The Spatial Distribution of Tree Populations and Its Policy Drivers in Medieval Areas of Cities. Case Studies From East-central Europe

Abstract

Trees in the densely built-up historical cores of cities play an important role in increasing the aesthetic values of the cityscape as well as lowering the effect of the urban heat island. The research aimed to determine the spatial distribution of tree populations in the medieval parts of cities according to local policy. The investigation included three cities in Central and Eastern Europe: Poznań and Lublin in Poland and Lviv in Ukraine. The oldest parts of these cities share similar origins, the same continental biogeographical region, and comparable climatic conditions.This study considered indicators of occurrence, density, species composition, and spatial distribution; and the number of trees planted since the political transition to democracy has also been considered, taking into account the composition of their species. Local policy documents on greenery management, revitalisation, and adaptation to climate change were analysed.The study identified different types of management concerning trees. In Poznań, trees are actively introduced in public spaces, but private backyards are managed by their owners. In Lublin, although there are relatively few new plantings, there is the largest share of trees in the backyards and self-seeding is common. In Lviv, there are new plantings in private and public spaces. Lviv is distinguished by its large share of native trees, with naturally shaped crowns, and in Poznan and Lublin, new plantings include artificially shaped, small spherical crowns. The local policy documents don't contain operational directives regarding the cultural, environmental, social, and technical conditions for new planting.

Preferences of public space users towards trees and other forms of greenery in Lublin's old town

“…According to these results, it is the large trees with wide crowns presented in the visualisations that were the most frequently chosen form of greenery for the Old Town in our research. However, it seems that also, in accordance with the preferences regarding the shape of crowns in historic parts of cities in Poland, grafted maples and spherically crowned black locusts (Robinia pseudoacacia) are currently planted (Mizgajski et al, 2021). In the conducted research, such forms were very popular in the selections of women and the oldest age group.…”

“…However, there is a visible change of the dominant function from residential and commercial to representative and touristic. Lublin is visited annually by over 1,000,000 people, for whom the oldest part of the city is the main attraction (Mizgajski et al, 2021).…”

“…The third simulation included small trees grafted onto a trunk (2-5m) and planted in large pots. Such trees are used in Lublin as urban plantings and considered to be the equivalent of tall greenery in the city centre (Mizgajski et al, 2021).…”

“…Most often, building density is highest in the oldest parts of cities. Such are the structures of historical cities, such as those of medieval origin (Mizgajski et al, 2021). This creates numerous functional and spatial problems.…”