While North American forests today are growing due to more sustainable harvesting practices and new planting, it hasn’t always been that way. In the first centuries of European settlement, deforestation was significant. Before colonization, 46% of U.S. land area was carpeted in forest cover – over 1 billion acres in 1630.
For three centuries following the arrival of Europeans, however, the land was cleared, predominantly for agriculture, to feed a growing population. One to two hectares of land was cultivated for every additional resident.
As a result, deforestation followed in the path of settlement, reaching its lowest point in 1872. Almost two-thirds of the net conversion to other uses occurred in the second half of the 19th Century. By 1910, the area of forest land had declined to an estimated 754 million acres or 34% of the total land area.
The good news, however, is that deforestation has been curbed in North America. In the last Century, forest cover has become stabilized and has begun to expand. In the 20th Century, it has remained relatively constant, and has started to expand. Forest cover grew between 2010 and 2020, increasing at a rate of 0.03% annually, according to FAO (Food and Agriculture Organization of the United Nations).
In addition, there are opportunities to reforest even more of the contiguous U.S., focusing on the most cost-effective and feasible options. A new online tool, the interactive “Reforestation Hub” is a collaboration of The Nature Conservancy and American Forests.
The most comprehensive analysis available, according to the group, it identifies up to 133 million acres of formerly forested lands in the United States that could be reforested to boost carbon storage. That would translate into absorbing an additional 333 million metric tons of carbon per year — equivalent to the carbon emissions from all of the passenger vehicles in California, Texas, and New York combined, or 72 million vehicles.
The Reforestation Hub allows stakeholders such as foresters, land managers, and private landowners to explore the study’s findings. It identifies the number of acres — down to the county level — potentially available for different types of reforestation.
“People are excited about reforestation for good reason,” said lead scientist Susan Cook-Patton, Senior Forest Restoration Scientist at The Nature Conservancy. “New trees represent a powerful natural solution to global warming. But until our analysis, there was no quick and easy way to figure out where exactly we might put all those new trees. This work provides a menu of possibilities to get it done.”
Cook-Patton hopes this granular analysis will help land managers and policymakers find the options that best meet local, state, and national goals around growing trees for public and private benefit.
The Reforestation Hub uses several filters for isolating the most promising places for new forests: where forests grew in the past; current land ownership; land type; benefits to wildlife and watersheds; and cost. In sum, the study highlights the potential for 60 billion new trees to be grown across the country with 1.3 billion already planted annually.
Among ten different reforestation options, the Reforestation Hub suggests that three of them provide the most potential: formerly forested lands now used for pasture (49% of potential); floodplains (17%); and urban open space (14%). But the top results change by county, so the Reforestation Hub allows users to find the places with the most potential in their area.
Land ownership is also an important consideration. “Over one-third of the total potential for reforestation within existing forestland is on federal lands,” said Jad Daley, President, and CEO of American Forests. “That means we have a massive lever for climate action right in our hands, because we have the power to reforest these lands if the federal government simply allocates sufficient staff and funding.”
According to The Nature Conservancy, several existing reforestation programs could be scaled up to put the new Reforestation Hub’s information to work. On public lands, this includes the Reforestation Trust Fund, which can be enhanced via the soon-to-be-introduced REPLANT Act to fully fund the reforestation of America’s national forests.
On private lands, they include the U.S. Department of Agriculture’s Environmental Quality Incentives Program (EQIP) and Conservation Reserve Program (CRP), as well as state conservation agency cost-share programs.
Stakeholders are encouraged to visit the Reforestation Hub to inform their tree planting programs. Questions about the Reforestation Hub and its underlying study can be directed to ReforestationHub@tnc.org
*This post was based on the following press release:
City planners around the world increasingly recognize the importance of trees and are working to increase canopy cover. Urban tree research tells us that green canopy can play an important role in the liveability of cities. Increased tree coverage contributes to lower city temperatures by blocking shortwave radiation and increasing water evaporation. Trees also help reduce air pollution, while absorptive root systems can help reduce the threat of flood during severe rains and storms.
No surprise, the World Economic Forum’s (WEF) Global Agenda Council on the Future of Cities have listed green canopy cover in its ranking of top ten urban initiatives.To support cities in their efforts to implement green canopy, MIT’s Treepedia, in collaboration with WEF, has developed a metric —the Green View Index—by which to evaluate and compare canopy cover. It relies on calculations based on input from Google Street View. By using street view panoramas rather than satellite imagery, the GVI represents human perception.
The GVI Index is presented on a scale of 0-100, showing the percentage of canopy coverage of a particular location. The group cautions that its calculation is imprecise. It includes only street trees in its calculation due to the limitations of Google Street View. While forested parks are important, for example, they are not considered, aside from street visibility.
Treepedia developers stress that its rankings should not be construed as a competition. “Treepedia is not about rating cities to compete in a green Olympics,” it notes. “Treepedia aims to raise a proactive awareness of urban vegetation.”
Another important constraint that the study is not comprehensive. It includes only 30 cities, globally. It noteworthy that four of the top ten cities with the most tree cover are in North America, including Tampa (#1), Vancouver BC (#4), Montreal (#6) and Sacramento (#9).
A ranking of select North American cities, followed by the estimated proportion of urban canopy, are as follows:
Tampa, Florida — 36.1%
Vancouver, Canada — 25.9%
Montreal, Canada — 25.5%
Sacramento, California — 23.6%
Seattle, Washington — 20%
Toronto, Canada — 19.5%
Miami, Florida — 19.4%
Boston, Massachusetts — 18.2%
Los Angeles, California — 15.2%
Treepedia underscores that only selected cities have been included in its Green View Index. The group encourages other cities to calculate their GVI. More information can be found at this link: (https://github.com/mittrees/Treepedia_Public)
Leading North American tree cities are also recognized in the Tree Cities of the World program, sponsored by the FAO (The Food and Agricultural Organization of the United Nations) and the Arbor Day Foundation. Their intention is to promote more resilient and sustainable cities.
Rather than a ranking of overall canopy or green cover, these cities are recognized for “demonstrating leadership in the management of their urban trees and are serving as part of the solution to many of the global issues we face today.” Of the 68 “Tree Cities of the World” recognized, nine of them are Canadian, and 27 from the United States.
Another useful source of information is the U.S. Forest Service. Its urban forest data are being collected from across the United States based on top-down aerial approaches and bottom-up field data collection. This site links to various data sets and reports for urban forest data at the state level, county level, county subdivision level and local community or place level. Users are encouraged to explore states or communities of interest to see what data are available.
Resources mentioned in this article:
Tree Cities of the World: https://treecitiesoftheworld.org/directory.cfm
U.S. Forest Service Urban Forest Data: https://www.nrs.fs.fed.us/data/urban/
Urban trees are one of those remarkable stories that largely flies under the radar. We appreciate how a large canopy can shield us from the intense summer sun or help keep us dry during an unexpected downpour, but most of the time, we take them for granted. We shouldn’t.
According to the Food and Agricultural Organization of the United Nations, urban trees offer a wealth of benefits. Did you know that a mature tree can absorb up to 150 kg of CO2 per year? Aside from sequestering carbon and creating biodiversity, trees help filter pollutants and fine particulates. They also reduce energy requirements for air conditioning and heating when strategically placed.
Research has found that trees aid city dwellers’ physical and mental health and their presence even boosts real estate value. But for urban trees, the story hasn’t always had a happy ending. At the end of life, too often, they have ended up in the waste stream, chipped or burnt, a low repayment for many decades of civic service. The rise of the urban wood movement, however, offers a more promising path.
The sustainability case for upcycling harvested urban wood is compelling. Approximately 3.8 billion board feet of urban wood harvested annually from U.S. cities could be processed into lumber – not counting fire salvage or orchard rescue trees. Utilizing just 10% of that urban wood harvest currently chipped or left to rot would have an equivalent impact on removing 732,000 cars from the street.
The urban wood movement has been growing in recent decades as people have increasingly recognized the value of harvested city trees that had long been underutilized. One of those many stories is told by Jennifer Alger, Director of the Urban Wood Network Western Region, a not-for-profit organization.
She grew up, she said, riding in her dad’s truck as he scoured neighborhoods looking for trees that needed to be taken down. He had been a contract logger by summer and a burl buyer for a firearms manufacturer in winter.
But when the logging business bottomed in the early 1980s, “I spent my childhood in a vehicle with Dad buying these random dead or dying trees from people’s houses,” she recalled. And so he was doing urban lumber before the term ‘urban lumber’ was even coined. At that time, they were cutting for firewood and cellophane wrapping bundles of it for retailers.
Her father recognized the value of timber from the wood world, and it pained him to be cutting perfectly good lengths of material into firewood. “Why are we cutting these logs into firewood?”, he asked Jennifer, “These logs are gorgeous”.
They began setting aside the best logs and stockpiled them. Finally, they bought their first portable band sawmill in the 1990s, allowing them to mill lumber. Similar stories are told around the country by other companies and participants who recognize the value of harvesting urban wood.
Like others in the urban wood recovery business, Jennifer found a knowledge void regarding its potential value. With that thought in mind, she began networking informally in the early 2000s with the help of CalFire and the United States Forest Service to reach out to arborists and other stakeholders about more sustainable outcomes for urban trees. “We were importing all these hardwoods from either the East Coast or from overseas and here in California, we were spending hours on chipping them, burning, or landfilling – all of these scenarios,” she recalled.
One of the myths that needed to be overcome was that urban trees would be too expensive to mill because of embedded steel objects.” Everybody told me that it costs too much to mill these urban trees because they have nails in them, and so it’s just going to be too costly.” She responded that they were already milling urban trees at her company, and with the value of a blade only $17 or $20, “not that big of a deal.”
In 2016, Urban, Salvaged, & Reclaimed Woods Inc., a West Coast non-profit network was incorporated. In networking with other groups around the country, however, group members discovered that different regions had slightly different perspectives about urban wood. For example, some regional networks included reclaimed lumber from deconstruction, while others included only urban trees.
“The urban wood movement is big and it’s catching on worldwide,” Jennifer said. “But we recognized that we were fragmented.” That fragmentation was standing in the way of building a stronger industry. Collectively, the urban wood communities recognized the need to rebrand, as well as to create standards and certification programs that would help build consumer trust and shield customers from poor quality suppliers.
After much discussion with each of the networks around the country, it was determined that we would unite under the Urban Wood Network with the previous West Coast group becoming the Urban Wood Network Western Region. As a result of that collaboration, urban wood can be described as:
“Any wood that was not harvested for its timber value and was diverted from or removed from the waste-stream and developed or redeveloped into a product. Urban wood can come from three sources: Deconstruction, fresh-cut urban trees, & salvaged wood.”
The group is working towards several initiatives to increase the professionalism of the industry, including the establishment of lumber grades specific to urban timber and chain of custody certification program.
Jennifer is currently working with an expert team of developers and customer experience specialists on the build-out of AncesTREE™ an Inventory Management System and enterprise application that will allow users to easily adhere to the industry standards, track the chain-of-custody, manage their inventory, and generally better manage and grow their urban lumber businesses.
An integrated approach is increasingly being sought, involving cities, municipalities, and large corporate or educational campuses. Attention to pruning and tree care with eventual salvage in mind can boost the marketable value of timber.
The establishment of urban forest management plans and policies can make an important difference for the industry going forward. The establishment of policies will make the urban wood industry less vulnerable to the loss of key urban wood supporters in key decision-making roles.
There are several forces at play that are helping drive the urban wood movement. On one hand, there are increasing restrictions regarding the landfilling of wood waste. On the other hand, people recognize the substantial benefits of using urban wood. With its beautifully unique appearance, it creates one-of-a-kind home products, while supporting local businesses. Using local urban wood also is a celebration of local history, while playing a part in diverting waste and sequestering carbon.
These days, many individuals and organizations are helping to script a more sustainable end of life scenario for urban trees through solid wood recovery. “By networking together, we can build awareness that brings these trees back into the social and economic lives of the communities they came from in the form of lumber, slabs, flooring, siding, furniture, art, architecture and other value-added wood products,” the Urban Wood Network states at its website.
For her part, Jennifer believes that the groundwork the Urban Wood Network is creating today will set the stage for the growth of the urban wood movement and a more sustainable outcome for city trees. Through its focus on education, standards, and promotional assistance, she sees a bright future. “We expect in the next two to five years an absolute explosion of the urban network and its membership,” she concluded.