Softwoods usually come from evergreen conifers that grow fast, replenishing timber quickly while sequestering carbon dioxide. However, some softwoods don’t last very long, especially compared to hardwood species. So we have to ask: Which softwoods are the most sustainable option for our wood projects?

The most sustainable softwoods are slash pine and Douglas fir, thanks to their high strength-to-weight ratios. These fast-growing species are also abundant in the US. Other durable softwoods with fast replacement rates are bald cypress, Sitka spruce, Nootka cypress, Ponderosa pine, and white pine. 

In this article, we’ll walk you through the life-cycle of the seven most sustainable softwoods commonly used in woodworking. Then, we evaluate their sustainability, potentials, and shortfalls. And in the end, we’ll show you tips for buying sustainable softwoods.

Here’s How We Assessed the Sustainability of All Types of Softwoods

In general, softwoods are a sustainable material because of timber trees’ carbon sequestration potential and the carbon offset value at the end of the softwood product. 

“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

However, some softwoods are more sustainable than others. One way of assessing the sustainability of softwood is to go through the life-cycles of wood products and evaluate each stage’s sustainability. This life-cycle assessment (LCA) is a method to assess the environmental impacts of products and materials. Over the years, companies have strategically used LCA to research and create more sustainable products. So, let’s have a look at the LCA of some most sustainable softwoods!

In this article, we’ll use the cradle-to-grave perspective of the LCA, examining the five stages of the life-cycle of softwoods. Where it is relevant, we also use data from cradle-to-gate assessments. 

These five stages of the life-cycle of softwood are as follows:

1. Growing of the softwood
2. Manufacturing of the softwood
3. Transportation of the softwood
4. Usage of the softwood
5. End-of-life of the softwood

The life-cycle assessment typically covers some or all of the following environmental impacts:

• Global warming potential 
• Primary energy demand from resources 
• Acidification potential
• Freshwater eutrophication potential 
• Marine eutrophication potential 
• Photochemical ozone creation potential 
• Resource depletion

The global warming potential impact reflects the risk of accelerating climate change through the emissions of greenhouse gases. It focuses CO₂ and other greenhouse gasses (CH₄, nitrous oxide, and chlorofluorocarbons) released throughout a product’s life-cycle. This impact is measured in kg of CO₂ equivalent emitted per unit of a product, or the carbon footprint. 

“Carbon footprint: the amount of greenhouse gases and specifically carbon dioxide emitted by something (such as a person’s activities or a product’s manufacture and transport) during a given period”

Merriam Webster

Deciding factors for (high or low) carbon emissions during softwood life-cycle are: 

• Drying requirements of timber
• Distribution of timber trees 

As trees grow, they sequester carbon dioxide from the atmosphere. The carbon uptake can often compensate fully for carbon emitted during all the stages of the softwood life-cycle. It indicates a negative carbon balance, which is environmentally favorable. The lower the carbon balance stays below zero, the better it is for the climate. Relevant factors to the actual carbon balance in softwood are: 

• Tree sizes 
• Tree growth rate 
• Natural durability 

In this article, we’ll cover seven most sustainable softwoods. Specifically, we’ll zoom into species’ growth rate, tree size, distribution, woodworking properties, and natural durability, as these are the deciding reasons behind the carbon balance of woods. 

These Are the 7 Most Sustainable Types of Softwoods

These woods have an environmentally favorable carbon balance, thanks to relatively high carbon sequestration and low transporting footprint. 

Overall, these softwoods are sustainable. However, the actual environmental impact depends on many factors, especially the distance and mode of transportation. Let’s dive deeper into each wood and the stages of its life-cycle next.

Slash Pine Wood: Exceptionally Strong Softwood From Fast-Growing Conifers 

Slash pine is one of the most sustainable softwoods because its exceptional strength keeps it last longer as carbon storage, extending the environmental benefit from carbon uptake during forestry. Slash pine’s fast growth rate and abundance also set it apart, in terms of sustainability, from other southern yellow pines like shortleaf species (requiring long rotations) or longleaf species (endangered species). Loblolly pine is comparable to slash pine but slightly less hard. 

Here are the life-cycle stages of slash pine wood and each stage’s sustainability assessment:

• Growing of slash pine wood: Slash pine (Pinus elliottii) has a sustainable population across the southeastern US, largely thanks to the species’ fast growing rate and adaptation to even the more challenging sites. During the first 15 years, young slash pine trees can grow about three feet annually. Slash pine is, in fact, one of the fastest growing southern yellow pines. 

• Manufacturing of slash pine wood: It takes 30 to 150 days to air dry green 25-mm lumber of slash pine to 20% moisture content. That is shorter than the air-drying time of some other softwoods in this list, including Douglas fir and bald cypress. The fast drying property indicates a low manufacturing carbon footprint because kiln drying is usually the most energy-intensive and carbon-heavy process for wood products. 

• Transportation of slash pine wood: Slash pine trees of the two varieties, standard and south, grow within a large range across the south and the east of the US. Consequently, the transporting footprint of slash pine is relatively small, especially within the region. The standard slash pine subspecies can be found as far north as Virginia and west as Texas, while the south slash pine subspecies grow from center to south Florida.

• Usage of slash pine wood: Slash pine is a durable material because, like all other southern yellow pine, it is hard, dense, and possesses an excellent strength-to-weight ratio. Slash pine is harder than some hardwoods like basswood or cottonwood. 
  
  Using long-lasting softwood is sustainable because it means storing carbon in the wood for an extended amount of time. 

• End-of-life of slash pine wood: Because of slash pine’s strength, it can be used in natural form in household and construction projects. Natural pine wood can be disposed of sustainably in biomass or upcycling projects. 

Slash pine and other southern yellow pines are the strongest, by quite a margin, of all US softwoods. These woods can take more bending and compression than all other softwoods from the US forests. Like other southern yellow pines, slash pine wood makes long-lasting material, especially in heavy construction. Thus, it stores carbon for a long time (instead of releasing carbon dioxide back into the atmosphere). Slash pine trees also grow and replenish the timber quickly, making it possible to harvest the wood without harming the forest. 

Douglas Fir: Strong Softwood From Widely Distributed Conifers

Douglas fir wood comes from one of the tallest tree species on the North American continent. It is also one of the best carbon capture trees on the planet, sequestering 17 pounds of carbon each and every year. 

Here are the life-cycle stages of Douglas fir wood and each stage’s sustainability assessment:

• Growing of Douglas fir wood: The high carbon sequestration potential makes growing Douglas firs (Pseudotsuga menziesii) for timber sustainable. 5 acres of Douglas fir trees capture 127 tons a year, offsetting the carbon footprint of over 1,000 people. In old-growth forests, these tree species can grow as tall as 250 feet and as big as six feet in diameter. The record for Douglas fir height is 330 feet, more than double the height of a tall black walnut tree. 

• Manufacturing of Douglas fir wood: Douglas fir lumber can be air-dried from green to a 20% moisture content. The drying time varies significantly depending on the season and location (20 to 200 hours). Using a kiln takes about 32 hours to dry 1/8 inch-sized Douglas fir lumber from green to 15% moisture content. 

• Transportation of Douglas fir wood: Douglas fir trees are distributed widely in the US: they populate the largest section of western states. Consequently, transporting carbon footprint is relatively low, especially if compared with rarer US softwoods like hemlock.

• Usage of Douglas fir wood: Douglas fir is one of the strongest western softwood species (twice as hard as cedar per square meter). Its naturally-occurring resin provides a strong protection against decay and fungal attack, making it a long-lasting material, especiall for exterior applications. 
  
  Using long-lasting softwood is sustainable because it means storing carbon in the wood for an extended amount of time. 

• End-of-life of Douglas fir wood: The end-of-life stage for Douglas fir wood is sustainable when the wood is reused or burned as bioenergy.

Douglas fir is a beautiful and long-lasting softwood. These fast-growing, towering conifers account for a fifth of North America’s total softwood reserves – a healthy and sustainably managed stock for timber harvesting. It is a particularly hard with a high strength-to-weight ratio and some resistance to decay.

Bald Cypress Wood: Durable Softwood from Adaptive Native Species

Bald cypress is a unique coniferous species that loses its needles during the winter (hence the name “bald”). These trees can thrive in wet, swampy areas throughout southeastern states. 

Here are the life-cycle stages of bald cypress wood and each stage’s sustainability assessment:

• Growing of bald cypress wood: Bald cypress (Taxodium distichum) trees have a high carbon sequestration potential thanks to their large sizes: 150 feet in height and 12 feet in diameter (carbon accounts for nearly 50% of the dry weight of a tree). As bald cypress trees grow, they absorb CO₂ from the atmosphere while releasing oxygen. They act as a carbon sink during their long lifespan of around 1,200 years, helping to mitigate the climate crisis. 

• Manufacturing of bald cypress wood: Bald cypress is a slow-drying wood, partly due to the high moisture content of this swamp species. (The air-drying time from green to 20% moisture content is about 100 to 300 hours.) It signifies a high manufacturing footprint because kiln-drying is the most carbon-intensive step in lumber production. 

• Transportation of bald cypress wood: Because bald cypress timber is light and locally available throughout the US, its transportation footprint is lower than heavy imported woods. 

• Usage of bald cypress wood: Bald cypress is a long-lasting material, especially for outdoor construction projects, thanks to its decay resistance and extreme strength. The natural oils in bald cypress wood keep it at a level of rot and insect resistance similar to cedar. However, bald cypress’s bending strength is about 1,5 times higher than white cedar. 
  
  Outdoor benches made with old-growth cypress can last 40 years with little maintenance. Even cypress lumber from younger trees has a lifespan of around 20 years outdoors. 
  
  Using long-lasting softwood is sustainable because it means storing carbon in the wood for an extended amount of time. 

• End-of-life of cypress wood: Because of its natural durability, the wood is seldom treated with preservatives, even for outdoor usage. Thus, bald cypress furniture can be fully recycled or burned for bioenergy. Both scenarios are sustainable. 

Bald cypress is more sustainable than many other softwoods, largely thanks to its strength and resistance against insects and rot. Patio sets, garden benches, or outdoor pavilions made with bald cypress can last for decades, keeping the stored carbon from being released back into the atmosphere. 

Sitka Spruce Wood: Locally Available Softwood From a Fast-Growing Conifer Species

Sitka spruce has an excellent strength-to-weight ratio, making it a durable softwood for applications requiring strong yet light material. Plus, Sitka spruce trees grow in abundance in the US forests. 

Here are the life-cycle stages of Sitka spruce wood and each stage’s sustainability assessment:

• Growing of Sitka spruce wood: Sitka spruce (Picea sitchensis) is one of the fastest-growing tree species in North America. In ideal conditions, young trees’ height may increase by 5 feet yearly. They also grow large and tall: a Sitka tree can weigh more than 300 tons and have an impressive height of 300 feet. Their size signifies a high carbon sequestration potential as carbon accounts for nearly 50% of the dry weight of a tree. 

• Manufacturing of Sitka spruce wood: Sitka spruce dries fairly quickly: air-drying green 1-inch lumber of Sitka spruce to a 20% moisture content takes 40 to 150 days. Fast-drying wood tends to have a lower manufacturing carbon footprint because kiln-drying is the most carbon-intensive step in lumber production.

• Transportation of Sitka spruce wood: Thanks to the abundance of Sitka spruce in the US, the transport footprint of this softwood is lower than imported hardwoods. 

• Usage of Sitka spruce wood: Sitka Spruce has an outstanding stiffness-to-weight ratio. Thus, it makes long-lasting furniture and musical instruments (like a guitar). 

• End-of-life of Sitka spruce wood: The end-of-life stage of Sitka spruce is sustainable when the wood is upcycled for other projects or burned for bioenergy. 

Spruce is highly available, thanks to the large population, the quick growth, and the enormous tree size. The excellent strength-to-weight ratio of Sitka spruce is behind its durability. Furniture and musical instruments made with this wood can last many years, keeping their carbon storage role. Also, Sitka spruce dries quickly, resulting in a relatively low manufacturing carbon footprint. 

Nootka Cypress Wood: Strong and Decay Resistant Softwood 

Nootka cypress wood comes from medium-size, long-lived conifers native to the west coast of North America. This Cupressus nootkatensis species belongs to the Cypress family but is also commonly called a cedar, as in Alaska yellow cedar or yellow cedar. 

Here are the life-cycle stages of Nootka cypress wood and each stage’s sustainability assessment:

• Growing of Nootka cypress wood: As Nootka cypress (Cupressus nootkatensis) trees grow, they absorb CO₂ from the atmosphere while releasing oxygen. They act as a carbon sink during their long lifespan. Nootka cypress can live as long as 3,500 years. 
  
  As a carbon sink, Nootka cypress trees pull greenhouse gasses out of the atmosphere, helping to mitigate the climate crisis. Trees store as much carbon as 50% of their dry weights. Thus, a tree stores more carbon as it grows taller and bigger. Nootka cypress trees can reach 120 feet in height. 

• Manufacturing of Nootka cypress wood: Nootka cypress is stable wood with little tendency to warp and check while drying. It takes four and a half days to kiln dry 1-inch timber to a 7% moisture content. 

• Transportation of Nootka cypress wood: Along the west coast, it’s possible to source Nootka cypress wood at a relatively short distance, lowering the transportation footprint. 

• Usage of Nootka cypress wood: Nootka cypress is highly durable, thanks to the heartwood’s chemical compounds that inhibit fungal growth. It has excellent decay resistance and is also resistant to most insect attacks. Regarding strength, it is among the strongest US softwoods (comparable to Douglas fir), making it an long-lasting material, specially for exterior projects like decking.
  
  Using long-lasting softwood is sustainable because it means storing carbon in the wood for an extended amount of time. 

• End-of-life of Nootka cypress wood: Because of its natural durability, the wood is seldom treated with preservatives, even when in contact with the ground. Thus, Nootka cypress wood products can be fully recycled or burned for bioenergy. Both scenarios are sustainable. 

Nootka cypress is a sustainable softwood because of its excellent stability, strength, and decay resistance. Furniture and outdoor decking made with this material can last for a long time, keeping the role of carbon storage. 

Ponderosa Pine Wood: Strong and Fast-Drying Softwood

Ponderosa pine trees are abundant throughout Western North America. It has decent bending strength yet is light to transport and easy to work with, some tell-tale signs of its sustainability. 

Here are the life-cycle stages of Ponderosa pine wood and each stage’s sustainability assessment:

• Growing of Ponderosa pine wood: Growing Ponderosa pines (Pinus ponderosa) is sustainable because of the trees’ carbon sequestration potential. As carbon accounts for 50% of trees’ dry weight, tall and large trees like Ponderosa pines tend to have high carbon uptakes. Mature Ponderosa pine trees can reach 200 feet in height (and can live for 500 years). 

• Manufacturing of Ponderosa pine wood: It takes 15 to 150 days to air dry green 25-mm lumber of Ponderosa pine to 20% moisture content. That is shorter than the air-drying time of some other woods in this list, including Douglas fir and bald cypress. The fast drying property indicates a low manufacturing carbon footprint because kiln drying is usually the most energy-intensive and carbon-heavy process for wood products. 

• Transportation of Ponderosa pine wood: Ponderosa Pine has a very wide distribution throughout western North America, largely thanks to its adaptation to various soils and climates and the ability to survive fires that consume other species. Thus, the transporting footprint of this timber can be relatively small, especially between states on the west side.

• Usage of Ponderosa pine wood: Of all pine species, Ponderosa pine is second only to southern yellow pines in the bending strength properties. Doors, panels, and even cabinets made with Ponderosa pine can last many years, providing indoor usage. 

• End-of-life of Ponderosa pine wood: Natural pine furniture can be disposed of sustainably in biomass or upcycling projects. 

Ponderosa pine is a sustainable softwood because it is fast to dry, easy to machine, and light to transport. Also, this relatively strong pine species is widely distributed in the western states of the US, further reducing the transporting carbon footprint. 

Eastern White Pine Wood: Highly Replenishable Softwood With Excellent Bending Strength

Eastern white pine trees are abundant throughout the east side of the US. Despite having a low density, eastern white pine possesses a decent strength to weight ratio, making it a moderately durable material for indoor projects. 

Here are the life-cycle stages of eastern white pine wood and each stage’s sustainability assessment:

• Growing of eastern white pine wood: Eastern white pine (Pinus strobus) is one of the fastest-growing pine species. Annual growth increases have been reported between 2 feet to 5 feet, depending on locations. Such rapid growth indicates that eastern white pine is easily replenished, and it is possible to harvest the timber without harming the forest. 

• Manufacturing of eastern white pine wood: It takes 60 to 200 days to air dry green 25-mm lumber of eastern white pine to 20% moisture content – longer than another other commercial pine woods. It signifies a relatively high manufacturing footprint because kiln-drying is the most carbon-intensive step in lumber production. 

• Transportation of eastern white pine wood: Eastern white pine is fairly abundant on the East Coast. Thus, the transporting footprint of this timber can be relatively small, especially between states on the east side.

• Usage of pine eastern white wood: Because of its minimal rot resistance, eastern white pine wood won’t last long outside. However, its decent strength-to-weight ratio means that it can be a durable material for indoor projects. 

• End-of-life of eastern white pine wood: Natural pine furniture can be disposed of sustainably in biomass or upcycling projects. 

Eastern white pine is a sustainable softwood because it is fast to grow and replenish. Trees of the eastern white pine species grow naturally throughout the east coast of the US, so the timber can have a relatively low transporting carbon footprint.

How Can You Buy More Sustainable Wood

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 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

Improperly managed logging (including illegal activities) can cause many problems for forest equality and diversity. One example is when loggers only cut down the biggest and tallest trees. That pattern would cause a reduction in the genetic diversity and quality of the trees within the stand, leading to gradual degradation of tree quality. 

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. 

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

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 softwood products as long as the material comes from sustainably managed forests. These seven softwoods – slash pine, Douglas fir, bald cypress, Sitka spruce, Nootka cypress, Ponderosa pine, and eastern white pine – are among the most sustainable softwoods in the US. It is thanks to the relatively low carbon emissions during harvesting, manufacturing, and transporting. You can make it even more sustainable by using furniture or household items made with these woods for as long as possible. Then, look into upcycling the material to extend its usage and/or arrange for it to be recycled fully.

Stay impactful,

Sources

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