The technical term reduced yield stands – sometimes reduced yield soils – is widely used in the Finnish forest literature. However, there is no clear definition of the notion reduced yield and no explanation of how this notion is measured in the classifications. Some committee reports and bill proposals and some laws and statutes use the reduced yield forest soil. No definition can be found. In my opinion the term reduced yield forest soils ought to be completely abolished until forest soil experts can perhaps define what it means, if they consider such a concept useful.

Explanations for the term reduced yield stands can be found in the descriptions of classification systems of stands. According to them, the criterion is partly silvicultural (site, species of tree), partly mensurational (volume, sometimes growth), partly economic. No explanation is found as to how the economic aspect is measured, nor about the limit of a full yield and reduced yield.

In my opinion such a term is confusing. I therefore suggest that the term reduced yield stand ought to be abolished. If something is needed instead, I suggest the term understocked stand, defined as a growing stock under certain percentage of a fully stocked stand. The notion of economic reduced yield cannot be generally tied to certain silvicultural and mensurational characteristics of stands. The economic aspect of certain kinds of stands may differ, depending on the owner of the forest and his economic situation, the location of the forest, the composition of the whole forest ownership unit, etc.

The PDF includes a summary in English.

Saari, E-mail: es@mm.unknown

Category : Research article

article id 255, category Research article

Claude Vidal, Adrian Lanz, Erkki Tomppo, Klemens Schadauer, Thomas Gschwantner, Lucio di Cosmo, Nicolas Robert. (2008). Establishing forest inventory reference definitions for forest and growing stock: a study towards common reporting. Silva Fennica vol. 42 no. 2 article id 255. https://doi.org/10.14214/sf.255

Keywords: national forest inventories; reference definitions; growing stock; harmonisation; analytical decomposition

Abstract | View details | Full text in PDF | Author Info

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/).

Vidal, Inventaire Forestier National, Château des Barres, Nogent-sur-Vernisson, France E-mail: claude.vidal@ifn.fr
Lanz, WSL/FNP, Abteilung Landschaftsinventuren, Birmensdorf, Switzerland E-mail: al@nn.ch
Tomppo, Finnish Forest Research Institute, Vantaa Research Unit, Vantaa, Finland E-mail: et@nn.fi
Schadauer, Bundesamt und Forschungszentrum für Wald, Wien, Austria E-mail: ks@nn.at
Gschwantner, Bundesamt und Forschungszentrum für Wald, Wien, Austria E-mail: tg@nn.at
di Cosmo, ISAFA, Villazzano, Italy E-mail: ldc@nn.it
Robert, Inventaire Forestier National, Ch‰teau des Barres, Nogent-sur-Vernisson, France E-mail: nr@nn.fr

Category : Review article

article id 463, category Review article

Thomas Gschwantner, Klemens Schadauer, Claude Vidal, Adrian Lanz, Erkki Tomppo, Lucio di Cosmo, Nicolas Robert, Daisy Englert Duursma, Mark Lawrence. (2009). Common tree definitions for national forest inventories in Europe. Silva Fennica vol. 43 no. 2 article id 463. https://doi.org/10.14214/sf.463

Keywords: harmonisation; COST Action E43; tree definitions; shrub definitions; tree elements; tree variables; tree characteristics

Abstract | View details | Full text in PDF | Author Info

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.

Gschwantner, Federal Research and Training Centre for Forests, Natural Hazards and Landscape, Wien, Austria E-mail: thomas.gschwantner@bfw.gv.at
Schadauer, Federal Research and Training Centre for Forests, Natural Hazards and Landscape, Wien, Austria E-mail: ks@nn.at
Vidal, French National Forest Inventory, Nogent-sur-Vernisson, France E-mail: cv@nn.fr
Lanz, Swiss Federal Institute for Forest, Snow and Landscape Research, Birmensdorf, Switzerland E-mail: al@nn.ch
Tomppo, Finnish Forest Research Institute, Vantaa, Finland E-mail: et@nn.fi
di Cosmo, Agricultural Research Council – Forest Monitoring and Planning Research Unit, Trento, Italy E-mail: ldc@nn.it
Robert, French National Forest Inventory, Nogent-sur-Vernisson, France E-mail: nr@nn.fr
Englert Duursma, Finnish Forest Research Institute, Vantaa, Finland E-mail: ded@nn.fi
Lawrence, Northern Research Station, Roslin, Midlothian, Great Britain E-mail: ml@nn.uk

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