Seed regeneration of green ash (Fraxinus pennsylvanica Marshall) in green spaces of Petrozavodsk city

2024

Hortus Botanicus, Vol 19, Iss 1 (2024)

Green ash (Fraxinus pennsylvanica Marshall) is an invasive species in many European countries and regions of Russia. A number of experts recommend limiting the use of this species in landscaping due to its intensive rapid and the possible spread of a dangerous pest Agrilus planipennis F. The study was carried out in Petrozavodsk (Republic of Karelia), located in the middle taiga subzone, where green ash is common in street landscaping, parks, and courtyards. Seed productivity of the trees, morphometric parameters, and germination rate of seeds were estimated in 2023. The number of flowers on the shoots is large: on female trees from 3.5 thousand to 6.5 thousand / 1 total meter of shoot (on average 4878 flowers), on male trees from 4.8 thousand to 7.4 thousand / 1 meter of shoot (average 5853 flowers). Potential seed productivity is almost 5 thousand seeds / 1 total meter of shoot. The sizes and morphology of the samaras correspond to the species characteristics. Field germination of seeds with stratification is 34%. By autumn, the seedlings have formed apical, and lateral buds, which increases the chances of young plants to survive in the winter. Seedlings of green ash in Petrozavodsk occur sporadically. Seed germination is limited possibly by deficit of light and moisture, competition from trees, shrubs and perennial grasses. At the same time, there are individual successful examples of self-seeding of green ash in Petrozavodsk, and the plants reach the age of several years and form seeds. Thus, the invasive potential of the plant in the conditions of South Karelia is not realized; mass self-seeding and widespread dispersal of this species outside the green spaces are not observed. The dangerous pest Agrilus planipennis is not registered in the republic. In the northern region there are not many beautiful broad-leaved woody species that demonstrate successful growth in urban environments. Green ash should not be excluded from the list of species used in landscaping in Petrozavodsk in present climate conditions. Botanical control and phytosanitary control of planting material in urban conditions is necessary.

article

Russian

Petrozavodsk State University, 2024.

биологические инвазии, семенное размножение, самосев, fraxinus pennsylvanica, oleaceae, Botany, QK1-989