Tag: forests

5 more things you never knew about forests

3 November 2017

Sustainable bioenergy

Forests have long been places of mystery for people. It’s within a dark wood that Virgil and then Dante locate the gates to the underworld, while Shakespeare’s magical Midsummer Night’s Dream plays out in a mystical forest near Athens.

And while fairies and portals may be the stuff of fantasy, the forests that inspired them remain a source of mystery to this day.

Here are five more things you might not know about forests.

The forest sector employs more than 50 million people around the world

Employment is one of the major driving forces of global urbanisation as waves of people in both developed and less developed countries head to cities in search of better wages and living standards. But outside of cities, industries still thrive – particularly forestry, which officially employs 13.2 million people around the world.

The World Bank even suggests that by counting people in informal forestry employment and those who earn a living indirectly through forests, timber or fuel, the number of people professionally involved in forestry is closer to 54 million worldwide.

Forestry’s total contribution to global GDP is also sizeable. It currently adds an impressive $120 billion directly – a number expected to grow by as much as 50% over the next 10 to 15 years. Even more impressive is the contribution of the wider timber and wood product sector, which generates as much as $600 billion – 1% of global GDP, according to the World Bank.

We will soon be able weigh the world’s forests

 We know forests blanket about 30% of the land on earth, but what about calculating the mass and volume of all those trees? That’s a different task entirely, but one which could offer important insights for sustainable forestry.

In 2021 the European Space Agency (ESA) will launch Earth Explorer Biomass, the first satellite to carry a P-band radar, which is capable of penetrating the forest canopies and capturing data on the density of tree trunks and branches. Essentially, it will be able to weigh the world’s forests.

Over the course of its five-year mission, it will produce 3D maps every six months, giving scientists data on forest density across eight growth cycles. The result will be a much clearer image of the amount of biomass present around the earth’s different forested areas and how it is changing over time as a result of carbon dioxide (CO2) absorption.

Forests are an energy source that clean up after themselves

For all the IKEA furniture made from wood, 50% of the world’s total wood production is still used for energy with some 2.4 billion people globally using it for heating, cooking and electricity generation.

The world’s forests have an energy content about 10 times that of the annual primary energy consumption, making it a hugely useful resource in helping meet energy demand – if it is managed and used in a sustainable way.

As with other energy sources that are combusted, wood releases CO2, . However, if this fuel is drawn from a responsibly managed forest or a sustainable system of growing forests, its carbon emissions are offset by new tree plantings, which absorb carbon as they grow. This means the only emissions produced are those that come from transporting the wood itself.

The US Food and Agriculture Organization predicts that by 2030, forestry mitigation – with the help of carbon pricing – could contribute to CO2 reductions of 0.2 to 13.8 gigatonnes a year. 

 

Forests improve drinking water

Forests provide what’s known as natural infrastructure, which not only regulate water levels but also improve the quality of drinking water. Root systems and organic material like the leaves and twigs that make up the forest floor absorb water, reducing runoff and erosion. They also play a part in absorbing nutrients that are harmful to water quality.

The forest canopy further helps this process by releasing water vapour, helping regulate rainfall and providing protection against aerial drifts of pesticides, which can filter back into water systems.

Forests can suck up a third of CO2 emissions

While governments around the world look to shift to cleaner, renewable energy sources and cut emissions, forests have been silently tackling climate change for centuries. Over the past few decades, the world’s forests have absorbed as much as 30% of annual global human generated CO2 emissions. In fact, their ability to deal with fossil fuel-derived carbon emissions is even written into the Paris Climate Agreement.

While natural forests can contribute massively to sequestering (absorbing and storing) greenhouse gases, managed forests can play an even more powerful role.

Younger trees absorb more CO2 to fuel their rapid growth compared to older trees with stored carbon reserves. Managed forests, with regular thinning and replanting of trees, ensure there are plentiful numbers of these carbon-hungry young trees around the world.

Read the original 5 things you never knew about forests here.

15 words foresters use

16 August 2017

Sustainable bioenergy
Wind-shaped tree in a field

In Japanese, there’s a single word to describe sunlight filtering through the leaves of a tree: komorebi. It’s a poetic term to describe an image almost everyone recognises, however English has no direct translation.

But while English lacks a ‘komorebi’ equivalent, it does contain a significant number of words that speak to the very specific features of the forestry industry – terms that describe the crooked nature of a tree open to the elements on a mountain side, or words for the process of stripping a grown tree of its limbs.

Here, we look at the unusual, the uncommon, and the whimsical words that make up the language of forestry.

Silviculture

Seen as both a science and an art, silviculture is the practice of controlling the establishment, growth, composition, health and quality of forests. This goes beyond just managing working forests for wood products markets, however, and includes those dedicated to everything from leisure to wildlife.

Comminution

One of the first steps in the production of biomass such as wood pellets is reducing down the raw materials like the fresh felled green wood, and this relies on a process known as comminution. This is carried out by a range of specifically designed machinery such as rotary hammer mills, chippers and grinders, but can also be done in the forest using mobile chippers to reduce tops and branches.

Krummholz

From the German word ‘krumm’ meaning crooked, bent or twisted, krummholz is a term for trees that are stunted and sculpted by harsh winds found near the tree line of mountains, or on coastlines where there are large quantities of salt in the air. Exposure to the elements often means these trees are windblown into surreal shapes, while branches on one side are often deformed or dead.

Underdog

A key component of any sports movie, the origins of the word underdog may actually have come from the logging industry.

In pre-mechanised times, logs would be placed over a sawpit and cut up the middle with a long two-handled saw. The unfortunate sawyer working at the bottom, often knee deep in rainwater, under a falling rain of sawdust, was known as an underdog. However, other theories exist which claim the term originates from dog fighting.

A hypsometer

A hypsometer, used to measure angles to determine the height of trees

Hypsometer

A hypsometer is a tool used to measure angles. When used by foresters, it can determine the height of a tree. To use it, foresters measure the top and bottom of the tree from a measured distance away and use trigonometry to calculate the height.

Hoppus foot

The standard measurement of volume used for timber across the British Empire, the hoppus foot was introduced by English surveyor Edward Hoppus in 1736. The imperial measurement was developed to estimate how much squared, useable timber could be converted from a round log, while allowing for wastage.

A mobile wood chipper

A mobile wood chipper in operation in Arkansas

Slash and brash 

Slash and brash are both terms for the woody debris left by logging operations. However, while slash can be chipped and sold as biomass, brash is not normally removed. Instead, it can be spread along routes used by forestry machinery to prevent ground damage in what are known as brash mats.

Leader

The very top stem of a tree. This typically develops from a tree’s ‘terminal bud’, which is the main area of growth in a plant and is found at the end of a limb.

Two men using a cart to transport a log

Foresters using horses and rail carts to transport timber in California, 1904

Hot logging

Hot logging is the process of loading logs onto lorries and removing them from forests immediately after felling – when they’re still hot from the saw. This is in contrast to the more common process of storing or decking logs on site before removing. Hot logging is often used when ‘whole tree harvesting’, as the trees are removed from site and processed at the mill to maximise recovery of high value saw timber material.

Snag  

Dead trees might not seem like the most useful plants in a forest, but snags prove otherwise. Snags are standing dead or dying trees, and they serve an important role in forest ecosystems. Often missing their top or most of their smaller branches, snags provide habitats for wide varieties of birds, mammals and invertebrates, as well as supporting decomposers such as fungi. In fresh water environments snags also make essential shelter for fish spawning sites.

Beating up

Towards the end of the growing season, trees that have died shortly after planting are counted and replanted in what is known as beating up. This process also allows foresters to identify and address any issues that may have affected growth.

Thinning

A staple of responsible forestry, thinning is the practice of periodically removing a proportion of trees from a forest to reduce competition and provide the healthiest, most valuable trees with greater access to water, sunlight and nutrients. As well as opening up more resources for the remaining trees, this process also provides feedstock for the biomass and paper industries.

Rotation

In managed forests, foresters keep a range of different age trees to ensure a constant flow of healthy and mature wood. Rotation is the term for the number of years required between new planting (typically of seedlings) and final harvesting. In the US south rotations of plantation pine are commonly about 25 years, and 45 years for naturally regenerated pine, while in the UK this is closer to 60. For the same species in even more northerly Finland rotations are typically between 80 and 90 years.

Snedding

Coming from the Scandinavian word snäddare, meaning smooth log, snedding is the process of stripping shoots and branches from a branch or felled tree. Known as limbing in US, snedding is carried out with by chainsaws or more heavy-duty harvesters and stroke delimbers.

Mensuration

How to you measure the total wood of a forest? Mensuration, that’s how. Mensuration is a form of mathematics that allows foresters to measure the volume of standing or felled timber. It is an important tool in not only the quantifying of how much product there is to sell, but in monitoring and managing the health and growth of a forest.

Active management of forests increases growth and carbon storage

28 July 2017

Sustainable bioenergy

A study on the historical trends in the forest industry of the US South, carried out by supply chain consultancy Forest2Market, and commissioned by Drax Group, the National Alliance of Forest Owners and the U.S. Endowment for Forestry and Communities, found that over the last 60 years, as demand for forestry products has increased, the productivity of the area’s forests has increased too. In short, the more we’ve come to use them, the more forests have grown.

A forest is not like a mine – there is not a finite amount of wood in the ground that disappears when it is extracted, never to return. Forests are a renewable resource that can be replanted, improved, and harvested for as long as the land is managed responsibly.

What’s more, landowners have a strong financial incentive to not only maintain their holdings but to improve their productivity – after all, the more of something you have, the more of it you have to sell. It is an economic incentive that works.

Six decades of growth

The Forest2Market report found that increased demand for wood is statistically correlated with more annual tree growth, more wood volume available in the forest, and more timberland.

For example, between 1953 and 2015, tree harvests increased by 57%, largely driven by US economic growth and increased construction. Over the same period, annual wood growth increased by 112%, and inventory increased by 108%. In total, annual growth exceeded annual removals by 38% on average.

Annual forest growth in the US South increased from 193 million cubic metres in 1953 to 408 million cubic metres in 2015. Inventory increased from 4 billion to 8.4 billion cubic metres.

The forest products industry funded private-public research projects to enhance the quality and performance of seedlings and forest management practices to ensure a stable supply of wood. Because of these efforts, landowners saw the value of active management techniques, changing their approach to site preparation, fertilization, weed control, and thinning, and the use of improved planting stock. Healthy demand made it easy for landowners to take a long-term view, investing in more expensive management practices up front for greater returns in the future. And the results were extraordinary: seedlings established in the last 20 years have helped plantations to become nearly four times as productive as they were 50 years ago.

A changing market

Markets for wood have changed over the last two decades, precipitated by decreased demand for writing paper and newsprint, increased demand for absorbent hygiene products and containerboard and increased demand for biomass. These changes in demand have not impacted the way that landowners manage timberland, however. As sawtimber (the largest trees in the forest) remains the most valuable timber crop, it also remains the crop the landowners want to grow. Pulpwood is harvested from the forest only when the forest is being thinned to create optimal conditions for growing sawtimber or when sawtimber is harvested and the forest is being cleared for replanting.

Pellet production has expanded rapidly in the US South, though its overall footprint is still small in comparison to more traditional forest product industries.

In some local wood basins, however, like the one surrounding Bastrop, Louisiana (the location of one of Drax’s US production facilities), the use of biomass to create pellets has filled a gap left by the closure of an 80-year old paper mill. Drax’s decision to locate in this area is integral to supporting forest industry jobs and landowners who carefully consider local demand when deciding whether to continue growing trees.

According to Tracy Leslie, Director of Forest2Market’s biomaterials and sustainability practice, “As history has shown, forests in the US South have benefitted from increased demand for all types of wood. The rise of the pulp and paper industry did not detract from landowner objectives to maximize production of higher value sawtimber nor did it result in a shift in focus to growing only pulpwood. This new demand did, however, provide landowners with important interim and supplemental sources of income. Forest2Market’s research shows that an increase in demand for pellets will have the same effect, incentivizing landowners to grow and re-grow forests, increasing both forest inventory and carbon storage.”

The real threat to forests

Not only does demand for forest products increase the productivity and carbon storage of forests and provide an incentive for landowners to continue growing trees, but it also helps counter factors that irrevocably destroy this natural resource. The real threat to forests in the US is not demand for wood, but urbanisation. Nearly half of all US forestland that converted to another use between 1982 and 2012 was cleared for urban development.

Commercial forestry protects forested lands from development; between 1989 and 1999, just 1% of managed pine plantations in the US South were cleared for non-forest development compared to 3% of naturally-regenerated forest types.

Urbanisation, not the forest products industry, places the most pressure on forests in the US South. Forest2Market’s findings demonstrate that demand associated with healthy timber markets promotes the productivity of forests and mitigates forest loss by encouraging landowners to continue to grow, harvest, and regenerate trees.

Read the full report: Historical Perspective on the Relationship between Demand and Forest Productivity in the US South. An At A Glance version plus an Executive Summary are also available as a separate documents.

 

What is a working forest?

1 June 2017

Sustainable bioenergy
An illustration of a working forest

For centuries, civilizations have relied on forests and forest products. Forests provided fuel, food and construction materials, and there were plenty of them.

But when, in 18th century Europe, the needs of growing industrialisation sent development into overdrive, a problem arose: forests were struggling to meet demand.

In Germany, the problem was acute. The growing steel industry had increased demand for wood to power its smelters and for wood used in mining operations. Large areas of forestland were stripped to meet industry’s needs and overall supply was quickly decreasing.

No one was more acutely aware of the challenge than Hans Carl von Carlowitz, who at the time was the head of the Saxon mining administration.

So, in 1713 he published ‘Silvicultura Oeconomica’, a book which advocated the conservation and management of German forests so they could provide for industries in the long term. Although he drew on existing knowledge from around Europe, it was the first time an important term was used: Nachhaltigkeit, the German word for sustainability.

Carlowitz explained this new term: “Conservation and growing of wood is to be undertaken in order to have a continuing, stable and sustained use, as this is an indispensable cause, without which the country in its essence cannot remain.”

It was arguably the start of the scientific approach to forestry, and although our needs of forests have changed (as have the words we use to describe them – working forest, plantation forest and managed forest all refer to largely the same thing), that same principle is at the heart of how a modern working forest functions: to ensure what exists and is useful today will still be there tomorrow.

This approach relies on responsible forest management, which sets out a few key principles on how a forest should be managed to sustain its life.

Providing room to breathe

Working forests are commonly managed to produced sawlogs – high value wood that can be sawn to make timber for construction or furniture. For a forester to optimise the quality and quantity of sawlogs, regular thinning is required. Thinning is the process of periodically felling a proportion of the forest to aid its overall health and vigour. This means there are fewer trees fighting for the same resources (water, sunshine, soil). More than that, thinning can promote diversity by providing more light and space for other flora.

Thinning can occur several times in a forest’s cycle. It can be used to increase the size and quality of the remaining trees and also to encourage new seedlings to establish in place of the harvested trees when managing for continuous forest cover.

Nothing should be wasted

The roundwood produced by thinning is often too small to be sold as sawlogs, but that doesn’t mean it’s worthless. It can be sold to the pulp industry to make paper, or for particleboard or to the biomass industry to make compressed wood pellets, which can be used to fuel power generation – as is done at Drax Power Station. These industries also provide a market for the lower grade roundwood removed when the more mature trees are finally harvested.

In areas where there was no robust market for this low grade wood, it would often be left on site and become a fire risk or a haven for pest and disease attack. Too much low grade material left on site can also inhibit the regrowth of the next tree crop. So markets for this material are important for the health of the forest and the value of the land to the forest owner. Also in the Baltic countries markets for pulpwood are limited and the energy sector provides a valuable opportunity to clear the site for replanting and provide additional revenue to the forest owner.

This process of utilising all parts of the forest is essential for a healthy working forest. On the one hand, the revenue can cover the cost of thinning. This husbandry enhances the quality of the final tree crop and ensures that money is available to invest in future planting and regeneration, ensuring the forest area is consistently maintained and improved.

The carbon benefits of a working forest

Rather than diminishing it, actively managing a forest helps its ability to sequester – or absorb and store – more carbon.

Carbon sequestration is directly related to the growth rate of a tree – a young, growing tree absorbs more carbon dioxide (CO2) from the atmosphere than an older one. Older trees will have more carbon stored (after a ‘childhood’ spent absorbing it), but if these are not harvested they are more susceptible to fire damage, pests and diseases and their carbon absorption plateaus.

In an actively managed forest, older trees ready for sawlog production can be harvested and replaced with vigorously growing young trees and in the process maximise the CO2 absorption potential of the forest.

The by-products of this process – the low grade wood and thinnings – can be used for the pulp and biomass industry, which both aids the health of the remaining forest, and provides revenue for the forester to invest in the long term life of his or her forest.

Three centuries of sustainability

In the 300 years since Carlowitz published his book on sustainability a lot has changed. And while it’s unlikely he foresaw forests providing fuel for renewable electricity and renewable heat, the approach remains as relevant.

What is a working forest? It is one that is as productive and healthy tomorrow as it is today. That we’re using the same resource today as we were 300 years ago is evidence to suggest it’s a practice that works.

How space tech helps forests

20 April 2017

Sustainable bioenergy
Satellite view of the Earth's forests

Can you count the number of trees in the world? Accurately, no – there are just too many, spread out over too vast an area. But if we could, what would we gain? For one, we would get a clearer picture of what’s happening in our planet’s forests.

They’re a hugely important part of our lives – not only for the resource they provide, but for their role in absorbing carbon dioxide (CO2). So properly understanding their scale and what is happening to them – whether increasing or decreasing – and designing strategies to manage this change is hugely important.

The trouble is, they exist on such a vast scale that we traditionally haven’t been able to accurately monitor them en masse. Thanks to space technologies, that’s changing.

A working forest

The view from up there

As far back as World War II, aerial imaging was being used to monitor the environment. In addition to using regular film cameras mounted to aeroplanes to follow troops on the ground, infrared film was used to identify green vegetation and distinguish it from camouflage nets.

As satellite and remote sensing technology developed through the 20th century, so too did our understanding of our planet. Satellites were used to map the weather, monitor the sea, and to create topological maps of the earth, but they weren’t used to track the Earth’s forests in any real detail.

But in 2021 the European Space Agency (ESA) will launch Biomass, a satellite that will map the world’s forests in unprecedented detail using the first ever P-band radar to be placed in Earth orbit. This synthetic aperture radar penetrates the forest canopy to capture data on the density of tree trunks and branches. It won’t just be able to track how much land a forest covers, but how much wood exists in it. In short, the Biomass will be able to ‘weigh’ the world’s forests.

Over the course of its five-year mission, it will produce 3D maps every six months, giving scientists data on forest density across eight growth cycles.

The satellite is part of ESA’s Earth Explorers programme, which operates a number of satellites using innovative sensor technology to answer environmental questions. And it’s not the only entity carrying out research of this sort.

California-based firm Planet has 149 micro-satellites measuring just 10cm x 30cm in orbit around the Earth, each of which beams back around three terabytes of data every day. To put it another way, each satellite photographs about 2.5 million square kilometres of the Earth’s surface on a daily basis.

The aim of capturing this information is to provide organisations with data to help them answer the question: what is changing on Earth? When it comes to forests, this includes identifying things like illegal logging and forest fires, but the overall aim is to create a searchable, expansive view of the world that enables people to generate useful insights.

Rocket flying over the earth

Keeping the world green

All this data is not only vital for developing our understanding of how the world is changing, it is vital for the development of responsible, sustainable forestry practices.

From 2005 to 2015, the UN rolled out the REDD programme (Reducing Emissions from Deforestation and forest Degradation), which, among other functions, allows countries to earn the right to offset CO2 emissions – for example through forestry management practices. Sophisticated satellite measurement techniques not only let governments know the rate of deforestation or afforestation in their respective countries, it can also help them monitor, highlight and encourage responsible forestry.

Satellite technology is increasingly growing the level of visibility we have of our planet. But more than just a clearer view on what is happening, it allows us the opportunity to see why and how it is happening. And it’s with this information that real differences in our future can be made.

Forests are more powerful than you think – here’s why

21 March 2017

Sustainable bioenergy

Almost one third of the earth’s land mass is covered by forests. That’s an area of around 4 billion hectares, or roughly four times the size of the US.

In addition to being a prominent feature across the global landscape, forests also play a significant role in how we live. They make the air cleaner in cities and absorb carbon from the atmosphere. They provide bio-diversity and habits for wildlife. They also provide essential forest products such as paper, building materials and wood pellets for energy.

To celebrate the UN’s International Day of Forests, we’re looking at some of the reasons why forests and wood fuel are more powerful than you might think.

They’re a major source of renewable energyFamily at home using renewable energy.

Nearly half of the world’s renewable energy comes from forests in the form of wood fuel. Roughly 2.4 billion people around the world use it for things like cooking, heating and generating electricity. In fact, about 50% of the total global wood production is currently used for these purposes.

However, it is critical that this resource is managed sustainably and responsibly. One of the key aims of the International Day of Forests is to encourage people to utilise their local forest resources sustainably to ensure it endures for future generations.

They can revitalise economiesA truck unloading.

Because wood fuel is such a widely used energy source, it also supports a healthy, vibrant industry. Roughly 900 million people work in the wood energy sector globally.

More than that, rural economies built on wood energy can be revitalised by modernisation, which can then stimulate local business. Investment can help finance better forest management, which in turn leads to forest growth, improvements in sustainability standards and in some cases, increased employment.

They can help mitigate climate changeYoung sapling forest.

The world’s forests have an energy content about 10 times that of the global annual primary energy consumption, which makes it a hugely useful resource in helping meet energy demand in a sustainable and renewable way.

When wood is used as fuel it releases carbon dioxide (CO2). However, if this fuel is drawn from a responsibly managed forest or sustainable system of growing forests this carbon is offset by new tree plantings. The only emissions produced therefore are the ones involved in transporting the wood itself. The US Food and Agriculture Organization predict that by 2030 forestry mitigation with the help of carbon pricing could contribute to reductions of 0.2 to 13.8 Gigatonnes (Gt) CO2 a year.

The biomass carbon story

Matthew Rivers, Director of Corporate Affairs, Drax, Group Special Advisor

23 February 2017

Sustainable bioenergy

There is an important difference between carbon dioxide (CO2) emitted from coal (and other fossil fuels) and CO2 emitted from renewable sources. Both do emit CO2 when burnt, but in climate change terms the impact of that CO2 is very different.

To understand this difference, it helps to think small and scale up. It helps to think of your own back garden.

One tree, every year for 30 years

Imagine you are lucky enough to have a garden with space for 30 trees. Three decades ago you decided to plant one tree per year, every year. In this example, each tree grows to maturity over thirty years so today you find yourself with a thriving copse with 30 trees at different stages of growth, ranging from one year to 30 years old.

At 30 years of age, the oldest has now reached maturity and you cut it down – in the spring, of course, before the sap rises – and leave the logs to dry over the summer. You plant a new seedling in its place. Through the summer and autumn the 29 established trees and the new seedling you planted continue to grow, absorbing carbon from the atmosphere to do so.

Winter comes and when it turns cold and dark you burn the seasoned wood to keep warm. Burning it will indeed emit carbon to the atmosphere. However, by end of the winter, the other 29 trees, plus the sapling you planted, will be at exactly the same stage of growth as the previous spring; contain the same amount of wood and hence the same amount of carbon.

As long as you fell and replant one tree every year on a 30-year cycle the atmosphere will see no extra CO2 and you’ll have used the energy captured by their growth to warm your home. Harvesting only what is grown is the essence of sustainable forest management.

If you didn’t have your seasoned, self-supplied wood to burn you might have been forced to burn coal or use more gas to heat your home. Over the course of the same winter these fuels would have emitted carbon to the atmosphere which endlessly accumulates – causing climate change.

Not only does your tree husbandry provide you with an endlessly renewable supply of fuel but you also might enjoy other benefits such as the shelter your trees provide and the diversity of wildlife they attract.

Mushroom - Brown cap boletus in autumn

No added carbon

This is a simplified example, but the principles hold true whether your forest contains 30 trees or 300 million – the important point is that with these renewable carbon emissions, provided you take out less wood than is growing and you at least replace the trees you take out, you do not add new carbon to the atmosphere. That is not true with fossil fuels.

It is true that you could have chosen not to have trees. You could instead build a wind turbine or install solar panels on your land. That would be a perfectly reasonable choice but you’ll still need to use the coal at night when the sun doesn’t shine or when the wind isn’t blowing. Worst of all you don’t get all the other benefits of a thriving forest – its seasonal beauty and the habitat that’s maintained for wildlife.

Of course, the wood Drax needs doesn’t grow in our ‘garden’. We bring it many miles from areas where there are large sustainably managed forests and we carefully account for the carbon emissions in the harvesting, processing and transporting the fuel to Drax. That’s why we ‘only’ achieve more than 80% carbon savings compared to coal.

5 things you never knew about forests

6 October 2016

Sustainable bioenergy
Background. Fir tree branch with dew drops on a blurred background of sunlight

Forests and the products we derive from them are one of the most ubiquitous aspects of human civilisation. Despite the rapid pace of modern life, that isn’t changing.

Forest still covers 30% of the world’s land and in the UK more than an estimated 55 million m3 of wood was used in 2015 – either directly through furniture, books or hygiene paper, or indirectly, in infrastructure like fences, railways or through biomass electricity generation.

Behind all this lies the forest and the industry surrounding it. But how much do you really know about forests?

In some regions forests are increasing

Mention forestry, and there are plenty of people who make the jump to the activities of unscrupulous developers and deforestation. But while forest land is declining worldwide (in fact, we’ve lost 129 million hectares since 1990), the good news is the rate of decline is dropping sharply, down 50% across the same period.

A lot of this is thanks to growing environmental awareness, responsible forestry management and reforestation around the world. 10,000 hectares of new woodland was created in the UK in 2014 and in the USA, where a third of all land is forested, forestland has been consistently increasing over the last 25 years. There’s been an increase of roughly 7.6 million hectares between 1990 and 2015.

Vigorously growing forests absorb CO2 faster

It’s well known that trees are “the lungs of the earth”, but not all trees or ages are equally effective at absorbing the greenhouse gas CO2. A growing, younger forest is a better sink for carbon dioxide than a forest that is mature and stable. This has implications for the way these resources are used – notably when it comes to the sourcing of material for compressed wood pellets.

Whereas coal releases carbon that has been trapped underground for millions of years, wood releases carbon captured within its lifetime, making it a very low carbon fuel once manufacturing and transportation are factored in. The technique is to harvest trees when they have stopped growing at a fast rate, use the wood for forest products such as timber, pulpwood or compressed wood pellets for energy and replant the area with new, high growth potential trees. The result is a forest with a steady stream of CO2-hungry young trees and a steady stream of renewable raw material.

Forests can stop floods

 A study led by the Universities of Birmingham and Southampton and funded by the Environment Agency, found that forests in Europe play an important role in mitigating the effects of heavy rain.

Thanks to the buffering abilities of the forest canopy and the enormous water absorption capacity of woods and forests, they can slow the flow of a sudden downpour of rain overfilling nearby streams or rivers. This water will eventually be released but slowing its movement mitigates flash flooding.

Different parts of the forest have different uses

The primary commercial product from forests is not a hard one to guess: wood. But there’s more to it than that. For construction timber, the lower, thicker parts of a tree’s trunk are used. Smaller parts of the trunk are used as pulpwood which can be used to make paper, panels or for energy. Residues from the wood processing industry such as sawdust can also be used for compressed wood pellets.

With the rise of the internet, smartphones and e-readers the paper market has been shrinking. Manufacture of high-density wood pellets helps replace demand for wood once used by the paper market, as pellets can be made using low-grade wood, thinnings and residues not used in construction or furniture.

Trees talk to each other

Until recently it was thought that trees perform most of their biological functions in isolation from each other. But biologists have learned in recent years that in fact they communicate and help each other.

Under the forest floor, trees’ roots are linked by bright white and yellow fungal threads, called mycelium. In a forest, these threads act as a kind of network, linking trees to one another.

These links enable trees to share nutrients, carbon and water. Some species of tree also increase nitrogen uptake in the soil and help to improve the conditions in which other species grow. In fact, research by the University of British Columbia, indicates that certain large, older trees that rise above the forest act as ‘mother trees’ which actively help to ‘manage’ the resources for the other trees in the forest.

Based on their findings, it seems trees not only talk to each other, but help each other grow too.