Forest: growing stock, increment and fellings

Indicator Assessment
Prod-ID: IND-155-en
Also known as: SEBI 017
Created 27 Jun 2017 Published 08 Dec 2017 Last modified 08 Dec 2017
12 min read
The ratio of forest fellings to increment is relatively stable and remains under 80 % for most countries across Europe. This utilisation rate has allowed Europe's forest stock to continue to increase.   The average growing stock density in European forests is 163 m 3 per hectare. While this varies considerably between countries, high individual values can be mainly put down to ecological conditions that favour tree growth, the protection of forest areas and, locally, forest harvesting difficulties.

Key messages

The ratio of forest fellings to increment is relatively stable and remains under 80 % for most countries across Europe. This utilisation rate has allowed Europe's forest stock to continue to increase. 

The average growing stock density in European forests is 163 m3 per hectare. While this varies considerably between countries, high individual values can be mainly put down to ecological conditions that favour tree growth, the protection of forest areas and, locally, forest harvesting difficulties.



Is forestry in Europe sustainable in terms of the balance between the increment of growing stock and fellings?

Forest utilisation rate per country (annual fellings as a percentage of annual increment)

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Mean growing stock density by country

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The ratio of forest fellings to increment is relatively stable and remains under 80 % for most countries across Europe. This utilisation rate has allowed the forest stock to increase. However, a fellings-to-annual-increment ratio of approximately 70 % is recommended to ensure the sustainable management of forests. Further continued expansion of forest fellings may result in unsustainable production. For instance, an increase in the demand for bioenergy would require an increase in the import of wood from outside Europe in order to allow forest biomass resources to be rebuilt to a sustainable level. However, such displacement of land use is very likely to lead to the collapse of forest resources, in the form of deforestation, in other parts of the world. According to the most recent data available (Figure 1), about one third of the countries in the EEA region do not fall within the recommended 70 % mark. Overall, this figure has remained constant over the past two decades, although felling-over-increment ratios have varied over time for most countries.

As shown in Figure 1, the amount of wood felled has been less than that planted and added as incremental growth. This has allowed for a build-up of growing stock. In addition, the growing stock in Europe has been increasing from a low level after having been cleared for agriculture and charcoal production in recent centuries. However, the ratio of fellings to increment is expected to increase during the coming years. This is because of an expected increase in the demand for woody biomass as a renewable energy source (Forest Europe, 2015).

Energy crops that are grown using short-rotation forestry (which is not considered forestry) compete with other land use sectors for the same land resource. Therefore, in the future, land abandonment is likely to decline and forest areas are likely to stabilise. The demand for fuelwood is expected to grow further in light of the EU renewable energy targets for 2020 and beyond. The targets for greenhouse gases and the dependency on fossil fuels might encourage more imports to the EU of wood to be used for bioenergy purposes. Currently, more than 30 % of the net primary production (NPP) of wood used in the EU stems from imported biomass and biomass products (EEA, 2016).

The growing stock of forest area per country is shown in Figure 2. The average growing stock density in European forest is 163 m3 per hectare (ha). This varies considerably between countries, from 10 m3/ha in Iceland to 352 m3/ha in Switzerland. High individual values can be mainly put down to ecological conditions in favour of tree growth, the protection of forest areas, as a result of silvicultural practices, and locally forest harvesting difficulties (Forest Europe, 2015). 

The increased use of woody biomass is likely to substantially affect forest biodiversity and forest ecosystem services. A study of 24 European countries (EEA, 2016) indicates that an increase in wood and residue removal to their maximum potentials would reduce the average amount of deadwood by 5.5 % by 2030, compared with 2005. Consequently, adverse effects are expected on deadwood-dependent species, which constitute an important component of biodiversity in European forests. The extraction of fuelwood as a substitute for fossil fuels may lead to additional revenues for forest owners, and it is also recognised as a way of balancing anthropogenic nitrogen deposition in forests. Other studies suggest negative impacts of the extraction of biomass from forests, such as an increase in soil erosion and compaction, a depletion of soil nutrient stocks and changes in nutrient cycling and an increase in non-forest vegetation. However, the potential impacts, whether positive or negative, on other services provided by forests will need to be considered, alongside impacts on biodiversity, in order to better understand the possible trade-offs. Understanding trade-offs and developing optimised management strategies are critical issues for forest management in Europe (EEA, 2016). 

The variation of forest management across Europe follows the diversity of site condition, the history of management and land use and heterogenic socio-economic factors such as ownership and the demand for forest products and services in the respective countries and regions (EEA 2016). Some regional characteristics include even-aged forest management including short rotation forestry in northern Europe, however with unmanaged forests in high altitude regions and in mountain areas. The western and central European forests are in general very fragmented and comprise a mix of forest management practices including intensive even-aged forest management including short rotation forestry. These patterns are also found in the Mediterranean region. Regions of south-west France and north-east Spain are characterized by a relatively large areas of intensive even-aged forest management. However, multifunctional forest (combined objective) management dominates in the Mediterranean region and south-eastern Europe with scattered mix of areas of intensive and short rotation forestry, and protected forest areas.


Indicator specification and metadata

Indicator definition

This indicator looks at the growing stock in forests and other wooded land. Growing stock is classified by forest type and by availability for wood supply. The indicator considers the balance between net annual increment and annual fellings of wood in forests to be made available for wood supply.

Units

The following units are used in this indicator:

Growing stock (m3 per hectare)
Ratio of fellings to increment (%)
Utilisation rate (%)


Policy context and targets

Context description

Growing stock is one of the basic statistics of any forest inventory and is useful for various purposes. The standing volume of growing stock can be converted into estimates of above and below-ground woody biomass by applying biomass expansion factors. Data on growing stock, increment and fellings are crucial for the calculation of carbon budgets in the forest sector.

How the indicator relates to the focal area

The balance between increment and fellings highlights the sustainability of timber production over time as well as the current availability and the potential for future availability of timber. For long-term sustainability, the annual fellings must not exceed the net annual increment, agreed to be less than 70 % over the long term.

An increase in growing stock relative to forest area is an indication of a maturing forest. The balance between growth and fellings in production forests is the best indicator to understand the forest's potential for wood production, and the conditions it provides for biodiversity, health, recreation and other forest functions. 

Targets

EU 2020 biodiversity target 3

Related policy documents

  • A new EU Forest Strategy
    A new EU Forest Strategy: for forests and the forest-based sector.  Communication from the Commission to the European Parliament and the Council, the Economic and Social Committee and the Committee of the Regions ‘A new EU Forest Strategy: for forests and the forest-based sector’, COM(2013) 659 final. The EU needs a policy framework that coordinates and ensures coherence of forest-related policies and allows synergies with other sectors that influence forest management. The new forest strategy is a key reference in forest-related policy development. EU forests and forest sector need to be positioned in a way that ensures their contribution to the EU’s objectives and targets. This implies to: • Ensure that the multifunctional potential of EU forests is managed in a sustainable and balanced way, enabling our forests’ vital ecosystem services to function correctly. • Satisfy the growing demand for raw material for existing and new products (e.g. green chemicals or textile fibres) and for renewable energy. This demand is an opportunity to diversify markets, but poses a significant challenge for sustainable management and for balancing demands. Demand for new uses in the bioeconomy and in bioenergy should be coordinated with traditional demands, and respect sustainable boundaries. • Respond to the challenges and opportunities that forest-based industries face in resource and energy efficiency, raw materials, logistics, structural adaptation, innovation, education, training and skills, international competition, climate policy beyond 2020 and information and communication, to stimulate growth. • Protect forests and biodiversity from the significant effects of storms and fires, increasingly scarce water resources, and pests. These threats do not respect national borders and are exacerbated by climate change. • Acknowledge that the EU does not only rely on its own production, and that its consumption has implications for forests worldwide. • Develop an adequate information system to follow-up on all of the above.
  • EU 2020 Biodiversity Strategy
    in the Communication: Our life insurance, our natural capital: an EU biodiversity strategy to 2020 (COM(2011) 244) the European Commission has adopted a new strategy to halt the loss of biodiversity and ecosystem services in the EU by 2020. There are six main targets, and 20 actions to help Europe reach its goal. The six targets cover: - Full implementation of EU nature legislation to protect biodiversity - Better protection for ecosystems, and more use of green infrastructure - More sustainable agriculture and forestry - Better management of fish stocks - Tighter controls on invasive alien species - A bigger EU contribution to averting global biodiversity loss

Methodology

Methodology for indicator calculation

Definition of terms:

Growing stock

The living tree component of the standing volume.
The standing volume refers to the volume of standing trees, living or dead, above-stump measured overbark to top (0 cm). It includes all trees with diameter over 0 cm at breast height (d.b.h., i.e.  typically at 130 cm above stump). Standing volume includes tops of stems, large branches, dead trees lying on the ground that can still be used for fibre or fuel. It excludes small branches, twigs and foliage (UNECE/FAO, 2000).

Gross annual increment

This is the average annual volume of increment over the reference period for all trees and is usually measured at a minimum d.b.h. of 0 cm. It includes the increment on trees that have been felled or that died during the reference period (UNECE/FAO, 2000).

Net annual increment

This is the average annual volume over the given reference period of gross increment minus the the volume of natural losses on all trees with a minimum diameter of 0 cm d.b.h. (UNECE/FAO, 2000).

Annual fellings

This is the average annual standing volume of all trees, living or dead, measured overbark to a minimum diameter of 0 cm d.b.h. that are felled during the given reference period, including the volume of trees or parts of trees that are not removed from the forest, other wooded land or other felling site. It includes silvicultural and pre-commercial thinnings and cleanings left in the forest, and natural losses that are recovered (harvested) (UNECE/FAO. 2000).

Various methods exist in countries to estimate fellings. Fellings are measured from standing trees, from already felled trees, at factory gates or by using a combination of techniques. Typically, estimates of fellings for energy and especially the fraction of fellings for domestic firewood are difficult to make. Another issue in some countries is illegal logging and ranges for the volume of illegally felled wood are difficult to assess without a large error margin.

Combined with forest scenario modelling, it is also possible to create outlooks for the future development of this indicator. Such data are developed under the auspices of UNECE/FAO as part of its European Forest Sector Outlook Studies (formerly: European Timber Trends Studies).

Measurement units for growing stock

Status: m3
Changes: m3/yr
Status: m3/ha
Changes: m3/ha/yr

Measurement units for increment and fellings

Status: m3.
Changes: m3/yr.

Methodology for gap filling

N/A

Methodology references

Uncertainties

Methodology uncertainty

No uncertainty has been specified

Data sets uncertainty

No uncertainty has been specified

Rationale uncertainty

MAIN DISADVANTAGES OF THE INDICATOR

  • The indicator should be interpreted carefully, for example, fast-growing non native species, fertilisation etc. may contribute to an increase in growing stock, but may also be detrimental to biodiversity.

 

ANALYSIS OF OPTIONS

Forest Europe quantitative indicators (http://foresteurope.org/sfm-criteria-indicators2/) all relate to sustainable forestry management. From this set, those with most direct relevance to biodiversity were selected.

Data sources

Generic metadata

Topics:

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DPSIR: Pressure
Typology: Descriptive indicator (Type A - What is happening to the environment and to humans?)

Contacts and ownership

EEA Contact Info

Katarzyna Biala

EEA Management Plan

2017 1.7.4 (note: EEA internal system)

Dates

Frequency of updates

Updates are scheduled every 4 years
European Environment Agency (EEA)
Kongens Nytorv 6
1050 Copenhagen K
Denmark
Phone: +45 3336 7100