Tag: forests

Ensuring British Columbia’s forests offer a sustainable source of fibre takes collaboration and careful management

Diane Nicholls, Vice President of Sustainability for North America, Drax

Key takeaways: 

  • British Columbia is 94% provincial Crown Land, meaning its 55-60 million hectares of forest cover is publicly owned, rather than privately held.  
  • Government legislation and regulation exists detailing what forestry practises can take place, working alongside First Nations, to ensure forests are used for the benefit of all.
  • Sustainable forest management practises offer a source of fibre for forest industries while also protecting forests from disease and wildfire.  
  • Although the biomass pellet industry is relatively new to the province, it offers a use for forest residues that were previously burned or landfilled, and for sawmill residues.  

As a business operating in the Canadian forest industry, we have a responsibility to work collaboratively with local and national governments, communities, and First Nations to ensure British Columbia’s forests are sustainably managed, protected from disease and fire, and preserved for future generations.  

British Columbia is a vast and diverse landscape. The second largest of Canada’s provinces, it contains 14 different bio geoclimatic zones ranging from coastal forest in the west, to alpine meadows on the eastern Rocky Mountains, with bogs, wetlands, and even arid land in between.   

The landscape of British Colombia is home to a wide range of flora and fauna. With roughly 55-60 million hectares (550,000-600,000 km2) of land covered in forest, it is a vital resource. More than 50,000 British Columbians work directly in the forest industry and even as cities like Vancouver and Victoria grow, it remains a central source of social value to rural economies.  

Sharing forests between government and First Nations

British Columbia has a long history of stewardship and sustainable forest management practices. Forestry began in the region in the 1800s with Sitka spruce, harvested predominantly to support ship building. Since then, forestry has become a major part of the province’s economy and the province is a world leader in sustainable forest management and environmental practises. 

As 94% of British Columbia is provincial Crown Land, the government sets the rules and regulations about what forestry practices, or any other natural resource extractions, can take place. Under legislation, any land where forest harvesting occurs must be reforested and it is illegal for a company to deforest British Columbia or Canada.   

For many years, an increasingly important component of the Canadian forestry industry has been the contribution that First Nations are making. There are 204 First Nations across British Columbia each with traditional territories used for cultural and spiritual purposes, as well as day-to-day needs like hunting, fishing, trapping, and housing.  

Many First Nations have their own land use plans that are utilised in forest management planning in the province. First Nations are also consulted and collaborated with by the province on forest management decisions. This creates partnerships between First Nations, industries working in the province’s forests, and governments at the provincial and federal levels. 

Protecting forests from pests and fire

Forest infected with mountain pine beetle in British Columbia

Managing forests is crucial to their longevity and ensuring they remain healthy and useable for future generations. This includes forestry practices to protect them from pests and the growing threat of forest fires.  

In 2017 and 2019 we saw the largest catastrophic fires we’ve ever had in British Columbia. At times it felt like the whole province was on fire. More recently, 2020 was another terrible year. Factors like climate change and storms are increasing the number of fires we see, but the intensity of fires is also exacerbated by debris left on forest floors from relatively recent mountain pine beetle infestations and other insects or diseases affecting forest health.  

 In the 1990’s several relatively warm winters led to the mountain pine beetle becoming endemic, and over the next 15 years millions of hectares of pine forest were lost to the bug. The government increased the allowable annual cut (harvesting levels) to remove the debris of such infestations which become dangerous fire hazards if not removed. 

To protect from fires, pests, and diseases, it’s important to open up forests through managed removals. This process creates more space and less dense stands of trees. It’s also crucial to reduce what’s left lying on the forest floor after forestry operations, while ensuring that the right wood is left to encourage biodiversity, soil health and habitat needs.  

These sustainable management practises are important to help the resilience of the forest and biomass offers a use for much of the wood removed through these practices that is not able to be manufactured into lumber.  

Biomass and the wood industry

Compared to lumber manufacturing, pellet production is relatively new to British Columbia’s forest industry, but it offers a practical use for materials that are unmerchantable or unsuitable for sawlogs. This includes, but is not limited to, forms of forest residues such as low-grade wood, treetops, and branches that are left behind from harvesting activities.   

Removing forest residues can provide more growing sites for new seedlings and helps to prevent intense forest fires. Slash and other low-grade wood are often simply burned along roadsides, but pellets offer a way to turn this fibre into a source of renewable energy. 

Forest residues from harvests, like slash and low-grade roundwood, accounted for approximately 8% and 10% of the fibre used in our Canadian pellet plants in the first half of 2022. The rest of the fibre we use comes from sawmill residues, such as wood chips, shavings, and sawdust. 

Drax operates eight pellet mills across British Columbia and two in neighbouring Alberta, but doesn’t own forests or carry out harvesting or wood sorting. Instead, we partner with forest companies that operate sawmills. These companies are awarded forest tenures, which allow them to harvest certain forest areas (which are identified by the provincial government) to produce solid wood products, which lock in carbon for years. In return, we obtain their sawmill residues. The economics of the wood pellet industry means the main driver of harvesting is still demand for high-grade timber.    

Through collaboration with our partners across the province, we help ensure British Columbia’s forests offer resources that benefit local communities and are sustainably managed for future generations.  

Supporting a circular economy in the forests

Every year in British Columbia, millions of tonnes of waste wood – known in the industry as slash – is burned by the side of the road.

Land managers are required by law to dispose of this waste wood – that includes leftover tree limbs and tops, and wood that is rotten, diseased and already fire damaged – to reduce the risks of wildfires and the spread of disease and pests.

The smoke from these fires is choking surrounding communities – sometimes “smoking out entire valleys,” air quality meteorologist from BC’s Environment Ministry Trina Orchard recently told iNFOnews.ca.

It also impacts the broader environment, releasing some 3 million tonnes of CO2 a year into the atmosphere, according to some early estimates.

Slash pile in British Columbia

Landfilling this waste material from logging operations isn’t an option as it would emit methane – a greenhouse gas that is about 25 times more potent than CO2. So you can see why it ends up being burned.

In its Modernizing Forest Policy in BC, the government has already identified its intention to phase out the burning of this waste wood left over after harvesting operations and is working with suppliers and other companies to encourage the use of this fibre.

This is a very positive move as this material must come out of the forests to reduce the fuel load that can help wildfires grow and spread to the point where they can’t be controlled, let alone be extinguished.

The wildfire risk is real and growing. Each year more forests and land are destroyed by wildfire, impacting communities, nature, wildlife and the environment.

In the past two decades, wildfires burned two and a half times more land in BC than in the previous 50-year period. According to very early estimates, emissions from last year’s wildfires in the province released around 150 million tonnes of CO2 – equivalent to around 30 million cars on the road for a year.

Alan Knight at the log yard for Lavington Pellet Mill in British Columbia

During my recent trip to British Columbia in Canada, First Nations, foresters, academics, scientists and government officials all talked about the burning piles of waste wood left over after logging operations.

Rather than burning it, it would be far better, they say, to use more of this potential resource as a feedstock for pellets that can be used to generate renewable energy, while supporting local jobs across the forestry sector and helping bolster the resilience of Canada’s forests against wildfire.

I like this approach because it brings pragmatism and common sense to the debate over Canada’s forests from the very people who know the most about the landscape around them.

Burning it at the roadside is a waste of a resource that could be put to much better use in generating renewable electricity, displacing fossil fuels, and it highlights the positive role the bioenergy industry can play in enhancing the forests and supporting communities.

Drax is already using some of this waste wood – which I saw in the log yard for our Lavington Pellet mill in British Columbia. This waste wood comprises around 20% of our feedstock. The remaining 80% comes from sawmill residues like sawdust, chips and shavings.

Waste wood for pellets at Lavington Pellet Mill log yard

It’s clear to me that using this waste material that has little other use or market value to make our pellets is an invaluable opportunity to deliver real benefits for communities, jobs and the environment while supporting a sustainable circular economy in the forestry sector.

What is sustainable forest management?

Sustainable forest management is frequently defined in terms of providing a balance of social, environmental, and economic benefits, not just for today but for the future too. It might be seen as the practice of maintaining forests to ensure they remain healthy, absorb more carbon than they release, and can continue to be enjoyed and used by future generations.

To achieve this, foresters apply science, knowledge, and standards that help ensure forests continue to play an important role in the wellbeing of people and the planet.

Managed forests, also called working forests, fulfil a variety of environmental, social, and economic functions. These range from forests managed to attract certain desired wildlife species, to forests grown to provide saw timber and reoccurring revenue for landowners.

How are forests sustainably managed?

How forests are managed depends on landowner goals – managing for recreation and wildlife, focusing on maximising production of wood products, or both. Each forest requires management tailored to its owner’s or manager’s objectives.

There are many ways to manage forests to keep them healthy – there is no ‘one size fits all’ – but keeping track of how they are doing can be tricky. One alternative for monitoring forests is to use satellite imagery.

One common sustainable forestry practice is thinning, which involves periodically removing smaller, unhealthy, or diseased trees to enable stronger ones to thrive. Thinning reduces competition between trees for resources like sunlight and water, and it can also help promote biodiversity by creating more space for other forest flora.

The wood removed from forests through thinning is sometimes not high-quality enough to be used in industries such as construction or furniture. However, the biomass industry can use it to make compressed wood pellets; a feedstock for renewable source electricity.

By providing a market for low-quality wood, pellet production encourages landowners to carry out thinnings. This practice improves the health of the forest, and helps support better growth, greater carbon storage, and creates more valuable woodland.

Fast facts

What are the environmental benefits of sustainably managed forests?

Through their ability to act as carbon sinks, forests are an important part of meeting global climate goals like the Paris Agreement and the UK’s own target of reaching net zero emissions by 2050.

When managed effectively through thinning or active harvesting, and replanting and regeneration, forests can often sequester – or absorb and store – more carbon than forests that are left untouched, increasing productivity and improving planting material.

Harvesting trees before they reach an age when growth slows or plateaus can help prevent fire damage, pests, and disease, so timing of final cutting is important. Though the vast majority of timber from such cutting will go to other markets (construction, furniture etc) and secure higher prices from those markets, being able to sell lower quality wood for biomass provides the landowner with some extra revenue.

Sustainably managed forests also help achieve other environmental goals, such as sustaining biodiversity, protecting sensitive sites and providing clean air and water. Managed forests also have substantial water absorption capacity preventing flooding by slowing the flow of sudden downpours and helping to prevent nearby rivers and streams from overfilling.

Wood from working forests also help tackle climate change in that high-value wood from harvested trees can be used to make timber for the construction or furniture sectors. These wood products lock up carbon for extended periods of time, and the wood can be used at end-of life to displace fossil fuels. Using wood also means materials such as concrete, bricks or steel are not used, and these materials have a large carbon footprint compared to wood.

What are the socioeconomic benefits of sustainably managed forests?

There are also social and economic benefits to managing forests. Sustainably managed working forests make vital contributions both to people and to the planet.

The commercial use of wood in industries like furniture and construction drives revenue for landowners. This encourages landowners to continue to replant forests and manage them in a sustainable way that continues to deliver returns.

Healthy forests can also improve living standards for local communities for jobs and helping to address unemployment in rural regions. Managed forests can also improve access for recreation. On a larger scale, sustainable forestry can offer a valuable export for regions and nations and foster trade between countries.

Go deeper 

Forests, net zero and the science behind biomass

Tackling climate change and spurring a global transition to net zero emissions will require collaboration between science and industry. New technologies and decarbonisation methods must be rooted in scientific research and testing.

Drax has almost a decade of experience in using biomass as a renewable source of power. Over that time, our understanding around the effectiveness of bioenergy, its role in improving forest health and ability to deliver negative emissions, has accelerated.

Research from governments and global organisations, such as the UN’s Intergovernmental Panel on Climate Change (IPCC) increasingly highlight sustainably sourced biomass and bioenergy’s role in achieving net zero on a wide scale.

The European Commission has also highlighted biomass’ potential to provide a solution that delivers both renewable energy and healthy, sustainably managed forests.  Frans Timmermans, the executive vice-president of the European Commission in charge of the European Green Deal has emphasised it’s importance in bringing economies to net zero, saying: “without biomass, we’re not going to make it. We need biomass in the mix, but the right biomass in the mix.”

The role of biomass in a sustainable future

Moving away from fossil fuels means building an electricity system that is primarily based on renewables. Supporting wind and solar, by providing electricity at times of low sunlight or wind levels, will require flexible sources of generation, such as biomass, as well as other technologies like increased energy storage.

In the UK, the Climate Change Committee’s (CCC) Sixth Carbon Budget report lays out its Balanced Net Zero Pathway. In this lead scenario, the CCC says that bioenergy can reduce fossil emissions across the whole economy by 2 million tonnes of CO2 or equivalent emissions (MtCO2e) per year by 2035, increasing to 2.5 MtCO2e in 2045.

Foresters in working forest, Mississippi

Foresters in working forest, Mississippi

Biomass is also expected to play a crucial role in supplying biofuels and hydrogen production for sectors of the global economy that will continue to use fuel rather than electricity, such as aviation, shipping and industrial processes. The CCC’s Balanced Net Zero Pathway suggest that enough low-carbon hydrogen and bioenergy will be needed to deliver 425 TWh of non-electric power in 2050 – compared to the 1,000 TWh of power fossil fuels currently provide to industries today.

However, bioenergy can only be considered to be good for the climate if the biomass used comes from sustainably managed sources. Good forest management practises ensure that forests remain sustainable sources of woody biomass and effective carbon sinks.

A report co-authored by IPCC experts examines the scientific literature around the climate effects (principally CO2 abatement) of sourcing biomass for bioenergy from forests managed according to sustainable forest management principles and practices.

The report highlights the dual impact managed forests contribute to climate change mitigation by providing material for forest products, including biomass that replace greenhouse gas (GHG)-intensive fossil fuels, and by storing carbon in forests and in long-lived forest products.

The role of biomass and bioenergy in decarbonising economies goes beyond just replacing fossil fuels. The addition of carbon capture and storage (CCS) to bioenergy to create bioenergy with carbon capture and storage (BECCS) enables renewable power generation while removing carbon from the atmosphere and carbon cycle permanently.

The negative emissions made possible by BECCS are now seen as a fundamental part of many scenarios to limit global warming to 1.5oC above pre-industrial levels.

BECCS and the path to net zero

The IPCC’s special report on limiting global warming to 1.5oC above pre-industrial levels, emphasises that even across a wide range of scenarios for energy systems, all share a substantial reliance on bioenergy – coupled with effective land-use that prevents it contributing to deforestation.

The second chapter of the report deals with pathways that can bring emissions down to zero by the mid-century. Bioenergy use is substantial in 1.5°C pathways with or without CCS due to its multiple roles in decarbonising both electricity generation and other industries that depend on fossil fuels.

However, it’s the negative emissions made possible by BECCS that make biomass  instrumental in multiple net zero scenarios. The IPCC report highlights BECCS alongside the associated afforestation and reforestation (AR), that comes with sustainable forest management, are key components in pathways that limit climate change to 1.5oC.

Graphic showing how BECCS removes carbon from the atmosphere. Click to view/download

There are two key factors that make BECCS and other forms of emissions removals so essential: The first is their ability to neutralise residual emissions from sources that are not reducing their emissions fast enough and those that are difficult or even impossible to fully decarbonise. Aviation and agriculture are two sectors vital to the global economy with hard-to-abate emissions. Negative emissions technologies can remove an equivalent amount of CO2 that these industries produce helping balance emissions and progressing economies towards net zero.

The second reason BECCS and other negative emissions technologies will be so important in the future is in the removal of historic CO2 emissions. What makes CO2 such an important GHG to reduce and remove is that it lasts much longer in the atmosphere than any other. To help reach the Paris Agreement’s goal of limiting temperature rises to below 1.5oC removing historic emissions from the atmosphere will be essential.

In the UK, the  CCC’s 2018 report ‘Biomass in a low-carbon economy’ also points to BECCS as both a crucial source of energy and emissions abatement.

It suggests that power generation from BECCS will increase from 3 TWh per year in 2035 to 45 TWh per year in 2050. It marks a sharp increase from the 19.5 TWh that biomass (without CCS) accounted for across 2020, according to Electric Insights data. It also suggests that BECCS could sequester 1.1 tonnes of CO2 for every tonne of biomass used, providing clear negative emissions.

However, the report makes clear that unlocking the potential of bioenergy and BECCS is only possible when biomass stocks are managed in a sustainable way that, as a minimum requirement, maintains the carbon stocks in plants and soils over time.

With increased attention paid to forest management and land use, there is a growing body of evidence that points to bioenergy as a win-win solution that can decarbonise power and economies, while supporting healthy forests that effectively sequester CO2.

How bioenergy ensures sustainable forests

Biomass used in electricity generation and other industries must come from sustainable sources to offer a renewable, climate beneficial [or low carbon] source of power.

UK legislation on biomass sourcing states that operators must maintain an adequate inventory of the trees in the area (including data on the growth of the trees and on the extraction of wood) to ensure that wood is extracted from the area at a rate that does not exceed its long-term capacity to produce wood. This is designed to ensure that areas where biomass is sourced from retain their productivity and ability to continue sequestering carbon.

Ensuring that forestland remains productive and protected from land-use changes, such as urban creep, where vegetated land is converted into urban, concreted spaces, depends on a healthy market for wood products. Industries such as construction and furniture offer higher prices for higher-quality wood. While low-quality, waste wood, as well as residues from forests and wood-industry by-products, can be bought and used to produce biomass pellets.

A report by Forest 2 Market examined the relationship between demand for wood and forests’ productivity and ability to sequester carbon in the US South, where Drax sources about two-thirds of its biomass.

The report found that increased demand for wood did not displace forests in the US South. Instead, it encouraged landowners to invest in productivity improvements that increased the amount of wood fibre and therefore carbon contained in the region’s forests.

A synthesis report, which examines a broad range of research papers,  published in Forest Ecology and Management in March of 2021, concluded from existing studies that claims of large-scale damage to biodiversity from woody biofuel in the South East US are not supported. The use of these forest residues as an energy source was also found to lead to net GHG greenhouse emissions savings compared to fossil fuels, according to Forest Research.

Importantly the research shows that climate risks are not exacerbated because of biomass sourcing; in fact, the opposite is true with annual wood growth in the US South increasing by 112% between 1953 and 2015.

Delivering a “win-win solution”

The European Commission’s JRC Science for Policy literature review and knowledge synthesis report ‘The use of woody biomass for energy production in the EU’ suggests  a win-win forest bioenergy pathway is possible, that can reduce greenhouse gas emissions in the short term, while at the same time not damaging, or even improving, the condition of forest ecosystems.

However, it also makes clear “lose-lose” situations is also a possible, in which forest ecosystems are damaged without providing carbon emission reductions in policy-relevant timeframes.

Win-win management practices must benefit climate change mitigation and have either a neutral or positive effect on biodiversity. A win-win future would see the afforestation of former arable land with diverse and naturally regenerated forests.

The report also warns of trade-offs between local biodiversity and mitigating carbon emissions, or vice versa. These must be carefully navigated to avoid creating a lose-lose scenario where biodiversity is damaged and natural forests are converted into plantations, while BECCS fails to deliver the necessary negative emissions.

In a future that will depend on science working in collaboration with industries to build a net zero future continued research is key to ensuring biomass can deliver the win-win solution of renewable electricity with negative emissions while supporting healthy forests.

What is bioenergy with carbon capture and storage (BECCS)?

What is bioenergy with carbon capture and storage (BECCS)? 

Bioenergy with carbon capture and storage (BECCS) is the process of capturing and permanently storing carbon dioxide (CO2) from biomass (organic matter) energy generation.

Why is BECCS important for decarbonisation? 

Sustainably sourced biomass-generated energy (bioenergy) can be carbon neutral, as plants absorb CO2 from the atmosphere as they grow. This, in turn, offsets CO2 emissions released when the biomass is combusted as fuel.

When sustainable bioenergy is paired with carbon capture and storage it becomes a source of negative emissions, as CO2 is permanently removed from the carbon cycle.

Experts believe that negative emissions technologies (NETs) are crucial to helping countries meet the long-term goals set out in the Paris Climate Agreement. As BECCS is the most scalable of these technologies this decade, it has a key role to play in combating climate change.

How is the bioenergy for BECCS generated?

Most bioenergy is produced by combusting biomass as a fuel in boilers or furnaces to produce high-pressure steam that drives electricity-generating turbines. Alternatively, bioenergy generation can use a wide range of organic materials, including crops specifically planted and grown for the purpose, as well as residues from agriculture, forestry and wood products industries. Energy-dense forms of biomass, such as compressed wood pellets, enable bioenergy to be generated on a much larger scale. Fuels like wood pellets can also be used as a substitute for coal in existing power stations.

How is the carbon captured?

BECCS uses a post-combustion carbon capture process, where solvents isolate CO2 from the flue gases produced when the biomass is combusted. The captured CO2 is pressurised and turned into a liquid-like substance so it can then be transported by pipeline.

How is the carbon stored?

Captured CO2 can be safely and permanently injected into naturally occurring porous rock formations, for example unused natural gas reservoirs, coal beds that can’t be mined, or saline aquifers (water permeable rocks saturated with salt water). This process is known as sequestration.

Over time, the sequestered CO2 may react with the minerals, locking it chemically into the surrounding rock through a process called mineral storage.

BECCS fast facts

Is BECCS sustainable?

 Bioenergy can be generated from a range of biomass sources ranging from agricultural by-products to forestry residues to organic municipal waste. During their lifetime plants absorb CO2 from the atmosphere, this balances out the CO2that is released when the biomass is combusted.

What’s crucial is that the biomass is sustainably sourced, be it from agriculture or forest waste. Responsibly managed sources of biomass are those which naturally regenerate or are replanted and regrown, where there’s a increase of carbon stored in the land and where the natural environment is protected from harm.

Biomass wood pellets used as bioenergy in the UK, for example, are only sustainable when the forests they are sourced from continue to grow. Sourcing decisions must be based on science and not adversely affect the long-term potential of forests to store and sequester carbon.

Biomass pellets can also create a sustainable market for forestry products, which serves to encourage reforestation and afforestation – leading to even more CO2 being absorbed from the atmosphere.

Go deeper:

  • The triple benefits for the environment and economy of deploying BECCS in the UK.
  • How BECCS can offer essential grid stability as the electricity system moves to low- and zero-carbon sources.
  • Producing biomass from sustainable forests is key to ensuring BECCS can deliver negative emissions.
  • 5 innovative projects where carbon capture is already underway around the world
  • 7 places on the path to negative emissions through BECCS

Evaluating regrowth post-harvest with accurate data and satellite imagery

  • Drax has been using effective post-harvest evaluations, which includes remote sensing technology and satellite imagery

  • Alongside sustainable forest management, monitoring can help support rapid regrowth after harvesting

  • Evidence shows healthy managed forests with no signs of deforestation or degradation

As part of Drax’s world-leading programme of demonstrating biomass sustainability, including ongoing work on catchment area analysis (CAA), responsible sourcing policy and healthy forest landscapes (HFL). We have also been trialling the use of high-resolution satellite imagery to monitor forest conditions on specific harvesting sites in the years after harvesting has taken place, in addition to the catchment area level monitoring of trends and data. Post-harvest evaluations (PHE) are an essential part of an ongoing sustainability monitoring process, ensuring that the future forest resource is protected and maintained and that landowners restore forests after harvesting to prevent deforestation or degradation.

The most effective form of PHE is for an experienced local forester to walk and survey the harvesting site to check that new trees are growing and that the health and quality of the young replacement forest is maintained.

Rapid regrowth

The images below show some of the sites surrounding Drax’s Amite Bioenergy pellet plant in Mississippi, with trees at various stages of regrowth in the years after harvesting.

A full site inspection can therefore enable a forester to determine whether the quantity and distribution of healthy trees is sufficient to make a productive forest, equivalent to the area that was harvested. It can also identify if there are any health problems, pest damage or management issues such as  weed growth or water-logging that should be resolved.

Typically, this will be the responsibility of the forest owner or their forest manager and is a regular part of ongoing forest management activity. This degree of survey and assessment is not practical or cost-effective where a third-party consumer of wood fibre purchases a small proportion (typically 20-25 tonnes per acre) of the low-grade fibre produced at a harvest as a one-off transaction for its wood pellet plant..  It is time consuming to walk every acre of restocked forest and it is not always possible to get an owner’s permission to access their land.

Forests from space

Therefore, an alternative methodology is required to make an assessment about the condition of forest lands that have been harvested to supply biomass, without the need to physically inspect each site.  One option is to use remote sensing and satellite imagery to view each harvested site in the years after biomass sourcing, this helps to monitor restocking and new tree growth.

Drax has been testing the remote sensing approach using Maxar’s commercial satellite imagery.  Maxar has four satellites on orbit that collect more than three million square kilometres of high-resolution imagery every day. Drax accesses this imagery through Maxar’s subscription service SecureWatch.

To test the viability of this methodology, Drax has been looking at harvesting sites in Mississippi that supplied biomass to the Amite Bioenergy pellet plant in 2015 and in 2017.  As part of the sustainability checks that are carried out prior to purchasing wood fibre, Drax collects information on each harvesting tract. This includes the location of the site, the type of harvest, the owner’s long-term management intentions and species and volume details.

This data can then be used at a later date to revisit the site and monitor the condition of the area. Third-party auditors, for instance Through Sustainable Biomass Program (SBP) certification, do visit harvesting sites, however this is typically during the year of harvest rather than after restocking. Maxar has historical imagery of this region from 2010, which is prior to any harvesting for wood pellets.  The image below shows a harvesting site near the pellet plant at Gloster, Mississippi, before any harvesting has taken place.

March 2010 (100m)

Satellite image © 2021 Maxar Technologies.

The image below shows the same site in 2017 immediately following harvesting.

December 2017 (100m)

Satellite image © 2021 Maxar Technologies.

If we look again at this same site three years after harvesting, we can see the rows of trees that have been planted and the quality of the regrowth. This series of images demonstrates that this harvested area has remained a forest, has not been subject to deforestation and that the regrowth appears to be healthy at this stage.

August 2020 (50m)

Satellite image © 2021 Maxar Technologies.

Another site in the Amite catchment area is shown below. The image shows a mature forest prior to harvesting, the site has been previously thinned as can be seen from the thinned rows that are evident in the imagery.

May 2010 (200m)

Satellite image © 2021 Maxar Technologies.

Looking at the same site in the year after harvesting, the clear cut area can be seen clearly. Some green vegetation cover can also be seen on the harvested area, but this is weed growth rather than replanted trees. Some areas of mature trees have been left at the time of harvesting, and are visible as a grey colour in the 2010 image. These are likely to be streamside management zones that have been left to maintain biodiversity and to protect water quality, with the grey winter colouring suggesting that they are hardwoods.

September 2018 (200m)

Satellite image © 2021 Maxar Technologies.

Three years after the harvest, in a zoomed in view from the previous image, clear rows of replanted trees can be seen in the imagery.  This demonstrates that the owner has successfully restocked the forest area and that the newly planted forest appears healthy and well established.

August 2020 (50m)

Satellite image © 2021 Maxar Technologies.

While examining different harvesting sites in satellite imagery, Drax noted that not every site had evidence of tree growth, particularly within the first three years after harvesting. Deliberate conversion of land to non-forest use, such as for conversion to pasture, agricultural crops or urban development, is likely to be evident fairly soon after harvesting.

Preparing for planting

Some forest owners like to leave a harvested site unplanted for a couple of years to allow ground vegetation and weed growth to establish, this can then be treated to ensure that trees can be planted and that the weed growth does not impede the establishment of the new forest, this process can mean that trees are not visible in satellite imagery for three to four years after harvesting.

The image below shows a site three years after harvesting with no evidence of tree growth.  Given that no conversion of land use is evident and that the site appears to be clear of weed growth, this is likely to be an example of where the owners have waited to clear the site of weeds prior to replanting.  This site can be monitored in future imagery from the Maxar satellites to ensure that forest regrowth does take place.

November 2020 (100m)

Satellite image © 2021 Maxar Technologies.

Drax will continue to use Maxar’s SecureWatch platform to monitor the regrowth of harvesting sites and will publish more detailed results and analysis when this process has been developed further.  The platform allows ongoing comparison of a site over time and could prove a more efficient method of analysis than ground survey.  In conjunction with the CAA and HFL work, PHE can add remote sensing as a valuable monitoring and evidence-gathering tool to demonstrate robust biomass sustainability standards and a positive environmental impact.

Go deeper: 

Discover the steps we take to ensure our wood pellet supply chain is better for our forests, our planet and our future here, how to plant more trees and better manage them, our responsible sourcing policy for biomass from sustainable forests and a guide to sustainable forest management of the Southern Working Forest.

The science behind measuring and analysing trees

Weyerhaeuser working forest in Amite catchment area

We have published independent Catchment Area Analysis (CAA) reports for around 68% of the total biomass wood pellet supply to Drax Power Station in 2019. Within that, 73% of the pellets were manufactured in the US South accounting for 49% of that year’s total supply quantity.

A key component of CAA analysis are measurements, data and calculations provided by the National Forest Inventory (NFI). Bespoke wood price data, mill production capacity, market trends and interviews with local experts complete the picture.

The NFI in each country or region can be quite different in its intensity and frequency of measurement and overall degree of accuracy. In this article we examine the Forest Inventory and Analysis (FIA) database produced by the US Department of Agriculture Forest Service (USDA FS).

FIA traces its origin back to the McSweeney – McNary Forest Research Act of 1928 and began the first inventory in 1930. Since that time, it has been in continuous operation with a stated mission to: make and keep current a comprehensive inventory and analysis of the present and prospective conditions of and requirements for the renewable resources of the forest and rangelands of the US.

The fundamental science behind measuring tree height and diameter to calculate growth and volume has not changed much over the decades. A girth tape is used to measure the diameter at breast height (DBH), which is a point on the tree stem 1.37m above the base of the tree or the root collar (the exact height can vary by country). The height of a standing tree is conventionally measured using a clinometer or hypsometer, which measures the angle from the top of the tree to a measured distance away from the base. This forms a triangle from which the tree height can be calculated.

Example of girth and height measurement in the US South

The combination of height and girth are then used to estimate total tree volume based on historical models for that particular species in that country or region. Many decades worth of data measurements and modelling have been used to develop complex equations to estimate volume for each species and circumstance. This calculation process needs to estimate the rate of taper of the stem, or the difference in diameter between the base and the top of the tree. This can be consistent within a single species, but it can depend on growth rates and planting density (for example closely stocked trees may grow taller and thinner but more openly planted trees tend to be shorter and wider). Whether the site has been thinned, how many times, and at what age, can impact the degree of taper in the stem. Through many years of research, measuring and modelling the Southern Research Station (SRS) FIA team has developed the following formula for under-bark volume calculation:

under-bark volume calculation

This is then modified according to the parameters shown below, depending on species and stem characteristics.

Example of volume

Example of volume

Once the volume has been calculated, the basic density (solid wood per cubic metre) and moisture content can be used to calculate wet and dry weight, fibre content and yield.

A comprehensive record of data

The US Forest Service has built up an extensive historical record of data points through years of physical measurements – from both sampling and cutting down individual sample trees to determine the actual dimensions and statistics to compare against the estimated values. Over time, forest scientists are able to build up reasonably accurate tables for each tree species that can be used to estimate growth and volume based on the DBH and estimated tree height.

In the UK we have a forester’s handbook known as The Blue Book which contains a vast quantity of modelled data to help a forester calculate volume and growth in a range of different forest types across the country. This data has been collected and modelled by the Forestry Commission’s Forest Research branch. In the US they have a similar system of data collection and modelling but on a bigger scale, given the much larger forest area and greater variety in tree species and site type.

How can you measure an entire forest?

The forestland area of the US South covers more than 100 million hectares (ha) in total which can present quite a challenge to measure, survey and accurately predict forest growth and health. The FIA does this through a network of sample plots randomly but sequentially distributed across the forestland in each State with undisclosed locations so as to avoid biased management. Field crews collect data on forest type, site attributes, tree species, tree size, and overall tree condition on accessible forest land.

Recently, the programme has involved a five-year rolling measurement system where 20% of the plots are measured in each State, on an annual basis. At the end of a five-year period all plots will have been measured and the process begins again. This process is overseen by a robust quality assurance system to maintain and ensure the quality and accuracy of the fieldwork.

Plots are distributed at a rate of 1 plot per 6,000 acres of land (or one per 2,400 ha). This degree of plot distribution is at an extremely course scale if attempting to understand the growth of an individual stand or forest area. For example, The Blue Book recommends using 8-12 plots (and top height measurements) for a relatively uniform stand of around 10 ha. This degree of accuracy would be required to calculate the volume of standing wood for sale. In comparison, the FIA data would be completely inaccurate if trying to monitor growth and trends at an individual forest level or even at county level. This sampling intensity and the scale of measurement are the most critical factors in assessing the validity of data and trends that are identified through the FIA and through the CAA analysis.

Quantifying the level of accuracy

The physical measurement procedure and volume modelling are well established processes with data and analysis collected over many decades to support the findings; this leads to a clearly quantifiable degree of error for each measured plot. The challenge comes when using plot data to estimate the values in the surrounding forest. At this scale, the level of accuracy will depend on the ratio of plots to total forest area and the total number of plots measured. The ratio of plots per ha in the US South is pre-determined, limited by the physical and financial constraints of actually measuring trees on the ground. However, the total number of plots used to evaluate trends can vary according to how large an area is assessed.

Fundamentally, if a single county is assessed then the total number of sample plots will be low and the potential for error will be high. If an entire State is assessed, then the number of plots is much larger (despite the same ratio of plots per ha) therefore the data and the trend is statistically much more accurate. Drax’s CAA analysis falls somewhere in between these two points, with each catchment area including multiple counties but not quite at the same scale as State level analysis. An example of the variation in error is shown in the table below.

Degree of error for key metrics in Drax’s CAA analysis

Degree of error for key metrics in Drax’s CAA analysis

The data showing total inventory (volume of wood growing in the forest) has been assessed for the Chesapeake catchment area in North Carolina and Virginia. When looking at each individual county, the data error calculation is +/- 46.5%, therefore not very accurate. If looking at State level, the data error is only +/- 2.7%. This degree of error is much more accurate and demonstrates more credible and reliable data due to the much larger number of plots available across the entire State. The Drax CAA analysis for inventory in the Chesapeake area is +/- 4.7% which is reasonably close to the State level accuracy due to the large number of countries that are included in the CAA analysis.

Since the catchment area boundary is defined by the pellet mill’s historical and future sourcing pattern, this can vary in size according to each mill’s procurement strategy and local market conditions. For example, the Amite BioEnergy pellet plant sources from a much smaller area close to the mill and therefore the catchment area includes fewer counties. This can lead to a higher degree of error than in the other CAA reports as the total number of plots used is smaller.

A long history of measurement and analysis

Despite this, the overall degree of error is still in single figures and can be considered reasonable in each CAA report by the standards of forest measurement and modelling, an error of under 10% is generally considered acceptable. Measuring standing trees that are still growing is not an exact science – it is an estimation. Trees cannot be accurately weighed or measured until they are cut down. Therefore, there will always be degree of error in estimated data. In the US South, the long history of measurement, analysis and data modelling and the relatively homogenous nature of the main commercial species (southern yellow pine), mean that the error is relatively uniform and predictable if a large sample area is considered.

The potential for remote sensing data collection and analysis to replace traditional field measurement is an interesting and developing field. At an individual forest or stand level, it is possible to carry out intensive measurement with Laser or Lidar, to calculate volume and growth. However, there is currently no reliable, accurate and cost-effective way to do this at a large-scale across several million hectares. This may be a possibility as the technology and data interpretation tools continue to develop and Drax is working closely with remote sensing specialists to trial and develop this process. Until then, we can rely on boots on the ground and traditional fieldwork for an accurate view of the forest trends across our supply chain.

This blog supports a series of catchment area analyses around the forest biomass pellet plants supplying Drax Power Station with renewable fuel. Read more.

 

Burns Lake and Houston pellet plant catchment area analysis

British Columbia, near Barriere, North Thompson River, aspen trees, dead pine trees behind infected with pine bark beetle (aka mountain pine beetle)

The eigth report in a series of catchment area analyses for Drax looks at the fibre sourcing area surrounding two compressed wood pellet plants operated by Pinnacle.

This part of interior British Columbia (BC) is unique in the Drax supply chain. Forest type, character, history, utilisation, natural challenges, logistics, forest management and planning are all very different to the other regions from which Drax sources biomass. Recently devasted by insect pest and fire damage, Arborvitae Environmental Services has produced a fascinating overview of the key issues and challenges that are being experienced in this region.

Figure 1: Catchment area map of the region [Click to view/download]

A positive response to natural disasters

Like the entire BC Interior, the area has suffered a devastating attack of Mountain Pine Beetle (MPB) damage over the last 20 years which has completely dominated every forest management decision and action. Within the catchment area, the MPB killed an estimated 157 million cubic metres (m3) between 1999 and 2014, representing 42% of the estimated 377 million m3 of total standing timber in the catchment area in 1999.  In addition, severe wildfires in 2018 burned an estimated 7.1 million m3.

These natural events have had a devastating impact on the forest resource. Harvesting increased significantly to utilise the dead and dying timber as lumber in sawmills whilst it was still viable.

Net carbon emissions in Canada’s managed forest: All areas, 1990–2017; illustrates that the impact of fires and insect damage have been far more significant, by hectares affected, than forestry activity; Chart via Natural Government of Canada

The Pinnacle pellet mills at Burns Lake and Houston were established alongside the sawmills to utilise the sawmill residues as there were no other viable markets for this material. These sawmills draw fibre from a large distance, up to 300 miles away. Therefore, the size of the catchment area in this piece of analysis is determined by the sourcing practices of the sawmills rather than the economic viability of low grade roundwood transport to the pellet mill (see Figure 1).

Damage to pine trees by Mountain Pine Beetle (MPB)

Utilising forest residues

The two mills producing high-density biomass pellets have provided an essential outlet for residue material that would otherwise have no other market and until very recently were supplied almost entirely by mill residuals. As the quantity of dead and dying timber has reduced and sawmill production has declined, the pellet mills are beginning to utilise more low-grade roundwood and forest residues (that are otherwise heaped and burned at roadside following harvest) to supplement the sawmill co-products.

Primarily State owned managed forests

The total land area in the catchment for Burns Lake and Houston is 4.47 million hectares (ha) of which 3.75 million ha is classed as forest land, 94% of the catchment area is public land under provincial jurisdiction. The provincial forest service is responsible for all decisions on land use and forest management on public land, in consultation with communities and indigenous groups, determining which areas are suitable for timber production and which areas require protection. Approximately 34% of the catchment area is not available for commercial timber harvesting because it is either non-forested or it has low productivity, and other operational challenges, or it is protected for ecological and wildlife reasons.

The Chief Forester for the province sets the Annual Allowable Cut (AAC) which determines the quantity of timber that can be harvested each year. Ordinarily this will be based on the sustainable yield capacity of the working forest area, but in recent years the MPB damage has necessitated a significant increase in AAC to facilitate the salvage of areas that have been attacked and damaged (see Figure 2).

Figure 2: Changes in Annual Allowable Cut 1980 to 2018 (Source: Nadina District FLNRORD) [Click to view/download]

The catchment area is in the Montane Cordillera ecozone and the Canadian Forest Service reports that between 1980 and 2017, the area of forest in the ecozone declined from 31,181,000 ha to 31,094,000 ha, a decline of 87,000 ha or 0.28 % of the forest area. Deforestation in the catchment area was estimated at 300 ha per year. Most deforestation in the ecozone occurred because of conversion to agriculture, as well as other contributing factors, such as mining, urban expansion and road construction (including forest roads).

The forest area is dominated by coniferous species (see Figure 3) predominantly lodgepole pine, spruce and fir (90% of the total area), with hardwood species (primarily aspen) making up just 8% of the total area.

Figure 3: Species composition of forest land in the catchment area.

Managing beetle damaged areas

The annual harvest volume was at a peak in the early part of the last decade at over 12 million m3 in 2011. This has now declined by around 4.5 million m3 in 2019 (see Figure 4) as the beetle damaged areas are cleared and replanted. The AAC and harvesting levels are expected to be reduced in the future to allow the forest to regrow and recover.

Figure 4: Annual change in harvest volume of major species

Future increases in forest growth rates

Historically, the forest area has naturally regenerated with self-seeded stands reaching a climax of mature pine, spruce, and Abies fir mixtures.  As the forest matured, it would often be subject to natural fires or other disturbance which would cause the cycle to begin again. Following the increase in harvesting of beetle damaged areas, many forests are now replanted with mixtures of spruce and pine rather than naturally regenerated. This is likely to lead to an increase in forest growth rates in the future and a higher volume of timber availability once the areas reach maturity (see Figure 5).

Figure 5: Forecast of future volume production

Timber markets in the catchment area are limited in comparison to other regions like the US South.  The scale of the landscape and the inaccessible nature of many of the forest areas limit the viability of access to multiple markets. Sawmills produce the highest value end-product and these markets have driven the harvesting of forest tracts for many years. Concessions to harvest timber are licensed either by volume or for a specific area from the provincial forest service. This comes with a requirement to ensure that the forest regrows and is appropriately managed after harvesting.

There are no pulp mills within the catchment area and limited alternative markets for the lowest grades of roundwood or sawmill residuals other than the pellet mills; consequently, the pellet mills have a close relationship with the sawmills.

Wood price trends

Prices for standing timber on public land are determined by the provincial government using results from public timber sales and set according to the species and quality of timber produced (from the highest-grade logs through to forest residuals). The lack of market diversity and challenging logistics mean that there is little competition for mill residuals and low-grade fibre. The price differential in end-product value between sawtimber and wood pellets ensures that fibre suitable for sawmill utilisation does not get processed by the pellet mill. A very small volume of larger dimension material can end up in a low value market when there are quality issues that limit the value for sawtimber (e.g. rotten core, structural defects) but this represents a very small proportion of the supply volume. There is no evidence that pellet mills have displaced other markets within this catchment area.

Read the full report: Catchment Area Analysis: Pinnacle Renewable Energy’s Burns Lake & Houston Mills.

This is part of a series of catchment area analyses around the forest biomass pellet plants supplying Drax Power Station with renewable fuel. Others in the series can be found here