1,721,033 research outputs found
Forest vegetation and old-fields colonization by woody species in a region of the Julian Prealps, Taipana-Udine
No full textSpecies composition of woody vegetation, density, health, regeneration, evolution trend in the short time and landscape dynamics in recent time (last 50 yr) were studied. Secondary succession models have been described by reconstructing the phases of colonization by forest vegetation in old fields. Fast colonization and success of woody vegetation, particularly Fraxinus excelsior, Alnus glutinosa and Acer pseudoplatanus characterize the process
The impact of pruning and mortality on urban tree canopy volume
No full textUrban trees provide a wide range of ecosystem services for city residents, with tall, mature trees with wide crowns generally regarded as preferable. The tree biomass which is responsible for shading, pollution removal, rain runoff retention etc. gets periodically reduced by the municipal tree management practice of pruning. This is a necessary activity, which reduces the risk of infrastructure damage and falling branches, but many estimates of ecosystem service provision in cities do not consider its impact explicitly. Tree mortality is also higher in cities, preventing trees from attaining and remaining at large sizes. This study used extensive field measurements of tree structure to estimate the impact of pruning on 8 tree species in two Italian cities: Taranto and Florence. Crown widths were reduced by 1.6 m on average, however there is large variation between species variation with branches more often being removed for thinning crowns resulting in larger gap fractions, which increased by 15% on average. No significant differences were observed for crown widths or gap fraction between trees pruned 3 and 4 years previously, suggesting that tree crowns structurally recover from pruning after 3 years. A deterministic model revealed that current urban forest pruning rates (every 6 years) and mortality (1%) may create a situation in which a city dominated by the species studied benefits from 93.5% of the maximum ecosystem services possible. This work will allow more nuanced estimates of urban forest services to be calculated
Thermal comfort and perceptions of the ecosystem services and disservices of urban trees in florence
No full textModern urban lifestyles have most likely generated a loss of awareness of the bio‐cultural benefits derived from the presence of trees and forests in cities. The present study aimed at understanding the level of awareness and the ability to express significant relationships, both positive and negative, on ecosystem services and disservices by the citizens of a Mediterranean city where thermal comfort during the summer period can be particularly problematic. A questionnaire consisting of multiple‐choice and open‐ended questions was disseminated to citizens of Florence, Italy. The open questions allowed respondents space to describe what they perceive are the benefits and dis-benefits of urban trees. Meanwhile, geospatial and climate data were processed in order to check the vegetation and microclimate conditions of the city areas where the 592 respondents live. The vast majority of respondents felt Florence is unbearably hot in summer with 93% agreeing the city needs more trees, and shaded places were perceived as the most important feature of urban green space. The results reveal many positive and negative associations to different species of trees and bring out a rich mosaic of perceptions towards urban green spaces and the features they contain. People are generally aware of a wide range of the benefits trees provide to communities and a good knowledge of the microclimate modification properties was revealed. Many of the popular public tree genera in the city, such as Tilia, Platanus and Pinus were favoured by residents however there was some overlap with trees that provoke negative experiences, and this information can be useful to city planners aiming to maximise ecosystem services and minimise ecosystem disservices
Summer thermal comfort of pedestrians in diverse urban settings: A mobile study
No full textUrban planning must consider the outdoor thermal comfort of city dwellers, particularly in cities where climate and the effects of climate change may severely influence human health and wellbeing in increasingly hot summers. The role of the urban forest in ameliorating this problem is decisive. The present study is based on a campaign of meteorological measurements in a large number of sites using a mobile data collection system to allow a human-centred approach. The aim is to quantify the different microclimates and thermal comfort conditions in six classes of urban morphology, discriminating landtypes with or without trees. In the case study of Florence, local physical characteristics of the sites; Sky View Factor (SVF), tree shade, ground surface cover, and canyon effect, can moderate human exposure to potentially uncomfortable thermal conditions during a typical Mediterranean summer. Significant differences in Universal Thermal Comfort Index (UTCI) were observed between treeless piazzas and streets and landtypes with trees or high height to width ratio (narrow alleys). Varying levels of SVF and tree cover in the sites allowed the construction of multivariate models, which revealed that, during common summer afternoon conditions, decreases of SVF by 12.5% or increases of tree cover by 25% can reduce the UTCI by 1°. Additionally, the total site factor, by incorporating temporally integrated sun exposure with the sky view factor, revealed itself a promising variable for future studies to use
Integration of nature-based solutions (NBS) in local policy and planning toward transformative change. Evidence from Barcelona, Lisbon, and Turin
No full textThe attention given to nature-based solutions (NBS) in urban governance is often hindered by the fragmentation of responsibilities in technical and administrative services and by rigid structural conditions within urban regimes. This drastically harms NBS implementation and their co-benefits. There is limited information regarding NBS integration across levels and scales of urban governance, in particular a lack of studies that access such integration in urban policy and planning. This study aims to address this gap by exploring the integration of NBS in urban policy and planning in Barcelona, Lisbon, and Turin, the three European municipalities participating in the H2020 project CONEXUS. The objectives are: (1) to understand the state of top-down and bottom-up integration of NBS in urban policy and planning in the three cities; (2) to understand barriers in integration that might hinder the evolution of the NBS agenda in said instruments; (3) to identify policy and planning entry points that can catalyze forms of cross-sectoral, multi-level, and interdisciplinary governance of NBS toward transformative change. The methods used include an in-depth analysis of official municipal, metropolitan, regional, and national documents and expert interviews. The results show that NBS integration in urban policy and planning is novel in all cities but advancing considerably with initial dialogues among the public sector, academia, and local actors of various provenances. Planning in silos persists, negatively impacting any possible confluence of actions toward NBS integration and implementation. However, a constellation of national and international plans including NBS, combined with the development of cross-cutting policies and plans, and an increasing interest from the municipalities and citizens, reveal an enabling environment for NBS integration in urban policies. Our findings are translated into insights that can support policy and decision makers to operationalize NBS integration in their municipal agendas, policies, and plans
Growth Pattern and Architecture in Quercus Ilex L. and Fraxinus Ornus L. Vegetative Regeneration After Coppicing in Maremma Nature Park (Central Italy)
No full textThe growth pattern and architecture of Quercus ilex L. and Fraxinus ornus L. resprouting after coppicing has been study to test the space occupation dynamics by the new meta-population of shoots. In the early years after coppicing, Fraxinus ornus L. rapidly occupies the vertical space by long spring flushes, while Quercus ilex L. occupies both the vertical and horizontal available space by a complex apical architecture of primary meristems. The two different behaviors have been interpreted as strategic resilience response of the species to environmental disturbances
Urban forest research in the Mediterranean: A systematic review
No full textThe Mediterranean region is facing many challenges, some of which can be addressed by nature-based solutions such as urban forests and green space. However, at best, urban forest research from Mediterranean countries has been only briefly addressed in review papers up to date. This Scopus-based review paper provides first insights into the development of urban forest research in the Mediterranean in the 20-year period from 1996 to 2015. The purpose of the review was to a) analyse distribution of urban forest research in the Mediterranean and identify countries that are forerunners based on the number of publications, b) to analyse distribution of research themes across the Mediterranean and per country, and hence point to research gaps and needs. Researchers from Italy, Turkey and Spain were the most productive in the analysed period. Research is mainly concentrated in the North, while it is scarce to non-existent in South and Eastern Mediterranean countries (excluding Turkey and Greece). Papers dealing with pollution, human health and sociocultural values were the most frequent. Some countries exhibited research specialisation with regard to certain themes. For instance Italian researchers mostly focused on topics related to pollution and urban forest management, the majority of Spanish papers addressed urban forests in the context of human health, while sociocultural values were the main research theme for researchers from Turkey. Papers were analysed also based on research methods, approaches and study locations. Suggested future research includes analysis of the quality of knowledge related to urban forests in the Mediterranean as well as of collaboration between researchers, research institutions and countries
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