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Standing deadwood is an important structural component of forest ecosystems. Its occurrence and dynamics influence both carbon fluxes and the availability of habitats for many species. However, deadwood is greatly reduced in managed, and even in many currently unmanaged temperate forests in Europe. To date, few studies have examined how environmental factors, forest management and changing climate affect the availability of standing deadwood and its dynamics. Data from five periods of the Austrian National Forest Inventory (1981-2009) were used to (I) analyse standing deadwood volume in relation to living volume stock, elevation, eco-region, forest type, ownership and management intensity, (II) investigate the influence of forest ownership and management intensity on snag persistence and (III) define drivers of standing deadwood volume loss for seven tree genera (Abies, Alnus, Fagus, Larix, Picea, Pinus and Quercus) using tree-related, site-related and climate-related variables, and predict volume loss under two climate change scenarios. Standing deadwood volume was mainly determined by living volume stock and elevation, resulting in different distributions between eco-regions. While forest type and management intensity influenced standing deadwood volume only slightly, the latter exhibited a significant effect on persistence. Snag persistence was shorter in intensively managed forests than in extensively managed forests and shorter in private than in public forests. Standing deadwood volume loss was driven by a combination of diameter at breast height, elevation, as well as temperature, precipitation and relative humidity. Volume loss under climate change predictions revealed constant rates for moderate climate change (RCP2.6) by the end of the 21st century. Under severe climate change conditions (RCP8.5), volume loss increased for most tree genera, with Quercus, Alnus and Picea showing different predictions depending on the model used as the baseline scenario. We observed trends towards faster volume loss at higher temperatures and lower elevations and slower volume loss at high precipitation levels. The tree genera most susceptible to climate change were Pinus and Fagus, while Abies was least susceptible. Synthesis and applications. We recommend to protect standing dead trees from regular harvesting to ensure the full decomposition process. The consequences for decomposition-dependent species must be taken into account to evaluate the influences of management and climate change on standing deadwood dynamics., Journal of Applied Ecology, 60 (4), ISSN:0021-8901, ISSN:1365-2664

Land-use changes and forest management decisions can profoundly alter soil organic carbon (SOC) stocks. Therefore, the objective of this study was to investigate whether existing SOC stocks in the forests of Singapore can be related to successional stages of forest vegetation following disturbances. A forest classification system was developed using information about land use history and vegetation data from 21 inventory plots collected within the framework of Singapore’s IPCC-compatible greenhouse gas reporting system. The forest successional classes obtained were related to SOC stocks (0–50 cm) determined on the same plots. The inventory plots were assigned to four classes. Primary forests (Class 1) were dominated by late succession native species. Secondary forests representing natural forest succession (Class 2) contained younger native trees and a few large trees. Secondary forests after tree plantation/fruit orchard (Class 3) and after agricultural crop cultivation (Class 4) were characterised by large proportions of exotic tree species. Maximum stocks of SOC declined from Class 1 (127.7 Mg ha−1) to Class 4 (35.2 Mg ha−1). The results of a principal component analysis confirmed our forest classification. Plant-related parameters can be successfully used to classify the forests in Singapore, which also show clear differences in SOC.

Wood resources have been essential for human welfare throughout history. Also nowadays, the volume of growing stock (GS) is considered one of the most important forest attributes monitored by National Forest Inventories (NFIs) to inform policy decisions and forest management planning. The origins of forest inventories closely relate to times of early wood shortage in Europe causing the need to explore and plan the utilisation of GS in the catchment areas of mines, saltworks and settlements. Over time, forest surveys became more detailed and their scope turned to larger areas, although they were still conceived as stand-wise inventories. In the 1920s, the first sample-based NFIs were introduced in the northern European countries. Since the earliest beginnings, GS monitoring approaches have considerably evolved. Current NFI methods differ due to country-specific conditions, inventory traditions, and information needs. Consequently, GS estimates were lacking international comparability and were therefore subject to recent harmonisation efforts to meet the increasing demand for consistent forest resource information at European level. As primary large-area monitoring programmes in most European countries, NFIs assess a multitude of variables, describing various aspects of sustainable forest management, including for example wood supply, carbon sequestration, and biodiversity. Many of these contemporary subject matters involve considerations about GS and its changes, at different geographic levels and time frames from past to future developments according to scenario simulations. Due to its historical, continued and currently increasing importance, we provide an up-to-date review focussing on large-area GS monitoring where we i) describe the origins and historical development of European NFIs, ii) address the terminology and present GS definitions of NFIs, iii) summarise the current methods of 23 European NFIs including sampling methods, tree measurements, volume models, estimators, uncertainty components, and the use of air- and space-borne data sources, iv) present the recent progress in NFI harmonisation in Europe, and v) provide an outlook under changing climate and forest-based bioeconomy objectives.

National Forest Inventory (NFI) data are the main source of information on forest resources at country and subcountry levels. This chapter explores the strengths and limitations of NFI-derived indicators to assess forest development with respect to adaptation to and mitigation of climate change, that is, the criteria of Climate-Smart Forestry (CSF). We reflect on harmonizing NFI-based indicators across Europe, use literature to scrutinize available indicators to evaluate CSF, and apply them in 1) Switzerland, where CSF is evaluated for NFI records and simulation model projections with four management scenarios; 2) 43 selected European countries, for which the indicators for Sustainable Forest Management (SFM) are used. The indicators were aggregated to composite indices for adaptation and mitigation and to an overall CSF rating. The Swiss NFI records showed increased CSF ratings in mountainous regions, where growing stocks increased. Simulations under business-as-usual management led to a positive CSF rating, whereas scenarios of increased harvesting decreased either only adaptation or both mitigation and adaptation. European-level results showed increases in CSF ratings for most countries. Negative adaptation ratings were mostly due to forest damages. We discuss the limitations of the indicator approach, consider the broader context of international greenhouse gas reporting, and conclude with policy recommendations.

International audience; National Forest Inventories (NFIs) perform systematic forest surveys across space and time. They are hence powerful tools to understand climate controls on forest growth at wide geographical scales and account for the effects of local abiotic and biotic interactions. To investigate the effects of climate change upon growth dynamics of four major European conifer species along elevation and continentality gradients, we herein provide an original harmonization of the French and Austrian NFI datasets. The growth of Norway spruce, Scots pine, silver fir and European larch over the 1996-2016 period was studied in pure and evenaged plots across different ecological regions. We derived climate-driven growth trends from > 65, 000 radial increment series filtered-out from major biotic and abiotic influences using statistical modeling. We further identified primary environmental drivers of conifer growth by regressing growth trends against regionally-aggregated biotic and abiotic forest attributes. Negative growth trends were observed in continental regions undergoing the most rapid warming and thermal amplitude contraction over the study period. Negative trends were also associated with lower forest structural heterogeneity and, surprisingly, with greater available water capacity. Remarkably, we observed these associations both at the inter-and intraspecies levels, suggesting the universality of these primary growth determinants. Our study shows that harmonized NFI data at the transnational level provide reliable information on climate-growth interactions. Here, greater forest structural complexity and greater water resource limitation were highlighted as drivers of greater forest resilience to climate change at large-scale. This result forms crucial bases to implementing climate-smart forest management.

Key message Truncating the angle count sampling plots leads to a higher stock estimate because fewer trees are missed. It also causes a higher uncertainty of the estimates. Context The Austrian National Forest Inventory changed its plot design to angle count sampling plots that are limited to circles of 300 m2. A fixed plot size is beneficial for multistage inventory systems. Aims This study aims to quantify the ensuing effects on the national forest inventory on the plot and the national level regarding stock estimates and their uncertainty along with effects on as well as of upper diameter models. Methods Fully surveyed large-scale plots with simulated angle count samples were used to gauge the increase of variability. The full NFI 2007/09 data set was employed to simulate truncations at different distances as well as to parameterise eight alternatives for upper diameter models and to analyse the effects on the stock estimates. Results There is an increase in the stock estimate because the probability of missing sample trees is reduced. The change in upper diameter models had little effect. Conclusion The truncation removes a source of bias, facilitates field work, and is a favourable way forward.

• Key message A dataset of forest resource projections in 23 European countries to 2040 has been prepared for forest-related policy analysis and decision-making. Due to applying harmonised definitions, while maintaining country-specific forestry practices, the projections should be usable from national to international levels. The dataset can be accessed at https://doi.org/10.5061/dryad.4t880qh . The associated metadata are available at https://metadata-afs.nancy.inra.fr/geonetwork/srv/eng/catalog.search#/metadata/8f93e0d6-b524-43bd-bdb8-621ad5ae6fa9 .

Key message Volume predictions of sample trees are basic inputs for essential National Forest Inventory (NFI) estimates. The predicted volumes are rarely comparable among European NFIs because of country-specific dbh-thresholds and differences regarding the inclusion of the tree parts stump, stem top, and branches. Twenty-one European NFIs implemented harmonisation measures to provide consistent stem volume predictions for comparable forest resource estimates. Context The harmonisation of forest information has become increasingly important. International programs and interest groups from the wood industry, energy, and environmental sectors require comparable information. European NFIs as primary source of forest information are well-placed to support policies and decision-making processes with harmonised estimates. Aims The main objectives were to present the implementation of stem volume harmonisation by European NFIs, to obtain comparable growing stocks according to five reference definitions, and to compare the different results. Methods The applied harmonisation approach identifies the deviations between country-level and common reference definitions. The deviations are minimised through country-specific bridging functions. Growing stocks were calculated from the un-harmonised, and harmonised stem volume estimates and comparisons were made. Results The country-level growing stock results differ from the Cost Action E43 reference definition between − 8 and + 32%. Stumps and stem tops together account for 4 to 13% of stem volume, and large branches constitute 3 to 21% of broadleaved growing stock. Up to 6% of stem volume is allocated below the dbh-threshold. Conclusion Comparable volume figures are available for the first time on a large-scale in Europe. The results indicate the importance of harmonisation for international forest statistics. The presented work contributes to the NFI harmonisation process in Europe in several ways regarding comparable NFI reporting and scenario modelling.

The current state of research shows that there is big potential for the use of wood, particularly harvested wood products (HWP) to mitigate climate change and increase carbon stocks. Despite of discussions on different accounting approaches, the forest-based sector can contribute with the production of long-lasting wood products to reach international climate goals. This leads to high demands on forests and on what they can deliver both at EU and the national levels. In Austria it has been bemoaned by the Environmental Agency in its recent –eleventh- control report, that a comprehensive concept for the use of wood is missing. The report asks for consideration of increasing future needs for raw wood and energy under considerations of sustainability and under inclusion of all actors involved. Apparently there are some disparities within the different policy instruments. In order to successfully concertise the national policy framework it is of paramount importance to gather the policy actors involved and examine their suggestions for solving the issue. The article is enquiring amongst a number of high level Austrian experts and stakeholders about their perspectives and solutions for enhancing the contribution of the forest based sector to combat climate change. We examine the nature of the suggested instruments and outline the perceived options for action within the capacities of the forest based sector. This is done by way of a triangulation of face-to-face qualitative interviews, moderated focus group discussions and one survey. For the increase in carbon efficiency, all the participants notably emphasise long lasting material use and increase in use. Yet the opinions are contradicting when it comes to energetic use. Our findings indicate that the expert views reflect diverging perspectives on the use of wood for energy consumption. Some opt for policies that support energy consumption of wooden biomass to replace fossil fuels, others want any energy use of wood to become restricted drastically. As a final result, the article derives 16 principle policy measures and instruments that were brought up and assessed by the stakeholders in several rounds of interaction. We conclude that small improvements to existing measures could have ample impacts.

International audience; AbstractKey messageIn order to obtain the necessary information for decision making etc., it is of increasing importance to be able to assess increment in a reliable way. Only repeated measurements on permanent sample plots in national forest inventories can provide accurate and comprehensive information on the various components of annual increment. Such inventory systems are increasingly employed in European countries. The felling/increment ratio, characterizing wood use sustainability, should be expressed as the ratio of felled living trees (excluding dead trees) and net increment.ContextReporting of gross and net annual increment is an element of international forest resource assessments and crucial for sustainable forest management. A number of approaches exist for the estimation of increment and its various sub-components. AimsThe main objectives of the study are to assess in detail what methods European countries have used and are planning to use in the future for international reporting of increment. Also, the usefulness of the various approaches for the assessment of increment is evaluated.MethodsA questionnaire asking about their assessment methods was distributed among the UNECE/FAO national correspondents of all European countries and members of the UNECE/FAO Team of Specialists on Monitoring Sustainable Forest Management. Databases of the Temperate and Boreal Forest Resource Assessment 2000 and of the State of Europe’s Forests 2011 were also used. Furthermore, the methodological background was described on the basis of relevant literature sources and some examples for country groups presented.ResultsCountries have indicated what methods they used for assessment of various increment components, and the percentage of countries, forest area, and growing stock corresponding to these replies has been calculated. With regard to gross annual increment, these metrics represent about one third for inventories based on permanent sample plots, but this percentage is on the increase.ConclusionThe concept of the “control method” for forest management was developed more than 100 years ago but only utilized at the local level. The same methodology is now widely used at the national and regional level due to the implementation of modern national forest inventories using permanent sample plots. Care should be taken to utilize the data correctly for international forest resource assessments, in order to, e.g., avoid double counting of dead trees.

14 Pág., The quantification of forests available for wood supply (FAWS) is essential for decision-making with regard to the maintenance and enhancement of forest resources and their contribution to the global carbon cycle. The provision of harmonized forest statistics is necessary for the development of forest associated policies and to support decision-making. Based on the National Forest Inventory (NFI) data from 13 European countries, we quantify and compare the areas and aboveground dry biomass (AGB) of FAWS and forest not available for wood supply (FNAWS) according to national and reference definitions by determining the restrictions and associated thresholds considered at country level to classify forests as FAWS or FNAWS. FAWS represent between 75 and 95 % of forest area and AGB for most of the countries in this study. Economic restrictions are the main factor limiting the availability of forests for wood supply, accounting for 67 % of the total FNAWS area and 56 % of the total FNAWS AGB, followed by environmental restrictions. Profitability, slope and accessibility as economic restrictions, and protected areas as environmental restrictions are the factors most frequently considered to distinguish between FAWS and FNAWS. With respect to the area of FNAWS associated with each type of restriction, an overlap among the restrictions of 13.7 % was identified. For most countries, the differences in the FNAWS areas and AGB estimates between national and reference definitions ranged from 0 to 5 %. These results highlight the applicability and reliability of a FAWS reference definition for most of the European countries studied, thereby facilitating a consistent approach to assess forests available for supply for the purpose of international reporting., This research was supported by the Specific contract n. 18 “Use of National Forest Inventories data to estimate area and above ground biomass in European forests not available for wood supply” in the context of the Framework contract for the provision of forest data and services supporting the European Forest Data Centre 2012/ S 78-127532 of 21/04/2012 of the Joint Research Centre of the European Commission; the EG-013-72 agreement of the Ministry of Agriculture, Fisheries and Food (MAPA) and the INIA belonging to the Spanish Ministry of Science and Innovation (MICINN); and the project No.APVV-15-0265 granted by the Slovak Research and Development Agency.

We simulated Austrian forests under different sustainable management scenarios. A reference scenario was compared to scenarios focusing on the provision of bioenergy, enhancing the delivery of wood products, and reduced harvesting rates. The standing stock of the stem biomass, carbon in stems, and the soil carbon pool were calculated for the period 2010&ndash, 2100. We used the forest growth model C&acirc, ldis and the soil carbon model Yasso07. The wood demand of all scenarios could be satisfied within the simulation period. The reference scenario led to a small decrease of the stem biomass. Scenarios aiming at a supply of more timber decreased the standing stock to a greater extent. Emphasizing the production of bioenergy was successful for several decades but ultimately exhausted the available resources for fuel wood. Lower harvesting rates reduced the standing stock of coniferous and increased the standing stock of deciduous forests. The soil carbon pool was marginally changed by different management strategies. We conclude that the production of long-living wood products is the preferred implementation of climate-smart forestry. The accumulation of carbon in the standing biomass is risky in the case of disturbances. The production of bioenergy is suitable as a byproduct of high value forest products.

International audience; Key messageThe potential of European National Forest Inventories to harmonise stem quality estimation in European forests was identified despite considerable differences in existing national approaches.ContextKnowledge on stem quality and assortments structure in European forests is highly important for policy makers and the timber industry and also for carbon life cycle analysis due to the fact that different timber products have different end use and thus store carbon for different time periods.AimsThe study aim was to evaluate the potential of European National Forest Inventories (NFI) to objectively report on the stem quality in European forests in a harmonised manner.MethodsA comprehensive questionnaire was conducted as the first important step to evaluate the current status of stem quality assessment and assess the existing level of harmonisation.ResultsDirect stem quality assessment or classification is used in 19 out of 28 European NFIs. Only eight countries provide timber assortment estimates from their NFIs. In addition, different sampling strategies for stem quality assessment are used among NFIs. Tree parameters relevant for stem quality assessment on standing trees were identified for the purpose of harmonisation. Several methods towards harmonisation between European NFIs for the purpose of reporting on stem quality of European forests were suggested.ConclusionCurrent European NFIs are not capable of reporting the stem quality of European forests in a harmonised manner at this stage and considerable efforts will need to be taken before the harmonised stem quality estimation can be prepared. However, the inquiry also revealed that there is a potential to develop the harmonised estimations in future.

National forest inventories typically estimate individual tree volumes using models that rely on measurements of predictor variables such as tree height and diameter, both of which are subject to measurement error. The aim of this study was to quantify the impacts of these measurement errors on the uncertainty of the model-based tree stem volume estimates. The impacts were investigated using two approaches: the law of propagation of error and Monte Carlo simulation. Estimates of total uncertainty also included variability associated with the model itself. Results for both approaches indicate that the relative standard deviation over plots of the volume estimates for all tree species is approximately 11%. A partition of the total uncertainty by sources indicates that error in measurement of the upper diameter makes the greatest contribution. Thus, the greatest potential for improvement in the precision of overall estimates lies in increasing the accuracy of upper diameter measurements. Although the uncertainty of individual tree stem volume estimates may be considered negligible for nationwide assessments of growing stock volume, it is relevant for small-scale and plot-level estimates used as training or accuracy assessment data for remote sensing applications that rely on emerging technologies such as airborne laser scanning.

International audience; AbstractKey messageThe application of the ITOC model allows the estimation of available biomass potentials from forests on the basis of National Forest Inventory data. The adaptation of the model to country-specific situations gives the possibility to further enhance the model calculations.ContextWith the rising demand for energy from renewable sources, up-to-date information about the available amount of biomass on a sustainable basis coming from forests became of interest to a wide group of stakeholders. The complexity of answering the question about amounts of biomass potentials from forests thereby increases from the regional to the European level.AimsThe described ITOC model aims at providing a tool to develop a comparable data basis for the actual biomass potentials for consumption.MethodsThe ITOC model uses a harmonized net annual increment from the National Forest Inventories as a default value for the potential harvestable volume of timber. The model then calculates the total theoretical potential of biomass resources from forests. By accounting for harvesting restrictions and losses, the theoretical potential of biomass resources from forests is reduced and the actual biomass potentials for consumption estimated.ResultsThe results from ITOC model calculations account for the difference between the amounts of wood measured in the forests and the actual biomass potentials which might be available for consumption under the model assumptions.ConclusionThe gap between forest resource assessments and biomass potentials which are available for consumption can be addressed by using the ITOC model calculation results.

International audience; AbstractKey messageThe increment estimation methods of European NFIs were explored by means of 12 essential NFI features. The results indicate various differences among NFIs within the commonly acknowledged methodological frame. The perspectives for harmonisation at the European level are promising.ContextThe estimation of increment is implemented differently in European National Forest Inventories (NFIs) due to different historical origins of NFIs and sampling designs and field assessments accommodated to country-specific conditions. The aspired harmonisation of increment estimation requires a comparison and an analysis of NFI methods.AimsThe objective was to investigate the differences in volume increment estimation methods used in European NFIs. The conducted work shall set a basis for harmonisation at the European level which is needed to improve information on forest resources for various strategic processes. MethodsA comprehensive enquiry was conducted during Cost Action FP1001 to explore the methods of increment estimation of 29 European NFIs. The enquiry built upon the preceding Cost Action E43 and was complemented by an analysis of literature to demonstrate the methodological backgrounds. ResultsThe comparison of methods revealed differences concerning the NFI features such as sampling grids, periodicity of assessments, permanent and temporary plots, use of remote sensing, sample tree selection, components of forest growth, forest area changes, sampling thresholds, field measurements, drain assessment, involved models and tree parts included in estimates. ConclusionIncrement estimation methods differ considerably among European NFIs. Their harmonisation introduces new issues into the harmonisation process. Recent accomplishments and the increased use of sample-based inventories in Europe make perspectives for harmonised reporting of increment estimation promising.

A willingness to create precise definitions for terms describing forest resources between the National Forest Inventory (NFIs) data providers and UN international organisations dates back to the late nineties. European NFIs enhanced this harmonisation process by introducing the concepts of (i) reference definitions agreed by consensus but enforcing a more rigorous interpretation of such definitions (ii) bridges that allow for the transformation of national data into comparable data using an associated reference definition. Illustrative examples of some key definitions and case studies for generating comparable data are the core focus of this chapter. Discussions on recent harmonisation processes, including the way of working and a framework for future proposals are given by way of conclusion.

The main objective of COST Action Usewood was to improve and harmonise data and information from National Forest Inventories (NFIs) on the potential supply of wood resources at European level considering the actual extent. This will improve the quality of data available to describe wood resources and possible wood uses. Such high quality information could be used for future scenario modelling and help inform political decision making for the renewable energy sector. The harmonisation of NFIs is based on reference definitions. Four different topics in terms of wood supply are covered and described in this chapter: forest available for wood supply, change estimation, stem quality, other wooded land and trees outside forest. These definitions will enable data comparison between countries and consequently, this will imply a transparent, comprehensive and robust information for decision-making.

Key message This analysis of the tools and methods currently in use for reporting woody biomass availability in 21 European countries has shown that most countries use, or are developing, National Forest Inventory-oriented models whereas the others use standwise forest inventory--oriented methods. Context Knowledge of realistic and sustainable wood availability in Europe is highly relevant to define climate change mitigation strategies at national and European level, to support the development of realistic targets for increased use of renewable energy sources and of industry wood. Future scenarios at European level highlight a deficit of domestic wood supply compared to wood consumption, and some European countries state they are harvesting above the increment. Aims Several country-level studies on wood availability have been performed for international reporting. However, it remains essential to improve the knowledge on the projection methods used across Europe to better evaluate forecasts. Methods Analysis was based on descriptions supplied by the national correspondentsinvolved in USEWOOD COST Action (FP1001), and further enriched with additionaldata from international reports that allowedcharacterisation of the forests in these countries for the same base year. Results Methods currently used for projecting wood availability were described for 21 European countries. Projection systems based on National Forest Inventory (NFI) data prevail over methods based on forest management plans. Only a few countries lack nationwide projection tools, still using tools developed for specific areas. Conclusions A wide range of NFI-based systems for projecting wood availability exists, being under permanent improvement. The validation of projection forecasts and the inclusion of climate sensitive growth models into these tools are common aims for most countries. Cooperation among countries would result in higher efficiency when developing and improving projection tools and better comparability among them. © 2016, INRA and Springer-Verlag France.

The collection of information on the approaches of wood resources assessment was essential to provide background details necessary to meet the objectives of COST Action Usewood. This chapter describes the processes that were used by COST Action Usewood to review the wood resource assessment methods used in NFI’s and gives an insight into the differences and similarities of definitions and methods applied by European NFIs. To address the specific objectives of COST Action Usewood, the activities of WG1 were organised into four sub-groups that would comprehensively describe the assessment of wood resources. The four sub-groups dealt with the topics of; Forest Available for Wood Supply, Stem Quality, Change Estimation and Other Wooded Land and Trees Outside Forest. The information provided through questionnaires and country reports provided the raw materials required to understand the differences between the definitions and components that make up the definitions that are applied nationally by the various NFIs. Results from the four sub-groups are presented outlining the diversity and similarities among the assessment of wood resources between countries.

Anthropogenic GHG emissions add a fast reinforcing feedback cycle to global carbon dynamics which continues to influence GHG concentrations in the Earth's atmosphere. When looking at forest carbon cycles there is potential in utilizing another feedback cycle, namely the carbon cycle involving harvested wood products. To assess the potential of the mitigation options arising from these carbon flows, the forest-based sector in Austria was modelled to assess causal links, dependencies and dynamics involved in GHG-relevant processes. Carbon dynamics were investigated in forests and forest soil carbon, the forest product chain and life-cycle analyses for substitution of conventional products with wood products in a cascade of different modelling approaches and paradigms, and the results synthesized. It was found that material use of products from domestic timber sources has the highest climate change mitigation efficiency when originating from sustainably managed forests regarding biomass stocks. The emissions saved through building up a carbon stock from harvested wood products and through emissions substitution can be as high as ∼20 years of total annual Austrian emissions in 90 years. Additional conservation measures while sustaining sawnwood production and the related GHG benefits at a high level had the highest contribution to an overall carbon sink.

For international reporting purposes, information on forest resources often has to be supplied according to international definitions. Nevertheless, the country reports of the Food and Agriculture Organization (FAO) Global Forest Resources Assessment 2005 indicate that countries either prefer to use their own forest definitions or use national classes of forest and other biomes as a basis for reclassification to resolve the discrepancy between national and international forest definitions. These preferences are due to the complexity encountered when dealing with the problem of transforming national estimates into estimates according to an international definition but are also due to the lack of a methodological foundation. In view of the multitude of existing national forest definitions and the increasing international reporting requirements, a thorough methodological consideration of the problem appears to be particularly necessary. Therefore, a mathematical approach for comparing national definitions to an international definition is developed. After formalization of definitions and illustration of the peculiarities in national forest definitions, the basics of set theory and simple logic are applied to derive six relevant cases that describe how national definitions of forest are distinct from that of FAO. As a result, we are able to assign each country to a specific case and thus provide a basis for further analyses. We also reflect on the reclassification problem and describe two examples that illustrate the influence of assessment methods in the aim to report according to a common definition.

The evolution of national forest inventories (NFIs) has varied enormously between countries, and the process still continues. This evolution is documented in the histories of European NFIs, as well as others in North and South America, Asia, and New Zealand that are included in the NFI Reports section of this book. COST Action E43 has been a catalyst for harmonising European definitions that have resulted from these varied evolutions and has produced a template that can be used for harmonisation in other regions. The purpose of this chapter is to summarize the NFI reports, albeit by illustrating the diversity in NFI features as partial motivation for Chapter 3 which describes harmonisation procedures and touts the successes of the Action. Much of the information in this chapter is presented in the form of tables that report details of NFIs for individual countries. However, because the purpose of the tables and the entire chapter is primarily to illustrate the diversity of NFI features, only selected details for selected countries are reported. The complete details for all countries submitting NFI reports may be found in the NFI Reports section of this book.

The overall objective of COST Action E43 was to enhance national forest inventories (NFI) for purposes of national and global reporting. In the process of accomplishing this objective the Action promoted scientifically sound methods for assessing forest resources, forest carbon pools and forest biodiversity. Beginning with international reporting requirements and the current status and practices of the NFIs, COST Action E43 focused on establishing reference definitions that could be commonly accepted by the participants and that would be applicable for international reporting. As explained in the previous chapters, these definitions are called reference definitions. However, common agreement was not achieved for a small proportion of proposed reference definitions, leaving need for further work. In addition to establishing definitions, techniques were developed to convert estimates based on national definitions to estimates based on reference definitions. These techniques can be viewed either as an intermediate step on the way to adoption of reference definitions or as permanent solutions if a country chooses not to use the reference definitions. This chapter briefly summarizes the main accomplishments of COST Action E43 and identifies future challenges.

At the international level, various definitions have been established for the compilation and publication of forest resources assessment results over the last decade. These international definitions frequently rely on terms that are not precisely specified for inventory purposes and do not completely cover the requirements arising from the application of National Forest Inventory (NFI) data. Also, with respect to conventional topics such as forest area and growing stock estimation, several terms and expressions referring to individual trees are not, or are only vaguely, defined until now. Since the individual tree is the basic element of any forest resources assessment, the clarification of tree-related terms is an important part of COST Action E43 to harmonise common reporting of National Forest Inventories. Based on a review of existing definitions and on the requirements for harmonised reporting, common tree-related definitions are established. One objective of this study is to refine and enhance the applicability of available tree and shrub definitions, in particular with regard to the distinction between trees and shrubs. The study also focuses on the parts or “elements” of trees and on the distinction between these elements as they are of particular importance in growing stock and biomass definitions. Furthermore, several definitions for tree characteristics such as “living” and “standing”, as well as tree variables such as height, length, diameter at breast height, and crown projection area are adjusted with respect to NFI purposes. A concluding discussion reflects upon the reviewed, refined and newly established definitions. The definitions presented in this paper provide a firm basis for a common set of harmonised reference definitions developed by COST Action E43 and contribute to the precise and consistent use of terms.

International agreements such as the Kyoto protocol and Convention on Biological Diversity (1992), as well as, criteria and indicator processes require reports on the status of nations’ forests. Any comparison of the current status and trends of forest resources among nations presumes that the nations’ applied definitions and concepts produce comparable estimates of the status of forests. In spite of this, the FAO has already collected global information for 60 years and made noticeable efforts in creating common definitions, but forest related data are still collected using diverse definitions, even regarding basic concepts such as forest and forest area. A simple consequence is that the cross-countries estimates are not comparable. The reasons behind the differences in the definitions are diverse histories, and sometimes different use of forests. In an ideal case, national forest inventories should fulfil both national and international needs. In addition to the FAO’s Forest Resources Assessment process, other efforts are made to assess the status of forests in European countries, e.g. European Forest Information and Communication System (EFICS). EFICS produced reports about forest inventories but does not suggest any common definition or method to convert estimates from one definition to another one. This article presents principles and methods to create commonly acceptable and adoptable definitions for forest inventories. The principles and methods are demonstrated using two examples: the reference definitions of forest and growing stock. The article is based on the work of COST Action E43 (http://www.metla.fi/eu/cost/e43/).