Reflections on the Forests of the Past

I was privileged enough to be able to spend a brisk fall day at the Tannersville Cranberry Bog Preserve recently. Wetlands often get a bad rap (think Washington politics “drain the swamp” messaging), but what I experienced was nothing short of wondrous. As I was guided through the bog on a floating boardwalk, reddened high bush blueberry leaves greeted me and cotton grass waved in the autumn wind next to a bunch of purplish-red-veined pitcher plants. Bright red cranberries nestled among the soft spongy deep green sphagnum mosses. Two different hawk species flew overhead as I stepped around the scat of river otter and black bear. Pole thin golden deciduous tamaracks and bright evergreen black spruce commanded a reverential quietude to the bog belying the wisdom of their lived centuries. Up the slope from this glacially formed wetland, the winds sang through the falling leaves of oak, pine, maple and birch forest as chipmunks and squirrels dashed from one moss covered rock to another, acorns in mouth and hand. Next to the upland forest, fire marks were evident on several eastern white pine trees in an open field from a prescribed burn meant to transition an old hay field back to a grassy meadowland that would be teaming with birds and insects come spring. 

This 1,000-acre (400 ha) preserve is one of the first tracts of land protected by the Nature Conservancy from development in Pennsylvania and is also a National Natural Landmark. It is a rare example of a boreal bog in the region. It is a place where one can experience directly in a very short distance the diversity that is the premise of nature. Protection of the bog garnered attention because of a tireless local advocate, botanist William Niering, and the very real impact its presence had in the Flood of 1955. Massive damage was incurred to the bridges in the area, except for those downstream of the bog. Peat bogs are ~95% water, with the sphagnum mosses able to hold 10-20 times their weight in water. 

Being in this space got me thinking about the importance of mosaic landscapes when it comes to balancing the impacts of disturbances like floods or wildfires. As Robin Wall-Kimmerer states in her book, Gathering Moss, “the apparent destruction of a disturbance is in fact an act of renewal, provided the balance is right.”

And this brought to mind the recent policy shifts in how our country’s leadership is approaching land management, particularly the claim that many of those shifts will help reduce wildfire risk. This claim to any environmental scientist or land steward immediately rings as completely disassociated with our current scientific and ecocultural knowledge. But as the philosopher Byung Chul Han notes, knowledge only comes when you contemplate how the present moment connects to the past and the future. To that end, I want to walk you through a high-level view of what we know about our forests and the impact wildfire has on them in this first part. In my next post (part two) we will explore how our country’s past with forest management and wildfire has shaped our present, and what that means for our future management efforts. 

Forests as life givers

Forests blanket roughly one-third of Earth’s land surface, but their influence extends far beyond their area. They act as the lungs of our planet, pulling in carbon dioxide and breathing out oxygen. Forests absorb about 30% of the carbon emissions from burning fossil fuels each year​, mitigating climate change impacts. By storing more carbon than they release, forests perform an “incredible service to our planet,” as ecologist Lucy Hutyra notes​.

Forests also play a critical role in the water cycle. Tree canopies and soils trap and filter rainfall, slowly releasing it to recharge groundwater and streams. In doing so, forested watersheds provide clean drinking water for wildlife and people alike as well as help regulate river flows which reduces flooding and erosion. In the western United States, for example, the majority of drinking water originates in mountain forest watersheds. In fact, maintaining adequate supplies of clean water was a central reason for the establishment of the first federally protected forest reserves through the 1891 Forest Reserve Act.

“One thing I have learned in the woods is that there is no such thing as random. Everything is steeped in meaning, colored by relationships, one thing with another.” 

-Robin Wall-Kimmerer

Forests are bastions of biodiversity. They are home to an estimated 80% of the world’s terrestrial species​ – an astonishing variety of plants, animals, fungi, and microbes intertwined in complex biological systems. Every layer of a forest, from the canopy to the forest floor, teems with life performing unique ecological roles. This diversity underpins the resilience of ecosystems. Ecological complexity, including richness in species, interspecies reciprocal relationships, as well as age and size classes means more robust pollination, pest control, nutrient cycling, moisture retention, and adaptability in the face of stress.

Beyond tangible services, forests provide cultural, spiritual, and recreational benefits. Communities around the world revere forests as sacred spaces and sources of inspiration. Visualize a hiker finding peace among towering western redcedars, Douglas firs, and western hemlocks in a North American temperate rainforest. Listen to the quiet flow of the Pike River around the waders of an angler surrounded by maples, oaks, and prairie grasses in the Great Lakes region. Feel the warmth of community of the salmon ceremony welcoming and honoring the returning Chinook, Chum, Coho, and Pink salmon at the Cascade Head. These experiences underscore that forests enrich our quality of life in profound ways.

Healthy forests are invaluable for all the ecological and cultural wealth they provide. Ensuring these benefits endure requires understanding and working with the natural processes that maintain forest health – and few processes are more influential in many forests than fire.

Wildfire: a natural shaper of ecosystems

Wildfire, paradoxically, is both creator and destroyer in forest ecosystems. Many forest types, from the Sierra Nevada coniferous forests and oak woodlands to the pine savannas of the Southeast or the boreal forests of the far north, evolved with recurring fires as a normal disturbance. These historical and present day fire regimes vary widely. Some ecosystems experience low-intensity surface fires every few years, clearing out underbrush without killing big trees. Other areas undergo stand replacing high intensity fires that would sweep through once a century. The plants and animals adapted to the regional frequency, intensity and seasonality of wildfire. 

Periodic wildfire brings balance to the landscape through revitalizing wildlife habitat and replenishing soils​. By burning off accumulated leaf litter and dead wood, wildfire returns nutrients to the soil, effectively fertilizing the forest floor​. Fire opens up sunny clearings where fresh plant growth can emerge, supporting herbivores and pollinators. Some species are even fire-dependent. For example, many conifers (e.g., giant sequoia, pitch pine) have resin-sealed, or serotinous, cones that only open and release their seeds in the intense heat of wildfire. In both forests (and grasslands, which play their own important ecosystem service roles), wildfire also clears away competing vegetation allowing their seeds to sprout and grow in a nutrient-rich ash bed improving both the health and success of the next generation.

It’s also crucial to recognize that humans have long used fire as a land management tool and are an integral part of fire-adapted landscapes. For millennia, cultural burning was (and is still) used by North American Indigenous Peoples to clear underbrush, stimulate the growth of useful plants (e.g., berries), and create habitat for wildlife. Cultural burning often creates a mosaic of burned and unburned patches across the landscape​. This mosaic pattern of different vegetation ages and densities actually limits the spread of future fires. Patches that burned more intensely would be adjacent to patches that remained more intact, breaking up the continuity of fuels and preventing any one wildfire from sweeping across massive areas​. 

Wildfire, whether ignited by lightning or by knowledgeable stewards, plays a critical role in sustaining healthy ecosystems and the organisms that depend on them, including humans. This concludes Part 1, in part 2 we will take our awareness of the importance of forests to life on Earth, and examine how land management decisions in the past have shaped the forests of the present.

Author

Jennifer Riehl, Ph.D.
2023-2025 Executive Branch Fellow at the U.S. National Science Foundation 

Editor

Andrew Czeidinski, Ph.D.
2023-2026 Executive Branch Fellow at the U.S. National Science Foundation