Fraxinus excelsior
Common ash

Common ash (Fraxinus excelsior) is a medium-sized deciduous tree, and the largest tree in the genus Fraxinus. The natural range of the tree covers most of Europe, with the exception of the most northern and southern parts of the continent. The timber of common ash is hard and elastic and withstands pressure, which makes it very suitable for tool handles, sports equipment as well as for furniture, veneer and flooring.

Common ash requires a rich soil and is highly tolerant to seasonal flooding and soil acidity. It is requires a significant amount of light and can typically be found in slopes and ravines or in disturbances of forest stands.

Since the mid-1990’s, an ash dieback has widely spread in Europe, causing the death of over 90% of all ash trees in several countries.

Read more about the ash dieback

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EUFORGEN’s publications on Abies alba

Technical guidelines for genetic conservation and use

Fraxinus excelsior - Technical guidelines for genetic conservation and use for common ash

Publication Year: 2003
Author: Pliûra, A.; Heuertz, M.

Genetic conservation aims at ensuring continuous survival and adaptability of the target species. These objectives are met when the Multiple Population Breeding System (MPBS) is applied. Ideally in MPBS, a breeding population is subdivided into subpopulations which are then grown over a wide range of site conditions.

In each country where common ash is found, an inventory should be undertaken to define the geographical distribution of the species, conservation status, threats and potential use patterns. Ecogeographic zones (provenance regions) should be delimited according to climatic variation, topography, soil and vegetation. Trees are generally best adapted to the ecological conditions of the region where they evolved. Therefore, local material should be used for plantations wherever possible, unless otherwise recommended as the result of data from provenance trials.

To ensure the adaptive potential of Fraxinus excelsior in Europe, it is recommended that two complementary gene conservation networks of populations are established, specifically: (1) a network of 20-30 in situ populations throughout provenance regions; and (2) a network of ex situ populations (progeny trials, provenance trials, collections). Whenever possible, in situ conservation activities should be undertaken jointly for other Noble Hardwoods.

Where common ash occurs in large populations in a country, in situ conservation is sufficient, with the selection of up to three gene conservation populations/ gene reserves of 5-15 ha in size, with at least 100 flowering trees in each provenance. A high density of in situ gene conservation populations should be established in Southeast Europe, especially in Romania and Bulgaria, which have been colonised by populations from different ice age refuges. In these regions, neutral genetic markers show high differentiation among populations, suggesting that they may have different potentials to cope with future climatic conditions. Specific conservation efforts are also recommended in northern central Europe, due to the high level of differentiation between populations in southern Sweden, although the historical origin of this differentiation still needs to be verified.

In situ gene conservation populations need to be managed to increase their adaptive potential by ensuring the natural regeneration of the target species, creating multi-age structure and habitat diversity, and increasing generation turnover.

To conserve an even-aged mature stand in situ, parts of the population should be opened (thinned or cut in narrow strips of 15-30 m width) to create conditions for natural regeneration. Preferably, this should be undertaken in the year following the mast, when maximum seed is produced by the stand. An area adjacent to the gene reserve could be set aside for natural regeneration, and could later be incorporated as part of the reserve.

To promote regeneration in clear-cut strips, randomly selected, abundantly flowering seed trees should be left. If the population consists of some stands or groups of trees of different ages but there is no regeneration, the oldest stands or groups should be cut as soon as the mast years have produced sufficient seed yield or regeneration under the canopy or in areas set aside. Increasing the number of stands or demes (groups of trees) of different ages in the population enhances intra-population genetic variation as the portion of trees involved in regeneration increases. Regeneration can also be stimulated by site scarification and weed control. If these regeneration support measures are not successful, it is recommended that material originating from the population is planted: seed should be collected from at least 50 trees per population, preferably from central parts of the gene reserve. To prevent gene flow from outside the gene reserve, a buffer zone of 100- 150 m should be created by gradually removing mature flowering ash trees within this zone.

To secure the sustainability of each population, careful tending is required. Effective treatment including adequate silvicultural measures, protection against disease or insect outbreaks, fire or other factors must be undertaken promptly. Thinning should be undertaken from below, removing suppressed and injured trees, thus simulating and stimulating the natural selection processes in the forest, and stand regeneration. Each gene conservation population must be constantly monitored, including the health status and regeneration success.

For populations that are marginal, isolated, endangered, growing under special ecological conditions or carrying rare features, in situ conservation should be complemented by ex situ measures. The most effective form is through progeny trials, which permits joint gene conservation and breeding. On a national scale, 1-3 progeny plantations for conservation/breeding (each of 2-4 ha in size) should be established in each provenance region with entries sampled from single trees randomly chosen from 10- 20 stands within the region and from marginal populations if applicable. As soon as reproductive age is reached, open pollination of the best individuals selected within each family should ensure the next generation. About 50 optimally adapted individuals should be the founders of each new gene conservation/ breeding sub-population

Genetic conservation aims at ensuring continuous survival and adaptability of the target species. These objectives are met when the Multiple Population Breeding System (MPBS) is applied. Ideally in MPBS, a breeding population is subdivided into subpopulations which are then grown over a wide range of site conditions.

In each country where common ash is found, an inventory should...

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Acknowledgements

This distribution map has been developed by the European Commission Joint Research Centre (partly based on the EUFORGEN map) and released under Creative Commons Attribution 4.0 International (CC-BY 4.0)


Caudullo, G., Welk, E., San-Miguel-Ayanz, J., 2017. Chorological maps for the main European woody species. Data in Brief 12, 662-666. DOI: https://doi.org/10.1016/j.dib.2017.05.007

The following experts have contributed to the development of the EUFORGEN distribution maps:

Fazia Krouchi (Algeria), Hasmik Ghalachyan (Armenia), Thomas Geburek (Austria), Berthold Heinze (Austria), Rudi Litschauer (Austria), Rudolf Litschauer (Austria), Michael Mengl (Austria), Ferdinand Müller (Austria), Franz Starlinger (Austria), Valida Ali-zade (Azerbaijan), Vahid Djalal Hajiyev (Azerbaijan), Karen Cox (Belgium), Bart De Cuyper (Belgium), Olivier Desteucq (Belgium), Patrick Mertens (Belgium), Jos Van Slycken (Belgium), An Vanden Broeck (Belgium), Kristine Vander Mijnsbrugge (Belgium), Dalibor Ballian (Bosnia and Herzegovina), Alexander H. Alexandrov (Bulgaria), Alexander Delkov (Bulgaria), Ivanova Denitsa Pandeva (Bulgaria), Peter Zhelev Stoyanov (Bulgaria), Joso Gracan (Croatia), Marilena Idzojtic (Croatia), Mladen Ivankovic (Croatia), Željka Ivanović (Croatia), Davorin Kajba (Croatia), Hrvoje Marjanovic (Croatia), Sanja Peric (Croatia), Andreas Christou (Cyprus), Xenophon Hadjikyriacou (Cyprus), Václav Buriánek (Czech Republic), Jan Chládek (Czech Republic), Josef Frýdl (Czech Republic), Petr Novotný (Czech Republic), Martin Slovacek (Czech Republic), Zdenek Špišek (Czech Republic), Karel Vancura (Czech Republic), Ulrik Bräuner (Denmark), Bjerne Ditlevsen (Denmark), Jon Kehlet Hansen (Denmark), Jan Svejgaard Jensen (Denmark), Kalev Jðgiste (Estonia), Tiit Maaten (Estonia), Raul Pihu (Estonia), Ülo Tamm (Estonia), Arvo Tullus (Estonia), Aivo Vares (Estonia), Teijo Nikkanen (Finland), Sanna Paanukoski (Finland), Mari Rusanen (Finland), Pekka Vakkari (Finland), Leena Yrjänä (Finland), Daniel Cambon (France), Eric Collin (France), Alexis Ducousso (France), Bruno Fady (France), François Lefèvre (France), Brigitte Musch (France), Sylvie Oddou-Muratorio (France), Luc E. Pâques (France), Julien Saudubray (France), Marc Villar (France), Vlatko Andonovski (FYR Macedonia), Dragi Pop-Stojanov (FYR Macedonia), Merab Machavariani (Georgia), Irina Tvauri (Georgia), Alexander Urushadze (Georgia), Bernd Degen (Germany), Jochen Kleinschmit (Germany), Armin König (Germany), Armin König (Germany), Volker Schneck (Germany), Richard Stephan (Germany), H. H. Kausch-Blecken Von Schmeling (Germany), Georg von Wühlisch (Germany), Iris Wagner (Germany), Heino Wolf (Germany), Paraskevi Alizoti (Greece), Filippos Aravanopoulos (Greece), Andreas Drouzas (Greece), Despina Paitaridou (Greece), Aristotelis C. Papageorgiou (Greece), Kostas Thanos (Greece), Sándor Bordács (Hungary), Csaba Mátyás (Hungary), László Nagy (Hungary), Thröstur Eysteinsson (Iceland), Adalsteinn Sigurgeirsson (Iceland), Halldór Sverrisson (Iceland), John Fennessy (Ireland), Ellen O'Connor (Ireland), Fulvio Ducci (Italy), Silvia Fineschi (Italy), Bartolomeo Schirone (Italy), Marco Cosimo Simeone (Italy), Giovanni Giuseppe Vendramin (Italy), Lorenzo Vietto (Italy), Janis Birgelis (Latvia), Virgilijus Baliuckas (Lithuania), Kestutis Cesnavicius (Lithuania), Darius Danusevicius (Lithuania), Valmantas Kundrotas (Lithuania), Alfas Pliûra (Lithuania), Darius Raudonius (Lithuania), Robert du Fays (Luxembourg), Myriam Heuertz (Luxembourg), Claude Parini (Luxembourg), Fred Trossen (Luxembourg), Frank Wolter (Luxembourg), Joseph Buhagiar (Malta), Eman Calleja (Malta), Ion Palancean (Moldova), Dragos Postolache (Moldova), Gheorghe Postolache (Moldova), Hassan Sbay (Morocco), Tor Myking (Norway), Tore Skrøppa (Norway), Anna Gugala (Poland), Jan Kowalczyk (Poland), Czeslaw Koziol (Poland), Jan Matras (Poland), Zbigniew Sobierajski (Poland), Maria Helena Almeida (Portugal), Filipe Costa e Silva (Portugal), Luís Reis (Portugal), Maria Carolina Varela (Portugal), Ioan Blada (Romania), Alexandru-Lucian Curtu (Romania), Lucian Dinca (Romania), Georgeta Mihai (Romania), Mihai Olaru (Romania), Gheorghe Parnuta (Romania), Natalia Demidova (Russian Federation), Mikhail V. Pridnya (Russian Federation), Andrey Prokazin (Russian Federation), Srdjan Bojovic (Serbia) , Vasilije Isajev (Serbia), Saša Orlovic (Serbia), Rudolf Bruchánik (Slovakia), Roman Longauer (Slovakia), Ladislav Paule (Slovakia), Gregor Bozič (Slovenia), Robert Brus (Slovenia), Katarina Celič (Slovenia), Hojka Kraigher (Slovenia), Andrej Verlič (Slovenia), Marjana Westergren (Slovenia), Ricardo Alía (Spain), Josefa Fernández-López (Spain), Luis Gil Sanchez (Spain), Pablo Gonzalez Goicoechea (Spain), Santiago C. González-Martínez (Spain), Sonia Martin Albertos (Spain), Eduardo Notivol Paino (Spain), María Arantxa Prada (Spain), Alvaro Soto de Viana (Spain), Lennart Ackzell (Sweden), Jonas Bergquist (Sweden), Sanna Black-Samuelsson (Sweden), Jonas Cedergren (Sweden), Gösta Eriksson (Sweden), Markus Bolliger (Switzerland), Felix Gugerli (Switzerland), Rolf Holderegger (Switzerland), Peter Rotach (Switzerland), Marcus Ulber (Switzerland), Sven M.G. de Vries (The Netherlands), Khouja Mohamed Larbi (Tunisia), Murat Alan (Turkey), Gaye Kandemir (Turkey), Gursel Karagöz (Turkey), Zeki Kaya (Turkey), Hasan Özer (Turkey), Hacer Semerci (Turkey), Ferit Toplu (Turkey), Mykola M. Vedmid (Ukraine), Roman T. Volosyanchuk (Ukraine), Stuart A'Hara (United Kingdom), Joan Cottrell (United Kingdom), Colin Edwards (United Kingdom), Michael Frankis (United Kingdom), Jason Hubert (United Kingdom), Karen Russell (United Kingdom), C.J.A. Samuel (United Kingdom).
 

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