Vegetation of regional landscape and botanical natural monument «Aland’s Pine Forest» (Kvarkensky area of the Orenburg Region)

The paper presents a detailed analysis of regional landscape and botanical natural monument «Aland’s Pine Forest» (Kvarkensky area of the Orenburg Region) vegetation. The pine forest vegetation has rather high phytodiversity and dominance indexes. 71 plant vascular species have been identified (3 of them are included in the Red Book of the Orenburg Region (2019)) and 15-species’ pine communities prevail, but steppe species dominate in shrub and herb layers. The authors have revealed that the described pine forests are forest-steppe amphycoenosis. 13 plant associations have been identified by multivariate statistics methods, but their biotopes are not specific by fundamental abiotic factors. The authors have also established that forest conditions of Aland’s Pine Forest are of AB₁ and AB₁₋₂ types and light type of stand of trees structure by A.L. Betgard steppe forest typology. The detected pine vegetation associations form ordination series – sylvatic of steppe pine forest with wheat-grass (Elytrigia repens (L.) Nevski) and amphycoenotic of steppe pine forest with steppe herbs. The principal abiotic factors for pine forests coenotic structure forming are soil calcium and nitrogen regimes, soil moistening and acidity and porosity (aeration) of soils. Factors of biotope discrimination are thermal climate (radiation balance), cryoclimate (negative winter temperature), brightness regime and saline regime of soils.