First signs of carbon sink saturation in

European forest biomass

Gert-Jan Nabuurs

Professor European forest resources

Based on NCC 18 Aug 2013, with Marcus Lindner,

Hans Verkerk, Roman Michalak, Paola deda,

Giacomo Grassi, Katja Gunia

1. Introduction to European forests

2.Challenges in European forests that determine the C balance

3.Latest trends in C sink in forest biomass

4.Conclusions and new projections

1. Introduction to European forests

1x1 km, tree spp map (Hengeveld et al.2012; Brus et al. 2012 )

Northern hemispheric vegetation rebound

Large diversity in man-made systems

Supplying many goods.....

....and services for the urbanised society

Value of environmental services is ~3000 $ /ha.y

(De Groot 2012 )

Present state of European forests

Forest and other wooded land area: 178 Mha forest in EU27 countries, all actively managed;

Afforestation 0.5 Mha/y

Net increment: 4.7 m3 ha-1 y-1 , increased from 1950 to 2005

Volume: 153 m3 ha-1 and increasing

More than half coniferous

UN-ECE/FAO 2011, EFSOS II

2. challenges in European forests that

determine the C balance

Forests are ageing

Share of the forest at an age > 120 years. Vilen et al. 2012

Ever higher growing stocks lead to increased disturbances

Volume of damage

(schelhaas et al 2003)

Biodiversity decline

Common forest birds (EEA 2008)

Contribution of forest sector to country level GDP is minimal (UNECE/FAO 2011)

More challenges….

Weighted average size of forest holding for the EU = 2.7 ha/holding

Most recent trends in the sector - A sector under pressure, looking for new products

Production of paper and paperboard in Europe (UNECE 2013)

Pellets mostly from Canada, USA, Russia

Nanocellulose based polymers

Biomass: fiercely discussed

Volkskrant 13 January, based

on KNAW document

Trouw, 21 January

3. Latest trends in C sink in forest biomass

Methods

data analysis

Compiling/analysing main drivers, main trends as increment, harvest

Mostly based on national forest inventory data

Forest sector data (harvest)

Disturbance trends

Land use change data

UNFCCC reports

First time since 1960 that increment is

declining

Harvest has gone up as well, but stays behind

Rate of carbon sequestration in forest biomass

is curbing

Nabuurs et al. 2013

Regionally significant differences

Causes

Decline in increment of the mature forest and an increasing harvest — further enhanced by deforestation and by increased natural disturbances — seem to be causing the curbing of the sink strength

Decline in increment partly caused by an ageing forest, and an highly stocked forest

Climate-induced declines in productivity

4. Recommendations and new projections

Conserve high carbon-stock densities in old forests that are not at

a high risk of disturbance

Harvest mature forests that are at high risk of disturbance and

already have low productivity.

Probably time to stimulate a more rational forest management in

certain regions ..while paying due attention to other services

Optimize silvicultural techniques to arrive at a carbon-efficient

management scheme in forests that are grown primarily for

timber,

intensify management where the primary goal is biomass for

bioenergy

Continue afforestation schemes in Europe — particularly while

concomitantly curbing gross deforestation.

Forest NBP (2000-2005) C stock change in trees and soil

Eggers et al. 2008

EFISCEN: Providing insight in carbon balance,

and e.g. wood availability

Management can change the trend: gradual conversion of European forests to plantations

Nabuurs et al. 2014

Projecting the sink: We need to think

about a more spatially disaggregated

forest management across Europe ..

Hengeveld et al. 2012

Developing a high resolution modelling

approach based > 300,000 NFI plot data

from across Europe. Thanks to NFIs.

Levers et al. 2014, Verkerk et al In press

Large parts are hardly used/managed

Thank you !

Gert-jan.nabuurs@wur.nl