B. Papp szerk.: Studia Botanica Hungarica 35. 2004 (Budapest, 2004)

Szollát, György; Schmotzer, András: Contributions to the flora and vegetation of the environs of Balassagyarmat (Hungary)

Passing along the eastern two thirds section of the valley upwards to its head, the site gets drier and the vegetation becomes more and more degraded until the alder stand eventually disappears. Above the only crossing road within the site, in the dammed-up water Typha angustifolia, Lemna minor, Sparganium erectum are found. Among the notable species, Carex remota exists here, but (while moving upwards) as the ash-alder woodland gets thinner and poorer in species, hardly any other "good" species occur. In general, Carex acutiformis dominates the herb layer; further up nitrophytes, mostly Urtica dioica and Sambucus nigra take over. Finally, even the alder specimens get poorer and poorer until they give up and disappear. Site No. 10 Elevation: 145 m. Down from the confluence of the different arms of the Nyirjes stream its valley widens out. Before the streambed was recently deepened, the stream-water could spread out and nourish a larger area by its slow waterflow; this is no longer the case. Those former ecological conditions were needed to support the even now existing submontane stream ash-alder wood (Aegopodio-Alnetum), a good, almost natural stand, well representing the association. It differs markedly from the stands seen towards the upper reaches of the stream - which is attributed to the differences in water supply. The upper tree layer is dominated by Alnus glutinosa. In the lower tree layer Padus avium and, mainly at the edges, Salix alba and Salix fragilis are frequent, while Ulmus laevis and U. glabra are sporadical. In the shrub layer Sambucus nigra, Viburnum opulus and Frangula alnus, while in the drier parts of the site numerous Querco-Fagetea species, e.g. Euonymus europaeus and Cornus sanguinea are obseved. The protected Ribes nigrum (10-100 specimens) also occur here, besides Ribes rubrum represented by a similar number of specimens. In major parts of the site four Fagetalia species dominate in the herb layer: Ficaria verna, Aegopodium podagraria, Galeobdolon luteum, Lamium maculaturn; additional Fagetalia species worth mentioning are Paris quadrifolia, Athyrium fdix-fe mina, Stachys sylvatica, Glechoma hederacea. Along the streamsides and in the waterlogged places riverine (and partly swamp) woodland species - Caltha palustris, Cardamine amara, Chrysosplenium alternifolium, and Dryopteris carthusiana (100-200 specimens), Cirsium oleraceum, Filipendula ulmaria, Carex acutiformis, etc. - take over. Thus, the vegetation of this habitat - with slowly streaming or almost stagnant water - is regarded as a good, almost natural alder swamp wood (Angelico sylvestris-Alnetum glutinosae Borhidi in Borhidi and Kevey 1996).