Tag: forests

Longleaf Pine: how wood product markets help to conserve a protected species

22 September 2017

Sustainable bioenergy

Longleaf pine forests were once a dominant ecosystem across the Southern US’ Gulf and Atlantic states, spanning from the east coast in Virginia as far west as Texas. However, centuries of overuse and conversion to agriculture and to faster growing pine species mean today less than 5% of the estimated 90 million acres remain.

Restoration of the longleaf pine savanna is now underway and the careful management of both public and private forests is key to preserving this ecosystem. Wood product and biomass markets play an important role in this, ensuring there is an economic incentive for landowners to plant high-value longleaf pines and manage them in a way that promotes conservation.

An ecosystem shaped by fire

The ancient abundance of longleaf pines across the southern US owes to their highly pyrophytic nature, meaning they are resistant to fire. This allowed the trees to survive both the naturally occurring forest fires from summer thunderstorms and those started as land management by native Americans. These regular fires help give the longleaf savanna its distinctive features, with a limited canopy providing ample sunlight and allowing grasses and herbs to grow in the nitrogen-rich soil.

As colonial settlements expanded across North America, the long straight timber offered by the pines, as well as the resin and turpentine, made these forests a valuable resource. Longleaf pine ecosystems reached a depleted state.

The restoration push

Today, America’s Longleaf Restoration Initiative (ALRI) is taking strides to restore the species. The collaborative effort between public and private sector partners has set a 15-year goal of increasing longleaf acreage from 3.4 million to 8.0 million acres by 2025. 

These ecosystems are currently home to an estimated 900 endemic plants and 29 federally listed species including the red-cockaded woodpecker, gopher tortoise and indigo snake.

Restoring the environment in which the flora and fauna can flourish is not as simple as planting large numbers of longleaf pine trees.

“Conservation efforts must focus on not only the planting of the pine, but also the restoration, development, and maintenance of the pine savanna ecosystem,” says Kyla Cheynet, a forest ecologist at Drax Biomass. “This system requires predictable disturbance to maintain the open canopy and rich herbaceous vegetation.”

The role of the wood product market

These disturbances include prescribed fires and the careful harvesting of trees to ensure the landscape maintains its open canopy that allows plenty of sunlight to reach the grasses and other vegetation along the forest floor.

The ALRI’s 2016 report highlighted the importance of thinning and prescribed fires in conserving longleaf savanna. It found that while new planting of longleaf pines declined slightly (8%) from 2015, the wildlife quality, plant diversity and overall health of forests improved by removing competing tree species and allowing more sunlight to enter the forest.

Harvesting or thinning longleaf pine forests provides a small percentage of the fibre used to manufacture compressed wood pellets used at Drax Power Station, but these markets help to incentivise responsible forest management and offer a source of profit for landowners. These revenue-generating practices are crucial to ensuring the continued survival of longleaf pine forests by preventing them from being converted to agricultural land or lost to development.

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.

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.