrubs that thrive in the maturing forest.

Thawing time: Permafrost is ground that remains below 32°F (0°C) for two or more consecutive years. It contains water frozen in crystals, lenses, or wedges of ice, and large amounts of organic material (dead plants, animals, and microbes) that has accumulated over millennia. The boreal forest’s top layer of soil, known as the active layer, thaws from the surface downward each summer until reaching the permafrost below, then refreezes in winter. As the climate warms, the active layer thickens, incorporating deeper and older soils. Thawing soils release carbon and nitrogen, once locked in frozen material. Bacteria, Archaea, and Fungi, the microbial agents of decomposition, consume organic matter and release greenhouse gasses such as carbon dioxide (CO₂), methane (CH₄), and nitrous oxide (N₂O) into the atmosphere. This process, known as the “permafrost carbon-climate feedback,” accelerates warming by intensifying the greenhouse effect, creating a self-reinforcing, positive feedback loop.

Methane bubbles & ice: Beneath northern lakes, microbes in oxygen-poor, organic-rich sediments produce methane, a greenhouse gas more than 25 times more potent than carbon dioxide at trapping heat from the sun and warming the earth’s atmosphere. Some of these methane-making microbes, including those from permafrost soils, remain active even at temperatures below 32 °F (0°C). As methane forms, it rises through the water column, accumulating as bubbles. In winter, as ice forms on the lake surface, these bubbles become trapped beneath the frozen layer, delaying their release into the atmosphere. When temperatures warm in spring and the ice melts, the methane escapes, contributing to climate warming. Certain plants, like sedges, further accelerate methane movement by channeling gas from waterlogged soils through specialized pores in their tissues, known as aerenchyma, acting as chimneys for methane release.

Winter’s blanket: When snow covers the forest—much like a blanket—it insulates the environment below. Snow traps air and reduces the transfer of heat from the ground to the colder air above. Deep snow is like a thicker blanket, providing more insulation to what is beneath. If the snowpack thins from wind, melting, or rain on snow, it becomes less effective at keeping the ground warm. As a moderator of fluctuations in soil temperature, snow often keeps temperatures in the subnivean zone—the place between the snow and ground—just above 32°F. This protects plants and animals from frost damage while also keeping the soil warm enough for animals and microbes to remain active, even when air temperatures fall. Bumble bees and others depend on snow’s protective blanket.

Shrubs as architects: Shrubs, such as willows, catch and hold snow with their stems and branches. This deepens the snowpack and shifts the distribution of snow drifts, which in turn affects the timing of melt. The “snow-shrub hypothesis” describes a positive feedback loop where accumulated snow insulates the soil, maintaining warmer conditions that boost microbial activity and nutrient release, further promoting shrub growth. Shrub branches close to the snow surface can also serve as a thermal bridge, influencing ground temperatures by cooling permafrost in winter and warming the ground during spring melt. This effect occurs because branches conduct heat through the snowpack in winter and absorb solar radiation in spring. As perennial plants, willows draw upon their stored resources in spring. Their fuzzy buds, an anatomical adaptation to cold temperatures, provide warmth to tender tissues that develop in the autumn, remain dormant through the long winter, and awaken in the spring, ready for rapid growth.

Beetle’s boom: Spruce beetles, native to Alaska, bore into the bark of trees to lay their eggs. Their larvae feed on the phloem, the tissue that transports sugar from leaves to stems and roots, damaging the tree, eventually starving and killing it. The black-backed woodpecker (Picoides arcticus), a disturbance specialist, uses its bill to hammer into dead and dying trees, strip bark, and feed on insect larvae of wood-boring beetles such as bark beetles. Some beetles can survive extreme cold, but temperatures below -13°F (-25°C) are lethal. Since 2016, an ongoing outbreak has spread north about 150 miles (~240 km), affecting 2.25 million acres, equivalent to more than three times the size of Rhode Island. Warmer winters have sped up the beetles’ life cycle, allowing them to complete the cycle in one year instead of two. This shift in timing points to changing climate conditions that may allow for historically rare outbreaks in colder parts of Alaska. While these warmer conditions benefit the beetle, they threaten the stability of the snowpack that the bumble bee relies on for underground hibernation.

Forest in flux: The boreal forest, Earth’s largest terrestrial biome, covers 17% of the land and stores over 30% of terrestrial carbon in vegetation and surface soils, rising to 60% when deeper permafrost is included. This amount is more than double the carbon in the atmosphere. Warming temperatures are driving the boreal forest northward into tundra while simultaneously leading to forest loss at its southern edge. In Interior Alaska, conifer forests dominated by black spruce in the lowlands and white spruce in the uplands are increasingly shaped by large, frequent, and severe fires. Climate-driven changes in wildfire activity may favor the establishment of deciduous trees like aspen and birch. This shift can alter carbon storage by reducing belowground and increasing aboveground carbon. The future of the boreal forest as a carbon sink— an ecosystem that absorbs more carbon than it releases— remains uncertain. Will changes in forest structure impact permafrost stability and future disturbances?

Permafrost thaw and landscape change: Each spring, breakup marks the seasonal shift when ice and snow begin to thaw. This transition reveals a striking mix of frozen and thawed features, raising questions about the future of these ecosystems in a warming climate. Overflow ice, tinted yellow by compounds from plants and soil, forms as water is forced upwards to the snow’s surface. Trees tilt, signaling the degradation of permafrost. Rising ground temperatures have led to widespread permafrost thaw, increased active layer thickness, and ground subsidence, or thermokarst, where the ground deforms or collapses as ice within the permafrost melts. The sinking terrain can create wetlands, allowing aquatic plants to take hold, or it can promote drainage, exposing dry ground where woody shrubs could establish and introduce potential fuel for future wildfires. As temperatures rise above freezing, changes in the distribution and movement of water offer insights into the future of boreal forests.

Future forest: Wildfire plays an essential role in the boreal forest. Yet, climate-driven increases in wildfire frequency, severity, and size could profoundly reshape the landscape by altering dominant tree species and compromising permafrost integrity. Key fuels in the boreal forest are dried mosses and organic soils, which accumulate over decades between fire cycles. This spongy material, like snow in winter, insulates the ground and helps protect permafrost from summer heat. When a fire moves through, it burns away this insulating layer, allowing heat from aboveground to penetrate more easily and warm the permafrost below. With increased fire activity, forests may transition from spruce to birch and aspen. The mossy understory declines, and permafrost recedes or vanishes. Wildfire may also be quelled by this change in fuel type. The changing forest composition influences what the ecosystem provides: disturbance and climate regulation, food and fiber resources, and cultural and spiritual connection. As the forest’s future unfolds, the fates of the bumble bee, the beetle, and the woodpecker are interconnected. How will the ecosystem respond and transform in the face of a warming climate?

Threshold 32°F, a partnership with In a Time of Change and Bonanza Creek Long-Term Ecological Research, is on exhibit at the University of Alaska Museum of the North, in Fairbanks, from July to November, 2025.

About the Collaborators

Klara Maisch’s place-based paintings highlight climate change throughout Alaska. Her work examines processes of wildfire, permafrost thaw, glacier melt, and shifts in vegetation and treeline. As a lifelong Alaskan, Klara has developed a creative practice that’s rooted in a deep connection with the land. The Rasmuson Foundation, the Puffin Foundation, the Connie Boochever Fellowship, and the Alaska Wilderness League have supported Klara’s work. Find more of Klara Maisch’s work at www.klaramaisch.com.
 

Debbie Clarke Moderow writes creative nonfiction and poetry, exploring her lifelong relationship to wild landscapes in the context of change, both personal and global. Debbie has collaborated with scientists, visual artists, and writers since 2015. Her debut memoir, Fast Into the Night: A Woman, Her Dogs, and Their Journey North on the Iditarod Trail (Houghton Mifflin Harcourt 2016; Red Hen Press 2018), won the 2016 National Outdoor Book Award in Creative Nonfiction. Find out more about Debbie Clarke Moderow’s writing at debbieclarkemoderow.com.
 

Rebecca E. Hewitt studies how plant-microbe interactions influence plant function, ecosystem resilience, and biogeochemical cycling in tundra, boreal, and temperate rainforest ecosystems. Her research has been published in Nature, Science, and New Phytologist, with support from the National Science Foundation, the National Park Service, the Society for the Protection of Underground Networks, and Save the Redwoods League. Assistant Professor of Environmental Studies at Amherst College, she uses field-based, experiential learning to build scientific literacy and prepare students to tackle environmental challenges. Find out more about Rebecca E. Hewitt’s work at www.amherst.edu/people/facstaff/rhewitt.

 
Paintings by Klara Maisch, poems by Debbie Clarke Moderow, field notes by Rebecca E. Hewitt, and photos of artwork by Chris Arend.

This project was produced by In a Time of Change (itoc.alaska.edu) with funding from the National Science Foundation (DEB-2224776 and DEB-1636476) and the USDA Forest Service Pacific Northwest Research Station (RJVA-PNW-20-JV-11261932-018) through the Bonanza Creek Long-Term Ecological Research program (lter.uaf.edu).