Littérature scientifique sur le sujet « Cedar of Lebanon (Cedrus libani) »

The true cedars (genus Cedrus) are valuable timber trees and striking specimen plantings in the urban landscape that grow well in a variety of soil and climatic conditions. The wood is durable and decay resistant. Cedars have been successfully introduced into areas outside of their natural range. The 4 species of Cedrus, 3 of which are planted to some extent in the United States, are C. atlantka (Atlas cedar), C. brevijolia (Cyprian cedar), C. deodara (Deodar cedar), and C. libani (Cedar of Lebanon). In this review, the geographical distribution, taxonomic characteristics, propagation, and adaptation to the urban landscape of cedars are discussed. This information is relevant to horticulturists, botanists, foresters, and anyone interested in the field of arboriculture.

AbstractConiferous forests are an important component of the Lebanese landscape. Ten species of conifers in five genera are found as wild populations in Lebanon: Cilician fir Abies cilicica, cedar of Lebanon Cedrus libani, Mediterranean Cyprus Cupressus sempervirens, Syrian juniper Juniperus drupacea, Grecian juniper J. excelsa, willdenow J. foetidissima, prickly juniper J. oxycedrus, Calabrian pine Pinus brutia, Aleppo pine P. halepensis and stone pine P. pinea. Although none of these species are seriously threatened in a global context, they exist in Lebanon mostly as fragmented and degraded populations, and their habitats are under great pressure from urbanization and associated development. Conservation efforts in Lebanon have concentrated mainly on the cedar of Lebanon, with two cedar of Lebanon forests protected as Nature Reserves. Large areas of forest, coniferous and otherwise, remain unprotected. In this review, the need for an integrated approach to conservation of the coniferous landscape of Lebanon and the importance of the participation of local communities in this process are emphasized.

Somatic embryogenesis offers a great potential for large-scale production of Cedrus libani, which is important not only as a forest tree, but also for the development of a timber industry. In an attempt to optimize conditions for embryogenic callus induction, we used zygotic embryos at different developmental stages as explants, compared different media, and used several hormone levels and combinations. Results indicated that post-cotyledonary immature embryos had highest induction efficiency. Four different media namely 1/2 MS, Durzan, Litvay's, and Von Arnold supplemented with similar hormone levels showed no significant difference in efficiency of callus induction. Induction frequencies of embryogenic callus from explants subjected to different hormone levels and combinations were dependent on the developmental stage of the explant.

Lebanon cedar (Cedrus libani A. Rich) is an ecologically, economically, and historically important conifer species that currently mainly occurs in the Taurus Mountains in southern Turkey. In former times, extensive forests of this species were also found in Syria and Lebanon. However, because of intensive cutting, burning, and goat grazing, only small populations are left in these countries. Currently, the range of Lebanon cedar covers approximately 600,000 ha in Turkey, including extremely degraded stands and bare karstic land that was previously covered by this species (1). Therefore, efforts to protect existing forests and promote natural regeneration of this endangered tree species were undertaken in recent years. In addition, reforestations were carried out on bare karstic lands to expand the population of Lebanon cedar in Turkey. During disease surveys, carried out in October 2009 in the Mt. Dedegül Region of the western Taurus Mountains (37°36′54″N, 31°20′00″E), a dieback of lower branches and young plants of C. libani was observed at 1,700 to 1,885 m above sea level. The disease often occurred in scattered patches and was most evident near the timberline. Needles, shoots, and twigs of affected trees or entire small trees were covered or completely enmeshed in silky, shining, blackish brown mycelial felts. Symptoms resembled those of brown felt blight, also known as black snow mold, caused by Herpotrichia juniperi and Neopeckia coulteri on various other conifer species (2). For fungal isolation and identification, 18 twig samples from 14 different C. libani trees were collected. Two colonized needles from each twig were transferred to water agar (16 g liter–1 of agar and 0.1 g liter–1 of streptomycin) and incubated at 4°C for at least 8 days in the dark. Single hyphal-tip cultures were then established from only one of the developing colonies per twig and transferred to 1.5-ml microcentrifuge tubes containing 500 μl of potato dextrose broth. DNA extraction, directly from the mycelium, was performed after 20 days (3). DNA was amplified using primer pair ITS1 and ITS4 (4) and sequenced. Sequences of two representative fungal isolates from C. libani were deposited in GenBank (HM853976 and HM853977). Comparison of the 18 internal transcribed spacer sequences obtained from C. libani showed 99 to 100% nucleotide identity with those of reference strains of H. juniperi (2) from GenBank and variation among the 18 sequences was <1%, which is within the limits reported in a previous study (2). To our knowledge, this is the first report of C. libani as a new host of H. juniperi. Thus, brown felt blight is considered to have a significant impact on regeneration of C. libani as well as on the survival and growth of seedlings and young trees in the study area. References: (1) M. Boydak For. Ecol. Manag. 178:231, 2003. (2) M. Schneider et al. Mycol. Res. 113:887, 2009. (3) D. Smith and G. Stanosz. Phytopathology 85:699, 1995 (4) T. J. T. White et al. PCR Protocols: A Guide to Methods and Applications. Academic Press, New York 1990.

Abstract Ancient Taurus cedar (Cedrus libani A. Rich) wood samples from the Tumulus of King Midas at the Gordion archaeological site (about 2700 years old), near Ankara, Turkey, and from the Al-Aksa Mosque (about 1500 to 1900 years old), Jerusalem, Israel, were characterized by studying the sequences of ribosomal DNA (rDNA) internal transcribed spacers (ITS1 and ITS2). After extraction of the DNA, the ITS regions were amplified utilizing the polymerase chain reaction, followed by sequencing, BLAST searches for similar sequences, and phylogenetic analyses. Fifty-six sequences were obtained. In BLAST searches of existing sequence databases, most were closest to those from humans and fungi. However, two sequences exhibited similarities with conifer ITS sequences. One was an ITS1 region from the Gordion wood specimen, and the other one was an ITS2 region from the Al-Aksa wood specimen. Phylogenetic analyses indicated that both were closest to Taurus cedar (C. libani, also known as Lebanon cedar) ITS sequences from three recent samples of Taurus cedar from two sites in Turkey. However, they exhibited many differences from the recent C. libani rDNA ITS sequences from Turkey, probably due to degradation of the DNA in the ancient samples. The implications of the results on future studies are discussed.

Ongoing climate change increasingly affects growth conditions of native conifers such as Picea abies (Norway spruce) and Pinus sylvestris (Scots pine) in Central Europe. These conifers are primarily cultivated for wood production. To obtain ecologically and economically stable forests, forestry seeks alternative species that might be less prone to novel climatic conditions, such as Cedrus libani (Lebanon cedar). We aim at investigating growth responses to climatic factors of C. libani compared to native P. abies and P. sylvestris in Central Europe for 25 years (1994–2019). Growth responses were used as a proxy for tolerance towards climatic stress events, such as heat and drought. Height, diameter at breast height (DBH) and radial increment were measured for 40-year-old tree stands of C. libani and native conifers. Radial growth responses to selected climate parameters were analysed using bootstrapped correlations with detrended growth index chronologies and growth response indices for drought years (2003, 2012, 2015, 2018). For C. libani, radial growth was positively correlated with high water availability in late winter and spring, while for P. abies, February and summer and for P. sylvestris, July showed such a relationship. Cedrus libani exhibited the highest resistance, recovery, and resilience in response to climatic extremes. Against the background of climate change, C. libani could serve as an alternative conifer species to establish climate-resistant viable forests in Central Europe.

AbstractThe cedar web-spinning sawfly, Cephalcia tannourinensis Chevin (Hymenoptera: Pamphiliidae), is a pest that has been causing serious damage to cedar (Cedrus libani) forests in Lebanon since 1990. The existence of a sex pheromone was shown in field experiments in a cedar forest in Lebanon and in laboratory tests in olfactometers with and without airflow. More males were caught in traps baited either with virgin females or with a hexane extract of the whole female body than in traps baited either with males alone or with mixed males and females. Male and female C. tannourinensis were active during the day. Mating and pheromone production were observed to occur during midday hours (1000–1400) in the field and under laboratory conditions. Olfactometer tests with extracts prepared from different body parts of the female indicated that the pheromone is produced in the abdominal region, and tests with different dilutions of female extract showed that the male response is dose-dependent.

In this study, softwood cedar of Lebanon (Cedrus libani A.Rich.) and hardwood black poplar (Populus nigra L.), turned into cylinders by turning, were subjected to a surface densification process. Densification was carried out on the lathe using the spinning roller designed and manufactured for this purpose. Hardness, brightness and roughness (Rz) measurements were carried out on undensified and densified regions of the cylindrical solid wood materials. An increase in hardness and brightness and a decrease in roughness values occurred under all densification conditions. The highest surface hardness values occurred in cedar of Lebanon at 0.081 mm/rev feed, 200 rpm spindle speed, and 1 mm densification depth. On densified wood surfaces, as the feed from the densification parameters increases, the hardness decreases, and as the densification depth increases, the hardness increases-. The effect of surface densification parameters on the gloss and roughness results of the samples shows no linear effect in terms of experimental parameters. In both species, lower spring back was obtained at low depth of densification.

Cedrus libani, commonly known as Lebanon cedar, is one of the most important coniferous tree species in Turkey. Its main distribution is in the Taurus Mountains in the Mediterranean Region. The total area of pure Taurus cedar forest covers 109,440 ha in Turkey, all located in the southwestern regions of the country. Due to its drought resistance, Taurus cedar has been commonly used for afforestations in these semi-arid areas (1). In September 2011, during surveys for Phytophthora spp. in forest nurseries in Adapazari and İzmir in eastern Turkey, initial symptoms such as death of fine roots, yellowing, and wilting of Taurus cedar seedlings were observed. Soil samples were collected from 10 symptomatic C. libani seedlings and isolation tests for Phytophthora species were carried out using leaflets from young Quercus suber, Azalea sp., and Rhodendron sp. saplings as baits floated over flooded soil. Necrotic baits were blotted dry, cut into small pieces, and placed on selective PARPNH carrot agar. Out growing colonies were subcultured on carrot agar and kept at 12°C for morphological and molecular identifications (2). In total, six Pythiaceous isolates were obtained from the C. libani soil samples. The isolates were investigated using a light microscope and grouped according to their morphological characteristics (3). DNA was extracted from two representative isolates using Qiagen DNeasy Plant Mini Kit following the manufacturer's instructions. PCR amplifications and sequencing of the internal transcribed spacer (ITS) region of rDNA and the β-tubulin gene were performed using ITS1 and ITS4 and Tub1 and Tub2 primer sets (4). Sequencing of the PCR products in both directions was conducted by IonTek Inc. (Istanbul, Turkey) in an ABI PRISM automated sequencer. The obtained sequences were compared with those in the GenBank and Phytophthora database using BLAST search. On the basis of morphological features and molecular analyses, the two isolates were identified as Phytophthora syringae. Morphological characteristics on carrot agar were identical with the description of P. syringae (2). At 20°C, colonies reached 7 cm in diameter after 1 week. Sporangia were semipapillate to non-papillate, ovoid, with average length of 59 μm (SD ± 2.8) (range 58 to 70 μm). Oogonia were 38 μm (SD ± 5.4) in diameter (range 30 to 47 μm) with paragynous antheridia. The morphological identification was confirmed by sequence comparison at GenBank with 99% homology for both ITS and β-tubulin. The ITS sequences of the two isolates were deposited in GenBank with the accession nos. KF430614 and KF944377. Under-bark inoculation tests with mycelia plugs were conducted with both isolates of P. syringae at 18°C in a growth chamber on a total of six 1-year-old shoots cut from two C. libani trees. Lesions with an average length of 19 mm (SD ± 6) developed after 10 days. P. syringae was consistently re-isolated from the margins of necrotic tissues. Control shoots remained symptomless. To our knowledge, this is the first report of damage caused by P. syringae on C. libani seedlings in forest nursery in Turkey. References: (1) T. Çalışkan. Pages 109-130 in: Proceedings of Workshop “Hızlı gelişen türlerle ilgili rapor,” Ankara, Turkey, 1998. (2) T. Jung et al. Eur. J. For. Pathol. 26:253, 1996. (3) T. Jung et al. Mycol. Res. 107:772, 2003. (4) L. P. N. M. Kroon et al. Fung. Genet. Biol. 41:766, 2004.

Le changement climatique a profondément perturbé les écosystèmes naturels, particulièrement dans le bassin méditerranéen, une région caractérisée par une forte vulnérabilité face aux évolutions en cours du climat. Dans ce contexte, cette thèse vise à étudier la gamme climatique de plusieurs essences méditerranéennes et de mieux comprendre le rôle des facteurs abiotiques, biotiques et historiques dans la distribution et la persistance de ces essences forestières aux marges chaudes et froides de leur répartition. La thèse explore également si les limites altitudinales de leur répartition naturelle correspondent à leur niche climatique. En étudiant la survie et la croissance de ces essences au sein et au-delà de leurs marges climatiques actuelles, l'étude vise enfin à formuler des recommandations pour le reboisement et la gestion durable des écosystèmes méditerranéens. Un dispositif expérimental a été mis en place sur huit sites régulièrement répartis entre 110 et 2330 mètres d'altitude au Liban pour évaluer la survie et la croissance au stade juvénile de 4 essences : deux conifères Cedrus Libani et Pinus brutia et deux feuillus méditerranéens, l'un sclérophylle à feuilles persistantes : Quercus calliprinos et l'autre à feuilles caduques : Quercus infectoria. Plusieurs modalités d'irrigation et de compétition entre plants ont été étudiées dans chaque site. Le sol, le niveau de lumière disponible pour les plants, la compétition herbacée et la consommation par les herbivores ont été contrôlés et standardisés entre les sites pour garantir que seuls les effets climatiques soient étudiés. Les 4 espèces ont été plantées à 1 an selon les mêmes modalités de plantation dans tous les sites. Les mesures de croissance et de survie ont été réalisées pendant 3 ans. En complément de ce dispositif, des relevés de présence et d'absence des quatre espèces étudiées ont été effectués sur 1300 sites, afin de préciser leur gamme altitudinale dans des conditions naturelles. Les résultats montrent que la limite altitudinale « froide » des espèces dans les conditions naturelles est principalement déterminée par des facteurs physiologiques. La comparaison de survie entre modalités irriguées et non irriguées au-dessus de la limite haute de distribution met en évidence l'effet attendu des faibles températures mais aussi un effet de la sécheresse estivale comme drivers de la limite haute des essences. La limite altitudinale basse semble davantage influencée par des facteurs anthropiques et biotiques, tels que les interactions avec d'autres espèces, la compétition pour les ressources hydriques, ou encore les modifications historiques apportées par des millénaires d'activités humaines dans la région. Ainsi, la limite de survie et de croissance du cèdre se situe près de 1000 m de dénivelée sous sa limite altitudinale dans les écosystèmes naturels du Liban. En contexte méditerranéen, l'impact de la sécheresse sur la limite altitudinale « froide » des espèces mis en évidence dans cette étude remet en cause les modèles de colonisation naturelle des zones situées au-delà de la limite froide de distribution avec le changement climatique. Les résultats montrent également que les régressions prédites au pôle chaud de l'aire ne sont pas inéluctables pour certaines espèces du fait de leur capacité à survivre bien en deçà de leur limite chaude. Ces résultats ouvrent la voie à des interventions de gestion liées notamment à l'irrigation au stade juvénile et à la maitrise de la compétition comme mesures d'adaptation face aux impacts attendus du réchauffement climatique
Climate change has profoundly disrupted natural ecosystems, particularly in the Mediterranean basin, a region characterized by high vulnerability to ongoing climate change. In this context, this thesis aims to study the climatic range of several Mediterranean species and to better understand the role of abiotic, biotic and historical factors in the distribution and persistence of these forest species at the warm and cold margins of their distribution. The thesis also explores whether the altitudinal limits of their natural distribution correspond to their climatic niche. By studying the survival and growth of these species within and beyond their current climatic margins, the study aims to finally formulate recommendations for the reforestation and sustainable management of Mediterranean ecosystems. An experimental device was set up on eight sites regularly distributed between 110 and 2330 meters above sea level in Lebanon to evaluate the survival and growth at the juvenile stage of 4 species: two conifers Cedrus Libani and Pinus brutia and two Mediterranean deciduous trees, one evergreen sclerophyll: Quercus calliprinos and the other deciduous: Quercus infectoria. Several irrigation and plant competition modalities were studied in each site. Soil, the level of light available to plants, herbaceous competition, and consumption by herbivores were controlled and standardized between sites to ensure that only climatic effects were studied. The 4 species were planted at 1 year old according to the same planting methods in all sites. Growth and survival measurements were performed for 3 years. In addition to this system, measurements of the presence and absence of the four species studied were carried out on 1300 sites, in order to specify their altitudinal range under natural conditions. The results show that the "cold" altitudinal limit of species under natural conditions is mainly determined by physiological factors. The survival comparison between irrigated and non-irrigated modalities above the upper limit of distribution highlights the expected effect of low temperatures but also an effect of summer drought as drivers of the upper limit of species. The lower altitudinal limit appears to be more influenced by anthropogenic and biotic factors, such as interactions with other species, competition for water resources, or historical changes brought about by millennia of human activities in the region. Thus, the survival and growth limit of the cedar is nearly 1000 m of elevation drop below its altitudinal limit in the natural ecosystems of Lebanon. In the Mediterranean context, the impact of drought on the "cold" altitudinal limit of species highlighted in this study calls into question the natural colonization patterns of areas located beyond the cold limit of distribution with climate change. The results also show that the predicted regressions at the warm pole of the range are not inevitable for some species because of their ability to survive well below their warm line. These results pave the way for management interventions related in particular to irrigation at the juvenile stage and the control of competition as adaptation measures to the expected impacts of global warming

La tesi cerca di rispondere alla domanda: 'La libanese intifadha al-Iqtad poteva essere prevista?'. la tesi prima definisce l'evento politico, e. Successivamente esamina le condizioni epistemologiche in base alle quali una predizione del futuro possa essere considerata scientifica. In terzo luogo, propone uno schema di previsione organizzato in funzione del coinvolgimento degli agenti nella creazione della storia umana. Infine, analizza la intifadha al-Iqtad in base allo schema analitico proposto.
The thesis aims to answer the question 'could the Lebanese Intifadha al-Iqtad have been predicted?' In order to do so, it first of all tries to define the political event, in terms of features, dynamic, and outcome. Secondly, it outlines the epistemological assumptions on which a scientific prediction of the future could be based. Thirdly, it puts forward a framework for foreseeing the future organised on different levels and divided into macro-categories. Finally, it analyses the Lebanese Intifadha al-Iqtad according to the proposed framework.

La tesi cerca di rispondere alla domanda: 'La libanese intifadha al-Iqtad poteva essere prevista?'. la tesi prima definisce l'evento politico, e. Successivamente esamina le condizioni epistemologiche in base alle quali una predizione del futuro possa essere considerata scientifica. In terzo luogo, propone uno schema di previsione organizzato in funzione del coinvolgimento degli agenti nella creazione della storia umana. Infine, analizza la intifadha al-Iqtad in base allo schema analitico proposto.
The thesis aims to answer the question 'could the Lebanese Intifadha al-Iqtad have been predicted?' In order to do so, it first of all tries to define the political event, in terms of features, dynamic, and outcome. Secondly, it outlines the epistemological assumptions on which a scientific prediction of the future could be based. Thirdly, it puts forward a framework for foreseeing the future organised on different levels and divided into macro-categories. Finally, it analyses the Lebanese Intifadha al-Iqtad according to the proposed framework.

Most terrestrial carbon (C) is stored in forests, an important source of fiber and fuel for humans. Therefore, forests play an essential role in mitigating the effects of climate change by reducing the carbon level in the atmosphere. Field measurements and remote sensing techniques determine the stored above-ground carbon (AGC). This study used Sentinel-2 satellite image to estimate the amount of AGC in pure Taurus cedar (Cedrus libani A. Rich.) stands in Elmalı Forest Enterprise. Regression models were developed for AGC estimation with the reflectance and vegetation indices obtained from the Sentinel-2 satellite image. Within the scope of the study, the field measurement data obtained from 120 sample plots were used and AGCs of their corresponding stands were estimated with an allometric equation. The sample plots data was randomly divided into modeling (70%, 84 sample plots) and control data (30%, 36 sample plots) to fit the regression models and to test the accuracy of the models, respectively. Multiple linear regression analysis were conducted to develop the models, and three goodness-of-fit statistics (R2, RMSE and MAE) were used to compare the success of these models. When the achievements of the models were evaluated, it was revealed that the model containing the MSR vegetation indice gave more successful results (R2=0.488). Consequently, it was determined that the developed models were moderately successful in estimating AGC.