scholarly journals Identifying Tree Traits for Cooling Urban Heat Islands—A Cross-City Empirical Analysis

Forests ◽  
2020 ◽  
Vol 11 (10) ◽  
pp. 1064
Author(s):  
Carola Helletsgruber ◽  
Sten Gillner ◽  
Ágnes Gulyás ◽  
Robert R. Junker ◽  
Eszter Tanács ◽  
...  
Keyword(s):  
Ecosystem Services ◽  
Leaf Area ◽  
Tree Species ◽  
Urban Trees ◽  
Cooling Effect ◽  
Site Conditions ◽  
Area Index ◽  
Tree Management ◽  
Urban Heat ◽  
Tree Traits

Research Highlights: This paper presents a cross-city empirical study on micro-climatic thermal benefits of urban trees, using machine-learning analysis to identify the importance of several in situ measured tree physiognomy traits for cooling. Background and Objectives: Green infrastructure and trees in particular play a key role in mitigating the urban heat island (UHI) effect. A more detailed understanding of the cooling potential of urban trees and specific tree traits is necessary to support tree management decisions for cooling our progressively hot cities. The goal of this study was to identify the influence and importance of various tree traits and site conditions. Materials and Methods: Surface temperature, air temperature at 1.1 m and at tree crown height, as well as wet bulb globe-temperature of shaded and fully sun-exposed reference areas, were used to study the cooling effect of seven different urban tree species. For all 100 individuals, tree height, crown base, trunk circumference, crown volume, crown area, leaf area index (LAI) and leaf area density (LAD) were measured. Measurements were conducted in the cities of Dresden, Salzburg, Szeged, and Vienna as representatives for middle European cities in different climate zones. Results: Beside site conditions, tree species, height, height of crown base, as well as trunk circumference, have a great influence on the cooling effect for city dwellers. The trunk circumference is a very valuable indicator for estimating climate regulating ecosystem services and therefore a highly robust estimator for policy makers and tree management practitioners when planning and managing urban green areas for improving the availability and provision of ecosystem services.

scholarly journals Towards sustainable management of the stock and ecosystem services of urban trees. From theory to model and application

Trees ◽  
2021 ◽  
Author(s):  
H. Pretzsch ◽  
A. Moser-Reischl ◽  
M. A. Rahman ◽  
S. Pauleit ◽  
T. Rötzer
Keyword(s):  
Ecosystem Services ◽  
Carbon Sequestration ◽  
Leaf Area ◽  
Ecosystem Service ◽  
Sustainable Management ◽  
Environmental Changes ◽  
Urban Trees ◽  
Urban Tree ◽  
Age Class ◽  
Sustainable Planning

Abstract Key message A model for sustainable planning of urban tree stocks is proposed, incorporating growth, mortality, replacement rates and ecosystem service provision, providing a basis for planning of urban tree stocks. Abstract Many recent studies have improved the knowledge about urban trees, their structures, functions, and ecosystem services. We introduce a concept and model for the sustainable management of urban trees, analogous to the concept of sustainable forestry developed by Carl von Carlowitz and others. The main drivers of the model are species-specific tree diameter growth functions and mortality rates. Based on the initial tree stock and options for the annual replanting, the shift of the distribution of the number of trees per age class can be predicted with progressing time. Structural characteristics such as biomass and leaf area are derived from tree dimensions that can be related to functions such as carbon sequestration or cooling. To demonstrate the potential of the dynamic model, we first show how different initial stocks of trees can be quantitatively assessed by sustainability indicators compared to a target stock. Second, we derive proxy variables for ecosystem services (e.g. biomass for carbon sequestration, leaf area for deposition and shading) from a given distribution of the number of trees per age class. Third, we show by scenario analyses how selected ecosystem services and functions may be improved by combining complementary tree species. We exercise one aspect (cooling) of one ecosystem service (temperature mitigation) as an example. The approach integrates mosaic pieces of knowledge about urban trees, their structures, functions, and resulting ecosystem services. The presented model makes this knowledge available for a sustainable management of urban tree stocks. We discuss the potential and relevance of the developed concept and model for ecologically and economically sustainable planning and management, in view of progressing urbanization and environmental changes.

scholarly journals Leaf and Crown Optical Properties of Five Early-, Mid- and Late-Successional Temperate Tree Species and Their Relation to Sapling Light Demand

Forests ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 925 ◽  
Author(s):  
Marc Hagemeier ◽  
Christoph Leuschner
Keyword(s):  
Optical Properties ◽  
Leaf Area ◽  
Tree Species ◽  
Forest Floor ◽  
The Sun ◽  
Area Index ◽  
Minimum Light ◽  
Tree Canopies ◽  
Successional Species ◽  
Shade Leaves

The optical properties of leaves and canopies determine the availability of radiation for photosynthesis and the penetration of light through tree canopies. How leaf absorptance, reflectance and transmittance and radiation transmission through tree canopies change with forest succession is not well understood. We measured the leaf optical properties in the photosynthetically active radiation (PAR) range of five Central European early-, mid- and late-successional temperate broadleaf tree species and studied the minimum light demand of the lowermost shade leaves and of the species’ offspring. Leaf absorptance in the 350–720 nm range varied between c. 70% and 77% in the crown of all five species with only a minor variation from the sun to the shade crown and between species. However, specific absorptance (absorptance normalized by mass per leaf area) increased about threefold from sun to shade leaves with decreasing leaf mass area (LMA) in the late-successional species (Carpinus betulus L., Tilia cordata Mill., Fagus sylvatica L.), while it was generally lower in the early- to mid-successional species (Betula pendula Roth, Quercus petraea (Matt.)Liebl.), where it changed only a little from sun to shade crown. Due to a significant increase in leaf area index, canopy PAR transmittance to the forest floor decreased from early- to late-successional species from ~15% to 1%–3% of incident PAR, linked to a decrease in the minimum light demand of the lowermost shade leaves (from ~20 to 1%–2%) and of the species’ saplings (from ~20 to 3%–4%). The median light intensity on the forest floor under a closed canopy was in all species lower than the saplings’ minimum light demand. We conclude that the optical properties of the sun leaves are very similar among early-, mid- and late-successional tree species, while the shade leaves of these groups differ not only morphologically, but also in terms of the resource investment needed to achieve high PAR absorptance.

Synoptic representation of P.oceanica ecosystem services in the Italian seas

2020 ◽  
Author(s):  
Sergio Scanu ◽  
Simone Mellini ◽  
Daniele Piazzolla ◽  
Simone Bonamano ◽  
Emanuele Mancini ◽  
...  
Keyword(s):  
Ecosystem Services ◽  
Leaf Area ◽  
Posidonia Oceanica ◽  
Average Height ◽  
Natural Ecosystems ◽  
Habitat Directive ◽  
Area Index ◽  
Long Run ◽  
The Mediterranean ◽  
Object Of Study

<p>This work analyzes and quantifies the value of ecosystem services in the <em>P.oceanica</em> meadows of the Italian seas, defining methodological approaches and creating synoptic maps through the use of GIS. Ecosystem Services can be defined as benefits provided to mankind by natural ecosystems. Their contribution is essential for human progress and of fundamental importance in the long run.</p><p><em>Posidonia oceanica</em> was chosen as the object of study because its meadows represent one of the Mediterranean "climax community". <em>P. oceanica</em> is, therefore, one of the most important ecosystem in the Mediterranean and has been indicated as "priority habitat" according to the Habitat Directive (Dir. N. 92/43 / EEC), which groups together all the Sites of Community Importance (SCI) that need to be protected.</p><p>The method of evaluating the ecosystem services for <em>P.oceanica</em> is derived from what reported in Costanza et al. (1997) applying the specific site approach for the definition of benefits and services (Marcelli et al. 2018).</p><p>The identified benefits for <em>P.oceanica</em> are carbon sequestration, oxygen production, erosion protection, bioremediation and food production.</p><p><em>P.oceanica</em> data are organized from the dataset collected by the Italian Institute for the Protection of the Environment and Research (ISPRA) for the Marine Strategy Framework Directive and include parameters such as coverage and shoots number (m<sup>2</sup>), average leaf area, leaf area index, average number of leaves, average height of the rhizomes, average foliar and rhizomes production. The data were used for the calculation of the benefits of <em>P. oceanica</em> which are represented in synoptic maps through GIS with the creation of the Atlas of the values ​​of ecosystem services in the Italian seas.</p>

scholarly journals Intra-specific variation in leaf attributes of four savanna tree species across a rainfall gradient in tropical Australia

2005 ◽  
Vol 53 (4) ◽  
pp. 323 ◽  
Author(s):  
L. D. Prior ◽  
D. M. J. S. Bowman ◽  
D. Eamus
Keyword(s):  
Leaf Area ◽  
Tree Species ◽  
Annual Rainfall ◽  
Leaf Mass Per Area ◽  
Rainfall Gradient ◽  
Area Index ◽  
Australian Monsoon ◽  
Specific Variation ◽  
Tropical Australia ◽  
Leaf Density

Leaf attributes of four savanna tree species were measured along a rainfall gradient (1650–950 mm per annum) in the Australian monsoon tropics. As the mean annual rainfall decreased, leaf thickness increased for three of these four species. However, a corresponding decrease in leaf density for two species meant that leaf mass per area increased significantly only for one species. Physiological measurements were made during both the wet and dry seasons on comparable stands of vegetation near the extremes and middle of this gradient. Assimilation per unit mass was similar at all three sites but assimilation per leaf area was higher at the drier sites because leaves were thicker with higher mass per area. These results probably reflect reduced tree density and leaf area index at the drier sites, which offsets the lower rainfall, potentially allowing similar rates of assimilation per unit carbohydrate invested in leaves.

scholarly journals The Removal Efficiencies of Several Temperate Tree Species at Adsorbing Airborne Particulate Matter in Urban Forests and Roadsides

Forests ◽  
2019 ◽  
Vol 10 (11) ◽  
pp. 960 ◽  
Author(s):  
Myeong Ja Kwak ◽  
Jongkyu Lee ◽  
Handong Kim ◽  
Sanghee Park ◽  
Yeaji Lim ◽  
...  
Keyword(s):  
Particulate Matter ◽  
Tree Species ◽  
Morphological Characteristics ◽  
Urban Forests ◽  
Urban Trees ◽  
Widespread Species ◽  
Area Index ◽  
Canopy Density ◽  
Leaf Surfaces ◽  
Removal Efficiencies

Although urban trees are proposed as comparatively economical and eco-efficient biofilters for treating atmospheric particulate matter (PM) by the temporary capture and retention of PM particles, the PM removal effect and its main mechanism still remain largely uncertain. Thus, an understanding of the removal efficiencies of individual leaves that adsorb and retain airborne PM, particularly in the sustainable planning of multifunctional green infrastructure, should be preceded by an assessment of the leaf microstructures of widespread species in urban forests. We determined the differences between trees in regard to their ability to adsorb PM based on the unique leaf microstructures and leaf area index (LAI) reflecting their overall ability by upscaling from leaf scale to canopy scale. The micro-morphological characteristics of adaxial and abaxial leaf surfaces directly affected the PM trapping efficiency. Specifically, leaf surfaces with grooves and trichomes showed a higher ability to retain PM as compared to leaves without epidermal hairs or with dynamic water repellency. Zelkova serrata (Thunb.) Makino was found to have significantly higher benefits with regard to adsorbing and retaining PM compared to other species. Evergreen needle-leaved species could be a more sustainable manner to retain PM in winter and spring. The interspecies variability of the PM adsorption efficiency was upscaled from leaf scale to canopy scale based on the LAI, showing that tree species with higher canopy density were more effective in removing PM. In conclusion, if urban trees are used as a means to improve air quality in limited open spaces for urban greening programs, it is important to predominantly select a tree species that can maximize the ability to capture PM by having higher canopy density and leaf grooves or trichomes.

scholarly journals Farm Rejuvenation-Induced Changes in Tree Spatial Pattern and Live Biomass Species of Cocoa Agroforests in Central Cameroon: Insights for Tree Conservation Incentives in Cocoa Landscapes

2021 ◽  
Vol 13 (15) ◽  
pp. 8483
Author(s):  
Frederick N. Numbisi ◽  
Dieudonne Alemagi ◽  
Ann Degrande ◽  
Frieke Van Coillie
Keyword(s):  
Ecosystem Services ◽  
Tree Species ◽  
Temporal Changes ◽  
Mixed Effect ◽  
Tree Management ◽  
Conservation Incentives ◽  
National Implementation ◽  
Live Biomass ◽  
Farm Structure ◽  
On Farm

Cocoa agroforests sustain ecosystem services (ESs) to varying degrees. These services are otherwise mostly provided by other non-cocoa shade or companion trees. However, the density of shade trees is associated with services and/or disservices that drive farm-specific tree management successions. Considering the growing impacts of climate crisis on farm productivity and the need for adaptation strategies, the ESs are increasingly provisional and contingent on the prevailing vegetation, land tenure, and management successions, amongst others social and ecological factors. To assess the temporal changes in shade management, we surveyed an age gradient of “family farms” in cocoa agroforests created from forest (fCAFS) and savannah (sCAFS) land cover. We evaluated the temporal changes in farm structure, relative tree abundance, and live aboveground biomass of the major canopy strata. We used a spatial point process and linear mixed effect analysis to assess the contributions of associated perennial trees (AsT) on farm rejuvenation patterns. The density of cocoa trees was inconsistent with farm age; this was significantly high on farms in sCAFS (1544 trees ha−1) with spatially random configuration across farm age. On farms in fCAFS, we observed a transition of the cocoa tree configuration in the order regular, random, and clustering from young (with highest density of 1114 trees ha−1) to old farms. On a temporal scale, there is no clear distinction of farm structure and biomass between fCAFS and sCAFS. However, the cycle of tree species and structural composition of the canopy strata are dissimilar; the live biomass allocation for the considered use groups of tree species was different with farm age. The observed dynamics in canopy tree structure and live biomass provide insights into farmers’ temporal allocation of uses and prioritization of different tree species with farm age. We recommend the consideration of such landscape-specific, tree management dynamics in proposing on-farm tree conservation incentives. Our results are also conducive to reliable estimates of the ecosystem services from CAFS in the national implementation of conservation mechanisms such as REDD+.

scholarly journals Using the dendro-climatological signal of urban trees as a measure of urbanization and urban heat island

2021 ◽  
Author(s):  
Christoph Schneider ◽  
Burkhard Neuwirth ◽  
Sebastian Schneider ◽  
Daniel Balanzategui ◽  
Stefanie Elsholz ◽  
...  
Keyword(s):  
Urban Heat Island ◽  
Tree Ring ◽  
Air Temperature ◽  
Tree Species ◽  
Urban Climate ◽  
Ring Width ◽  
Urban Trees ◽  
Pedunculate Oak ◽  
Heat Island ◽  
Urban Heat

AbstractUsing dendroclimatological techniques this study investigates whether inner city tree-ring width (TRW) chronologies from eight tree species (ash, beech, fir, larch, lime, sessile and pedunculate oak, and pine) are suitable to examine the urban heat island of Berlin, Germany. Climate-growth relationships were analyzed for 18 sites along a gradient of increasing urbanization covering Berlin and surrounding rural areas. As a proxy for defining urban heat island intensities at each site, we applied urbanization parameters such as building fraction, impervious surfaces, and green areas. The response of TRW to monthly and seasonal air temperature, precipitation, aridity, and daily air-temperature ranges were used to identify climate-growth relationships. Trees from urban sites were found to be more sensitive to climate compared to trees in the surrounding hinterland. Ring width of the deciduous species, especially ash, beech, and oak, showed a high sensitivity to summer heat and drought at urban locations (summer signal), whereas conifer species were found suitable for the analysis of the urban heat island in late winter and early spring (winter signal).The summer and winter signals were strongest in tree-ring chronologies when the urban heat island intensities were based on an area of about 200 m to 3000 m centered over the tree locations, and thus reflect the urban climate at the scale of city quarters. For the summer signal, the sensitivity of deciduous tree species to climate increased with urbanity.These results indicate that urban trees can be used for climate response analyses and open new pathways to trace the evolution of urban climate change and more specifically the urban heat island, both in time and space.

scholarly journals Spatial Distribution of Tree Species Governs the Spatio-Temporal Interaction of Leaf Area Index and Soil Moisture across a Forested Landscape

PLoS ONE ◽  
2013 ◽  
Vol 8 (3) ◽  
pp. e58704 ◽  
Author(s):  
Kusum J. Naithani ◽  
Doug C. Baldwin ◽  
Katie P. Gaines ◽  
Henry Lin ◽  
David M. Eissenstat
Keyword(s):  
Spatial Distribution ◽  
Soil Moisture ◽  
Leaf Area Index ◽  
Leaf Area ◽  
Tree Species ◽  
Area Index ◽  
Spatio Temporal ◽  
Temporal Interaction
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