Invasive disease could nearly wipe out the UK’s ash trees this century

By Chrissy Sexton
Professor Matthew Evans from the University of Hong Kong created a computer model to estimate how ash dieback disease may affect the UK’s 125 million ash trees.

Human-induced changes to the environment are increasing the rate at which pests and diseases are introduced, which is severely threatening to native species. Long-lived species that reproduce slowly, such as forest trees, are particularly susceptible to new pathogens.

It is estimated that in 2015, 100 million hectares of forest were affected by pests and diseases around the globe. However, the subsequent impacts to any given forest ecosystem cannot be detected for years, so experts use computer models to predict future outcomes.

In a recent study, Professor Matthew Evans from the University of Hong Kong created a computer model to estimate how ash dieback (ADB) disease may affect the UK’s 125 million ash trees.

ADB disease, which is caused by a fungus native to East Asia, was introduced to the UK seven years ago. This incurable infection leaves diamond-shaped scars on the bark and causes the leaves to fall off of the trees.

About one in every 100 ash trees is able to resist the fungus and avoid infection. This is likely due to a genetic advantage which allows the trees to shed their leaves earlier to prevent the fungus from establishing itself.

Professor Evans found that at the current level of resistance, 95 percent of the UK’s ash trees could be wiped out by the end of the century. He determined that breeding more ash trees with resistance will prevent millions of deaths.

Source: Invasive disease could nearly wipe out the UK’s ash trees this century – Earth.com, 2019-08-29

What it feels like … to work with trees

By Susan Swarbrick
Ben Quarcoo, operations forester for Forestry and Land Scotland

I HAVE worked in forestry for 14 years and cover the central belt stretching all the way from South Lanarkshire up towards Stirling.

My area includes Whitelee Forest at Eaglesham Moor, the Kilpatrick Hills, Lennox Forest, the Campsie Fells and into the Carron Valley. Most of the land isn’t within high population areas, but there are some woods in or around towns or cities such as Cardowan Moss in Easterhouse, Drumchapel Woods and Greenoakhill near Glasgow.

I was born and grew up in Ghana. It is in the tropical belt and the persistent heavy downpours – there is only a short dry season – help to create broad-ranging diversity. The trees grow almost year-round, but here in Scotland we have two distinct growing seasons: spring and summer.

Before moving to the UK, I worked for the University of Science and Technology in Kumasi where I researched forest management, soil civilisation, tree establishment and water catchment quality. I completed a master’s degree in environmental forestry management at Bangor University in Wales and joined Forestry and Land Scotland, formerly Forest Enterprise Scotland.

My role involves everything from ensuring ground conditions are well prepared to managing drainage. There are utility services across the forest estate with gas pipelines, underground cables, water supplies and overhead powerlines all criss-crossing, so you need to know what you are doing and where you are digging. We construct firebreaks – clearing a strip of open space at least five metres wide – so that if wildfire breaks out it can’t quickly ravage the forest.

Source: What it feels like … to work with trees – HeraldScotland, 2019-05-14

First tree planted in ‘Northern Forest’

By Thomas Barrett
The first tree has been planted in a new ‘Northern Forest’ that will connect five community forests across the north of England.

Over the next 25 years, the Woodland Trust and Community Forest Trust are aiming to plant more than 50 million trees from Liverpool to Hull, connecting the Mersey Forest, Manchester City of Trees, South Yorkshire Community Forest, the Leeds White Rose Forest and the HEYwoods Project.

Spanning more than 120 miles, the Northern Forest will help boost habitats for woodland birds and bats and protect iconic species such as the red squirrel, alongside providing a tranquil space to be enjoyed by millions of people living in the area.

Forestry minister David Rutley joined the Woodland Trust, Community Forest Trust, government Tree Champion Sir William Worsley and students from St Andrew’s CE Primary School in Radcliffe, where they began the planting of 200 saplings as part of the government’s £5.7m investment.

Tree planting rates are dramatically low with tree planting in 2016 being only 700 hectares against the Government’s target of 5,000 hectares a year.

Woodland cover across the north is at just 7.6%, below the UK average of 13% and far below the EU average of 44%.

Forestry Minister David Rutley said: ‘It is a privilege to be here to see the Northern Forest take root, and to plant the first of many government-funded trees which will contribute to what will one day be a great forest.

Source: First tree planted in ‘Northern Forest’ – Environment Journal, 2018-12-05

City forests store rainforest-levels of carbon, study finds

By Morgan Erickson-Davis
Nations are hurrying to reduce greenhouse gas emissions and slow global warming, and one way they’re going about this is by encouraging the protection of forests. Trees trap carbon in their biomass and in the soil, and it’s hoped that keeping them in the ground will keep their carbon out of the atmosphere.

Climate-focused forest conservation policies and programs tend to be focused on rainforests. Covering vast areas, rainforests have earned the moniker “lungs of the planet” for their ability to sequester carbon dioxide while producing oxygen.

But pound for pound, other types of forest give rainforests a run for their money. A hectare of mangrove, for instance, can store four times more carbon than can a hectare of rainforest. And now, new research shows that even temperate forests in cities may be able to sequester nearly as much carbon as a similarly sized area of rainforest.

The study was conducted by a team of scientists from University College London, who mapped the carbon stores of areas of tree cover in the London Borough of Camden. Their results were published recently in the journal Carbon Balance and Management.

The team used remotely sensed LiDAR (which stands for “Light Detection and Ranging”) data that provided high-resolution information about tree structure. Armed with specific numbers on the dimensions and extent of Camden’s aboveground biomass (i.e., the parts of trees that aren’t underground), the researchers were able to estimate how much carbon is contained in each pocket of urban forest.

“Urban trees are a vital resource for our cities that people walk past every day,” said lead author Phil Wilkes. “We were able to map the size and shape of every tree in Camden, from forests in large parks to individual trees in back gardens. This not only allows us to measure how much carbon is stored in these trees but also assess other important services they provide such as habitat for birds and insects.”

Their results indicate Camden’s trees contain more carbon than estimated by previous studies. And while, as a whole, the borough’s median carbon density is on the low side when compared to many natural ecosystems – roughly equivalent to subtropical steppe – its urban forests are carbon storage powerhouses. The maximum value they uncovered was in a large, 320-hectare park called Hampstead Heath. There, carbon density approaches that of tropical rainforest.

Source: City forests store rainforest-levels of carbon, study finds – Mongabay, 2018-06-29

‘There is no oak left’: are Britain’s trees disappearing?

By Fiona Harvey and Sandra Laville
The first national ‘tree champion’ is charged with reversing the fortunes of the country’s woodlands and beleaguered urban trees.

England is running out of oak. The last of the trees planted by the Victorians are now being harvested, and in the intervening century so few have been grown – and fewer still grown in the right conditions for making timber – that imports, mostly from the US and Europe, are the only answer.

“We are now using the oaks our ancestors planted, and there has been no oak coming up to replace it,” says Mike Tustin, chartered forester at John Clegg and Co, the woodland arm of estate agents Strutt and Parker. “There is no oak left in England. There just is no more.”

Earlier this month, the government appointed the first “tree champion”, who will spearhead its plans to grow 11 million new trees, and conserve existing forests and urban trees. Sir William Worsley, currently chairman of the National Forest Company, has been given the task of overseeing trees in England and Wales, including England’s iconic national tree, and ensuring that trees are not felled unnecessarily. Worsley is a former chief of the Country Land and Business Association, which represents landowners and rural businesses.

Source: ‘There is no oak left’: are Britain’s trees disappearing? – The Guardian, 2018-06-27

Use of high carbon North American woody biomass in UK electricity generation

In July 2014, DECC published the Bioenergy Emissions and Counterfactual (BEAC) model, which investigates the impact on carbon emissions of various ways of sourcing woody biomass from North America to produce electricity in the UK. The calculator estimates the greenhouse gas intensity by taking into account the counterfactual land use for the scenario (i.e. what the land or wood would have been used for if it was not used for bioenergy). BEAC shows that some scenarios could save considerable carbon emissions compared to fossil fuels, whilst if others occurred they could cause emissions greater than fossil fuels. BEAC did not assess the likelihood of particular scenarios so, in spring 2015, DECC commissioned an independent study (led by Ricardo-AEA and including North American forestry experts) to assess the likelihood that the most carbon intensive BEAC scenarios are happening now or if they might happen in the future, and what might drive or constrain them.

The study found that the majority of the high carbon scenarios identified in the BEAC report are unlikely to occur, but there are four that may be already happening or may happen in the future, although their scale is likely to be limited or uncertain.

The research identified economic decision making as driving forestry practices: the main value of a tree is in sawtimber, not biomass for wood pellet production. It is therefore unlikely that demand for biomass would cause foresters to change behaviour to harvest sooner than they intended, or to switch to supplying wood for bioenergy, but they may increase the intensity with which they manage forests.

Source: Use of high carbon North American woody biomass in UK electricity generation – GOV.UK, 2017-03-08

Britain’s biomass generation carries big emissions risk, report claims

The UK’s renewable energy industry has hit back at new economic analysis which finds that biomass power could be causing more carbon pollution than burning coal or natural gas, claiming it is “distorting the facts”.

A study released today (17 October) by US-based environmental organisation the Natural Resources Defense Council (NRDC) examines the ‘full system costs’ of wind and solar energy relative to biomass for replacing coal and meeting the UK’s clean energy targets for the period 2020-25.

Considering the latest technology costs; the cost of ensuring reliability of supply, and carbon costs, the NRDC concludes that wind and solar power are likely to be less expensive than burning trees for biomass, and that many forms of biomass – such as that from forests – have been producing higher carbon emissions than coal and natural gas for decades.

However, the report has been discredited by the Renewable Energy Association (REA), which in 2013 founded the Wood Heat Association to support the modern wood heat & biomass generation.

The REA’s head of policy and external affairs James Court told edie: “It is a shame that yet again, misleading reports are fundamentally distorting the facts with a misunderstanding of how the biomass industry works. The REA and wider industry are always eager to engage with any report into the carbon savings that biomass can achieve, something this organisation did not try to obtain.”

Source: Britain’s biomass generation carries big emissions risk, report claims

Research Note explores issues of converting conifers to native woodland

The Forestry Commission has issued a Research Note which explores the benefits and drawbacks of converting non-native planted woodlands to native woodlands.

The note also evaluates woodland owners’ and managers’ attitudes towards, and experiences of, conversion.

Increasing the area of native woodlands, including the conversion of non-native conifer woodland to native woodland, where appropriate, is an aim of the UK Forestry Standard Guidelines on Biodiversity.

The Research Note reports that attitudes and experiences vary according to owners’ objectives. Managers whose primary objective is conservation are prepared to invest time and resources converting their woodlands. However, those whose primary objective is timber production are reluctant to pay for conversion because they can be concerned that it will reduce productivity, especially where competition, herbivory and biosecurity threats to native tree species are a potential issue.

Read the full report

Source: Research Note explores issues of converting conifers to native woodland – Horticulture Week