Author: Alice Roberts

What is the national grid?

Electricity grid

What is the grid?

The national grid, or simply the grid, is the network of powerlines, pylons, gas lines and interconnectors that makes up Great Britain’s electricity and gas systems — and the engineers, technology and rules responsible for their seamless operation. It ensures electricity generated anywhere, by any source, can be transmitted to meet the demand for power wherever it’s needed across the country. It heats homes and businesses. It helps us to cook our food.

The national electricity grid consists of a high voltage transmission system, which connects electricity from power stations to substations and smaller local networks – called Distribution Network Operators, or DNOs – which transport electricity into homes and businesses.

Key national grid facts

How does it work?

Transporting electricity around the grid is more complicated than just connecting cables to power generators. In order to move power around the country, things like voltage and frequency of electricity must be balanced and kept uniform at all times. Without this, unstable electricity could damage equipment and ultimately lead to blackouts.

The National Grid Electricity System operator (ESO) is a separate entity from the National Grid company, and is responsible for maintaining the correct voltage, frequency and reserve power levels to ensure electricity is transmitted safely and efficiently at all times.

It does this by working with power generators and energy storage facilities to provide what are known as ‘ancillary services’ – a set of processes that keep the power system in operation, stable and balanced.

The national grid is the network of power stations, powerlines and electricity infrastructure that allows electricity to be generated, transported and used across the country.

Who controls it?

In Great Britain the National Grid company owns and operates the transmission systems which ensure electricity is delivered safely and reliably across the country.

The local distribution system is made up of 14 regional DNO companies, which deliver electricity at a lower voltage from substations to homes and businesses.

Great Britain’s grid incudes England, Scotland, Wales and several surrounding islands. Northern Ireland is part of an island-wide electricity system with the Republic of Ireland.

National grid fast facts

  • Great Britain’s grid is made up of more than 7,000 kilometres of cables, 90,000 pylons, 346 substations, and 1,500 kilometres of underground cables
  • Construction of the grid began on 14 July 1928 and was completed on 5 September 1933
  • It was originally designed to operate as 7 separate, connected grids, before a group of rebellion engineers attempted to run it as one on 29 October 1938. It has run as one grid ever since
  • A decade ago, Britain had 80 individual points of generation to manage. Today there are nearly one million
  • All electricity in Great Britain operates at a frequency of 50Hz. A deviation of just 1% above or below could cause damage

How is the grid changing?

As the sources that generate Great Britain’s electricity change to include more renewables, the grid has also changed.

The grid was built to work with large power stations that operate huge spinning turbines. With decarbonisation it’s evolved to include a greater variety of intermittent weather dependent sources such as wind, solar and decentralised power sources that serve individual buildings or communities.

This makes managing the grid’s stability more complicated, and requires the use of more ancillary services, usually delivered by flexible generators such as thermal power stations.

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What is climate change?

Climate change

What is climate change?

Climate change refers to the change in weather patterns and global temperature of the earth over long periods of time. In a modern context, climate change describes the rise of global temperatures that has been occurring since the Industrial Revolution in the 1800s.

What causes climate change?

While there have been natural fluctuations in the earth’s climate over previous millennia, scientists have found that current-day temperatures are rising quicker than ever due to the excessive amount of carbon dioxide (CO2) and other greenhouse gasses being released into the atmosphere.

Key climate crisis facts

An excess of CO2 in the atmosphere accentuates something called the ‘greenhouse effect’. As CO2 traps heat in the earth’s atmosphere, it warms the planet and causes a rise in average global temperature. International efforts, such as the Paris Climate Accords, are dedicated to ensuring temperatures do not rise 2 degrees Celsius above pre-industrial levels, which could lead to catastrophic conditions on the planet.

In the modern context, climate change describes the rise of global temperatures occurring since the Industrial Revolution in the 1800s.

How do humans contribute to climate change?  

Industries such as transport, agriculture, energy and manufacturing have traditionally relied on the use of coal, oil and other fossil fuels. These fuels, when combusted or used, emit large amounts of CO2 into the atmosphere, further advancing the greenhouse effect and contributing to climate change.

Human reliance and consumption of these products mean today CO2 levels are the highest they’ve been in 800,000 years.

Why are rising temperatures harmful to the planet?

Our planet has a history of experiencing periods of extreme weather conditions – for example the last Ice Age, which finished 12,000 years ago. However, the rapid rise in temperatures seen today is harmful because a hotter planet completely affects our natural environment.

A steep rise in global temperature can melt ice sheets and cause higher sea levels which can, in turn, contribute to more extreme storms and even threaten entire islands and coastal communities. As the planet warms, extreme weather events, such as bushfires could become more common, which can destroy homes, impact agriculture and degrade air quality, while entire ecosystems, habitats and animal and insect species could also be threatened by climate change. 

What can be done to mitigate the effects of climate change?

Reducing CO2 emissions is a key way of slowing down the pace of climate change. To do so, industries across the global economy must decarbonise to become less dependent on fossil fuels, such as coal and petrol, and adopt new lower carbon energy sources.

Decarbonisation will rely on a number of factors, including a technological response that sees the development and implementation of carbon neutral and carbon negative ways of creating heat, electricity and fuels, including the use of innovations such as carbon capture and storage (CCS).

There is also a need for a policy and governmental response that promotes investment in new cleaner technologies and disincentivises dirtier industries through mechanisms like the carbon tax. Countries and economies will need to work collaboratively to achieve common, climate-oriented goals that will also enable smaller scale action to be taken by individuals around the world. 

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Button: What is the grid?

What are ancillary services?

Ancillary services

What are ancillary services?

Ancillary services are a set of processes that enable the transportation of electricity around the grid while keeping the power system operating in a stable, efficient and safe way.

Why do we need ancillary services? 

When electricity makes its way through the country, it needs to be managed so that the power generation and electricity useage levels are equal.

The regulating of elements such as frequency and voltage has to be carefully managed, so that the massive amounts of electricity moving – or transmitted – are able to be used safely in homes,  businesses, schools and hospitals around the country.

Ancillary services enable the power system to operate in a stable, efficient and safe way.

 What do ancillary services offer?

Ancillary services include a wide variety of electrical efficiency and safety nets, all focussed on ensuring the power system delivers enough output to meet demand yet remains stable:

Frequency: The UK’s power system runs at a frequency of 50 hertz – to stay balanced, it has to remain at that frequency. Turbines and generators adjust the speed at which they spin automatically to increase or decrease power in line with demand and ensure that the system is kept stable.

Voltage: Different parts of the UK’s transmission system use voltages of either 400, 275 or 132 kilovolts. To ensure that voltage remains within 5% of those figures at all times, to be safe for domestic electricity use, power stations can produce or re-absorb excess energy as reactive power, keeping the overall system reliable.

Inertia: Turbine use is important in keeping the system operating in its current state, even with disruptions and sudden changes. The electricity system uses the weight of heavy spinning turbines to create stability, acting as dampeners and smoothing out unexpected changes in frequency across the network.

Reserve: An important part of ancillary servicing is making sure that there are no surprises – so holding back powerto release if something unexpected happens means that the network can function confidently, knowing that there are generators and other power providers such as pumped hydro storage waiting ready to back it up.

Key facts about ancillary services

Who manages ancillary services?

In the UK the grid’s stability is managed by National Grid Electricity System Operator (ESO) – a  separate company of National Grid Electricity Transmission (ET). The ESO works with ancillary service providers to either sign long-term contracts or make short term requests for a service.

These partners are often power stations, such as Drax Power Station, which have large spinning turbines capable of controlling voltage, frequency, providing inertia and serving as a source of reserve power. 

What is the future of ancillary services, as we move to a more renewable system?

As the UK’s electricity system continues to change, so to do its requirements for different ancillary services. The switch from a few very large power stations to a greater variety of different electricity sources, some of which may be dependent on the weather, as well as changes in how the country uses electricity, means there is a greater need for ancillary services to keep the grid stable.

These services have historically been delivered by thermal power stations, but new innovations are enabling wind turbines to provide inertial response and overcome changes in frequency, and batteries to store reserve power that can then be supplied to the power system to ensure balance.

Ancillary Services

Ancillary services fast facts  

  • Batteries can in some cases be cheaper ancillary alternatives to conventional sources of energy. The Hornsdale Power Reserve, which runs on a Tesla battery in South Australia, lowered the price of frequency ancillary services by 90% after just four months of use.
  • Ancillary services usually work from habit; knowing when to slow electricity production, or increase supply based around the general public’s standard working hours, dinner time and the early morning rush.
  • But during the COVID-19 lockdown, electricity consumption on weekdays fell by 13% and so National Grid ESO had to intervene with ancillary services to keep the lights on.
  • Every year, the ESO’s ancillary services move 300 terawatt hours (TWh) of electricity, which is equal to 4 trillion kettles boiling at once.

With recent innovations around renewable energies, there are a wider variety of ways for ancillary services to generate power.

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Button: What is decarbonisation?

What is reforestation and afforestation?

Reforestation and afforestation

What is reforestation and afforestation?

Reforestation is the process of planting trees in a forest where the number of trees has been decreasing.

Afforestation is when new trees are planted or seeds are sown in an area where there were no trees before, creating a new forest.

Why carry out reforestation and afforestation?

Reforestation and afforestation are two of the leading nature-based solutions for tackling the effects of climate change. For commercial foresters and landowners, these two practices are essential to ensuring they can grow wood for wood products and continuously meet demand in a sustainable way.

Reforestation is crucial in combating or preventing deforestation or forest degradation, where forests shrink in size or are completely removed. As well as reducing a forest’s ability to absorb carbon dioxide (CO2), deforestation can destroy wildlife habitats and contribute to the likelihood of flooding in certain areas.

Afforestation can also help avoid desertification, where fertile land turns into a desert as a result of drought or intensive agriculture.

Reforestation is the process of planting native trees in a forest where the number of trees has been decreasing.

How does reforestation and afforestation limit the effects of climate change?

Forests are a natural way of keeping the earth’s CO2 levels in check. The more trees there are, the more CO2 is captured and converted into oxygen through photosynthesis.

By absorbing CO2, forests help to lower the amount of greenhouse gasses in the atmosphere and reduce the effects of climate change.

Reforestation and afforestation help maximize these abilities of forests by increasing the overall amount of forested land on the planet.

Key forest facts

Did you know?

Different types of forests, such as tropical, swamps or mangroves, all absorb CO2 at different rates.

The age of a forest also impacts absorption. Young, rapidly growing, trees absorb CO2 at a faster rate than more mature ones, which have large amounts of carbon locked in already.

Afforestation is when new trees are planted or seeds are sown in an area where there were no trees before.

What roles does reforestation play in commercial forestry?

The global wood products industry depends on sustainable forests to supply the wood needed to make furniture, create construction materials and provide fuel for energy.

The supply chain will often start with what’s called a ‘working forest’ – a commercially-run forest which is often privately owned. The landowner will grow a working forest to a certain stage of maturity and then harvest some or all of the trees to sell the wood. Once the wood has been sold for use as lumber, wood products or fuel, the landowner will reforest the areas to regrow the trees.

Foresters will typically do this in stages across their land to ensure there are multiple stands of forest at different stages of growth across their land, which ensures there is consistent, sustainable growth at all times.

Fast facts

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Button: What is carbon capture?

What is decarbonisation?

Decarbonisation

What is decarbonisation?

Decarbonisation is the term used for the process of removing or reducing the carbon dioxide (CO2) output of a country’s economy. This is usually done by decreasing the amount of CO2 emitted across the active industries within that economy. 

Why is decarbonisation important?

Currently, a wide range of sectors – industrial, residential and transport – run largely on fossil fuels, which means that their energy comes from the combustion of fuels like coal, oil or gas.

The CO2 emitted from using these fuels acts as a greenhouse gas, trapping in heat and contributing to global warming. By using alternative sources of energy, industries can reduce the amount of CO2 emitted into the atmosphere and can help to slow the effects of climate change.

Key decarbonisation facts

Why target carbon dioxide?

 There are numerous greenhouse gases that contribute to global warming, however CO2 is the most prevalent. As of 2018, carbon levels are the highest they’ve been in 800,000 years.

The Paris Agreement was created to hold nations accountable in their efforts to decrease carbon emissions, with the central goal of ensuring that temperatures don’t rise 2 degrees Celsius above pre-industrial level.

With 195 current signatories, economies have begun to factor in the need for less investment in carbon, with the UK leading the G20 nations in decarbonising its economy in the 21st century.

How is decarbonisation carried out?

There are numerous energy technologies that aim to reduce emissions from industries, as well as those that work towards reducing carbon emissions from the atmosphere.

Decarbonisation has had the most progress in electricity generation because of the growth of renewable sources of power, such as wind turbines, solar panels and coal-to-biomass upgrades, meaning that homes and businesses don’t have to rely on fossil fuels. Other innovations, such as using batteries and allowing homes to generate and share their own power, can also lead to higher rates of decarbonisation. As the electricity itself is made cleaner, it therefore assists electricity users themselves to become cleaner in the process.

Other approaches, such as reforestation or carbon capture and storage, help to pull existing carbon from the air, to neutralise carbon output, or in some cases, help to make electricity generation – and even entire nations – carbon negative.

Alternative power options means that homes and businesses don’t have to rely on traditional carbon fuels.

What is the future of decarbonisation?

For decarbonisation to be more widely adopted as a method for combating climate change, there needs to be structural economical change, according to Deloitte Access Economics. Creating more room for decarbonisation through investing in alternative energies means that “there are a multitude of job-rich, shovel-ready, stimulus opportunities that also unlock long-term value”.

 Decarbonisation fast facts

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Button: What is biomass?

 

The science making new discoveries in forests

Weyerhaeuser tree nursery in the US South

Scientific research isn’t all test tubes and lab coats – sometimes it’s bark and soil. It might be a world away from the image of a sterile laboratory, but the world of forestry is one that has seen significant scientific progress since the 18th century, when it first emerged as an area of study.

The development of environmental sciences and ecology, as well as advances in biology and chemistry mean there are still new discoveries being made – from trees’ ability to ‘talk’ to each other through underground fungi networks, to forests’ positive impact on mental health.

Fostering greater awareness and understanding of fragile forest ecosystems such as the cypress swamps of the Atchafalaya Basin in Louisiana, forestry has also allowed for the improvement of working forests — landscapes planted to grow wood for products and services that often avoid the use of fossil fuel-based alternatives.

Cypress forests in the Atchafalaya Basin in Louisiana are an example of a forest landscape where the suitable management practice is protection, preservation and monitoring

Cypress forests in the Atchafalaya Basin in Louisiana are an example of a forest landscape where the suitable management practice is protection, preservation and monitoring

By enhancing the genetic stock, tree breeding ensures seedlings and plants are better adapted to their environment (soil, water, temperature, nutrient level, etc.). Science can now help trees to grow more quickly, storing more carbon. It can also give trees better form — straighter trees can produce more saw-timber which can, in turn, lock more carbon in buildings made predominantly or partially of the natural, renewable product that wood is.

But more than just uncovering surprising insights into the ins and outs of our natural world, forestry science is contributing to a far bigger goal: tackling climate change.

The science of forests

When the scientific study of forests first emerged in 18th century Germany, it was with the aim of sustainability in mind. Industries were concerned forests wouldn’t be able to provide enough timber to meet demand, so research began into how to manage them responsibly.

Forestry today encompasses much more than just providing saw logs and the research going into it remains driven by the same goal: to ensure sustainability. Its breadth, however, has grown.

The UK Forestry Commission’s research and innovation strategy highlights the scope it should cover: “It must be forward-looking to anticipate long-term challenges, strategic to inform emerging policy issues, and technical to support new and more efficient forestry practices.”

Pine trees grown for planting in the forests of the US South where more carbon is stored and more wood inventory is grown each year than fibre is extracted for wood products such as biomass pellets

Being able to deliver on this breadth has relied on rapid advances in technology – including taking forestry research into space.

The technology teaching us about trees

As in almost every industry, one of the major drivers of change in forestry is data, and the ability to collect data from forests is getting more advanced.

At ground level, techniques like ‘sonic tomography’ allow foresters and researchers to ‘see’ inside trees using sound waves, measuring size, decay and overall health. This, in turn, offers a bigger picture of forests’ wellbeing.

At the other end of the scale, satellites and mapping technology are playing a major role in advancing a macro view of the world’s forests – particularly in how they change over time. As well as a potent tool in monitoring and helping fight deforestation, satellite images have revealed there is nine per cent more forest on earth than previously thought.

Space satellite with antenna and solar panels in space against the background of the earth. Image furnished by NASA.

The European Space Agency’s Earth Explorer programme will go a step further and use radar from satellites to penetrate the forest canopy, measuring tree trunks and branches rather than just the area covered by forest. Determining the volume of wood in forests around the planet will effectively enable researchers to ‘weigh’ the world’s forest biomass.

The masses of data these advances in tech are providing, is playing a major role in how we manage our forests, including how we can use them to fight global warming.

Taking on the climate crisis

Forests are one of the key defences against climate change – so much so they’re included in the Paris Agreement. Trees’ abilities to absorb carbon dioxide (CO2) has long been established knowledge. Thanks to what climate scientists call IAMs or integrated assessment models, we  now know how much they can extract from the atmosphere and how long they can continue to do so, as CO2 levels rise.

One optimistic hypothesis says trees will take in more CO2, as the levels rise. To test this, researchers in the UK are blasting controlled sections of a forest  with CO2 to increase its density by 40%, representing expected global levels by 2050. By tracking how trees react they hope to highlight the role they can play as carbon sinks.

Science also suggests they could not only help slow climate change, but actively fight it. The research considers that as well as absorbing CO2, trees are reported to emit gases that reflect sunlight back into space, ultimately contributing to global cooling.

However, planting more trees isn’t necessarily the only answer. In places experiencing drought such as the western US, thinning forests can reduce competition and allow healthier trees capable of absorbing more oxygen to flourish.

The increasing body of research on forests’ impact on climate change could prove vital in shaping both the forestry industry and national governments’ approaches forests. However, as a science, forestry could be considered to be in its infancy. At this crucial time for the planet’s future, forestry is becoming one of the most important environmental sciences, but a lot more attention, investment and research and development are required if we are able to fully understand and manage the world’s forest resources. We have barely scratched the surface.

Notice of half year results announcement

Biomass domes at Drax Power Station
RNS Number : 6129T
Drax Group PLC

Drax Group plc (“Drax”) confirms that it will be announcing its Half Year Results for the six months ended 30 June 2020 on Wednesday 29 July 2020.

Information regarding the results presentation meeting and webcast is detailed below.

Results presentation and webcast arrangements

Management will host a webcast presentation for analysts and investors at 9:00am (UK Time), Wednesday 29 July 2020.

The presentation can be accessed remotely via a live webcast link, as detailed below. After the meeting, the webcast recording will be made available and access details of this recording are also set out below.

A copy of the presentation will be made available from 7:00am (UK time) on Wednesday 29 July 2020 for download at: www.drax.com/uk>>investors>>results-reports-agm>> #investor-relations-presentations or use the link https://www.drax.com/uk/investors/results-reports-agm/#investor-relations-presentations

Event Title: Drax Group plc: Half Year Results

Event Date: Wednesday 29 July 2020, 9:00am (UK time)

Webcast Live Event Link: https://secure.emincote.com/client/drax/drax007

Conference call and pre-register Link: https://secure.emincote.com/client/drax/drax007/vip_connect

Start Date: Wednesday 29 July 2020

Delete Date: Thursday 31 December 2020

Archive Link: https://secure.emincote.com/client/drax/drax007

For further information, please contact Rosie Corbett: [email protected]

Website: www.drax.com/uk

LaSalle catchment area analysis

LaSalle Bioenergy Pellet Plant

The wood supply catchment area for Drax’s LaSalle BioEnergy biomass pellet plant in mid-Louisiana is dominated by larger scale private forest owners that actively manage and invest in their forest for saw-timber production. Eighty-three per cent (83%) of the forest is in private ownership and 60% of this area is in corporate ownership.

The Drax Biomass pellet mill uses just 3.2% of the roundwood in the market and therefore has limited impact or influence on the overall trends. By contrast, the pulp and paper industry consumes 74% of the total pulpwood demand as the most dominant market for low grade fibre.

Forest in LaSalle catchment area

Forest in LaSalle catchment area

The catchment area has seen an increase in total timberland area of 71 thousand hectares (ha) since 2008, this is primarily due to planting of previously non-stocked land. Hardwood areas have remained stable but planted pine has increased, replacing some of the naturally regenerated mixed species areas. The data below shows that deforestation or conversion from pure hardwood to pine is not occurring.

Timberland area by management type

Timberland area by management type

The overall quantity of stored carbon, or the inventory of the standing wood in the forest, has increased by 7% or 32.6 million metric tonnes since 2008. This total is made up of a 49 million tonne increase in the quantity of pine and a 16 million tonne decline in the quantity of hardwood. Since the area of pure hardwood forest has remained stable, this decline is likely to be due to the conversion of mixed stands to pure pine in order to increase saw-timber production and to provide a better return on investment for corporate owners.

Historic area and timberland inventory

Historic area and timberland inventory

Forest in LaSalle catchment area

Forest in LaSalle catchment area

The growth-to-drain ratio and the surplus of unharvested pine growth has been increasing year-on-year from two million tonnes in 2008 to over five million tonnes in 2016.

This suggests that the LaSalle BioEnergy plant (which almost exclusively utilises pine feedstocks) has not had a negative impact on the growth-to-drain ratio and the surplus of available biomass.

The latest data (2016) indicates that the ratio for pine pulpwood is 1.54 and for pine saw-timber 1.24 and that this has been increasing each year for both categories.

Historic growth and removals by species

Historic growth and removals by species

Stumpage prices for all product categories declined between 2010 and 2011. This was followed by a peak around 2015-16 with the recovery in demand post-recession and prices then stabilised from 2016 to 2019. The data indicates that there has been no adverse impact to pine pulpwood prices as a result of biomass demand. In fact, pine pulpwood prices are now nearly 20% lower than in 2014 as shown on the chart below.

LaSalle BioEnergy market historic stumpage prices, USD$:tonne

LaSalle BioEnergy market historic stumpage prices, USD$:tonne

The character of the pine timberland is one of a maturing resource, increasing in the average size of each tree. The chart below chart shows a significant increase in the quantity of timber in the mid-range size classes, indicating a build-up of future resources for harvesting for both thinning and final felling for sawtimber production.

With balanced market demand, the supply of fibre in this catchment area should remain plentiful and sustainable in the medium term.

Historic pine inventory by DBH (diameter at breast height) class

Historic pine inventory by DBH (diameter at breast height) class

Forisk summary of the impact of LaSalle BioEnergy on key trends and metrics in this catchment area

Is there any evidence that bioenergy demand has caused …

Deforestation

No

Change in forest management practices

No

Diversion from other markets

Possibly. Bioenergy plants compete with pulp/paper and oriented strand board (OSB) mills for pulpwood and residual feedstocks. There is no evidence that these facilities reduced production as a result of bioenergy markets, however.

Increase in wood prices

No. There is no evidence that bioenergy demand increased stumpage prices in the market.

Reduction in growing stock of timber

No

Reduction in sequestration of carbon / growth rate

No

Increase in harvesting above the sustainable yield

No 

The impact of bioenergy on forest markets in the LaSalle catchment is …

Growing stock

Neutral

Growth rates

Neutral

Forest area

Neutral

Wood prices

Neutral

Markets for solid wood

Neutral to Positive. Access to viable residual markets benefits users of solid wood (i.e. lumber producers).

Forest in LaSalle catchment area

Forest in LaSalle catchment area

Read the full report: LaSalle, Louisiana Catchment Area Analysis. Read how a $15m rail link from LaSalle BioEnergy to the Port of Greater Baton Rouge helps Drax reduce supply chain emissions and biomass costs here. Take a 360 immersive experience and video tour of LaSalle BioEnergy.

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 include: Georgia MillChesapeakeEstonia, Latvia and Drax’s own, other two mills Morehouse Bioenergy and Amite Bioenergy.

Plant more forests and better manage them

Working forests in the US South

There is an ongoing debate about forests’ contribution to fighting the climate crisis.

Forests can act as substantial and effective tools for carbon sequestration during a high growth phase. They can also function as significant and extensive carbon storage areas during maturity and throughout multiple stages of the age class cycle, if managed effectively at a landscape level. Or, they can be emitters of carbon if over-harvested, subject to fire, storm, pest or disease damage.

Different age class forest stands in Louisiana

In a natural state, forests will go through each of these life phases: rapid early growth; maturity and senescence; damage, decay and destruction through natural causes. Then they begin the cycle again, absorbing and then emitting carbon dioxide (CO2) in a continual succession.

Recently, loud voices have argued against forest management per se; against harvesting for wood products in particular, suggesting that this reduces both forest carbon stocks and sequestration capacity.

Pine cut in into wood for different wood products markets in Louisiana. Big, thick, straight higher value sections go to sawmills and smaller and misshapen low-grade wood not suitable for timber production is sold to pulp, paper or wood pellet mills.

Many foresters consider that this is just not correct. In fact, the opposite is true. Research and evidence clearly support the foresters’ view. Active forest management, when carried out appropriately, actually increases the amount of carbon sequestered, ensures that carbon is stored in solid wood products, and provides substantial savings of fossil fuels by displacing other high carbon materials (e.g. concrete, steel, brick, plastic and coal).

Oliver et al.(2014)[1] compared the impact of forest harvesting and the use of wood products to substitute other high-carbon materials, concluding that: ‘More CO2 can be sequestered synergistically in the products or wood energy and landscape together than in the unharvested landscape. Harvesting sustainably at an optimum stand age will sequester more carbon in the combined products, wood energy, and forest than harvesting sustainably at other ages.’

This research demonstrated that an increase in the use of structural timber to displace concrete and steel could lead to substantial emissions savings compared to unharvested forest. The use of wood for energy is an essential component of this displacement process, although it is important to use appropriate feedstocks. Burning wood that could be used for structural timber will not lead to a positive climate impact.

The message here is to manage working forests for optimum sawlog production for long-life solid wood products and utilise the by-products for energy where this is the most viable market, this provides the best all-round climate benefit.

What happens when you close the gate

Closing the forest gate and stopping all harvesting and management is one option being championed by some climate change campaigners. There is certainly a vital role for the preservation and protection of forests globally: primary and virgin forests, intact landscapes, high biodiversity and high conservation value areas all need to be protected.

That doesn’t necessarily mean that there is no forest management. It should mean careful and appropriate management to maintain and ensure the future of the resource. In these cases, management is with an objective to reduce the risk of fire, pests and disease, rather than for timber production.

Globally, we need better governance, understanding and implementation of best practice to achieve this. Forest certification and timber tracing systems are a good start. This can equally apply to the many hundreds of millions of hectares of ‘working forest’ that do not fall into the protection categories; forests that have been managed for many hundreds of years for timber production and other purposes. Harvesting in these forests can be more active, but governance, controls and the development of best practice are required. Better management not less management.

During the 1970s there was a significant change of policy in the US, aimed at removing massive areas of publicly owned forest from active management – effectively closing the gate. The drivers behind this policy were well meaning; it was intended to protect and preserve the habitat of endangered species, but the unintended consequences have also had a substantial impact. In the 1970s little thought was given to the carbon sequestration and storage potential of forests and climate change was not at the top of the agenda.

The west coast of the US was most substantially affected by these changes, more than in the US South, but the data below looks at the example of Mississippi which is primarily ‘working forest’ and 88% in private ownership.

Pine trees in Mississippi working forest

This is the location of Drax’s Amite pellet mill. The charts below show an interesting comparison of forest ownership in Mississippi where limited or no harvesting takes place and where active management for timber production occurs. In the short term the total volume of timber stored per hectare is higher where no harvesting occurs. This makes sense since the forest will keep growing until it reaches its climax point and succumbs to fire, pest or disease.

Average standing volume per unit area in the private sector, where active management occurs, is the lowest as timber is periodically removed for use in solid wood products. Remember that the Oliver et al. analysis (which does not include re-growth), showed that despite a short-term reduction in forest carbon, the total displacement of high-carbon materials with wood for structural timber and energy leads to a far higher emissions saving. It is better to have a lower stock of carbon in a working forest and to be continually sequestering new carbon for storage in solid wood products.

Average standing volume per acre by ownership class, Mississippi[2]

Comparing the average annual growth rates across all forest types in Mississippi, annual growth in the private sector is almost double that in the unharvested public forest. This differential is increased even further if only commercial species like pine are considered and a comparison is made between planted, well managed forests and those that are left to naturally regenerate.

Average growth rates per acre by ownership class, Mississippi[3]

The managed forest area is continually growing and storing more carbon at a materially higher rate than less actively managed forest. As harvesting removes some forest carbon, these products displace high carbon materials in construction and energy and new young forests are replacing the old ones.

We know that forests are not being ‘lost’ and that the overall storage of carbon is increasing. For example, the Drax catchment area analysis for the Amite biomass wood pellet plant showed an increase in forest area of 5,200 ha and an increase in volume of 11 million m3 – just in the area around the pellet mill. But what happens to protected forest area, the forest reserve with limited or no harvesting?

Over the last 20 years the average annual loss of forest to wildfire in the US has been 2.78 million ha per year (the same as the UK’s total area of productive forest). According to the USFS FIA database the average standing volume of forests in the US is 145 m3 per ha (although in the National Park land this is 365 m3 per ha). Therefore, wildfires are responsible for the average annual combustion of 403 million m3 of wood p.a. (equal to the total annual wood harvest of the US) or 2.5 billion m3 if entirely in National Parks.

One cubic metre equates to a similar quantity of CO2 released into the atmosphere each year, therefore wildfires are responsible for between 407 million and 2.5 billion tonnes of CO2 emissions in the US each year[4].

Wildfires in the US

Starrs et al. (2018)[5] demonstrated that the risk of wildfire was significantly higher in federally owned reserved forest (where harvesting and management were restricted), compared to privately owned forests with active management.

In California, the risk of wildfire in federal forest (2000-15) was almost double the risk in private forests where both had State firefighting resources. The risk of fires in federal lands had increased by 93% since 1950-66, compared to only 33% in non-federal forests, due to the change in forest management practice in the 1970s.

Forest fire in California

Closing the gate means that the carbon stock is maintained and grows in the short term, but there is no opportunity for carbon to be stored in solid wood products, no high-carbon materials are displaced (concrete, steel and fossil fuels) and the rate of sequestration declines as the forest ages. Eventually the forest will reach its natural climax and die, releasing all of that carbon back into the atmosphere. The managed forest, by contrast, will have a lower standing volume at a certain point in time, but will be in a continual cycle of sequestration, storage and regrowth – with a much lower risk of fire and disease. If managed correctly, the rate of growth and standing volume will also increase over time.

How should we manage the forest

Forests are extremely variable, there are a vast variety of tree species, soil, geological features, water regimes, temperature, climate and many other factors that combine to make unique ecosystems and forest landscapes. Some of these are rare and valuable for the exceptional assemblages they contain, some are commonplace and widespread. Some are natural, some man-made or influenced by human activity.

Forests have many important roles to play and careful management is required. In some cases that management may be protection, preservation and monitoring. In other cases, it may be active harvesting and planting to optimise growth and carbon storage.

Cypress forests in the Atchafalaya Basin in Louisiana are an example of a forest landscape where the suitable management practice is protection, preservation and monitoring

For each forest type and area, we need to recognise the highest or best purpose(s) for that land in the objectives set and carefully plan the management to optimise and sustain that value. The primary value could be in species and habitat diversity or rarity; provision of recreation and aesthetic value; production of timber, forest products and revenue generation; carbon sequestration and storage; water management and other ecosystem benefits.

Most likely it will be a combination of several of these benefits. Therefore, best management practice usually involves optimising each piece of forest land to provide the most effective combination of values. Forests can deliver many benefits if we are sensible about how we manage them.

In a recent study Favero et al. (2020)[6] concluded that: Increased bioenergy demand increases forest carbon stocks thanks to afforestation activities and more intensive management relative to a no-bioenergy case. Some natural forests, however, are converted to more intensive management, with potential biodiversity losses…the expanded use of wood for bioenergy will result in net carbon benefits, but an efficient policy also needs to regulate forest carbon sequestration.

[1] CHADWICK DEARING OLIVER, NEDAL T. NASSAR, BRUCE R. LIPPKE, and JAMES B. McCARTER, 2014. Carbon, Fossil Fuel, and Biodiversity Mitigation with Wood and Forests.
[2] US Forest Service, FIA Database, 2020.
[3] US Forest Service, FIA Database, 2020.
[4] Assumes an average basic density of 570kg/m3 and 50:25:25 ratio of cellulose, lignin and hemicellulose.
[5] Carlin Frances Starrs, Van Butsic, Connor Stephens and William Stewart, 2018. The impact of land ownership, firefighting, and reserve status on fire probability in California.
[6] Alice Favero, Adam Daigneault, Brent Sohngen, 2020. Forests: Carbon sequestration, biomass energy, or both?