Sequoia sempervirens is an extraordinary tree.
It has been the focus of a recent conservation, sustainability, and life-cycle assessment (LCA) study by Forest Products Laboratory (FPL) researchers Richard Bergman PhD and Kamalakanta Sahoo PhD. Their study, “Environmental Impacts of Redwood Lumber: A Cradle-to-Gate Assessment,” measured environmental performance ofthe coastal redwood through LCA by tracking material flows, energy consumption, and emissions from forest management through the lumber manufacturing process. Bergman and his team used SimaPro modeling software to estimate raw material consumption, environmental outputs, and associated impacts along its supply chain.
Like the public, concerns about protecting these trees and keeping forests as forests are also at the forefront of FPL researchers’ minds.
“There are two things that we want the public to know,” Bergman explains. “One, redwood products are being harvested on a sustainable basis while adhering to forest certification schemes along with California Forest Practices Rules which are some of the most stringent regulations found in the United States today. What this means specifically is that the gain-growth of the redwood forest exceeds the loss-mortality or cutting of the redwood forest. Two, the redwood products have very low environmental impacts compared to non-wood products and are a natural solution to mitigating GHG emissions.”
Old-growth redwood forests, the 5% or about 110,000 acres remaining, are nearly all protected within national and state parks. Today, the only redwoods that are being logged are second and third growth trees. In terms of diameter, redwood mills are no longer able to even process old-growth trees.
As climate change becomes more deeply part of public awareness and sustainable products are receiving higher consumer demand, LCA is an effective way to assess how a building material’s harvest, production, use, re-use ability, and disposal (cradle-to-grave) will create an environmental footprint.
Essentially, LCA creates a holistic view of a product’s life and impact on the planet.
“The wood products industry and their products have a low environmental impact compared to non-wood products and are able to be harvested at a sustainable pace unlike any other fossil-based product on the market. As one of the solutions to mitigating greenhouse gas (GHG) emissions, sustainably harvested wood products are an excellent resource in substituting for fossil fuel-intensive products,” explained Bergman.
What sets coastal redwood timber apart from others in the environmental market?
Coastal redwood is basically a super-wood. Aside from being the world’s tallest tree and one of the oldest, these trees have evolved in surprisingly resilient ways. Redwoods have extremely thick bark, do not produce resin or pitch, and have high amounts of tannins. These attributes make redwoods naturally resistant to fire, insects, decay, and fungi.
Redwood lumber also requires shorter or no kiln-drying times, a process that is necessary in most timber operations to keep timber from decay. Kiln-drying uses a lot of energy compared to other parts of the wood product supply chain. And additional energy savings are made because most kiln-drying is powered from on-site by-products of lumber manufacturing in the form of wood chips and bark (i.e. hog fuel). In the climate change market, this is a significant result when sourcing natural instead of fossil fuel resources for energy production during manufacturing.
Coastal redwood is a sustainable environmental superstar for other reasons as well. They can outpace nearly any tree in growth and means they have a higher rate of carbon sequestration than other trees. In ideal conditions, coastal redwoods can grow anywhere between two to ten feet per year. These fast-growing trees offer a harvest ready timber in a relatively short period of time.
And most astounding, they store massive amounts of carbon. Coastal redwoods can store more tons of carbon than most any other tree in the world. As lumber, Bergman’s study found that redwood “stored about 12 times the total GHG emissions released during cradle-to-gate product manufacturing.”
In the future, Bergman sees an increased demand for information on the lifecycle impacts of building products, particularly wood products. “The wood industry as a leader will be able to provide real-time data to monitor their environmental impacts from the forest (cradle) to production (the mill) to construction (the building) while utilizing old building material into new buildings. Also, we are looking at how we can actually extend the service life of products or reuse them. The new areas of research will be developing artificially intelligent tools to enhance industry data collection and analysis along with the unique position of wood in a society where we are transitioning from a linear to a circle economy.”
Bergman loves his work and along with his team will continue to find innovative ways to protect our planet and its natural resources, “The research I do gives me joy because I feel I am doing what I do in service as a public employee looking out for the well-being of forests along with our country’s need for a sustainable building materials and economic development.”
To find out more about the amazing advancements our scientists are making, visit the Forest Products Laboratory at: https://www.fpl.fs.fed.us/