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Forests and climate change - Questions and Answers
What is climate change?
What are greenhouse gases (GHGs)?
Which are the most potent GHGs?
What is the difference between global warming and climate change?
What sorts of activities might foresters have to review in the light of climate change?
What role can forestry play?
Carbon captureHow much carbon do UK forests absorb?
How much total carbon is locked up in UK forests?
How much carbon does the UK emit?
Carbon offsettingWhat is the Forestry Commission’s position on tree planting for carbon offsetting?
How effective is carbon-offset tree planting?
How many trees would we need plant to offset our car travel, for instance?
What role is there for carbon markets, if any?
Will the Forestry Commission take carbon-market payments for planting trees?
Using woodWhy do you say it's a good thing to burn wood as fuel? Surely wood burned equals carbon emitted?
If it takes years for the new trees to absorb the carbon, but only days for the burned trees to emit it, surely that means a nett increase of carbon in the atmosphere?
You advocate using more wood generally, but how does that help to mitigate climate change?
UK action Should governments facilitate forest planting on a large scale to combat climate change?
What is the British experience?
What action can we take in the UK?
International actionIf the biggest problem is tropical deforestation, why is the UK involved?
What’s the Forestry Commission’s role in this?
Why haven’t international processes succeeded at this?
Isn’t the deforestation problem just too big to solve?
What are the circumstances that enable a country to reforest or expand its forest area?
AdaptationWhat does "planning to adapt to climate change" mean in practice?
What about other actions to combat climate change?
Climate change is the change in global weather patterns, including temperature and storms. More recently the term climate change has been linked to the activities of humans. Climate change is partly influenced by greenhouse gases. Top
The Earth's atmosphere consists almost entirely of nitrogen (about 78%) and oxygen (about 21%). While both of these gases play important roles in the vast number of processes that support life on Earth, they play almost no direct role in regulating the climate. This is carried out by some of the trace gases in the remaining 1% of the atmosphere which occur in relatively small amounts: Carbon dioxide, methane, Nitrous oxide, ozone, water vapour and the halocarbons. Although the proportion of the trace gases in the atmosphere appears relatively small, they can still have a big impact on climate change, and they are mainly caused by human activities. Top
There are two factors that determine how much impact a particular GHG has. First there is the Global Warming Factor (GWF) – its ability to absorb and then release heat. Second is how much of the gas there is in the atmosphere. Although carbon dioxide is a weaker GHG than the others there is much more of it in the atmosphere, so it has the greatest impact. The concentrations in the atmosphere (shown as parts per billion) are - carbon dioxide 379,000, methane 1,774, Nitrous oxide 319, and halocarbons less than 1. (Source IPCC Fourth Assessment Report Working Group I report Chapter 2) Top
Global warming refers to the increase in the average temperature of the Earth’s atmosphere. Climate change refers to the changes in climate that might accompany the warming of the atmosphere, such as changes in the frequency and intensity of extreme weather and sea level rise. Many people use these expressions interchangeably. However, the word warming may be misleading, as it doesn’t embrace the full range of changes that could result. (Source - UKCIP website.) Top
We hope we're doing most things right already, and that there will be few activities we need to rethink completely. However, there are some areas where we are aware that our knowledge is incomplete, for example, in the carbon effects of soil disturbance caused by forestry activities. Other topics that the assessment group is looking at include the basic decisions that foresters everywhere have to make, such as species choice, site selection, lengths of crop rotation etc, and the effects that the different options might have in relation to climate change. Top
We've identified six key strands of action that we believe will ensure that forestry plays its full role in combating and adapting to climate change. They are:
- protecting and managing the forests we already have;
- reducing deforestation;
- restoring the world's forest cover;
- using wood for energy;
- replacing other materials with wood; and
- planning to adapt to a changing climate.
Top About four million tonnes a year. Top
There are an estimated 150 million tonnes of carbon locked up in UK forests and woodlands. Top
About 150 million tonnes a year, so the entire carbon store in UK forests and woodlands is equal to only 1 year’s emissions, and their “sink” effect – the 4 million tonnes that are absorbed each year - is less than 3 per cent of our annual emissions. Top In general terms, we certainly encourage people to plant more trees, provided they are the right trees in the right places. Their personal reasons for doing so are not for us to judge.
Carbon offsetting schemes are popular, and they're here to stay, so it’s important that they work to robust standards based on sound science. Some of the early schemes have suffered from poor quality and negative reporting, so we've taken the lead in the UK in working to assemble a new code of practice for woodland offsetting schemes. Top
Growing more trees will sequester more carbon in the trees and in the underlying soil, and add to the amount that the UK is allowed to offset in its national greenhouse gas accounting procedures. Every little helps, but it’s important to recognise that we cannot just tree-plant our way out of trouble – we would need to plant a forest twice the size of the UK to offset the UK’s total emissions. Globally, there is an important place for planting new forests or restoring cleared forests in combating climate change.
We also need to remember that the "off-setting" effect of tree planting can only be temporary, because eventually a new forest becomes "carbon-neutral". This happens when the trees reach maturity and start dying and releasing their carbon back into the atmosphere while new trees that replace them sequester the carbon again. So at that point, the forest is no longer offsetting the emissions from anyone's car travel or power station or plane flights; it is only recycling the carbon; balancing out its own emissions.
The long-term climate change benefit of off-set planting is therefore in the establishment of a carbon "sink", or carbon store, locking up carbon that might otherwise be in the atmosphere contributing to climate change. That's why it is very important that we make sure we get the right trees in the right places. If climate change meant that those trees died, for example, because of drought, storms or pests, and were not replaced, then the carbon stored would be released again.
What we certainly do not encourage is that tree planting, or other forms of sequestration, distracts us from the paramount need to reduce our greenhouse gas emissions if we are to prevent climate change catastrophe. Top
As a rough guide it would take half a hectare (1.25 acres) of new woodland to offset the carbon emissions generated by one average car driver over his or her lifetime. However, as explained above, the benefit to the car driver lasts only as long as the woodland is young and growing and, therefore, absorbing more carbon than it is emitting. When the trees start dying, the off-set benefit ceases. Top
Carbon markets can be part of the solution, but not the whole solution. One of the reasons why forests are being lost is because they are under-valued, and carbon markets are one way of giving them a value. Payments for carbon sequestration might be the only way to make forest conservation profitable and feasible in large parts of the world.
Like carbon offsetting schemes, some early carbon trading schemes have been poorly thought out and received negative press, and for people to have confidence in them in the long term it’s important that they, too, operate transparently to robust standards based on sound science. Top
It’s possible. We are already involved in extensive tree planting throughout Great Britain, and we haven’t ruled it out. Top
Provided the wood is grown sustainably, that is, the trees that are harvested for woodfuel are constantly replaced by planting new trees (or allowing them to regenerate), using woodfuel can be "carbon-lean" in terms of the carbon emitted by any fossil fuels used in producing the woodfuel. That's because while they are growing, the new trees "sequester", or absorb, the same amount of carbon into their tissues as the burned trees emit, in a perpetual "carbon-out, carbon-in" cycle. No such cycle exists in the case of fossil fuels. The greatest benefit of woodfuel is therefore gained when we substitute wood for fossil fuel, such as by replacing a gas-fired boiler with a wood-fuelled boiler, rather than simply adding woodfuel to existing fossil fuel use. Top
We need think of it in the context of the carbon cycle of the whole woodland, not simply the part just burned and the part just replanted. Take, for example, a 200-hectare woodland being grown for woodfuel on a 20-year sustainable "rotation". Each year we harvest and burn 10 hectares, and each year we replant 10 hectares. So each year there are always 190 hectares of growing trees sequestering the carbon being released by that year's 10 hectares of woodfuel being burned. That's how the absorption of carbon by the growing trees stays in balance with the emissions of carbon by the burning trees. Top
Like woodfuel, provided the wood is grown in constantly replanted or regenerating forests, its use can be "carbon lean" in terms of the fossil fuels involved. And by deploying wood in long-term uses, such as buildings, we continue to lock up the carbon in it for potentially longer than it would have been locked up had it been left in the trees. That's because the trees would eventually die and release some of their carbon into the atmosphere as they decompose. Meanwhile, the new trees replacing those harvested for timber can sequester yet more carbon back in the forest.
Some of the alternatives to timber are products such as concrete, steel and brick, whose manufacturing processes emit considerably more greenhouse gases than timber. None of these are sustainable, renewable resources but timber is. Top
Deforestation is the second biggest source of greenhouse gas emissions, so, yes, we are encouraging action to reduce deforestation and to start restoring the forest cover we've lost. It's largely a question of where we can do it. In a small, crowded island such as Great Britain there is a limit to the area of new woodland we can plant, although we are continuing to expand our woodland area. And there is not enough land in the UK to plant enough trees to make a significant difference globally, although more tree planting will help to buy us some crucial time to make other changes.
We also always stress that it must be the right trees in the right places - simply planting any trees anywhere could end up doing more harm than good. This could happen, for example, on types of soils whose disturbance could release more carbon than the trees would sequester.
Where we believe the UK can be most effective is as an exemplar, honest broker and source of expertise, helping other countries to learn from our experience of deforestation and reforestation, and helping them to identify and act upon opportunities for woodland expansion and restoration. There are many places in the world that desperately need more trees and forests, not only to combat climate change, but also to provide food, fuel, shelter and timber for their people and livestock, and to aid water, soil and wildlife conservation. Top
Great Britain lost nearly all of its forest cover over thousands of years as our ancestors cleared them for fuel, farmland, development and timber. However, under the Forestry Commission's leadership and successive governments' policies of encouraging reforestation, its woodland area has more than doubled over the past 100 years, from an estimated 5-6 per cent of the land area to nearly 12 per cent now - and it's still increasing. Top
Along with other developed countries, we can try to lead by example, ensuring that we have our own house in order, and we can point to sustainable, flourishing forests as well as modern, developed societies. We must share our knowledge and expertise with those who want it, and we must look at making our forestry and timber-using industries more effective, more efficient and more competitive. We must also maximise the use of sustainably produced wood for things such as renewable energy and materials for construction and packaging. Top
Although deforestation affects mostly tropical regions, it is often closely connected with global issues, such as poverty and world trade. For example, the increasing demand in the "emerging economy" countries for a Western-style diet rich in meat, milk, and cereals, and for biofuels from plants such as oil palm and soya, is driving some of the clearance of forest for cropping and grazing land in other countries. Therefore developed countries such as the UK have a responsibility to help achieve a concerted and co-ordinated approach internationally. The UK also has a great deal of experience in restoration and sustainable forest management that is being sought by others. Although deforestation is a big problem, it is only part of the picture. The forestry sector also has important contributions to make to tackling climate change through sequestering carbon, fuel and product substitution and adaptation. Top
The Forestry Commission and its agency, Forest Research, have assets, knowledge and expertise across a broad range of areas that we can bring to these issues, such as:
- foresters, who are used to looking far into the future. Among our great strengths is our ability to plan for the long term;
- extensive land management experience, so our solutions are practical ones that we know we can help to deliver;
- world-class scientists and a knowledge base that means we don’t start from scratch - we are building on many years of research and experience in our specialist fields; and
- we think we are trusted and respected by the international forestry community. We can see how we can bring all this to the problem to act as advisor, facilitator and honest broker.
We already work with the international forestry community, and we can see how we can bring all of this to the problem to act as adviser, facilitator and honest broker. We are also restructuring Forest Research to include a Centre for Forestry & Climate Change to bring a stronger research focus to bear on climate change. Top
Land use is a very complex issue which in many countries impacts greatly on national economies and the survival of whole communities and individuals. Getting international consensus on changing that will always be difficult, even with the driver of climate change. Top
No, there is every reason to be optimistic. For example, many countries, mostly in the temperate latitudes (the UK included), are already increasing their areas of forest after centuries of deforestation. One of the keys might be to identify the social, economic and environmental circumstances that have enabled those countries to reverse the deforestation process in the expectation that others can use the experiences (good and bad) to inform their own solutions to the problem. Top
It’s probably fair to say that prosperity is among the key factors. It is probably no accident that the world’s richest countries, by and large, are the ones that have expanding forests, and those with large proportions of poor people and restricted trading opportunities are among the countries losing forest. Top
Some degree of climate change is now inevitable; in fact it is already happening, so we need to prepare for the changes ahead. For foresters, it means taking into account the kind of climate we are likely to have when they are planning the forests of the future. For example, foresters in parts of the country that are likely to have less rainfall in the future need to think about planting species that are better adapted to a drier climate, and so on. So we are likely to see the species composition of the woodlands in our landscape gradually changing over time in some areas.
Trees and woodland can also help wider society to adapt to climate change in other ways. For example, well sited trees in towns and cities can significantly help to cool buildings, reducing the need for carbon-emitting air conditioning in places where temperatures are likely to rise as a result of climate change. Another example is that the right type of woodland in the right places can help to manage and ameliorate flooding during episodes of heavy rainfall, and we're working on research projects to identify such opportunities. Top
We've been a leading champion of sustainable forest management globally. At home, we've been instrumental in developing, with the private and voluntary sectors, standards for sustainable forest management, and in encouraging their use. All of the forests in our care in England, Scotland and Wales are independently certified as being sustainably managed.
We are also keen to “green” the rest of our activities, pursuing woodfuel, sustainable building, sustainably produced biofuels, recycling and other means of reducing our environmental footprint, and we have set up a project to take this as far we can. Top
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