Posts Tagged: forest
Clearing California's forests of dense overgrowth is a critical first step for curbing catastrophic wildfire in the state. But forest restoration — whether through prescribed burning or thinning — comes at a high price: Not only are these treatments costly, but cutting down or burning vegetation can release stored carbon dioxide, accelerating the impacts of climate change.
A new analysis by researchers at the University of California, Berkeley, provides a roadmap for how the state can effectively reduce wildfire risk through forest thinning while continuing to limit its carbon emissions.
By creating a market for small diameter trees and other woody biomass — particularly by encouraging the use of long-lived “innovative wood products,” such as oriented strand board — the state can both create an economic incentive for effective forest management and prevent the carbon stored in this vegetation from entering the atmosphere.
“It's hard to manage our forests without releasing carbon,” said study first author Bodie Cabiyo, a Ph.D. candidate in UC Berkeley's Energy and Resources Group. “But if we're really efficient and careful about how we are using the wood and invest in innovative wood products that can use waste wood, then we can achieve both net carbon benefits and wildfire mitigation benefits in California.”
In 2018, former California Gov. Jerry Brown committed the state to achieving full carbon neutrality by the year 2045, a goal that will require both reducing emissions and investing in carbon sinks, such as forests, that can remove existing carbon from the atmosphere. Two years later, California and the U.S. Forest Service jointly committed to managing a total of 1 million acres of state forest land annually through thinning, prescribed burning and industrial harvesting — treatments that could send some of that carbon back into the air.
“A lot of people are pointing towards forests as a source of sucking carbon out of the air and not adding carbon to the atmosphere,” Cabiyo said. “And while the goal to manage a million acres per year is fantastic and absolutely necessary, the reality is that a million acres per year will cost a lot of money to manage, and it's still unclear where that money is going to come from.”
While data is limited on exactly how much of the state's forests are currently managed, the researchers estimate that it is currently much less than the 1 million acre-a-year target. Their analysis shows that, with the right set of policies and incentives, the use of innovative wood products could provide both the state and private landowners with necessary funding to expand forest thinning treatments while still limiting carbon emissions.
“California has been on the forefront of both climate change mitigation and adaptation,” said study senior author Daniel Sanchez, an assistant cooperative extension specialist in UC Berkeley's Department of Environmental Science, Policy, and Management. “We hope our study helps align these two goals, showing how the state can meet both its emissions reduction goals and reduce wildfire hazard, while providing a framework for managing temperate forests across the world while trying to meet the needs of a changing climate.”
Burn piles the size of school buses
To create forests that are more resilient to severe wildfire, forest managers usually focus on removing smaller trees and underbrush, leaving many of the larger and more fire-resistant trees in place. However, while larger trees can be harvested and sold to sawmills as timber, the smaller wood residues produced by forest thinning have little market value in California and are often burned or left to decay.
“If you drive through these forest treatment projects, you'll see massive burn piles that can be over 20 feet tall — the size of multiple school buses — and they're just sitting there waiting to be combusted,” Cabiyo said. “That's a lot of carbon that is going to go back into the atmosphere.”
Small trees and woody residues aren't useless, however. Industries in other parts of the world, including the southeastern U.S., create engineered lumber by mixing wood residues with adhesives and then compressing them into large sheets. This engineered lumber is strong enough for construction, and many houses in California are already built with imported engineered wood, Sanchez said.
Woody residues can also be converted in biofuel plants to create electricity or liquid fuels, and if these plants are outfitted with carbon capture technology, this energy can be produced while removing carbon dioxide from the atmosphere.
“When it comes to carbon storage or sequestration, some people focus only on what's in the forest,” Sanchez said. “We wanted to assess the carbon emissions associated with the whole life cycle of these new products.”
The study calculated future carbon emissions under both a business-as-usual scenario, assuming limited forest management, and a scenario in which the state has created a market for wood residues. To make the comparison, the researchers conducted a cradle-to-grave analysis, looking at the carbon emissions associated with every single life stage of a product — from the moment the wood is harvested until the end of the product's life.
By investing in local industries that create innovative wood products or that convert biomass into biofuels using carbon capture technology, the state could create a market for wood residues that does not add significant carbon emissions, the study found. The study also proposes a model scenario in which the state incentivizes the use of engineered wood in the construction of multi-unit affordable housing.
“If California starts doing thinning treatments at a large scale, then we're going to be producing a lot more lumber and wood residues, and where that material goes is a question,” Cabiyo said. “We found that using that new material for building affordable housing could produce massive carbon benefits, largely because those buildings otherwise would be built with steel and cement, which have significant carbon emissions associated with them.”
Thinning treatments also reduce the risk of severe wildfires that can incinerate millions of acres of vegetation at once and kill even large trees, helping California's forests maintain their long-term ability to store carbon. Study co-author Brandon Collins, a research scientist with Berkeley Forests and with the U.S. Forest Service, points out that these treatments have also been shown to provide numerous ecological benefits, including increased water availability and habitat diversity.
“Creating a market for forest biomass produced by forest thinning could reduce wildfire hazard, prevent air pollution from smoke, and potentially displace fossil fuels and increase water availability,” Collins said. “We need to deal with this small diameter biomass, and there is a solution if we could just find a way to connect the dots politically and economically.”
Additional co-authors of the study include Jeremy S. Fried of the U.S. Forest Service and William Stewart and Jun Wong of UC Berkeley. This research was supported in part by a National Science Foundation Graduate Research Fellowship and the Conservation 2.0 Program.
Sometimes you can't see the forest for the trees. Sometimes you can't see the trees for the forest. And sometimes you can't see the spider at all...
A honey bee visiting a flowering artichoke. (Photo by Kathy Keatley Garvey)
Packing white pollen, a honey bee makes a return visit to the flowering artichoke while she cleans her proboscis (tongue). (Photo by Kathy Keatley Garvey)
Two honey bees are dusted with pollen from the flowering artichoke. (Photo by Kathy Keatley Garvey)
Bee-ware! A honey bee touches down--nearly on a tiny crab spider. (Photo by Kathy Keatley Garvey)
Forestland owners can learn how to survey the trees on their property from four new videos produced by UC Cooperative Extension, setting them on a course for sustainable management of their forestland. The videos are available on the UC ANR YouTube channel (http://youtube.com/UCANR).
Learning the tools and techniques used for centuries by professional foresters and research scientists allows private forest owners to collect data that paints a picture of the land and trees' current condition.
“Whether it's managing to reduce wildfire, control invasive species, protect the nature beauty or maximize timber harvest, you need to know what you have so you can select the right actions to achieve your goals,” said Kimberly Ingram, UC Cooperative Extension forest stewardship education academic coordinator.
While about two-thirds of California's 33 million acres of forests are public lands held by state and federal government agencies, the rest is in private hands. In 2019, with funds from CAL FIRE, UCCE launched a program to reach out to the 87,000 private landowners who manage portions of California's forests.
Before the COVID-19 outbreak, three-day field workshops were offered to groups of forest owners to help them develop a plan to improve and protect their forestlands in an ecologically and economically sustainable manner. Because of the pandemic, alternative approaches are being used, including video training, online workshops and limited outdoor field days in locations where social distancing is feasible.
“We're using the flipped classroom method,” Ingram said. “The learner reads and watches videos beforehand and then, when they come to the online classroom and field day sessions, we're delving into real-world examples.”
Kestrel Grevatt, a member of the Grizzly Corps, an AmeriCorps program developed by UC Berkeley that addresses community needs related to climate change, was enlisted to create videos that demonstrate forest measurement practices.
The videos are for landowners who participate in the workshop series and for other forest owners who wish to begin collecting data on their own.
Susie Kocher, UCCE forestry and natural resources advisor in the Central Sierra Cooperative Extension office, narrates and conducts demonstrations in each of the videos. They cover the following topics:
Tree measurement tools
Learn the basics of forest inventory and what measurements you need to quantitatively represent your forest. It covers the usage of a diameter tape, Spencer logger's tape and Biltmore stick (or CA tree stick).
Using a clinometer to measure tree height
A clinometer is a simple tool which can be used to measure heights. In this video, you will learn how to use a clinometer to accurately measure tree height as part of a forest inventory.
Plot establishment tools
Learn how to use a compass, reel fiberglass tape and cruise vest to establish plots. The video covers how to think about your own inventory system and what you will want to take with you when you head into the woods.
Plot layout and inventory system
Learn what it looks like to collect plot data. This video includes a review of plot layout, the measurements and observations to note, and how sample data can represent your entire forest.
Three more forest stewardship workshops have been scheduled:
Feb. 2 - April 13, tribal-focused stewardship workshop: Online and at the Big Sandy Rancheria. Registration now open.
March 22 - May 27, online and in Humboldt County. Registration now open.
April 21 - June 16, online and in San Bernardino County. Registration opening soon.
Workshop registration is $60. Breakfast and lunches are provided for in-person field days. Register at http://ucanr.edu/forestryworskhopregistration.
A scientific research project may initially be deemed a failure, but failure can lead to success. It did recently at the University of...
Forest entomologists Jackson Audley (left) and the late Steve Seybold next to a black walnut tree, the victim of thousand cankers disease, in downtown Davis. (Photo by Kathy Keatley Garvey)
The walnut twig beetle is about the size of a grain of rice. In association with a fungus, it causes thousand cankers disease. (Photo by Kathy Keatley Garvey)
To effectively reduce these adverse effects of harvest, foresters first need to know the precise causes of sediment increases. Historically, researchers investigating the effects of timber harvest on the land have considered two primary drivers: hydrologic changes following timber harvest or fuel reduction that drive sediment transport, and increased sediment supply from ground disturbances and/or mass movements that result from those harvest or fuel reduction activities.
While these causes are tightly linked, little is understood about the relative role each plays in transporting sediment from the watersheds. In other words, which is dominant in increasing sediment delivery and transport: increased streamflow due to greater water availability that can sweep up and transport sediment, or a greater supply of sediment entering the waterway in the first place?
A new analytical approach developed by Safeeq Khan, UC Cooperative Extension specialist in water and watershed sciences at UC Merced, and collaborators now provides valuable insights into this issue, and ways to target effective mitigation strategies.
Published in the Journal of Hydrology last fall, the team's study analyzed long-term (1952-2017) streamflow and sediment data from two adjacent paired watersheds in the H. J. Andrews Experimental Forest in the western Cascades Range of Oregon. One of the watersheds was harvested and replanted in the 1960s, while the second was not disturbed and used as a control.
“The data is from Oregon, but highly relevant for our work in the Sierra Nevada,” said Khan, lead author of the study. “We have tried to quantify the effect of hydrologic changes and increased sediment supply from logging activities on total sediment yield.”
To isolate the relative contributions of streamflow changes and increased sediment supply on sediment transport, Khan and colleagues developed a statistical reconstruction technique to account for the hydrologic changes following harvest.
“This approach allows us to analyze and estimate background sediment production in the treated watershed during the post-treatment period as if the harvest had not occurred, which is remarkable,” said Khan.
The new approach demonstrated that sharp increases in sediment following harvests can be confidently attributed to ground disturbances associated with timber harvest or thinning operations to reduce fuel. Changes in sediment supply overwhelmingly dominate streamflow in terms of contributions to increased sediment in the watershed. Streamflow increases alone led to modest increases in sediment, less than 10%, with the watershed transporting about twice as much total sediment than it would have had the area been left unharvested. This effect diminishes more or less exponentially over time, especially with respect to suspended sediment, as bare areas revegetate, which reduces hillslope sediment supply, and as streamflow returns to pre-treatment levels.
“Once we know the background sediment production, we can easily attribute how much of the increase is due to what mechanisms” said Gordon Grant, a hydrologist with the U.S. Forest Service Pacific Northwest Research Station and co-author on the study.
“Determining that increased sediment in watersheds after harvests is primarily driven by ground disturbance is crucial in targeting mitigation efforts,” explained Khan. “Now, we know that strategies that limit ground disruption – like suspending logs while transporting instead of dragging them, avoiding heavy machinery when and where possible, and mastication and mulching – are likely to be highly effective in reducing sediment yields.”
These changes are most pronounced in the first few years following harvest, but the treated watershed did not return to pre-harvest levels of sediment for two decades, underscoring the long-term effects of harvest on a forest's hydrologic and geomorphic systems.
While clearcutting is no longer practiced on U.S. federal land, it is still the primary timber harvest method used across the globe. Additionally, many other types of forest disturbances such as wildfires, mass tree die-offs, and salvage logging create hydrogeomorphic conditions not too different from clearcutting.
"Our findings provide insights that can help land managers and foresters better target land management and restoration in the future,” said Khan. “We're hopeful that these results will lead to strategies that minimize the long-term impacts and legacies of intense land-use disturbances.”
The full study, titled “Disentangling effects of forest harvest on long-term hydrologic and sediment dynamics, western Cascades, Oregon" is available online in the Journal of Hydrology at https://www.sciencedirect.com/science/article/pii/S0022169419309941?via%3Dihub.