Zonal light-coniferous forests are widespread on long-frozen soils in Southern Siberia. Their individuality was first recognised in 1982 by Guinochet, who proposed a new suballiance for them, Pino-Laricenion sibiricae, within the alliance Vaccinio-Piceion. Later, attempts were made to raise the suballiance to the rank of an alliance. However, they failed to publish the name Pino sibiricae-Laricion sibiricae validly according to the International Code of Phytosociological Nomenclature (ICPN). Therefore, the name is validated here after discussing the reasons for rejecting all previous proposals. The validity of the corrected and mutated syntaxon names Rhododendro tomentosi-Laricetalia gmelinii and Rhododendro tomentosi-Laricion gmelinii, which are related to the alliance Pino sibiricae-Laricion sibiricae, is confirmed. Corrections and mutations of two association names are also performed. Taxonomic reference: World Flora Online Plant List (WFO) (https://wfoplantlist.org/) [accessed 28 July 2024]. Abbreviations: ICPN = International Code of Phytosociological Nomenclature (Theurillat et al. 2021); WFO = World Flora Online Plant List.

The classification of pine (Pinus brutia var. pityusa) forests of the Colchis (Western Caucasus) is based on quantitative analysis (Ward’s method, Euclidian distance) of 22 relevés and comparative syntaxonomic analysis. Two associations — Seselo rupicolae–Pinetum brutiae Ermakov et Leiba ass. nov. and Vinco majoris–Pinetum brutiae Ermakov et Leiba ass. nov., and non-rank community Crataegus microphylla–Pinus brutia var. pityusa were described. The ass. Seselo rupicolae–Pinetum brutiae represents rare natural pine forests preserved only on the calcareous steep (12–60°) southern slope of the Gagrskiy mountain ridge in the Kholodnaya River basin at altitudes of 50–260 m. Diagnostic species are Campanula alliariifolia, Campanula longistyla, Galium mollugo, Genista abchasica, Laser trilobum, Muscari neglectum, Tanacetum corymbosum, Rhus coriaria, Seseli rupicola, Sesleria alba, Stachys atherocalyx, Teucrium chamaedrys, Thalictrum minus, Tragopogon graminifolius. The ass. Vinco majoris–Pinetum brutiae occupies only sandy-gravel see terrace near Pitsunda town at altitudes of 2–6 m. Diagnostic species are Carex divulsa, Corylus avellana, Cardamine quinquefolia, Potentilla indica, Festuca drymeja, Galium aparine, Geranium robertianum, Geum urbanum, Hedera colchica, Prunus laurocerasus, Ligustrum vulgare, Luzula forsteri, Crataegus germanica, Poa nemoralis, Polypodium cambricum, Ulmus glabra, Vinca major subsp. hirsuta, Viola reichenbachiana, Vitis sylvestris. The non-rank community Crataegus microphylla–Pinus brutia var. pityusa includes almost disappeared mesophilous pine forests occasionally occurring on pediments of gentle shaded mountain slopes of the Gagrskiy ridge, near narrow river valleys at altitudes of 90–130 m. All described syntaxa in the Colchis province were included in the Campanulo longistylae–Pinion brutiae Litvinskaya et Postarnak ex Ermakov et Ermakova 2023, the order Pinetalia pallasianae-kochianae Korzhenevsky 1998. The results of comparative syntaxonomic analysis of all Pinus brutia var. pityusa forests of the Western Caucasus and Crimea demonstrated two ecological and phytosociological groups. Pine (Pinus brutia var. pityusa) forests of the humid Colchis province were included into the class Erico-Pinetea Horvat 1959 because of absolute predominance of moderately mesophilous sub-Mediterranean and European species. Pine forests of more arid province of North-Western Caucasus and Crimea were attributed to the alliance Jasmino fruticantis–Juniperion excelsae Didukh, Vakarenko et Shelyag-Sosonko ex Bonari et al. 2021, order Berberido creticae–Juniperetalia excelsae Mucina in Mucina et al. 2016 and class Junipero–Pinetea sylvestris Rivas-Mart. 1965 because of predominance of hemi-xerophilous sub-Mediterranean species.

Validation and description of new syntaxa of the boreal light coniferous forests of North Asia in the Braun-Blanquet system was carried out in accordance with the latest 4th edition of the International Code of Phytosociological Nomenclature. These are the alliance Ledo palustris–Laricion cajanderi Ermakov all. nov. and the order Ledo palustris–Laricetalia cajanderi Ermakov ord. nov. For all these syntaxa, the diagnostic species, peculiarities of ecology and phytocenotic structure, as well as geographical area are indicated. Prodromus of the validated order Ledo palustris–Laricetalia cajanderi is presented.

A classification of Caucasian oak (Quercus macranthera) forests from Dagestan (Eastern Caucasus) using the Braun-Blanquet method has been developed. Three new associations were described: Ranunculo buhsei–Quercetum macrantherae ass. nov., Betonico macrantherae–Quercetum macrantherae ass. nov. and Calamagrostio arundnaceae–Quercetum macrantherae ass. nov. These communities are characterized by the leading role of sub-Mediterranean thermophilous species and Euro-Siberian meadow-steppe meso-xerophytes which allowed them to be assigned to the class Quercetea pubescentis Doing-Kraft ex Scamoni et Passarge 1959. The results of the study of ecological and plant-geographical properties of described communities revealed their unique feature – the presence of a large group of endemic subalpine Caucasian species. The combination of these ecologically contrasting species groups indicates moderately dry and continental climate of the oak (Q. macranthera) forests range in Dagestan and occurring them in the buffer zone between forest, steppe and alpine belts at altitudes of 1400–2100 m. Similar important ecological and floristic features are not typical for other forests of the class Quercetea pubescentis in Europe and Asia Minor. This made it possible to justify a new order Astrantio maximae–Quercetalia macrantherae ord. nov. containing a single alliance Astrantio maximae–Quercion macrantherae all. nov. Diagnostic species of the order and alliance are: Quercus macranthera, Astrantia maxima, Alchemilla sericata, Anthemis melanoloma, Betonica macrantha, Bupleurum polyphyllum, Calamagrostis arundinacea, Carum meifolium, Chaerophyllum aureum, Cephalaria gigantea, Centaurea salicifolia, Cicerbita racemosa, Erysimum armeniacum, Geranium sylvaticum, Heracleum asperum, Iris colchica, Lathyrus cyaneus, Lilium monadelphum, Medicago glutinosa, Primula macrocalyx, Viburnum lantana, Poa longifolia, Polygonatum verticillatum, Ranunculus buhsei, Rubus saxatilis, Primula ruprechtii, Psephellus dealbatus, P. daghestanicus, Pyrethrum leptophyllum, Pedicularis chroorrhyncha, Sedum oppositifolium, Trifolium canescens, Vicia grossheimii, Vincetoxicum funebre.

Validation and corrections of syntaxa of the sub-Mediterranean pine (Pinus brutia var. pityusa (Steven) Silba) forests of the Western Caucasus in the Braun-Blanquet system was carried out in accordance with the latest 4th edition of the International Code of Phytosociological Nomenclature. These are the alliance Campanulo longistylae–Pinion br utiae Litvinskaya et Postarnak ex Ermakov et Ermakova all. nov. and associations Epimedio colchici–Pinetum brutiae Litvitskaya et Posternak 2002 nom. corr.; Campanulo longistylae–Pinetum br utiae Litvinskaya et Postarnak 2002 nom. corr.; Ass. Trachystemo orientalis–Quercetum petraea Litvinskaya et Posternak 2002 nom. corr. The diagnostic species, peculiarities of ecology and geographical area are indicated. Prodromus of the validated alliance Campanulo longistylae–Pinion br utiae is represented.

The classification of oriental-beech (Fagus orientalis) forests of the Western Caucasus was developed on the basis of quantitative analysis (Ward’s method, Euclidian distance) of 200 relevés (Fig. 2) and comparative syntaxonomic analysis. All Caucasian beech forests were attributed to the class Carpino–Fagetea sylvaticae Jakucs ex Passarge 1968 and Euxine order Rhododendro pontici–Fagetalia orientalis Passarge 1981. The associations of floristically poor beech forests occurring on the acidic bedrocks were included in the alliance Fagion orientalis Soó 1964. These are Orobo–Fagetum orientalis Passarge 1981, Dentario–Fagetum orientalis Passarge 1981, Polysticho–Fagetum orientalis Passarge 1981, Rhododendro pontici–Fagetum orientalis Stefanov ex Tzonev et al. 2006 (syn. Rhododendro pontici–Fagetum orientalis Frantsuzov 2006), Rusco colchici–Castaneetum sativae Novák et al. 2019 and new association Rhododendro lutei–Fagetum orientalis Ermakov ass. nov. (diagnostic species — Rhododendron luteum, Cicerbita petiolata, Hedera colchica, Ilex colchica, Oreopteris limbrosperma, Vaccinium arctostaphylos, Viburnum orientale). Nomenclature type (holotypus) of the Rhododendro lutei–Fagetum orientalis Ermakov ass. nov. is relevé 14, Table 1 (field relevé nr. — 129NE19, Abkhasia Republic, the upper part of the Pskhu River basin, aspect — SWW, slope — 27°, altitude — 1645 m, cover of tree layer — 70 %, cover of shrub layer — 60 %, cover of herb layer — 12 %, coordinates: 43.4299° N, 40.8661° E, size of plot — 100 m2, Date: 28.07.2019, Authors: N. B. Ermakov and V. D. Leiba). The alliance Thlaspio macrophylli–Fagion orientalis Ermakov all. nov. includes rich in species beech forests growing preliminarily on calcareous bedrocks in ultra-humid climate of the Western Caucasus (Colchis, Abkhasia). They occupy mountain slopes of different aspects at altitudes of 150–1800 m. Diagnostic species of the alliance are Acer laetum, A. pseudoplatanus, Aristolochia iberica, Asarum intermedium, Dryopteris caucasica, Galeobdolon luteum, Geranium gracile, Hedera colchica, Phyllitis scolopendrium, Polystichum aculeatum, Potentilla micrantha, Sambucus nigra, Symphytum grandiflorum, Thlaspi macrophyllum, Tilia begoniifolia, Ulmus glabra, Vicia crocea. Nomenclature type (holotypus) of the Thlaspio macrophylli–Fagion orientalis is the association Thlaspio macrophylli–Fagetum orientalis Ermakov ass. nov. (described in this paper) — relevés 1–43 in Table 2; syntaxa 1–4 in Table 3. Diagnostic species of the association are the same as for the alliance Thlaspio macrophylli–Fagion orientalis. Nomenclature type (holotypus) of the Thlaspio macrophylli–Fagetum orientalis Ermakov ass. nov. is relevé 12 in Table 2 (field relevé nr. — 103NE19, Abkhasia Republic, near Pskhu village, 2 km S, aspect — N, slope — 12°, altitude — 775 m, cover of tree layer — 60 %, cover of shrub layer — 20 %, cover of herb layer — 65 %, coordinates: 43.3614° N, 40.8035° E, plot size — 100 m2, Date: 26.07.2019, Authors: N. B. Ermakov and V. D. Leiba). This association represents beech forests occupying steep and moderately steep (15–40°) mountain slopes of western, eastern and partly southern aspects at altitudes 1690–1800 m. The association Thlaspio macrophylli–Fagetum orientalis includes four variants — var. typica, var. Asarum intermedium, var. Hypericum xylosteifolium, var. Polystichum setiferum. The association Senecioni jacquiniani–Fagetum orientalis Ermakov ass. nov. includes beech forests occurring in the upper part of forest belt in the Gagrskiy Ridge at altitudes of 1100–1600 m. Diagnostic species: Calamintha grandiflora, Campanula rapunculoides, Fragaria vesca, Hordelymus europaeus, Polygonatum glaberrimum, Senecio jacquinianus, Solidago virgaurea). Nomenclature type (holotypus) is relevé 49 in table 2 (field relevé nr. — 22NE20, Abkhasia Republic, Gagrskiy Ridge, Momzyshkha mountain, middle part, aspect — W, slope — 15°, altitude — 1125 m, cover of tree layer — 60 %, cover of shrub layer — 20 %, cover of herb layer — 70 %, coordinates: 43.2857° N, 40.3209° E, plot size — 100 m2, Date: 24.08.2020, Authors: N. B. Ermakov and V. D. Leiba). The alliance Thlaspio macrophylli–Fagion orientalis includes also the association Sambuco nigrae–Fagetum orientalis Frantsuzov 2006 from the North-Western Caucasus. The alliance Acero heldreichii–Fagion orientalis Ermakov all. nov. represents the beech forests occurring in the upper part of the forest and subalpine belts of the Caucasus on acidic and calcareous bedrocks at altitudes of 1600–1850 m. Diagnostic species of the alliance are subalpine species (including a large number of the Caucasian endemic tall-forb plants): Acer heldreichii subsp. trautvetteri, Abies nordmanniana, Adenostyles platyphylloides, Aconitum orientale, Agasyllis latifolia, Astrantia major, Asyneuma campanuloides, Calamagrostis arundinacea, Cicerbita petiolata, C. pontica, Dolichorrhiza correvoniana, Dryopteris caucasica, Euphorbia macroceras, Gentiana schistocalyx, Kemulariella caucasica, Lonicera orientalis, Petasites albus, Polygonatum verticillatum, Ptarmica biserrata, Ranunculus cappadocicus, Solidago virgaurea, Valeriana tiliifolia, Woronowia speciosa. Nomenclature type (holotypus) of this alliance is the association Acero heldreichii–Fagetum orientalis Ermakov ass. nov. (described in this paper) — relevés 43–59 in Table 1; syntaxa 19–20 in Table 3. Nomenclature type (holotypus) of the association Acero heldreichii–Fagetum orientalis Ermakov ass. nov. is relevé 54 in Table 1 (field relevé nr. — 47NE20, Abkhasia Republic, Gagrskiy Ridge, Momzyshkha mountain, upper part, aspect — W, slope — 30°, altitude — 1740 m, cover of tree layer — 65 %, cover of shrub layer — 18 %, cover of herb layer — 60 %, coordinates: 43.3138° N, 40.3469° E, plot size — 100 m2, Date: 28.08.2020, Authors: N. B. Ermakov and V. D. Leiba). This association occurs in the upper part of the forest and subalpine belts of the Gagrskiy Ridge (Abkhasia Republic) at altitudes of 1690–1800 m. It includes 2 subassociations — A. t.–F. o. typicum Ermakov subass. nov. and A. t.–F. o. vaccinietosum arctoctaphyli Ermakov subass. nov. At present the alliance Acero heldreichii–Fagion orientalis includes also 3 associations described by Passarge (1980) from the Central Caucasus — Petasito–Fagetum orientalis Passarge 1981, Veratro–Fagetum orientalis Passarge 1981 and Pyrolo–Fagetum orientalis Passarge 1981.

Исследуется возможность автоматического выделения и классификации осиновых и березовых насаждений на RGB-изображениях сверхвысокого пространственного разрешения, полученных с беспилотного летательного аппарата (БПЛА). Показано, что применение сверточной нейронной на основе архитектуры U-Net позволяет достичь значения индекса Жаккарда ~0,784. The possibility of automatic selection and classification of aspen and birch plantations on ultra-high spatial resolution RGB images obtained from an unmanned aerial vehicle (UAV) is investigated. It is shown that the use of a convolutional neural network based on the U-Net architecture makes it possible to achieve the value of Jacquard index ~0,784.

A classification system of the Colchic spruce-fir forests (the Western Caucasus) was developed using the Brawn-Blanquet method. Two new associations Dryopterido caucasicae–Abietetum nordmannianae ass. nov., Pruno laucerasi–Abietetum nordmannianae ass. nov. and new alliance Dryopterido caucasicae–Abietion nordmannianae all. nov. were proposed after the comparative syntaxonomic analysis of dark coniferous forests from the Euxine province. Diagnostic species of the alliance are Acer pseudoplatanus, Actaea spicata, Athyrium filix-femina, Dentaria bulbifera, Dryopteris carthusiana, D. filix-mas, Fagus orientalis, Geranium robertianum, Gymnocarpium dryopteris, Impatiens noli-tangere, Oxalis acetosella, Paris incompleta, Polystichum aculeatum, Ranunculus grandiflorus, Rubus caucasicus, Salvia glutinosa, Symphytum grandiflorum. All described Colchic associations and alliance were placed in the order Abieti nordmannianae– Piceetalia orientalis Coban et Willner 2019 and the class Asaro europaeai–Abietetea sibiricae Ermakov et al. in Willner et al. 2016 uniting West Palearctic dark coniferous subnemoral forests from Europe, Asia Minor, Southern Urals and Western Siberia.

Систематизация и инвентаризация растительных сообществ (фитоценозов) — это фундаментальная основа для изучения и прогнозирования современных сложных процессов в биосфере, в том числе и в результате глобальных изменений климата. Созданная система классификации растительности обеспечивает взаимодействие специалистов различных областей знания при решении экологически ориентированных задач устойчивого развития от регионального уровня до биосферного. При этом категории растительности выступают надежными индикаторами естественных и антропогенных процессов на Земном шаре и играют фундаментально основополагающую роль при оценке и прогнозном моделировании состояния биоты. С 2019 года инициативной группой из специалистов-геоботаников институтов РАН и университетов начата реализация масштабного проекта «Создание Национальной классификации растительности России», целью которого является разработка и представление в монографическом издании системы классификации растительности России, отражающей естественные закономерности формирования сообществ растительных организмов на разных пространственно-географических уровнях и являющейся фундаментальной основой для прогнозирования биосферных процессов, научного управления биоресурсами, сохранения биоразнообразия и, в конечном счете, рационального природопользования для планирования устойчивого развития территорий. В настоящее время в проекте принимают участие 18 институтов РАН и 12 университетов России. Первоочередные задачи: 1. Разработка фундаментальных научных принципов классификации растительности путем обобщения достижений российской и мировой фитоценологии. 2. Систематизация и инвентаризация разнообразия растительных сообществ России на разных иерархических уровнях и опубликование «Продромуса растительности России». В настоящее время в процессе подготовка Продромуса растительности России проводится полная инвентаризация типов растительных сообществ и создание единой иерархической системы синтаксонов на основе эколого-флористического подхода. Полученные результаты будут использованы при создании многотомного издания «Растительность России», а созданная система классификации выступит основой актуального и прогнозного моделирования биосферных процессов, оценки природоохранной значимости растительных сообществ и экосистем. Исследование выполнено за счет гранта Российского научного фонда № 22-24-00527, https://rscf.ru/project/22-24-00527/

Classification of dark coniferous forests of the Eastern part of Europe, Southern Urals and Western Siberia was performed using data set of 55 low-rank syntaxa (association, subassociation and variant), results of cluster analysis (Ward method, Euclidian distance) and DCA ordination (Fig. 1, 2). The synoptic table of dark coniferous forests syntaxa (Table) was developed and clarification of their diagnostic features was made. In accordance with the “Vegetation of Europe ….” (Mucina et al., 2016), the entire diversity of the higher units of the dark coniferous forests was classified into two classes, two orders and eight alliances. At the highest hierarchical level, two classes were clearly distinguished — the Asaro europaei–Abietetea sibiricae Ermakov et al. in Willner et al. 2016 and Vaccinio-Piceetea Br.-Bl. in Br. Bl. et al. 1939. The class Asaro europaei–Abietetea sibiricae includes subnemoral dark coniferous forests occurring in southern part of forest zone in the Southern Urals and Western Siberia. These forests combine some important features of boreal and nemoral vegetation in the phytocoenotic structure (physiognomy) and floristic composition. Therefore, the diagnosis of the class Asaro europaei–Abietetea sibiricae is based on a combination of the following criteria. 1. The absolute predominance of cold-resistant boreal tree species (Picea obovata, Pinus sibirica, Abies sibirica) in the higher layer makes it impossible to assign them to the higher units of nemoral vegetation and fundamentally distinguishes them from the class Carpino–Fagetea sylvaticae Jakucs ex Passarge 1968. 2. The high constancy values of widespread Eurasian shade-tolerant species associated dominantly with dark coniferous forests: Dryopteris expansa, D. carthusiana, D. assimilis, D. dilatata, Phegopteris connectilis, Diplazium sibiricum, Gymnocarpium dryopteris, G. robertianum, Athyrium filix-femina, Oxalis acetosella, widespread European-Siberian nemoral species: Daphne mezereum, Dryopteris filix-mas, Viburnum opulus, Stachys sylvatica, Galium odoratum, Geranium robertianum, Festuca altissima, Asarum europaeum, Actaea spicata, Brachypodium sylvaticum, Aegopodium podagraria, Viola mirabilis, Sanicula europaea, Festuca gigantea, as well as nemoral species with narrower ranges located in southern Siberia: Osmorhiza aristata, Anemonoides altaica, Corydalis bracteata, Erythronium sibiricum, Anemonoides caerulea, Myosotis krylovii, Euphorbia Pilosa and European species with eastern boundaries of ranges running in the southern Urals: Ulmus glabra, Pulmonaria obscura, Polygonatum multiflorum, Cicerbita uralensis, Geum urbanum, Carex pilosa, Euonymus verrucose. All these species were included in diagnostic combination of the Asaro europaei–Abietetea sibiricae. 4. Absence or rare occurrence of typical boreal species (characteristic of the class Vaccinio-Piceetea) in the shrub and ground layers. Currently, the class Asaro europaei–Abietetea sibiricae is represented by one order Abietetalia sibiricae Ermakov 2006, since the analysis of the possibility of including the Central European sub-nemoral dark coniferous forests of the order Athyrio–Piceetalia abietis, close to them dark coniferous forests of Eastern Europe and Euxinian forests of the Abieti nordmannianae–Piceetalia orientalis Coban et Willner 2019 has not yet been analyzed. Synopsis of the Asaro europaei–Abietetea sibiricae. Cl. Asaro europaei–Abietetea sibiricae Ermakov, Mucina et Zhitlukhina in Willner et al. 2016. Ord. Abietetalia sibiricae Ermakov 2006. All. Milio–Abietion sibiricae Zhitlukhina ex Ermakov et al. 2000. Suball. Cruciato krylovii–Abietenion sibiricae Ermakov in Ermakov et al. 2000. Ass. Asaro europaei–Abietetum sibiricae Zhitlukhina ex Ermakov et al. 2000. Ass. Violo biflorae–Abietetum sibiricae Ermakov 2000. Ass. Violo uniflorae–Abietetum sibiricae Ermakov 2000. Ass. Anemonoido baicalensis–Abietetum sibiricae Ermakov et Stepanov in Ermakov 1995. Suball. Milio effusi–Abietenion sibiricae Ermakov in Ermakov et al. 2000. Ass. Cacalio hastatae–Abietetum sibiricae Ermakov 2000. Ass. Geranio robertiani–Tilietum sibiricae Ermakov et Maskayev in Ermakov 1995. Ass. Saussureo latifoliae–Abietetum sibiricae Ermakov 2013. Ass. Filipendulo ulmariae–Abietetum sibiricae Lashchinskiy 2009. All. Filipendulo ulmariae–Populion tremulae Ermakov in Ermakov et al. 2000. Ass. Dactylido glomeratae–Abietetum sibiricae Ermakov in Ermakov et al. 2000. Subass. D. g.–A. s. vicietosum sylvaticae Lashchinskiy 2009. Ass. Festuco giganteae–Populetum tremulae Ermakov 2000. Ass. Geranio sylvatici–Populetum tremulae Ermakov 2000. Ass. Saussureo latifoliae–Populetum tremulae Ermakov 2000. Ass. Anemonoido jenisseensis–Populetum tremulae Ermakov 1995. Ass. Equiseto pratensis–Padetum Falinski ex Ermakov et al. 2000. Ass. Matteuccio–Populetum tremulae Lashchinskiy 2009. All. Aconito septentrionalis–Piceion obovatae Solomeshch et al. in Martynenko et al. 2008. Suball. Tilio cordatae–Piceenion obovatae Martynenko et al. 2008. Ass. Brachypodio sylvaticae–Abietetum sibiricae Martynenko et al. 2007. Ass. Violo collinae–Piceetum obovatae Martynenko et Zhigunov in Martynenko et al. 2005. Ass. Chrysosplenio alternifolii–Piceetum obovatae Martynenko et al. 2007. Ass. Carici rhizinae–Piceetum obovatae Solomeshch et al. 1993. Ass. Frangulo alni–Piceetum obovatae Martyenko et Zhigunova 2007. Suball. Aconito septentrionalis–Piceenion obovatae Martynenko et al. 2008 Ass. Lathyro gmelinii–Laricetum sukaczewii Ishbirdin et al. 1996. Ass. Cerastio pauciflori–Piceetum obovatae Solomeshch et al. ex Martynenko et al. 2008. Ass. Asaro europaei–Piceetum obovatae Martynenko 2009 prov. All. Carici macrourae–Abietion sibiricae Lashchinskiy et Korolyuk 2016. Ass. Caragano arborescentis–Piceetum obovatae Lashchinskiy et Pisarenko 2016. Ass. Aegopodio padagrariae–Abietetum sibiricae Lashchinskiy et Korolyuk 2015. Ass. Melico–Abietetum sibiricae Ermakov et Lapshina 2013. In accordance with the concept proposed in the “Vegetation of Europe …” (Mucina et al., 2016), all boreal dark coniferous forests of the eastern part of Europe, Southern Urals and Western Siberia were assigned to the class Vaccinio-Piceetea and order Piceo obovatae–Pinetalia sibiricae Ermakov 2013. Diagnostic species of the order are Abies sibirica, Picea obovata, Pinus sibirica, Sorbus sibirica, Calamagrostis obtusata, Cerastium pauciflorum, Stellaria bungeana. The results of quantitative classification, ordination (Fig. 1, 2) and comparative syntaxonomic analysis of dark coniferous forests made it possible to correct the system of alliances. Syntaxonomic synopsis of the order Piceo obovatae–Pinetalia sibiricae Ermakov 2013. All. Aconito rubicundi–Abietion sibiricae Anekhonov et Chytrý 1998 Ass. Aconito septentrionalis–Piceetum obovatae Zaugolnova et Morozova in Zaugolnova et al. 2009 Ass. Bistorto majoris–Piceetum obovatae Martynenko 2009 ass. nov. prov. Ass. Adenophoro lilifoliae–Piceetum obovatae Martynenko 2009 ass. nov. prov. Ass. Linnaeo borealis–Abietetum sibiricae Lashchinskiy et Korolyuk 2015. Ass. Scutellario galericulatae–Piceetum obovatae Lashchinskiy et Pisarenko 2016. Ass. Rubo arctici–Abietetum sibiricae Ermakov et Makhatkov 2011. All. Pino sibiricae–Abietion sibiricae Ermakov in Ermakov et Lapshina 2013. Ass. Pino sibiricae–Abietetum sibiricae Ermakov et Makhatkov 2011. Ass. Ledo palustris–Abietetum sibiricae Ermakov et Lapshina 2013. All. Carici digitatae–Piceion obovatae all. nov. (described in this paper). Diagnostic species: Equisetum scirpoides, Chamaecytisus ruthenicus, Vicia cracca, Moehringia lateriflora, Cypripedium guttatum, Seseli krylovii, Campanula rotundifolia, Carex alba, C. digitata, Saussurea controversa, Gymnocarpium robertianum, Cortusa mathioli, Adonis sibirica, Cardamine trifida, Tephroseris integrifolia, Zigadenus sibiricus, Rhizomatopteris montana. Ass. Equiseto scirpoidis–Piceetum obovatae Martynenko et Zhigunova 2004. All. Vaccinio myrtilli–Piceion obovatae all. nov. prov. Ass. Vaccinio myrtilli–Piceetum obovatae ass. nov. (described in this paper) The ass. Carici macrourae–Abietetum sibiricae Ermakov et Lapshina 2013 can not be included in any existing alliances.

Mesic broad-leaved forests occupy a central place in the vegetation cover of Colchis. According to the Braun-Blanque classification system, they belong to the class Carpino-Fagetea Jakucs ex Passarge 1968. The purpose of the study is to present an overview of the classification of mesic broad-leaved forests of Colchis in the form of a synopsis of syntaxa based on an analysis of the existing concepts of higher categories of vegetation currently accepted in Europe and Asia Minor. In accordance with the classification of forests and developed Prodromus, all mesic broad-leaved forests widespread in the Western Caucasus mountain system belong to the class Carpino-Fagetea sylvaticae Jakucs ex Passarge 1968, which contains 2 orders of 5 alliances and 25 associations. The existing concept of this class at the hierarchical levels of alliances-orders represents the largest altitudinal patterns of division of the broad-leaved forests into two subbelts: the upper one is dominated by beech forests of the order Rhododendro pontici-Fagetalia orientalis Passarge 1981 (alliances Fagion orientalis Soo 1964, Alnion barbatae Quezel et al 1992) and lower one is dominated by oak and hornbeam forests of the order Lathyro-Carpinetalia caucasicae Passarge 1981 (alliances Crataego-Carpinion caucasicae Passarge 1981, Astran-tio-Carpinion caucasicae Passarge 1981, Castaneo sativae-Carpinion orientalis Quezel et al. 1992). At the levels of alliances and associations, more particular patterns of altitudinal differentiation of forests within the main subbelts, as well as their edaphotopic differences were reflected.

The classification of forests in the Bolshoy Agul river basin (Eastern Sayan) was developed using the Brawn-Blanquet method and cluster analysis. Two zonal forests categories in North Asia – boreal forests of the Vaccinio–Piceetea Br.-Bl. in Br.-Bl. et al. 1939 and hemiboreal forests of the Rhytidio–Laricetea Korotkov et Ermakov 1999 were revealed. Boreal coniferous forests are represented dominantly by two orders of the East Siberian-Mongolian type – Ledo–Laricetalia Ermakov et Alsynbayev 2004 and Lathyro–Laricetalia Ermakov et al. 2002. The first order includes alliance Pino sibiricae–Laricion Ermakov et Alsynbayev 2004 and two associations – Carici globularis–Pinetum sibiricae ass. nov. and Linnaeo–Pinetum sibiricae ass. nov. occurring on long-term frozen soils with different moisture regimes. The second order of the East Siberian-Mongolian type is represented by community Senecio nemorensis – Larix sibirica(Rhododendro–Laricion Ermakov in Krestov et al. 2009). The third order of boreal forests – Piceo obovatae–Pinetalia sibiricae Ermakov 2013 represents extra-zonal communities of the Ural-Siberian geographical type occurring in the moderately warm habitats. Hemiboreal light-coniferous forests of the East Siberian-Mongolian type (class Rhytidio–Laricetea Korotkov et Ermakov 1999, alliance Festuco–Laricion Korotkov et Ermakov ex Ermakov et al. 2000, Campanulo turczaninovii–Laricetum sibiricae ass. nov.) are locally found in the driest sites. The results of the classification and comparative plant-geographical analysis make it possible to correct the border between the East Siberian and Euro-Siberian geobotanical subregions as well as the boundaries of districts, provinces and regions in the forest zonation system of Southern Siberia.

Thirty years after the publication of the USSR vegetation syntaxa prodromus (Korotkov et al., 1991), the active work on the preparation of the Prodromus of the Russian Federation vegetation (Plugatar et al., 2020) has started. 29 contributions (incl. 5 via Skype), were represented at the Workshop “Theoretical problems of the classification of plant communities of Russia”, that took place in Yalta, Republic of Crimea, on November 1–3, 2021. Twenty six scientists (Fig. 1, 2) from St. Petersburg, Moscow, Novosibirsk, Ufa, Vladivostok, Yakutsk, Syktyvkar, Bryansk, Rostov on Don, Khanty-Mansiysk, Ekaterinburg, Nalchik, Kursk, Yalta) participated this meeting. The reviews of syntaxonomic systems of forests, steppes, meadows, and aquatic, halophytic, synantropic, alpine, arctic, petrophytic, see-shore vegetation and wetlands were represented. The problems, that have appeared after beginning the syntaxa checklists development, such as the validation of units, the dubiousness of some accepted syntaxonomic decisions, poor syntaxonomic knowledge of some regions were discussed. The directors of three Botanical Gardens (from Yalta, Novosibirsk and Vladivostok) of the Russian Academy of Sciences signed documents (Fig. 3) on the starting of a scientific consortium «National Network of Botanical Gardens of the Russian Federation», focused on joint fundamental researches in the vegetation science, ecology, bioclimatology and biogeography; on the development of the National classification of vegetation and National typology of habitats as a scientific basis for assessing the carbon balance, rational use of natural resources and vegetation conservation in the country. Resolution of the Workshop emphasizes the necessity to consider the development of the Russian national vegetation classification as a priority task for phytosociologists in Russian Federation for the next five years.

A review of the classification of pine forests (dominated by two-needle pines of the subgenus Diploxylon) of Russia using the Braun-Blanquet approach was carried out. All diversity of pine forests was included in 9 higher units – vegetation classes, of which 3 classes represent typical communities dominated by pine species (Erico–Pinetea Horvat 1959, Koelerio glaucae–Pinetea sylvestris Ermakov class nova hoc loco, Junipero–Pinetea Rivas-Mart. 1965). In the remaining six classes (Vaccinio–Piceetea Br.-Bl. in Br.-Bl.et al. 1939, Carpino–Fagetea Jakucs et Passarge 1968, Quercetea pubescentis Doing-Kraft ex Scamoni et Passarge 1959, Brachypodio–Betuletea Ermakov et al. 1991, Rhytidio–Laricetea Korotkov et Ermakov 1999 and Quercetea mongolicae Song ex Krestov et al. 2006), pine forests are represented as special higher categories (alliances, orders) along with other types of zonal and non-zonal forest vegetation. The characteristics of the main higher units (classes, orders and alliances) are presented, as well as their diagnostic features and problems of classification of some categories are discussed. As a result of the syntaxonomic revision, the name of the class Pyrolo–Pinetea sylvestris Korneck 1974 was rejected, since the alliance Cytiso–Pinion sylvestris Krausch 1962 (the only alliance of order Pulsatillo–Pinetalia Oberd. in Oberd. et al. 1967) was proposed in the original article as provisional (3b). It is proposed to include xerophilous psammophilous pine forests of Europe and Western Siberia into a new class Koelerio glaucae–Pinetea sylvestris class nova hoc loco. The nomenclature type of the class (holotypus) is the order Koelerio glaucae–Pinetalia sylvestris Ermakov 1999. Diagnostic species of the class are Festuca beckeri, Gypsophylla altissima, G. paniculata, Jurinea cyanoides, Koeleria glauca, Oxytropis campanulata, Potentilla humifusa, Veronica spicata, Silene baschkirorum, S. chlorantha, Stipa pennata subsp. sabuletorum, Helichrysum arenarium, Centaurea arenaria, C. marschalliana, Achillea gebleri, Genista tinctoria, Cytisus ruthenica, C. borystenica, Hieracium pilosella, Dianthus arenarius.

The study of diversity and ecological-phytocenotic mapping of the vegetation cover was carried out at the key area located in the eastern part of the Echki-Dag mountain range in the territory of the Lisya Bay Reserve (Eastern Crimea). A generalization of the classification and ecological patterns of vegetation was carried out to create a legend for a large-scale ecological-phytocenotic cartographic model (at the scale of 1:10000). The ecological-geomorphological series and combinations of xerophytic and mesoxerophytic plant communities indicating erosion-denudation processes on different substrates of the underlying parent rocks were the thematic basis of the cartographic model. The developed legend is based on the units of vegetation of the association rank obtained using the Braun – Blanquet method combined into ecological series in accordance with their position on the gradients of the leading ecological factors as well as on the hierarchy of phytochories determined by the categories of erosion-denudation relief of coastal slopes. The resulting vegetation map demonstrates the main regularities of the regional phyto-diversity and serves as the basis for assessing the resource potential of vegetation, its landscape-stabilizing and nature conservation value.

The syntaxonomic analysis of pine forests with Acer negundo occurring on fluvio-glacial sandy deposits of Altai Krai (South-East Siberia) was made based on 93 releves. It was established that Acer negundo takes a different phytocenotic part in 2 associations, 2 variants, and 6 no-ranked communities of 4 classes and 4 orders according to the Braun-Blanquet approach. The method of detrended correspondence analysis (DCA coordination) implemented in the DECORANA software package was used to confirm the ecological and floristic integrity of the identified vegetation units. New data on the spatial syntaxa distributions depend on the complex humidity gradient, soil fertility, and anthropogenic factors. Acer negundo is most abundant and common in the communities of the Brachypodio-Betuletea pendulae class, which are characterized by habitats with moderate moistening and greater soil fertility. In the spatial series considered, according to the soil fertility and humidity gradients, we observe an increase in Acer negundo in the Vicia sylvatica – Pinus sylvestris community and an increase in the activity of mesophytes and mesohygrophytes that are more demanding to soil fertility.

Three associations of the class Carpino-Fagetea Jakucs et Passarge 1968 were described as а result of the classification of forest communities of the Colchis Lowland (Westem Transcaucasia) using the Brown­ Blanquet method. Association Vaccinio arctostaphilli-Carpinetum betuli ass. nova prov. was included in the order Lathyro-Carpinetalia Passarge 1981, alliance Crataego-Carpinion Passarge 1981. Associations Truello thunbergii-Alnetum barbatae ass. nova prov. and Carici remotae-Pterocmyetum pterocarpae ass. nova prov. were included in the order Rhododendro ponticae-Fagetalia orientalis Quezel et al. 1992, alliance Alnion barbatae Quezel et al. 1992. The results of the DCA ordination and the interpretation of the leading axes demonstrated three well-distinguished ecological and floristic types of deciduous forests (ofthe association rank) forming the ecological series according to the leading ecological factors - the degree of humidity of habitats and the degree of drainage of substrates. Twenty-three plant species - thermophilous Tertiary rehcs were found in all three associations. Of these, eight evergreen species play а significant phytocoenotic role in the formation of the understory in forest communities.The pecuharities of the Tertiary rehc speciesdistributions in the floristic compositions of described associations are discussed.

ISHS VIII International Scientific and Practical Conference on Biotechnology as an Instrument for Plant Biodiversity Conservation (Physiological, Biochemical, Embryological, Genetic and Legal Aspects) Phytocoenotic map to evaluate plant diversity in eastern Crimea