Forest growth

Assessment versions

Published (reviewed and quality assured)

• Forest growth (CLIM 034) - Assessment published Nov 2012

Justification for indicator selection

Tree growth is controlled by complex interactions between climate and non-climate factors, with forest management having a significant effect. Trees have long been known to respond to changes in climate: variations in tree ring widths from one year to another are recognised as an important source of climatic information although difficult to interpret. Climate change is expected to influence forest composition and productivity. Increases in atmospheric CO₂, changes in temperature and the availability of water will affect the relative health and productivity of different species in complex ways. CO₂ has a direct impact on tree function and forest productivity. An increased concentration in the atmosphere stimulates photosynthesis and likely results in an increase in growth rates and leaf area, if other factors are not limiting. Increased temperatures generally speed up plant growth, rates of decomposition and nutrient cycling, though other factors like availability of water also influence these processes. Higher temperatures lengthen the growing season by advancing its start in spring and delaying its end in fall.

Climate change is expected to present several threats to forest growth and productivity such as increased frequency and severity of summer drought with impacts on drought-sensitive tree species, in particular on shallow, freely draining soils. Indirect effects on forest productivity are expected through changes to the frequency and severity of pest and disease outbreaks, increasing populations of damaging insects and mammals, and the impact of existing and new invasive species. Concurrent changes in nitrogen and sulphur deposition and increased levels of ozone pollution are also expected to have an impact. Nitrogen deposition can stimulate forest growth but it can also increase the susceptibility of trees to drought, diseases, pests and frost by causing acidification and nutrient imbalances, thus decreasing forest vitality. Based on the current understanding of these processes, the individual effects of climate and non-climate changes are difficult to disentangle.

Scientific references:

• IPCC, 2007. Climate Change 2007: Impacts, Adaptation and Vulnerability. Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Parry, K. L.; Canziani, O. F.; Palutikof, J. P.; van der Linden, P. J. and Hanson, C. E. (eds.), Cambridge University Press, Cambridge, UK.
• Forest Europe, UNECE and FAO (2011) State of Europe's forests, 2011: status & trends in sustainable forest management in Europe Ministerial Conference on the Protection of Forests in Europe, Forest Europe, Liaison Unit Oslo, Aas, Norway.

Indicator definition

• Forest area
• Volume of forest biomass

Units

• km²
• m³

Policy context and targets

Context description

In April 2009 the European Commission presented a White Paper on the framework for adaptation policies and measures to reduce the European Union's vulnerability to the impacts of climate change. The White Paper stresses the need to improve the knowledge base and to mainstream adaptation into existing and new EU policies. The European Commission will be publishing an EU Adaptation Strategy in 2013. A number of Member States have already taken action, and several have prepared national adaptation plans.

The European Commission and the European Environment Agency have developed the European Climate Adaptation Platform (Climate-ADAPT, http://climate-adapt.eea.europa.eu/) to share knowledge on observed and projected climate change and its impacts on environmental and social systems and on human health; on relevant research; on EU, national and subnational adaptation strategies and plans; and on adaptation case studies.

Targets

No targets have been specified.

Related policy documents

• Climate-ADAPT: Mainstreaming adaptation in EU sector policies
  Overview of EU sector policies in which mainstreaming of adaptation to climate change is ongoing or explored
• Climate-ADAPT: National adaptation strategies
  Overview of activities of EEA member countries in preparing, developing and implementing adaptation strategies
• DG Climate Action: What is the EU doing about climate change?
  Activities of the EU regarding climate change (both mitigation and adaptation)
• White paper - Adapting to climate change: towards a European framework for action
  EU framework for adaptation to climate change, leading to a comprehensive EU adaptation strategy by 2013

Methodology

Methodology for indicator calculation

Data stems from the report mentioned below.

Methodology for gap filling

Not applicable

Methodology references

• Forest Europe, UNECE and FAO (2011) State of Europe's forests, 2011: status & trends in sustainable forest management in Europe Ministerial Conference on the Protection of Forests in Europe, Forest Europe, Liaison Unit Oslo, Aas, Norway

Data specifications

EEA data references

• No datasets have been specified here.

External data references

• State of Europe's forests

Data sources in latest figures

Uncertainties

Methodology uncertainty

Not applicable

Data sets uncertainty

It is very difficult to separate the impacts of climate change on forests and forestry from non-climate influences (e.g. related to management) in observational data. Therefore, efforts to understand the impacts of climate change on forests and forestry are largely based on controlled experiments in laboratories and on small forest plots, and on model simulations.

Information on forest fires is collected in the European Fire Database at the JRC. The European forest fire database is an important component of the European Forest Fire Information System (EFFIS). Forest fire data are provided each year by individual EU Member States through several EU regulations, and additional data coming from other European countries have been checked, stored and managed by JRC within EFFIS. The quality of the data is high. A time series on forest fires exists back to 1980 for the five European countries most affected by forest fires. Currently, the database covers data from 22 countries in Europe and contains over 2 million individual fire event records.

Further information on uncertainties is provided in Section 1.7 of the EEA report on Climate change, impacts, and vulnerability in Europe 2012 (http://www.eea.europa.eu/publications/climate-impacts-and-vulnerability-2012/)

Rationale uncertainty

No uncertainty has been specified