TITLE: These scientists are taking an unconventional approach to save forests: Cutting down trees
https://www.providencejournal.com/story/news/local/2024/01/18/experiment-in-rhode-island-hillsdale-preserve-could-help-save-american-forests-climate-change-pests/71899032007/
EXCERPT: When the first Europeans arrived in the early 1600s in what would become Rhode Island, as much as 95% of the land was forested. Within just a few generations, however, settlers had clear-cut the vast majority of the area’s woodland to make way for farming. The first forest survey, in 1767, found that only 31% of the land remained forested, according to the University of Rhode Island.
Agriculture in the state peaked in the early 1800s, and as families moved west in search of more fertile land, abandoned farms were slowly reclaimed by forests. Regeneration continued until the 1950s, when the trend started reversing as developers carved out more and more open space for housing. Today, about half of Rhode Island is still forestland.
The state’s forests have a wide range of benefits, providing habitat to wildlife, removing pollutants from the air, keeping drinking water sources clean, absorbing floodwaters, and sequestering nearly 27 million tons of carbon, according to the Rhode Island Department of Rhode Island Management.
But development pressure continues, most prominently in recent years from private companies that are building sprawling solar farms. And so, too, do threats from disease and insects. Rhode Island’s trees have long suffered from periodic outbreaks of spongy moths, winter moths and forest tent caterpillars that feed on their leaves.
But the number of threats is growing. Warmer winters have allowed Southern pine beetles to expand their range northward, posing a risk to the area’s pines. The emerald ash borer, an invasive insect from Asia, is laying siege to ash trees in Rhode Island and other states. The spotted lanternfly, another invasive pest, has more recently reached the state. And beeches are being wiped out by a microscopic worm that appeared in Rhode Island four years ago.
Trees can often survive defoliation by budding new leaves, but successive years of damage will gradually weaken them to the point that they can no longer recover.
More extreme summers are making it even harder by depriving trees of much-needed moisture. In 2016, 2020 and 2022, Rhode Island and the rest of New England experienced drought conditions that the National Oceanic and Atmospheric Administration has described as “historic.”
It’s in the context of these changes that the experiment in the Hillsdale Preserve is taking place.
The research is being conducted as part of a larger project known as Adaptive Silviculture for Climate Change. In the narrowest sense, silviculture is the science of growing trees, but it more broadly encompasses techniques for managing forests for wildlife habitat, timber production and other goals.
The ASCC project aims to test methods to protect different forest ecosystems from the impacts of climate change. Trials are being conducted in British Columbia, Georgia, Colorado, Ohio and other parts of the United States and Canada.
The Hillsdale site is part of a trial coordinated by the University of Connecticut that’s focused on oak forests in Southern New England. Riely is overseeing the research in Rhode Island, along with William Walker, supervising forester with the DEM, which manages the Hillsdale property. They’re testing three techniques.
On one section of the land, they’re trying to enhance the natural resistance of the forest to the changing conditions. The aim is to maintain the current diversity of species – which include tulip poplar, black birch and white ash along with the dominant species of oak and hickory – while improving overall forest health. The only living trees that were removed were invasive species, though not many were found. Fewer dead trees were taken down, and wood debris was left on the ground. Only light clearing of the canopy was done.
In another section, they’re testing what they’re calling resilience. They cut down black birch and red maple that create mid-canopy shade in an effort to promote the growth of oak saplings. They also took out more dead trees as part of a larger effort to support new growth. Here, they’ll plant native tree species that have shown hardiness to more extreme summers. They include black, scarlet, white and chestnut oak, as well as hickory and hybrid chestnut.
A third area underwent the most sweeping changes, seeing the highest number of dead trees removed and the creation of the largest gaps in the canopy. This is known as the transition zone, and it will represent what a New England forest could look like in the not-too-distant future. Here, the researchers will plant oak species that are normally found farther south or west, types adapted to hotter areas such bur, chinkapin, Shumard, post and Southern red oak.
The new planting won’t come until the spring. As Riely, Walker and Tee Jay Boudreau, deputy chief of the DEM’s Division of Forest Environment, walked through the Hillsdale Preserve on a recent afternoon, parts of the forest looked pretty bare.
“If you came upon this without any context, you’d wonder what’s going on,” Riely said.
TITLE: A nature-based solution to restore and adapt western US dry forests to climate change
https://phys.org/news/2024-01-nature-based-solution-western-dry.html
EXCERPT: Nature effectively "managed" forests through millennia of major climate changes and episodes of natural disturbances (e.g., wildfires, droughts, bark-beetle outbreaks), so why would nature not now be best able to restore and adapt forests to climate change?
We focused on this question while investigating lower-elevation dry forests of the western U.S. dominated by ponderosa pine (Pinus ponderosa) or similar pines and dry mixed-conifer forests, in addition to other trees.
Dry forests cover 25.5 million ha (63 million acres) of the western U.S. These forests have altered structure (e.g., tree density) from extensive logging, livestock grazing, and fire suppression.
Dry forests are also recently experiencing more natural disturbances. Wildfires have at times become almost unstoppable, overwhelming firefighters and spilling over into the built environment. These trends continue in spite of billions of dollars spent annually to reduce fuels (e.g., thinning) and suppress fires and other disturbances in federal forests.
These failing command-and-control approaches (CACA) are leading to calls for new approaches in dry forests.
Working with natural processes is the premise of nature-based approaches. We recognize widespread concern that disturbances in dry forest are outside historical variability, so they are damaging. However, we found they are not; instead, they are effectively restoring and adapting dry forests to climate change.
The central constraint on using natural disturbances is an insufficiently protected nearby built environment, which can be remedied by redirecting CACAs to focus on protecting the built environment.
A formal Nature-based Solution (NbS), defined by the International Union for Conservation of Nature, has eight essential properties. These include societal benefits, biodiversity and ecosystem integrity, good governance, adaptive management, sustainability, and integration into existing jurisdictions.
We focused on the feasibility of an NbS, how long it may take, could it better restore and adapt dry forests to climate change, and what is needed to protect the built environment so an NbS is feasible and more broadly acceptable?
Is there enough natural disturbance to restore and adapt dry forests? To assess this, we calculated recent rates (2010–2019), using federal datasets on a study area of ~16 million ha (40 million acres) of dry forests on federal land in 11 western states.
Nature-based disturbances, including wildfires, combined droughts and bark-beetle outbreaks, annually affected 2.07% of the study area; it would require 48 years to affect an area equal to the study area. CACAs, including prescribed fires and mechanical (e.g., thinning) treatments, annually affected 0.79% of the study area, requiring 126 years to affect an area equal to the study area.
Disturbance severity is classified as low, moderate and high severity, based on levels of tree mortality. Low- and moderate-severity fires, 82% of total fire area from 2010–2019, are widely accepted as ecologically restorative and adaptive.
Only the 18% of total fire area that was high severity is controversial, but we have shown that high-severity fire is recently operating at rates and patterns within the range of historical variability. Nearly all drought/beetle effects have also been low to moderate severity, with <0.1% high severity, so drought/beetle effects are also ecologically restorative and adaptive.
Why are nature-based disturbances more restorative and adaptive to climate change than CACAs are? Wildfires provide strong selective pressure for trees to survive the fire itself, so they restore historical forest resistance, and select for adaptation to hotter and drier post-fire environments as climate changes.
All fire severities recently have been deficient relative to their rates in historical forests, so more fire of any severity is restorative and adaptive. Droughts/beetle outbreaks, which reduce tree density and basal area and increase snags in dry forests, were historically significant thinning agents.
Most recent events have been low to moderate severity, so also restorative and adaptive, providing selection for slower-growing trees, that are less attractive to future beetle outbreaks and also need less moisture. In contrast, CACAs select tree winners and losers without any knowledge of their genetic adaptations to future disturbances or climate change.
Ecological heterogeneity from natural disturbances is also essential for species to adapt to climate change. Nature-based disturbances best provide essential natural selection, genetic adaptation, and spatial heterogeneity needed for forest resistance, resilience, and adaptation to future climate change.
Since natural disturbances best provide beneficial ecological restoration and adaptation, what is a feasible goal for using them in an NbS? Droughts/beetles rose after 2015 to a higher level and likely will reach 250,000 ha/year as temperatures rise further. We show it is feasible to reach ~410,000 ha/year of total natural disturbances, which mimics the historical level of low- to moderate-severity fire, likely a reasonable initial goal.
We also think it is sensible to work with droughts/beetles as they are more consistently low- to moderate in severity and do not threaten the built environment as wildfires can.
Recent rates suggest natural disturbances alone could accomplish restoration and adaptation within ~40 years. However, if prescribed burning and managed fire for resource benefit were enhanced to be more natural, full restoration and adaptation could feasibly be met in ~30 years, by mid-century, a significant achievement.
TITLE: Sea Otters Helped Minimize Kelp Forest Loss in California, Study Finds
https://www.ecowatch.com/sea-otters-kelp-forest-conservation-california.html
EXCERPT: According to a new study published in the journal PLOS Climate, the recovery of Southern sea otters (Enhydra lutris nereis) in central California happened at the same time that kelp forests in the same region had significant increases from 1910 to 2016. At the same time, northern and southern California experienced kelp forest losses, and these were also areas where sea otters were heavily hunted nearly to extinction in the 1800s.
The major increases in kelp forests in central California, up 57.6% or 19.7 square kilometers, helped offset the dramatic kelp forests losses in other regions of the state. The study findings showed that northern California lost about 8.1 square kilometers of kelp forests, while southern California experienced an 18.3-square-kilometer decline.
As a whole, the state’s kelp forests spanned about 112 square kilometers in surveys from 2014 to 2016, down just slightly from the 120.4 square kilometers covered in 1910 to 1912.
The researchers noted that these findings could offer a nature-based solution that could help in the recovery of both native sea otters and coastal kelp forests.
“Our study showed that kelp forests are more extensive and resilient to climate change where sea otters have reoccupied the California coastline during the last century,” Teri Nicholson, lead author of the study and a senior research biologist with the Monterey Bay Aquarium’s Sea Otter Program, said in a press release. “Where sea otters are absent, kelp forests have declined dramatically. In fact, we found sea otter population density as the strongest predictor of change in kelp canopy coverage across this hundred-year span.”
Kelp forests are important habitats and food sources for a variety of marine life, so they are necessary in preserving biodiversity. As Pew Charitable Trusts reported, kelp can absorb about 20 times more carbon dioxide per acre than land forests, and kelp forests play an important role in mitigating coastal erosion.
But pollution, overharvesting and climate change are major threats to this vegetation, the National Oceanic and Atmospheric Administration (NOAA) reported. But a decline in sea otters can also mean that sea urchins can take over, and the urchins overgraze the kelp and leave behind “urchin barrens. ”