Phytosociological classification of forest vegetation of Kedrovaya Pad Reserve (Primorye Territory, Russia)
Authors: Petrunenko E. A. , Dzizurova V. D. 
Published: July 2024

Kedrovaya Pad Reserve is located in the southwestern part of Primorye Territory, Russian Far East. This nature reserve was established more than 100 years ago aiming to preserve unique stands of virgin south Manchurian mixed forest with Abies holophylla, Pinus koraiensis and numerous broadleaf species. The structure of vegetation was studied thoroughly, however, classification was performed with the emphasis on dominant species and geographical characteristics of the location (Vasilyev et al., 1984), which can be rather useful for forestry but usually does not reflect all peculiarities of described community. Proposed here classification based on Braun-Blanquet approach provides another glance on vegetation structure and allows to consider results within the frames of the existing syntaxonomic system for Northeast Asia.

We analyzed 109 relevés, which we collected during the years 2008–2018 (Fig. 1). Cover of each species was estimated in percent. We applied unsupervised classification — modified TWINSPAN (Roleček, 2009) via JUICE 7.0 (Tichý, 2002) to receive seven clusters (Fig. 2, Table 1). Clusters experienced expert revision and were turned into seven groups. These groups were interpreted as associations or subassociations (Table 2). Diagnostic species were identified basing on calculated constancy and phi coefficient (Chytrý et al., 2002).

The studied forest vegetation of Kedrovaya Pad Reserve is presented by six associations and three subassociations. One of the seven groups incorporates three relevés, which describe deciduous communities on freshly formed alluvial soils. However, these relevés differ significantly between each other and obtained group doesn’t have any syntaxonomic meaning.

Spodiopogono sibirici–Quercetum mongolicae ass. nov. hoc loco

Holotypus: relevé 18 in Table 4. Diagnostic species: Artemisia keiskeana, Polygonatum humile, Spodiopogon sibiricus.

Communities of this association prefer steep and moderate south or west slopes with mild water deficiency. Trees form one or two strata. Quercus mongolica dominates the canopy, often accompanied by Tilia amurensis. Second tree stratum, if presented, formed by Acer pseudosieboldianum and, again, Tilia amurensis. Typical for the shrub layer is Lespedeza bicolor. Most noticeable species of the herb layer are Artemisia keiskeana, Carex siderosticta & C. nanella, Melampyrum roseum, Spodiopogon sibiricus and Calamagrostis brachytricha.

Viti amurensis–Quercetum mongolicae ass. nov. hoc loco

Holotypus: relevé 10 in Table 5. Diagnostic species: Chloranthus japonicus, Geranium eriostemon, Heracleum dissectum, Vitis amurensis.

Important feature of the habitats for communities of this association is sufficient amount of moisture and this can be met in the lower parts of the slopes, as well as on the top of the ridges (450–500 m a. s. l.), where sea fogs bring additional humidity. Trees form two strata. Quercus mongolica, Tilia amurensis and Fraxinus rhynchophylla form the upper one. Acer mono is ordinary in the second stratum. Shrub layer is dominated by Corylus mandshurica, other species are Rubus crataegifolius, Philadelphus tenuifolius and Weigela praecox. Vines — Vitis amurensis, Schisandra chinensis and Actinidia kolomikta are also common. In the herb layer there are no strong dominants, most characteristic are Carex lanceolata & C. siderosticta, Artemisia stolonifera and several Vicia species.

Rhododendro mucronulati–Betuletum schmidtii ass. nov. hoc loco

Holotypus: relevé 9 in Table 6. Diagnostic species: Betula schmidtii, Carex nanella, Rhododendron mucronulatum.

Communities of this association occupy moderate slopes or tops of the ridges, facing north-east or north-west; soils are rocky and dry. Quercus mongolica and Betula schmidtii form the highest stratum. Acer pseudosieboldianum presents second stratum. Rhododendron mucronulatum dominates in shrub layer. Carex nanella, C. siderosticta and young shoots of vine Schisandra chinensis prevail in the herb layer.

Matteuccio struthiopteridis–Juglandetum mandshuricae ass. nov. hoc loco

Holotypus: relevé 13 in Table 7. Diagnostic species: Brachybotris paridiformis, Cardamine leucantha, Carex pallida, Filipendula palmata, Hylomecon vernalis, Juglans mandshurica, Matteuccia struthiopteris, Oxalis obtriangulata, Phlomoides maximowiczii, Sanicula rubriflora, Stellaria bungeana, Valeriana fauriei.

Communities of this association can be met within river terraces, which are most close to the floodplain. Amount of moisture is sufficient or excess. Upper trees belong to the vast number of species; most common are Tilia amurensis, Fraxinus mandshurica, Juglans mandshurica, Pinus koraiensis, Abies holophylla. Second stratum is also rich in species, with constant Acer mono. The latter one along with Carpinus cordata forms the third stratum. In the shrub layer common are Eleutherococcus senticosus, Viburnum sargentii and several Lonicera species. Among numerous species typical for the herb layer are diagnostic ones.

Two subassociations of this association are distinguished. M. s.–J. m. typicum subass. nov. hoc loco occupies the same habitat as specified for association and has the same set of diagnostic species. M. s.–J. m. chrysosplenietosum villosi subass. nov. hoc loco prefers more wet habitats with poorly drained soils. From the aforementioned subassociation it differs by the composition of the herb layer. Holotypus: relevé 6 in Table 7. Diagnostic species: Chrysosplenium pseudofaurie, C. villosum, Cornopteris crenulatoserrulata, Geum aleppicum, Pseudostellaria japonica.

Polysticho tripteron–Pinetum koraiensis typhicum Gumarova et al. ex Krestov et al. ex Krestov et al. 2023

Releves belonging to this syntaxon are presented in Table 8.

Communities belonging to this subassociation occupy north facing gentle or moderate slopes. The tree layer consists of three strata. The upper one is formed by Abies holophylla up to 50 m high. Besides fir, Tilia amurensis, Quercus mongolica, Pinus koraiensis and Kalopanax septemlobus are common. The second stratum is built by Abies holophylla and Tilia amurensis, accompanied by Acer mono. Acer pseudosieboldianum and Carpinus cordata form the lowest tree stratum. In shrub layer Philadelphus tenuifolius dominates. Species of the herb layer can be divided into two groups: constant with low abundance — Phryma asiatica, Maianthemum dilatatum, Thalictrum filamentosum и T.tuberiferum, Carex siderosticta; and ferns Dryopteris crassirhizoma & D. expansa, Osmundastrum asiaticum with the cover 5–50 % each. Vines Schisandra chinensis, Actinidia arguta & A. kolomikta are well pronounced.

Weigelo praecocis–Aceretum ukurunduensis ass. nov. hoc loco

Holotypus: relevé 4 in Table 9. Diagnostic species: Euonymus maximowicziana, Gymnocarpium dryopteris, Weigela praecox.

Communities of this association were observed only on the slopes of Mt. Uglovaya higher than 600 m a. s. l. The tree layer consists of two or three strata. Abies nephrolepis, Tilia amurensis and birches — Betula costata or B. lanata form the highest one. Lower strata are built by Acer ukurunduense, A. pseudosieboldianum & A. tegmentosum. For the shrub layer common are Weigela praecox, Philadelphus tenuifolius, Deutzia amurensis. In the herb layer Carex siderosticta is abundant, other noticeable group is ferns and vine Actinidia kolomikta.