Assessment of the decorativeness of woody plants in the context of greening urban areas of the Far North

Greening of the cities of the Far North is an important and complex task due to the harsh climate, permafrost and significant industrial development. Green plantings provide wind and snow protection, improve the microclimate. However, modern studies of urban green infrastructure concern mainly temperate and southern latitudes, leaving the Arctic zone without due attention. For the selection of woody plants, we use a polytomous key including criteria of ornamentality, phenotypics and phenology. The assessment is based on data on plants under conditions of their maximum productivity without anthropogenic intervention. We select the following trees for the study: dwarf birch, common rowan, goat willow, brittle willow, arctic willow, black alder, grey alder, aspen, bird cherry, Dahurian larch, Gmelin larch, Siberian larch, Norway spruce, blue spruce, Siberian spruce, Scots pine, Siberian cedar, common juniper, juniper horizontalis, Cossack juniper, Siberian juniper. We develop a polytomous key for assessing the decorativeness of deciduous and coniferous trees. The decorativeness of deciduous plants is determined by the appearance of the foliage (color, change and brightness of the color of the leaves during the growing season, duration of the foliage period), as well as the presence of flowers and fruits (color, size, aroma). The decorativeness of coniferous trees is determined by the shape of the crown, the color of the needles, the rate of growth, the presence of fruits, the color of the cones, etc. Ranking trees by decorativeness using the calculation of the total number of the polytomous key points reveals that the deciduous plants that have the greatest decorativeness are rowan, bird cherry and black alder; the most decorative conifers are the Siberian cedar (cedar pine), junipers (common, horizontal, Siberian, Cossack), and Scots pine.