Annals of Forest Science (2016) 73:789–792
DOI 10.1007/s13595-016-0586-x
LETTER TO THE EDITOR
Editorial: “Forest Inventories at the European level”
Jean Michel Leban 1,2 & Jean-Daniel Bontemps 2
Received: 19 September 2016 / Accepted: 22 September 2016 / Published online: 10 October 2016
# INRA and Springer-Verlag France 2016
In 1949, Egon Glesinger, the deputy director of the FAO
Forestry and Forest Products Division, published his famous
book entitled “The coming age of wood,” translated in French
in 1951, “Demain l’âge du bois.”Glesinger, 1951 This book
depicts the technical possibility and the perspective for a massive
shift from fossil to renewable resources, mainly from forests, for
producing with a low carbon footprint and wide spectrum of end
products needed worldwide. As an example he wrote,
“… forests can be made to produce fifty times their
present volumes of end products and still remain permanently self-renewing source for raw materials. Only forests – no other raw material resource – can yield such
return. The forest can, and so must, end the chronic
scarcities of material goods that have harassed man’s
experience since the beginning of history.”
This early vision formulated by a scientist from the forest and
wood science community is nowadays increasingly accepted in
the society: the new emerging challenge is to decouple the economic growth from the environmental degradations.
Handling Editor: Erwin Dreyer
* Jean Michel Leban
jean-michel.leban@inra.fr
Jean-Daniel Bontemps
jean-daniel.bontemps@ign.fr
1
Annals of Forest Science, Editorial bureau, INRA, Centre de
Nancy-Lorraine, F-54280 Champenoux, France
2
Laboratoire de l’Inventaire Forestier (LIF), Institut national de
l’Information Géographique et Forestière (IGN), 1 rue de l’Ile de
Corse, F-54000 Nancy, France
The world’s forests, by their ability to provide renewable
products and other social services, have and will have an increasing contribution to this challenge, as soon as they are
managed in a sustainable way and face the challenge of climate change. Such perspective implies one very accurate
knowledge, understanding, and quantitative description of
the forest resources and their evolution and dynamics.
As a consequence, there is an increasing demand on the
monitoring of forest resources, on forests statistics, and on
projections of future forest resource availability under various
scenarios of management and environmental changes, for
public policymakers, for industry as well as for scientists.
These needs are traditionally fulfilled by the National Forest
Inventory (NFI) programs, whose scope and methods have
evolved continuously to meet these demands. It is noteworthy
that the users of these outputs are not always aware of the
underlying scientific achievements and technical complexity.
Information on forest resources is also needed at wider continental scales, in view of the different international reporting
processes that aim at orienting forest policies (FAO 2015;
FOREST EUROPE 2015, Keenan et al. 2015). Here, the
European space faces the basic reality and major difficulty
that the NFIs have developed on national bases, with their
own purposes and methodologies. As a consequence, NFI
data harmonization has been the main topic for two successive European COST actions involving most European NFIs
(E43, http://www.metla.fi/eu/cost/e43/, Tomppo et al. 2010),
and more recently by the elaboration and launch of the EUfunded research project “Diabolo” (http://diabolo-project.
eu). Such effort may also constitute a possible benchmark
for future harmonization efforts in other regions of the world.
Annals of Forest Science is therefore proud to lift the veil on
what was recently done within the very active European
National Forest Inventory community. This issue is based on
results gained between 2010 and 2014 within the COST action
790
FP1001 “USEWOOD” entitled “Improving Data and
Information on the Potential Supply of Wood Resources. A
European Approach from Multisource National Forest
Inventories.”
These papers illustrate three main topics:
(i) The needs and approaches for the international forestry
reporting (Vidal et al. 2016; Tomter et al. 2016; Kuliešis
et al. 2016).
(ii) The identification and analysis of the differences
between countries in terms of methods and measurements and directions for harmonization concerning forest volume increment and wood quality assortments
(Gschwantner et al. 2016, Bosela et al. 2016, and
previously cited contributions).
(iii) The used models and tools allowing a quantitative
assessment of forest resources at different scales
(McRoberts and Westfall 2015; McRoberts et al.
2015; Mantau et al. 2016) and projections for investigating the different management strategy options for
wood production and/or mitigation of the occurring climatic changes (Barreiro et al. 2016; Fortin et al. 2016).
It is noticeable that three contributions (Tomter et al. 2016;
Kuliešis et al. 2016; Gschwantner et al. 2016) are dedicated to the
estimation of forest volume increment, pointing to the major role
of forest growth and its monitoring to assess the sustainability of
forest resource supply. Two contributions also focus on uncertainty in the estimates of present (McRoberts and Westfall 2015)
and future (Fortin et al. 2016) forest resource attributes, pointing
out to a growing need for precision in the assessment of these
resources. As original efforts to date, Barreiro et al. (2016) and
Bosela et al. (2016) further offers comprehensive reviews across
European countries of (1) existing models for wood resource
projection and (2) approaches to stem quality assortments and
directions for their harmonization.
1 International reporting on forests
The paper by Vidal et al. provides a detailed and comprehensive description of the different reporting processes involving
the contribution of the European NFIs, including the Global
Forest Resources Assessment, the Convention on Biological
Diversity, the United Nations Framework Convention on
Climate Change, and its Kyoto Protocol. This paper points
the key role of the National Forest Inventory community and
the need for a strengthened harmonization process and further
efforts to producing comparable National Forest Inventory
results and therefore useful at the international level.
Tomter et al. present the methods used for the estimation of
gross and net annual volume increments in 30 countries. The
authors sent a questionnaire to the UNECE/FAO national
J. M. Leban, J.-D. Bontemps
correspondents of all European countries and to the members
of the UNECE/FAO Team of Specialists on Monitoring
Sustainable Forest Management. The results are description
and quantitative analysis of the three main groups of methods
at use in Europe.
Kuliešis et al. intend to assess the reliability of stem wood
increment estimates produced in Europe, by assembling and
comparing one significant material resulting from a similar
questionnaire, and estimates provided by the FRA report and
the State of Europe’s forests databases. Estimations appear to
be more reliable when resulting from NFI programs than forest management inventories, in particular when permanent
plot designs are implemented. Estimates for forest losses remain a weak component of the growing stock budget.
2 Comparison of methods across different countries
and prospect for harmonization
Gschwantner et al. provide a comparison of methods used in 29
European National Forest Inventories for the estimation of volume increment. The enquiry was based on previous work from
COST E43 and an analysis of literature to provide scientific
background to the comparison. Various aspects of volume increment estimate show strong differences among countries. Beyond
differences in the inventory design, challenging ones include
sample tree selection, sampling thresholds, and tree fractions
are considered. In spite of these difficulties, recent developments
and implementation of sample-based inventories now set promising perspectives for harmonization of volume increment.
Bosela et al. address the original question of stem quality
assessment and assortments structure, from a review of practices among 28 countries. Such information is requested by
industrial stakeholders to meet the demand expressed by their
customers. For the first time, the authors describe the stem
quality assessment used in 19 countries among the 28
European NFIs surveyed. The study concludes that current
approaches of stem quality are not comparable, but identifies
several promising directions for harmonized stem quality
estimation.
3 Tools and models to assess and project forest
resources
3.1 Present state assessment of forest resources
McRoberts and Westfall address the issue of uncertainty in
large-area volume estimates, such standard statistics delivered
for long by national forest inventories. These estimates routinely rely on aggregating tree-level volume estimates based
on volume equations, to plot level and wider forest areas.
Measurement errors in height and diameter and errors in tree
Editorial: “Forest Inventories at the European level”
volume models thus influence the final large-area uncertainty
in the growing stock. The contribution highlights that model
uncertainty is depending on the sampling scheme and grows
significant with stratified sampling. This contribution thus
stresses that wide-area statistics delivered by classical NFI
come along with errors, and these matter for forest reporting.
In a second contribution McRoberts et al. address an issue
related to more recent multi-source forest inventory (MS-NFI)
which principle is to use fine-resolution maps as auxiliary
information to plot data, in order to gain precision in NFI
statistics. Time lags between map and field information indeed
often exist, are reinforced by the practice of continuous forest
inventory, and can hamper the gain in precision. In a case
study in Norway, where forest area changed over the study
period, it is shown that precision in the estimate of forest
biomass per hectare was strongly affected by a time lag in
map-field data of ~10 years.
Previous contributions deal with estimating and harmonizing forest growth and forest growing stock. There are however
many obstacles to harvesting forests, so that the sustainable
level of forest exploitation does not meet 100 % of volume
increment. Further, the growing demand for renewable energy
calls for estimating harvestable biomass and at scales wider
than that of countries. In this perspective, the contribution by
Mantau et al. is a presentation of the “ITOC” model, a tool that
combines the multiple purposes of (1) harmonizing national
volume increments produced by NFIs, (2) converting this volume into biomass, and (3) defining the sustainable fraction of
biomass increment available for supply. Such tools therefore
indicate promising directions to evaluate wood biomass available for consumption on a European level.
3.2 Projection of forest resources
In addition to estimating the present state of forest resources,
capacities for projecting their future state under specific scenarios are of increased need.
Barreiro et al. offer an original review of models implemented for forest resource projection across 21 countries in
Europe. A variety of modeling approaches is encountered,
including tree-level models, stand-level models as the dominant paradigm for homogeneous forests, and less frequent
large-scale demographic matrix models intended to simulate
more heterogeneous forests. The analysis highlights major
challenges associated to including climate change forcing
and coping with non-stationary management in these models.
Coupling these projection models with sector models
(representing the economic demand) and assessing projection
uncertainty also define perspectives for improvement.
Fortin et al. illustrate the large-scale demographic modeling
approach on a region of Spain and address the issue of prediction uncertainty. The contribution of sampling and modelrelated errors in this uncertainty is explored using Monte-
791
Carlo techniques similar to McRoberts and Westfall, and the
study concludes on improving estimators. At the same time,
this contribution also shows the technologic advancement of
such models where, e.g., site- and stock-dependent processes
are not explicitly represented, pinpointing further promising
directions to reduce uncertainty in these approaches.
This special issue is also an opportunity to highlight some
current major research challenges and trends in the field of
forest inventory.
Building on previous COST actions on forest inventory, the
recently EU-funded “Diabolo” project (http://diabolo-project.
eu/about/structure/) will first focus on essential aspects, such
as harmonization of forest statistics, and development of MSNFI approaches using fine-resolution remote-sensing data required for the delivery of accurate forest information at different scales ranging from local to continental. While statistics on
the larger scale remain fundamental to forest policies,
obtaining precision in estimates of local forest attributes is a
prerequisite to foster the economic use of renewable wood
resources. Other innovative aspects will be addressed in the
project including the monitoring of forest disturbances, and
development of multi-purpose forest inventory, required for
informing sustainable forest management through its three
societal, economic, and ecological dimensions.
Approaches to projection of forest resources also meet with
fundamental challenges that include the integration of possible
climate change impacts onto forest dynamics, with various
options including hybridization with process-based approaches, as well as the ability to cope with strongly nonstationary forest management, in the renewed context of bioeconomy, of CC mitigation, and of the “European forest conversion” aimed at moving forests away from the pure and
even-aged forestry paradigm. While a recent effort has been
paid on upgrading models for application to a European scale,
current technologies remain classical and are not necessarily
fit for addressing such challenges.
Also, while forest inventories traditionally estimate forest
growing stock, increment, and harvests on a volume scale, the
economic context assumes important efforts to be consented
to deliver accurate estimates of forest biomass and carbon and
their variability across forests, but also to evaluate the quality
of wood supply. This implies that appropriate quantifications
of stem and wood properties should be encouraged, with NFIs
as a measurement support, and calls for a narrower collaboration between forest inventory and wood science.
Sometimes, major progresses in a field are made by one
single man. The editors would therefore like to pay tribute to
Prof. Tiberius Cunia, passed away later April 2016, who greatly advanced the science of forest inventory, forest inventory
design, sampling with partial replacement, the quantification
of errors in forest inventory estimates (Cunia, 1989), and in
biomass equation estimation for which he received the
Humbolt award in 1984.
792
The editors last wish that the audience of Annals of Forest
Science will appreciate the content of this special issue.
References
Barreiro S, Schelhaas MJ, Kändler G, Antón-Fernández C, Colin A,
Bontemps JD, Alberdi I, Condés S, Dumitru M, Ferezliev A,
Fischer C, Gasparini P, Gschwantner T, Kindermann G,
Kjartansson B, Kovácsevics P, Kucera M, Lundström A, Marin G,
Mozgeris G, Nord-Larsen T, Packalen T, Redmond J, Sacchelli S,
Sims A, Snorrason A, Stoyanov N, Thürig E, Wikberg PE (2016)
Overview of methods and tools for evaluating future woody biomass
availability in European countries. Ann For Sci. doi:10.1007/
s13595-016-0564-3
Bosela M, Redmond J, Kučera M, Marin G, Adolt R, Gschwantner T,
Lanz A (2016) Stem quality assessment in European National Forest
Inventories: an opportunity for harmonised reporting? Ann For Sci
73:635–648. doi:10.1007/s13595-015-0503-8
Cunia T, (1989) Forest Inventory: On the Structure of Error of Estimates.
In “State-of-the-art methodology of forest inventory: a symposium
proceedings”, 169–176. Gen. Tech. Rep. PNW-GTR-263. Portland,
OR: U.S. Department of Agriculture, Forest Service, Pacific
Northwest Research Station. 635 pages. Editors, LaBau, Vernon J.;
Cunia, Tiberius.
FAO, 2015, Global Forest Resources Assessment 2015. FAO Forestry
Paper No. 1, UN Food and Agriculture Organization, Rome. 253
pages, ISBN 978-92-5-108826-5. http://www.fao.org/3/a-i4808e.
pdf Accessed 14 September 2016
FOREST EUROPE, 2015: State of Europe’s Forests 2015, Published by
the Ministerial Conference on the Protection of Forests in Europe.
314 pages, Project coordinator: Myriam Martí n Vallejo. http://www.
foresteurope.org/docs/fullsoef2015.pdf Accessed 14 September
2016
Fortin M, Robert N, Manso R (2016) Uncertainty assessment of largescale forest growth predictions based on a transition-matrix model in
Catalonia. Ann For Sci. doi:10.1007/s13595-016-0538-5
J. M. Leban, J.-D. Bontemps
Glesinger E (1951) Demain l’âge du bois. 247 pages, Paris, Berger-Levrault,
Editeur
Gschwantner T, Lanz A, Vidal C, Bosela M, Di Cosmo L, Fridman J,
Gasparini P, Kuliešis A, Tomter S, Schadauer K (2016) Comparison
of methods used in European National Forest Inventories for the
estimation of volume increment: towards harmonisation. Ann For
Sci. doi:10.1007/s13595-016-0554-5
Keenan RJ, Reams GA, Achard F, Freitas JV, De Grainger A, Lindquist E
(2015) Forest ecology and management dynamics of global forest
area: results from the FAO global Forest resources assessment 2015.
For Ecol Manag 352:9–20. doi:10.1016/j.foreco.2015.06.014
Kuliešis A, Tomter SM, Vidal C, Lanz A (2016) Estimates of stem wood
increments in forest resources: comparison of different approaches
in forest inventory: consequences for international reporting: case
studyof European forests. Ann For Sci doi. doi:10.1007/s13595016-0559-0
Mantau U, Gschwantner T, Paletto A, Mayr Ml, Blanke C, Strukova E,
Avdagic A, Camin P, Thivolle-Cazat A, Döring P, Petrauskas E,
Englert H, Schadauer K, Barreiro S, Lanz A, Vidal C (2016)
ITOC—Harmonized transformation of forest inventory data to data
on actual biomass potentials for consumption Ann For Sci
McRoberts RE, Westfall JA (2015) Propagating uncertainty through individual tree volume model predictions to large-area volume estimates. Ann For Sci:625–633. doi:10.1007/s13595-015-0473-x
McRoberts R, Næsset E, Gobakken T (2015) The effects of temporal
differences between map and ground data on map-assisted estimates
of forest area and biomass. Ann For Sci doi. doi:10.1007/s13595015-0485-6
Tomppo E, Gschwantner T, Lawrence M, McRoberts RE (2010) National
Forest Inventories—pathways for common reporting. Springer,
Berlin 612 p. ISBN 978-90-481-3232-4
Tomter SM, Kuliešis A, Gschwantner T (2016) Annual volume increment
of the European forests—description and evaluation of the national
methods used. Ann For Sci doi. doi:10.1007/s13595-016-0557-2
Vidal C, Alberdi I, Redmond J, Vestman M, Lanz A, Schadauer K
(2016) The role of European National Forest Inventories for international forestry reporting. Ann For Sci doi. doi:10.1007/s13595016-0545-6