Aspen has the widest natural range of all trees native to North America, making aspen timber a highly accessible material within the US. As aspen trees grow rapidly, any timber cut for furniture and household items can be quickly replenished. However, as the aspen trees support a lot of mammals, birds, and insects, cutting down the trees hurts wildlife. So we had to ask: How sustainable is it to buy products made out of aspen wood?

Aspen wood is sustainable thanks to the trees’ carbon sequestration. These species’ fast growth and ability to regrow from root suckers mean it’s possible to harvest the woods without harming the forests. Also, locally-grown aspen timber has lower transporting carbon emissions than imported woods.

In this article, we’ll walk you through the life-cycle of aspen wood used for furniture and household items. Then, we evaluate its sustainability, potential, and shortfalls. And in the end, we’ll show you tips for buying sustainable aspen wood.

Here’s How Sustainable Aspen Wood Is

Aspen wood is a sustainable material because of the aspen trees’ carbon sequestration potential and the carbon offset value at the end of any products made with aspen wood. 

“Sustainable: The ability to be maintained at a certain rate or level | Avoidance of the depletion of natural resources in order to maintain an ecological balance”

Oxford Dictionary

To understand the sustainability of aspen wood, we assess the life-cycle of aspen furniture and household items. This life-cycle assessment (LCA) is a method to evaluate the environmental impacts of each stage in a product’s life-cycle, from the making to the recycling. Over the years, companies have strategically used LCA to research and create more sustainable products. 

In this article, we’ll use the cradle-to-grave perspective of the LCA, examining the five stages of the life-cycle of furniture and flooring made with aspen wood. However, you will also find some cradle-to-gate data where relevant. 

Overall, we can say that aspen wood is sustainable. However, the actual environmental impact of a particular product, like a table or a door, depends on more specific factors, especially the distance and mode of transportation. Let’s dive deeper into each life-cycle stage and find out how you can buy aspen wood more sustainably. 

How Sustainable Is the Growing Aspen Wood

Growing aspen trees is sustainable thanks to these species’ wide distribution and regeneration ease, especially after clear-cutting or (repeated) fires. Most importantly, the potential for carbon sequestration makes growing aspen trees sustainable. 

What Type of Wood is Aspen and What Does This Mean for Sustainability

Aspen wood comes from fast-growing hardwood tree species of the Populus genus, sharing the same plant family with willow. Populus species, including aspen and cottonwood, are often referred to as true poplar. Despite being called yellow poplar, tulipwood is not in this genus, thus not related to either cottonwood or aspen. 

Height increases vary depending on growing conditions, especially regarding the existence of fires. New trees sprouting from root suckers grow much faster in burned plots than unburned ones. 

For example, in South Dakota, aspen seedlings grow 1.5 to 2.5 times faster in areas subjected to repeated fire than in areas with little or no fire. 

Individual aspen trees are short-lived, averaging 150 years old. However, aspen clones – groups of genetically identical trees sprouting from the same root system – can live around 10,000 years.

How Sustainable Does Aspen Wood Grow

Aspen’s sustainability lies in the potential for carbon sequestration, the high availability, and the ability to restore and reclaim burned lands. 

• Carbon sequestration: As aspen trees grow, they absorb CO₂ from the atmosphere while releasing oxygen. They act as a carbon sink during their lifespan. Though individual aspen trees don’t often live longer than 200 years, the average lifespan of aspen clones is from 5,000 to 10,000 years. 

Scientists estimate the age of Pando – the largest and oldest known aspen clone – to be around 80,000 years. It is the world’s largest single organism: an underground root system over 100 acres in size and 14 million pounds in weight. That means a lot of carbon being stored for a very long time. 

Being a carbon sink means that aspen trees and clones take greenhouse gasses out of the atmosphere, helping to mitigate the climate crisis. 

Individually, aspen trees can store fair amounts of carbon as they grow big and tall. Quaking aspen – Populus tremuloides – can reach 100 feet in height and 3 feet in trunk diameter. Bigtooth aspen trees, another aspen tree species native to the US, are smaller in size. Their height averages between 65 feet and 80 feet, and their trunk diameter is between 1.5 feet and 2 feet. 

• Availability: The trees’ wide native range, the speed and ease of regeneration, and sufficient growing stock contribute to aspen being highly available in the US market.
  

Quaking aspen is the most widely distributed tree species native to North America, growing in greatly diverse regions, environments, and communities. Hence, it is easy to source locally grown aspen with relatively short traveling distances. 

Aspen is a fast-growing species that can regrow from seedlings as well as from root suckers (spots on its long lateral roots). Root suckers grow faster than seedlings in the early years and quickly make up large clones of many genetically identical trees. 

Also, clear-cutting to harvest timber is beneficial as aspen regeneration tends to be better after clear-cutting. 

The US aspen growing stock is 637 million cubic meters – about 4.3% of US hardwood growing stock. Aspen’s population is not as large as some other American hardwoods like white oak, red oak, or tulipwood. However, there are more aspen trees in the US forests than, for example, birch, beech, or willow trees.

It takes 6.05 seconds for US forests to grow 1m³ of American aspen. In comparison, growing 1m³ of tulipwood takes much less time (1.82 seconds). However, timber like beech or walnut requires a longer time to replace: it takes more than 13 seconds for the US forests to grow 1m³ of either hardwood.

The US forests add about 1.5 million cubic meters of aspen every year after harvesting. The surplus means it is relatively sustainable to cut aspen trees for timber.

• Land usage: Quaking aspen trees can quickly colonize (and reforest) burned areas even if frequent fires occur. This tree species sprout along its long lateral roots more rapidly in burned sites than unburned sites. For example, in the Central Rocky Mountains, repeat wildfires result in extensive stands of aspen. 

Where Is Aspen Wood Usually Grown

Aspen trees are native to the Northern Hemisphere. Big-tooth aspen (Populus grandidentata) and quaking aspen (Populus tremuloides) can be found in a wide range across the US – wider than any other native tree. Populus tremula – or European aspen – is very similar to quaking aspen but native to Europe (as for the name). 

Spanning a wide range of 47 degrees of latitude (equal to half the distance from the equator to the North Pole) and 110 degrees of longitude (nine time zones), aspen trees grow in a variety of habitats. In the west of the US, they are generally found at 5,000 to 12,000 feet elevation. In general, aspen trees grow further north and higher up the mountain than other species in the Populus genus, including black cottonwood (Populus trichocarpa). 

In some areas, aspen trees grow in extensive pure stands. Otherwise, they make up a major component in the White Spruce-Aspen forest type and a minor part in many kinds of forests. 

Harvesting aspen timber is generally sustainable because these trees grow fast and regenerate easily after clear-cutting. However, it is still important not to forget aspen trees’ significant role for wildlife and the potential disruptions caused by cutting them down, especially within thousand-year-old clone systems. 

Aspen trees provide food and shelter for many species, especially those needing young forests. Here are some examples: 

• The leaves on quaking aspen trees are a food source for snowshoe hare, deer, elk, moose, and black bear. 
• Beavers use these trees for building materials as well as food. 
• Ruffed grouse use all age classes of aspen-sapling stands for brooding: pole stands for overwintering and breeding; older stands for nesting cover and winter food.
• Aspen trees also host many birds and butterflies.

Hence, cutting down aspen trees, especially when done illegally or unsustainably, can disrupt the forests’ wild animals. The only way for you as a consumer to tackle unsustainable logging practices is to source sustainable woods. We will point you in the right direction with aspen wood at the end of this article. 

In total, logging of forestry products from plantations accounts for 26% of forest loss, which is a combination of deforestation and forest degradation. However, the loss in bio-diverse forests in tropical climates is more significant (and sometimes less properly recorded) than in temperate, well-managed logging forests. 

How Sustainable Is the Manufacturing of Aspen Wood

Turning aspen wood into furniture has a relatively low carbon footprint because wood waste can be recycled fully as by-products or biomass pellets to offset the carbon emissions during harvesting and processing. 

The first step of manufacturing aspen furniture and flooring involves cutting down trees and turning them into lumber in a sawmill. Electricity is needed to run sawing machines. 

The next step is to dry lumber before turning it into furniture. If a piece of lumber can be air-dried to the desired moisture content, no added energy is needed for this step. However, if a kiln is used, it requires extra energy, which could mean higher carbon emissions.

Aspen lumber can be air-dried (or air-seasoned) from green to a moisture level of around 20%. It is reported that aspen logs, 4/4 (1 inch) thick, take 40 to 60 days. Under the most favorable conditions, the air-drying time can be reduced to less than a month. 

It is important to note that a 20% moisture content is often not low enough for making high-quality products. Furniture, for example, requires wood with a moisture content of 6 to 8 percent. Thus, extra kiln-drying is necessary. 

Kiln-drying aspen lumber is relatively easy. It can be done from green logs or air-dried logs. Experiments in the Forest Products Lab showed that it took 5 days to kiln-dry 6/4 aspen lumber from green to a moisture content of 6 to 8 percent.

The carbon footprint of the drying step for 1m³ of aspen lumber, 4/4 (1 inch) thick, is 38.5 CO₂-eq, according to the life-cycle assessment tool of the American Hardwood Export Council. That is 

• lower than the carbon footprint of drying many other American hardwoods, including white oak (98.3 kg CO₂-eq), red oak (89.7CO₂-eq), or hickory, black cherry and willow all of which being 42.7 kg CO₂-eq,
• similar to the carbon footprint of drying, for example, ash (38.5 kg CO₂-eq), 
• but higher than the carbon footprint of drying, for example, tulipwood (25.6 kg CO₂-eq).

However, a high proportion of energy (to power sawing machines and kilns) can come from burning wood waste. At least 90% of all thermal energy used for kiln drying in the US hardwood sector is derived from biomass (instead of fossil fuels).

How Sustainable Is the Transportation of Aspen Wood

Transporting is a relatively carbon-intensive stage in the life-cycle of aspen furniture due to the emissions associated with operating the hauling vehicles that take timber to sawmills and factories, then furniture to stores.

As aspen trees are distributed widely in the US, a piece of aspen wood furniture or household items would have a lower carbon footprint than that made from imported woods like mahogany, teak, rosewood or ipe, providing they are both sold in the US. 

Calculations made by the Norwegian Forest and Landscape Institute showed that smaller wood hauling trucks emitted more CO₂ per transported cubic meters of timber: 1.25 times more than larger wood hauling trucks, 1.3 times more than sea vessels, and six times more than freight trains. Therefore, the sustainable transportation option would be rail or large trucks running on biofuel. You can check with your wood suppliers how their products are transported and opt for the more sustainable option. 

According to the life-cycle assessment tool of the American Hardwood Export Council, transporting 1m³ of aspen lumber, 4/4 (1 inch) thick from the forest to the kiln results in 45.2 kg CO₂-eq, and from the kiln to the customer in Western Europe 169 kg CO₂-eq. Transporting carbon footprint (in this scenario) is more than five times higher than the drying step in manufacturing. 

Compared with some other American hardwoods, the growing, manufacturing, and transporting of aspen wood have a carbon footprint amongst the lowest. 

For example, PE International AG assessed the environmental impacts of 19 American hardwoods through stages from cradle to gate plus transport. They found a carbon footprint of 325 kg CO₂-eq for one cubic meter of kiln-dried aspen lumber, 4/4 (1 inch) thick. That is 

• lower than the carbon footprint of , for example, white oak (559 kg CO₂-eq), red oak (496 kg CO₂-eq), hickory (463 kg CO₂-eq), and hard maple (342 kg CO₂-eq),
• but higher than the carbon footprint of, for example, willow (310 kg CO₂-eq), cherry (301 kg CO₂-eq), and tulipwood (270 kg CO₂-eq).

How Sustainable Is the Usage of Aspen Wood

Using aspen furniture can be sustainable thanks to the carbon capture during the products’ long life. 

Quaking aspen is not a long-lasting wood that is also susceptible to insect attacks. Thus, aspen timber is not often used in building and construction. However, it is possible to have long-lasting furniture from aspen providing adequate care. Once protected with the right paint, aspen furniture has been reported to last more than a couple of decades.

When aspen wood is decayed, either naturally in the forest or because of damage caused by usage at home, the carbon stored in the wood is released back to the atmosphere. Therefore, long-lasting furniture can be considered a good way of keeping carbon out of the atmosphere. If the wood is then reclaimed for making another piece of furniture, its positive carbon storage environmental impact is even higher. 

How Sustainable Is the End-of-Life of Aspen Wood

The end-of-life stage for aspen wood furniture and household items is sustainable when the wood is reused or burned as bioenergy. 

There are a few scenarios for wood products – furniture and household items- at the end of their life: 

1. They can end up in landfills and don’t decompose. In this case, it keeps its role as carbon storage.
   
2. Wood products can also be upcycled and reused, extending their role as carbon storage and reducing the fossil CO₂ emitted as much as four times when comparing, for example, a recovered hardwood flooring with a new one. New wood products often travel much further to their markets, compared with recovered wood products. The latter is typically made in urban centers and sold locally, which lowers the transportation environmental burdens.
   
3. In another end-of-life scenario, products like an aspen door can be burned for biomass energy displacing coal or natural gas in generating electricity. 

With smaller household items, like a bowl or a chopping board, the offset won’t be as high as there is much less waste for burning. However, if such products are made from manufacturing wood waste as by-products, their carbon footprint is minimal. 

According to the life-cycle assessment done by the American Hardwood Export Council, the overall carbon emission of aspen wood is negative, largely thanks to the enormous carbon uptake during the forestry stage. 

How Can You Buy Aspen Wood More Sustainably

The key to sustainably buying any wood is to check on relevant environmental and original certifications. Reliable certifications for sustainable woods are: 

• Forest Stewardship Council: 

An FSC certification ensures that the aspen wood comes from responsibly managed forests that provide environmental, social, and economic benefits.

• Program for Endorsement of Forest Certification: 

PEFC’s approaches to sustainable forest management are in line with protecting the forests globally and locally and making the certificate work for everyone. Getting a PEFC certification is strict enough to ensure the sustainable management of a forest is socially just, ecologically sound, and economically viable but attainable not only by big but small forest owners. 

Why Is It Important to Buy More Sustainable Wood

Buying sustainable wood also means helping to prevent illegal or unsustainable logging, which harms the forests’ biosystems and accelerates climate change. 

Logging of forestry products from plantations accounts for 26% of forest loss. Cutting down trees for wood has a lesser impact on carbon storage than digging up the whole forest floor and turning it into farms or mines. However, if logging is not sustainably managed, it can badly damage wildlife.

When logging happens in tropical forests – the bio hotspots of our planet – the biodiversity loss can be much more damaging. Subtropical and tropical forests are packed with unique wildlife – endemic mammals, birds, and amphibians. The displacement of such wildlife during poorly managed logging would be a major contributor to global biodiversity loss. 

Sustainable management of forests also means that trees are cut down for timber only when they are mature. These trees will then be able to regrow and eventually replace the loss of canopy, absorb carbon from the atmosphere and reduce the effect of climate change. 

Final Thoughts

You can buy sustainable furniture made from aspen wood as long as the material comes from sustainably managed forests. And, to make it even more sustainable, use any aspen furniture for as long as you can, upcycle the material to extend its usage, and arrange for it to be recycled fully.

Stay impactful,

Sources

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• MIT SMR: Strategic Sustainability Uses of Life-Cycle Analysis
• European Environment Agency: cradle-to-grave
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• Impactful Ninja: How Sustainable Is Tulipwood? Here Are the Facts
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• THE WOOD DATABASE: BIGTOOTH ASPEN
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• Impactful Ninja: How Sustainable Is Birch Wood? Here Are the Facts
• Impactful Ninja: How Sustainable Is Beech Wood? Here Are the Facts
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• Impactful Ninja: How Sustainable Is Black Walnut Wood? Here Are the Facts
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• Impactful Ninja: How Sustainable Is Rosewood? Here Are the Facts
• Impactful Ninja: How Sustainable Is Ipe Wood? Here Are the Facts
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• Impactful Ninja: How Sustainable Is Maple Wood? Here Are the Facts
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