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Allotment gardens are a key feature of the urban landscape, providing numerous benefits beyond those of food production. These include ecosystem services such as local climate modification, pollination, and providing a pleasant location for socialising. The biodiversity of flora underpins many of these ecosystem services. The aims of this study are to assess the spontaneous vascular flora of urban allotment gardens and derive estimates of the species richness and diversity. In doing so, the specific position of allotment gardens within urban green infrastructure will be revealed and the role of allotment users in shaping local biodiversity determined. 358 species of spontaneous flora were recorded in 11 representative allotment garden estates (total area 150 ha) in Poznan, Poland. Fourteen biodiversity features were taken into account. The investigated areas exhibited high plant species richness, high diversity, low synanthropisation level, and contained valuable geobotanical elements, including plants of key importance for the European Community. For these reasons, allotment gardens should be considered as biodiversity hotspots for native species within urban green infrastructure. Based on an analysis of the spatial and functional organization of 110 individual plots, four types of usage, and corresponding plant diversity have been distinguished. The composition of the flora depends mostly on spatial and functional organization of allotment gardens and, to a much lesser extent, on the habitat conditions, which on individual plots varied very little. The high species richness and diversity in allotment gardens has important consequences for urban planning.

Climate action plans, with goals for carbon neutrality of cities, often rely on estimates of urban forest biomass and related annual carbon sequestration balanced against citywide carbon emissions. For these estimates to be successful, there is a need both for accurate quantification of urban tree populations and structure, and consideration of the net carbon sequestered when the fate of wood waste is factored in. This study provides a novel approach to providing a full city tree inventory for the city of Meran in northern Italy, using a combination of Light Detection and Ranging (LiDAR) and field techniques. Allometric equations, and the i-Tree application quantified the carbon storage in Meran as 8923 and 9213 Mg respectively, with an average carbon storage of 13.5 t/ha (5.47 kg C/m2). The percentage of traffic emissions sequestered annually is 0.61% falling to 0.17% when all emissions are considered. Differences between end-of-life wood management techniques were revealed, with burning with energy recovery for electricity being the most efficient with a carbon emissions/input ratio of 0.5. Landfill was the least efficient with a ratio of 121.9. The fate of this end-of-life wood has significant implications for carbon budget calculations in cities worldwide. © 2020 Elsevier Ltd

The physical nature of the built urban environment gives rise to urban heat islands (UHI), making many cities frequently thermally uncomfortable in the summer, with potentially serious effects on human health. When climate change effects of higher summer temperatures and prolonged heatwaves are factored in, it is clear that adaptive measures are needed to ensure the liveability of cities. The shade provided by planting trees is one such adaptation measure. This study, in Bolzano, Italy, used a thermal camera to record the surface temperatures of three common urban surfaces – asphalt, porphyry, and grass – in the shade of 332 single tree crowns, of 85 different species, during the peak temperature period of summer days. By comparing with the temperature of adjacent unshaded ground, estimates of the degree of surface cooling were made. Measurements at three locations within the shadow revealed higher cooling in the centre and at the western edge. The cooling was related to a multitude of tree traits, of which Leaf Area Index estimate (LAIcept) and crown width were the most important. Median average cooling of 16.4, 12.9 and 8.5 °C was seen in the western edge of the tree shade for asphalt, porphyry and grass, respectively. Maximum temperatures were reduced by roughly 19 °C for all surface types. Coniferous trees were capable of providing high cooling, however, crown dimensions may limit the receiving surface area. Descriptive and predictive multiple linear regression models were able to predict cooling with some success from several of the predictor variables (LAIcept and gap fraction). Strategic planting of single trees in cities can have significant impacts on the absorption of solar radiation by ground surface materials thus reducing the heat storage that contributes to UHIs.