forestry and climate change - issues and potential indicators

Forestry and Climate Change - issues and potential indicators

For UNECE/FAO Team of Specialists,

Edinburgh, 21-22 May 2007

Simon Gillam, UK

Simon Gillam for UNECE/FAO ToS May 20072

Forests and climate change

1. Carbon - how do trees affect the carbon balance?

2. How else do trees impact on climate?

3. How does changing climate affect trees and forest habitats?


1. Carbon balance

Trees sequester carbon as they grow

Trees are a store of carbon

Changes to soil carbon - positive and negative

Carbon released by forest fires or deforestation

Wood fuel can replace fossil fuels

Wood products can replace steel, concrete, etc

What else? …more later


2. Some other impacts of forests

If climate hotter, then shade from trees (e.g. streets and towns) becomes more valuable … but also forests trap heat.

If more storms, forests can reduce impacts of flooding

If water shortages, forests may be a shield against evaporation? ... but conifers also take up more water (not broadleaves?)


3. Some effects of climate change

Warmer climate - more rapid tree growth

Changes to natural ranges for some species

Insects and diseases move into new areas

More storms - more windblow

What else?


Carbon balance - what value/tonne?

Per tonne carbon or per tonne CO2

Social cost of carbon:• wide range of estimates for current value• carbon trading price not a good proxy• should it increase over time?• or should it be higher in the short run, because of

claimed urgency of action?• discounting to get Net Present Value?


Carbon balance - woodfuel

Common approach is just to estimate fossil fuel carbon saved.

This assumes that the woodfuel is carbon neutral.

Carbon emissions from woodfuel similar to fossil fuel; so need to consider whether the carbon sequestration balances the emissions.

Depends on where the woodfuel comes from...


Carbon balance - SRC

Short rotation coppice

Carbon sequestered balances carbon burned

Additional benefit from carbon stored while growing

Carbon stored in roots and stumps

Possible carbon losses from soil disturbance, and from machinery for harvesting and transport.


Carbon balance - existing forests

In short run, reduces carbon stored in forests

If part of good management (e.g. thinning), rate of carbon sequestration / hectare may be little affected (fewer trees left, each growing more)

If bringing neglected woodlands into management, may remove wood that would otherwise decay, and improve tree growth

But if badly managed, may remove growing trees that would otherwise sequester carbon in the future - worse than using fossil fuels.


Indicators - how to capture all this?

Carbon - sequestration rate, as well as amount stored?

Wood fuel - quantity used, by source - JWEE?

Other wood products - sustainable use?

Anything for other impacts of forests (e.g water - ecosystem services)?

For impacts on forests, are forest damage indicators sufficient?


Public Opinion Survey Q5

How much of an impact do you think climate change will have on the UK?

Large impact Slight impact No impact at all Don't know



Would you agree or disagree with the following statements about the ways in which forests and woodlands in the UK can impact on climate change?

(1) strongly agree

(2) agree

(3) neither agree or disagree

(4) disagree

(5) strongly disagree

don't know



• Trees are good because they remove carbon dioxide from the atmosphere and store it in wood

• Cutting down forests and woodland makes climate change worse, even if they are replanted

• Using wood for fuel is better for climate change than using fuels such as coal and gas

• Using wood for fuel makes climate change worse because it releases carbon dioxide

• Using wood for building is better for climate change than using materials such as concrete and steel.

• The UK could offset all its greenhouse gas emissions by planting more trees



Do you agree or disagree with the following statements regarding how UK forests and woodlands should be managed in response to the threat of climate change?

(1) strongly agree

(2) agree

(3) neither agree or disagree

(4) disagree

(5) strongly disagree

don't know



• There is nothing that anyone could do that would make any difference

• No action is needed; let nature take its course

• A lot more trees should be planted

• Trees should not be felled in any circumstances, even if they are replaced

• Different types of trees should be planted that will be more suited to future climates

• More information should be provided about the ways in which wood can be used to lessen our impact on the environment

forestry and climate change - issues and potential indicators

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