To learn more about the map elements, please download the "Pan-European strategy for genetic conservation of forest trees"
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).
Status of Liquidambar orientalis conservation in Europe
Genetic diversity in oriental sweetgum is typically low, although some populations located in optimal areas for the species’ growth do exhibit high genetic diversity (Alan and Ezen, 2018; Doğaroğlu et al., 2023). Genetic analysis revealed there are significant genetic differences within and between populations, with greater variation between populations; this has resulted in high genetic differentiation because of low gene flow (Alan and Ezen, 2018; Yuzer, Tonguç, and Doğaç, 2022). Up to 70% of genetic variation is between populations (Yuzer, Tonguç, and Doğaç, 2022). Northen populations and those at higher elevations are more genetically differentiated than more central populations (Alan and Ezen, 2018). Oriental sweetgum individuals at higher altitudes are found in smaller populations and have greater frost tolerance (Alan and Kaya, 2003). Low gene flow may have also caused genetic bottlenecking, reducing the species’ adaptability and resilience (Alan and Ezen, 2018).
The bibliographic review was conducted by James Chaplin of the EUFORGEN Secretariat in August 2024.
Two morphological variants of oriental sweetgum are observed, one which is smaller and produces oil, and a larger one that does not produce oil (Alan and Kaya, 2003). However, some research recognizes two varieties, Liquidambar orientalis var orientalis and Liquidambar orientalis var integriloba, distinguished by their morphological characteristics (Yuzer, Tonguç, and Doğaç, 2022). However, these two varieties cannot be genetically separated (Yuzer, Tonguç, and Doğaç, 2022; Doğaroğlu et al., 2023).
The bibliographic review was conducted by James Chaplin of the EUFORGEN Secretariat in August 2024.
Many oriental sweetgum trees have been damaged by overexploitation and poor oil production methods as wounding of the tree is required to stimulate oil production (Alan and Kaya, 2003; Alan and Ezen, 2018; Doğaroğlu et al., 2023). Oriental sweetgum often grows on fertile soils suitable for agriculture, and as a result many forest stands have been cleared for farmland (often illegally) (Alan and Ezen, 2018). Additional threats to the tree include overgrazing, tourism, habitat destruction, and fires (Alan and Kaya, 2003; Yuzer, Tonguç, and Doğaç, 2022; Doğaroğlu et al., 2023).
Oriental sweet gum was widespread across Europe in the Pleistocene and historically had a much wider range across Anatolia (Doğaroğlu et al., 2023). Seventy years ago, the species covered some 7 000 ha, the area declining to 3 200 ha 50 years later (Alan and Kaya, 2003). Because of these threats, reduced range, and limited options for range expansion, the species is now at risk of extinction (Yuzer, Tonguç, and Doğaç, 2022). Even sweetgum oil production has been reduced (Yuzer, Tonguç, and Doğaç, 2022).
To meet the specific conservation requirements, seed stands, nature conservation areas and clonal seed orchards should be revised to increase the population sizes and capture the adaptive variation in oriental sweet gum by ensuring representation of diverse habitats within the natural range of the species (Alan and Kaya, 2003). Natural regeneration should be favoured as seed production in oriental sweetgum is normally sufficient (Alan and Kaya, 2003). Local material should also be used for afforestation purposes wherever possible and in situ stands should be actively manged through thinning, understory clearing, and weeding (Alan and Kaya, 2003). Conservation stands can also be managed for oil production and can be mixed with oriental plane (Platanus orientalis) and oriental alder (Alnus orientalis) as oriental sweetgum often occurs naturally in mixed forests with these species (Alan and Kaya, 2003). Ex situ collections should utilize local seed sources and measures should be taken to protect them against undesired pollination from outside (Alan and Kaya, 2003).
The bibliographic review was conducted by James Chaplin of the EUFORGEN Secretariat in August 2024.
Genetic Characterisation of Liquidambar orientalis and its GCUs
Availability of FRM
FOREMATIS
Liquidambar orientalis - Technical guidelines for genetic conservation and use for oriental sweet gum
Publication Year: 2003The genetic structure of populations urgently needs to be investigated for conservation purposes.
Although there are currently no comprehensive conservation measures, some practices, such as seed stands, nature conservation areas and clonal seed orchards, have contributed to the dynamic conservation process of oriental sweet gum. To meet the specific conservation requirements, these programmes must be revised to increase the population sizes and ensure representation of diverse habitats within the natural range of the species.
For species with limited genetic information, it is often assumed that genetic variation follows geographic and ecological variation. To capture the adaptive variation in oriental sweet gum, ecogeographic zones should be defined according to climatic variation. The minimum effective size of a gene conservation population is 50 trees, and it is recommended that each population is composed of at least 150-200, to ensure enough flowering and fruiting trees.
Natural regeneration should be stimulated and used wherever ecological conditions allow. Seed production is normally sufficient and seed orchards can produce seed in about seven years. To conserve and enhance the diversity in small populations it is also recommended that effective population sizes are increased by planting local material.
Local material should also be used for afforestation purposes wherever possible. For the further improvement of oriental sweet gum plantations, “selected” and “tested” material (seed or clonal) should be used in future.
In situ stands should be tended, including thinning, understory clearing, and weeding. These and other silvicultural measures in gene conservation stands are more effective than if the stands are left unmanaged.
Multiple uses of the gene conservation stands are encouraged, including oil production. Recommended oil production methods (Topçuolu, 1968) should be followed to ensure sustainable oil production. The designated gene conservation stands should serve as a source of reproductive material for breeding, afforestation, oil production and landscape planting. Utilizing well adapted seed sources is the most effective tool in genetic conservation. Trees can also be planted in forest riverbeds to act as a firebreak for Pinus brutia, and this should be promoted to increase the use of this species.
In order to conserve sufficient genetic variation to maintain the adaptive potential of oriental sweet gum, it is recommended that a network of in situ gene conservation stands is established throughout the distribution area. Several fairly small populations could be selected for the establishment of such a network. Since oriental sweet gum exists in mixed stands with Platanus orientalis and Alnus orientalis which are also Noble Hardwoods, a few natural populations could be extended to conserve the associated species. This in situ network should be complemented with ex situ collections, which will also enable provenance research. The establishment of new clonal seed orchards should be especially considered for oil production to reduce the pressure on natural stands.
In regions where seed sources are limited, local ex situ collections (stands) should be established to serve both conservation and seed production. These collections should typically be established within the local region of provenance. Measures should be taken to protect them against undesired pollination from outside. These stands can be bulk collections, seedling seed orchards and clonal seed orchards. From a conservation perspective, priority should be given to resources that are threatened by extinction or contamination from undesired provenances, small populations and unique populations or individuals.
Contacts of experts
NA
Further reading
Özdilek, A. 2007. Genetic differentiation of Liquidambar orientalis Mill. varieties with respect to matK region of chloroplast genome. MSc thesis. Ankara, Middle East Technical University.
References
Alan, M. and Ezen, T. 2018. Magnitude of genetic variation in seedling traits of Liquidambar orientalis populations. Fresenius Environmental Bulletin, 27: 1522–1531.
Alan, M. and Kaya, Z. 2003. EUFORGEN Technical Guidelines for genetic conservation and use for oriental sweet gum (Liquidambar orientalis). Rome, International Plant Genetic Resources Institute. 6 pp.
Doğaroğlu, T., Günenç, E., Manap, R.Y., Taşkın, V., Taşkın, B.G., and Doğaç, E. 2023. Genetic structure and phylogenetic analysis of Liquidambar orientalis Mill. (Altingiaceae) populations based on non-coded psaA/ycf3 intergenic region in the chloroplast genome in Türkiye. Turkish Journal of Bioscience and Collections, 7(2): 45–58.
Yuzer, Ö., Tonguç, A., and Doğaç, E. 2022. Genetic characterization of endemic Liquidambar orientalis populations in Muğla province based on ISSR polymorphism. Research Square. https://doi.org/10.21203/rs.3.rs-1958799/v1
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