scholarly journals Transpiration rates of red maple (Acer rubrum L.) differ between management contexts in urban forests of Maryland, USA

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sarah Ponte ◽  
Nancy F. Sonti ◽  
Tuana H. Phillips ◽  
Mitchell A. Pavao-Zuckerman

AbstractThe hydrological functioning of urban trees can reduce stormwater runoff, mitigate the risk of flood, and improve water quality in developed areas. Tree canopies intercept rainfall and return water to the atmosphere through transpiration, while roots increase infiltration and storage in the soil. Despite this, the amount of stormwater that trees remove through these functions in urban settings is not well characterized, limiting the use of urban forests as practical stormwater management strategies. To address this gap, we use ecohydrological approaches to assess the transpiration rates of urban trees in different management settings. Our research questions are: Do transpiration rates of trees of the same species vary among different management contexts? Do relationships between environmental drivers and transpiration change among management contexts? These management settings included single trees over turfgrass and a cluster of trees over turfgrass in Montgomery County, MD, and closed canopy forest with a leaf litter layer in Baltimore, MD. We used sap flux sensors installed in 18 mature red maple (Acer rubrum L.) trees to characterize transpiration rates during the growing season. We also measured soil volumetric water content, air temperature, relative humidity, and precipitation at each site. In agreement with our initial hypothesis, we found that single trees had nearly three times the daily sum of sap flux density (JS) of closed canopy trees. When averaged over the entire measurement period, JS was approximately 260, 195, and 91 g H2O cm−2 day−1 for single trees, cluster trees and closed canopy trees, respectively. Additionally, single trees were more responsive to VPD than closed canopy and cluster trees. These results provide a better understanding of the influence of management context on urban tree transpiration and can help to identify targets to better manage urban forest settings to reduce urban stormwater runoff.

2014 ◽  
Vol 22 (3) ◽  
pp. 311-321 ◽  
Author(s):  
C. Ordóñez ◽  
P.N. Duinker

Climate adaptation is being embraced by many municipalities worldwide. An element of this is the planting and protection of urban trees. However, the fact that climate change will also have an impact on urban trees has been largely overlooked. We argue that climate vulnerability assessments are necessary for addressing climate adaptation in urban forests and contribute to successful climate adaptation in cities. We review and integrate the literature on climate vulnerability and urban forests to explore how the general notion of urban forest vulnerability to climate change can be developed into an operational framework for undertaking a vulnerability assessment. The framework characterizes climate exposure, impact, sensitivity, and adaptive capacity, as well as nonclimatic drivers and factors, in urban forests. The most important themes in this discussion include urban tree species selection and diversity, naturalization, resource access, social awareness and engagement, budget and economic valuation, liability issues, and governance structures. Climate change vulnerability assessments help us understand how and why urban forests are vulnerable to climate change, identify future areas for research, and determine what adaptation measures could be included in urban forest management. These assessments help bring climate change to the forefront of the decision-making process and contribute to successful urban adaptation to climate change.


HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 635b-635 ◽  
Author(s):  
Lorna C. Wilkins ◽  
William R. Graves ◽  
Alden M. Townsend

Use of cultivars resistant to high soil temperature could improve the performance of urban trees. The objective of this project was to examine selections of red maple (Acer rubrum L. and A. x freemanii E. Murray) for genotypic differences in resistance to root-zone heat stress. Development of roots and shoots from rooted single-node cuttings of seven genotypes grown in solution culture was optimal at about 28C. Shoot extension stopped within 3 weeks and terminal buds formed on plants of all genotypes at 36C. In a second experiment, the influence of 34C root-zone temperature on development varied significantly among six genotypes. Formation of terminal buds at 34C was observed only on plants of cv. Morgan and cv. Red Sunset. The reduction in new dry matter at 34C compared to plants at 28C ranged from 21% for cv. Schlesinger to 69% for cv. Morgan. We conclude that genotypes of red maple differ in resistance to high root-zone temperature.


2021 ◽  
Vol 1 ◽  
pp. 45
Author(s):  
Nadina Galle ◽  
William Brinton ◽  
Robin Vos ◽  
Fábio Duarte ◽  
Marcus Collier ◽  
...  

Background: Soil spatial variability is a major concern when deciding how to collect a representative topsoil sample for laboratory analysis. Sampling design to capture site-specific variability is documented in the agricultural literature, but poorly understood for urban forest soils where soils may be characterized by strong horizontal and vertical variability and large temporal anthropogenic disturbances. Methods: This paper evaluates the spatial variability of selected topsoil properties under urban trees to define a statistically robust sampling design that optimizes the number of samples to reliably characterize basal soil respiration (BSR), a property associated with soil health. To provide a reference on variability, two additional soil properties were measured, unrelated to BSR: electrical conductivity (EC) and bulk density (BD). Thirteen sampling sites comprising both park and street trees (Acer rubrum) were selected in Cambridge, MA, USA. Results: Results indicate street tree topsoil had approximately twice as much variation, requiring more intensive sampling, as did park tree topsoil, even though street trees had smaller soil sampling zones, constricted by tree pits. The variability of BSR was nearly identical to that of EC, and BD results varied least. A large number of samples would be required for acceptable levels of statistical reliability (90% CI - 10% ER) of 44.4, 41.7, and 6.4 for BSR, EC, and BD, respectively, whereas by accepting a lower level of certainty (80% CI - 20% ER) the number of required soil samples was calculated as 6.8, 6.4, and 0.4 for BSR, EC, and BD, respectively. Conclusions: The use of EC testing as a baseline measure to determine spatial variation in the topsoil is proposed, to alleviate the financial implications of more expensive BSR testing. Factors of topsoil disturbance and soil access restrictions at sites with severe root-sidewalk conflicts and the overall generalizability of the results are also discussed.


Author(s):  
Nancy F Sonti ◽  
Richard A Hallett ◽  
Kevin L Griffin ◽  
Tara L E Trammell ◽  
Joe H Sullivan

Abstract The provisioning of critical ecosystem services to cities of the eastern USA depends on the health and physiological function of trees in urban areas. Although we know that the urban environment may be stressful for trees planted in highly developed areas, it is not clear that trees in urban forest patches experience the same stressful environmental impacts. In this study, we examine chlorophyll fluorescence parameters, leaf traits, foliar nutrients and stable isotope signatures of urban forest patch trees compared with trees growing at reference forest sites, in order to characterize physiological response of these native tree species to the urban environment of three major cities arranged along a latitudinal gradient (New York, NY; Philadelphia, PA; Baltimore, MD). Overall, white oaks (Quercus alba L.) show more differences in chlorophyll fluorescence parameters and leaf traits by city and site type (urban vs reference) than red maples (Acer rubrum L.). The exceptions were δ13C and δ15N, which did not vary in white oak foliage but were significantly depleted (δ13C) and enriched (δ15N) in urban red maple foliage. Across all sites, red maples had higher thermal tolerance of photosynthesis (Tcrit) than white oaks, suggesting a greater ability to withstand temperature stress from the urban heat island effect and climate change. However, the highest average values of Tcrit were found in the Baltimore urban white oaks, suggesting that species suitability and response to the urban environment varies across a latitudinal gradient. Stomatal pore index (SPI) showed inter-specific differences, with red maple SPI being higher in urban trees, whereas white oak SPI was lower in urban trees. These results demonstrate that differences in native tree physiology occur between urban and reference forest patches, but they are site- and species-specific. Data on local site characteristics and tree species performance over time remain necessary to gain insight about urban woodland ecosystem function.


Author(s):  
Madalena Vaz Monteiro ◽  
Phillip Handley ◽  
Kieron J Doick

Abstract Urban trees are instrumental in providing ecosystem services to urban society. However, they are subject to many pressures linked to harsh site conditions created by the urban environment, climate change, attack by pests and diseases and the political and social influences that control how urban trees are perceived and managed. An ongoing provision of services from all trees within an urban area (known as the urban forest) can only be achieved through high resilience to these pressures. This study aims to examine the current state of composition, condition and structure of 12 urban forests across Great Britain, by reviewing data collected from i-Tree Eco city or town-wide surveys and recommending a framework to rate their sustainability. The study shows that urban forests are hardy to local winter temperatures and in good health, but lack in large size trees and tree species diversity. Also, several urban forests offer small percentage canopy cover. The wider application of this framework and the creation of detailed tree strategies could help local authorities to establish management strategies, set goals and monitor progress towards achieving greater sustainability.


Author(s):  
Covel R. McDermot ◽  
Vince D'Amico ◽  
Tara Trammell

Environmental conditions, such as temperature, carbon dioxide, and nutrient availability, are altered by urban conditions at regional scales with potential for impact on tree leaf structure. Our goal was to compare leaf morphological characteristics driven by physiological acclimation in red maple (Acer rubrum L.) trees in deciduous forests embedded in a small (Newark, DE) and a large (Philadelphia, PA) city. The study was conducted in six urban forests on eighteen mature red maple trees in a long-term urban forest network. We hypothesized that red maples in Philadelphia forests compared to Newark forests will have a thicker upper epidermal layer, spongy palisade and mesophyll layer, longer and wider stomates, and lower stomate density. Additionally, we hypothesized that red maples in Philadelphia forests compared to Newark forests will have lower leaf water content and specific leaf area, and greater leaf thickness, fresh leaf weight, dry leaf weight, and leaf dry matter content. Our results for stomate length and stomate width supported our predictions; red maple leaves had longer and wider stomates in Philadelphia forests than in Newark forests. The increased stomate size in red maple trees suggests potential altered gas exchange behavior and mutual abiotic stress mitigation responses in red maple to greater urbanization impacts in Philadelphia forests. This supports previous findings of possible physiological and biochemical acclimation of red maple trees to urban conditions. Furthermore, the findings from this study suggest red maple trees may be a good biomonitor of regional scale impacts in urban environments.


2020 ◽  
Author(s):  
Hingabu Hordofa Koricho ◽  
Ararsa Derese Seboka ◽  
Fekadu Fufa ◽  
Tikabo Gebreyesus ◽  
Shaoxian Song

Abstract Background this study was conducted to explore the ecosystem services of urban forests in Adama city, central Ethiopia. Attempts were made to quantify the carbon storage and sequestration, air pollution removal and hydrological benefits of urban trees. The urban forest stracture and composition of the city was surveyed and analyzed. The i-Tree Eco Model was employed to analyze the ecosystem services based on the current urban forests structure of the city. Results the result revealed that the urban trees of the Adama city stored a total of 116,000 tons of carbon. The tree species identified with higher CO2 sequestration per year were Melia azedarach (15%), Eucalyptusglobulus (8%, Carica papaya(7%), and Delonix regia (6%). Approximately 22, 12, 10 and 4% of carbon were stored by Eucalyptus globulus, Melia azedarach, Carica papaya and Delonix regia tree species respectively. Moreover, trees and shrubs spps. in the city removed about 188 thousand tons of air pollutants caused by O3, CO, NO2, PM2.5 and SO2 per year. In Adama, 35% of the urban trees’ VOC emissions were from Eucalyptus cinerea and Eucalyptus globulus. The monetary value of Adama urban forest in terms of carbon storage, carbon sequestration, and pollution removal was estimated to 43,781, 3,121 yr− 1 and 320,915,596 USD yr− 1, respectively. Conclusions it was concluded that significant quantiy of CO2 and air pollutnants were found being removed by the exotic tree and shrub species. However, every plant species found in the city does not mean ecologically important due their VOC emitting nature. Thus, proper planning and inventories of urban forests should be put in place by the key stakeholders such as government, urban foresters and city dwellers as urban trees mitigates climate changes and essential to alleviate urban pollution besides the trees add esthetic value to the city.


Author(s):  
Bo Wang ◽  
Xiaochen Zhang ◽  
Chenming Gu ◽  
Mei Zhang ◽  
Yuanhao Zhao ◽  
...  

Studies on the variation in the particulate matter (PM) content, Saturation Isothermal Remanent Magnetization (SIRM), and particle grain-size distribution at a high spatial resolution are helpful in evaluating the important role of urban forests in PM removal. In this study, the trees located in dense urban forests (T0) retained more PM than trees located in open spaces (T1–T4); the SIRM and PM weight of T0 were 1.54–2.53 and 1.04–1.47 times more than those of T1–T4, respectively. In addition, the SIRM and PM weight decreased with increasing distance to the road, suggesting that distance from pollution sources plays a key role in reducing the air concentration of PM. The different grain-size components were determined from frequency curve plots using a laser particle-size analyzer. A unimodal spectrum with a major peak of approximately 20 μm and a minor peak between 0.1 and 1 μm was observed, indicating that a large proportion of fine air PM was retained by the needles of the study trees. Additionally, more <2.5 μm size fraction particles were observed at the sampling site near the traffic source but, compared to a tree in a row of trees, the percentage of the >10 μm size fraction for the tree in the dense urban forest was higher, indicating that the particles deposited on the needle surface originating from traffic sources were finer than those from natural atmospheric dust. The exploration of the variation in the PM weight, SIRM, and grain size of the particles deposited on the needle surface facilitates monitoring the removal of PM by urban forests under different environmental conditions (e.g., in closed dense urban forests and in open roadside spaces), different distances to roads, and different sampling heights above the ground.


2016 ◽  
Vol 42 (3) ◽  
Author(s):  
Adam Dale ◽  
Elsa Youngsteadt ◽  
Steven Frank

Trees provide ecosystem services that benefit humans and the environment. Unfortunately, urban trees often do not provide maximum services due to abiotic stress and arthropod herbivores and borers. These problems often originate from trees being planted in unsuitable conditions. Cities are warmer than natural areas because impervious surfaces absorb and reradiate heat. Higher temperatures can increase pest insect abundance and water stress, and reduce street tree condition relative to natural forests. For example, the gloomy scale insect [Melanaspsis tenebricosa Comstock (Hemiptera: Diaspididae)], a pest of red maple (Acer rubrum) street trees, is more abundant in warmer than cooler urban sites. Acer rubrum, at warmer urban sites with more M. tenebricosa, are typically in poor condition. Here, researchers demonstrate these relationships and illustrate how impervious surface cover can be used to predict the condition of A. rubrum street trees. impervious surface thresholds were then developed to define suitable planting sites that can be used by individuals with access to GIS software. Researchers present the pace-to-plant technique, which can be used by landscape professionals to quickly estimate impervious surface cover around a planting site. These thresholds predict future tree condition based on planting site impervious surface cover. The hope is that more informed planting will minimize pest infestations and maximize the future vigor and performance of street trees.


Author(s):  
Johnny Boggs ◽  
Ge Sun ◽  
Jean-Christophe Domec ◽  
Steven McNulty

Quantifying species-specific tree transpiration across watershed zones is important for estimating watershed evapotranspiration (ET) and predicting drought effects on vegetation. The objectives of this study are to 1) assess sap flux density (Js) and tree-level transpiration (Ts) across three contrasting zones (riparian buffer, mid-hillslope, and upland-hillslope), 2) determine how species-specific Js responds to vapor pressure deficit (VPD), and 3) compare watershed-level transpiration (Tw) derived from each zone. We measured Js and Ts in eight tree species in the three zones in a 12-ha forested watershed. In the dry year of 2015, loblolly pine (Pinus taeda), Virginia pine (Pinus virginiana), and sweetgum (Liquidambar styraciflua) Js rates were significantly higher in the buffer when compared to the other two zones. In contrast, Js in tulip poplar (Liriodendron tulipifera) and red maple (Acer rubrum) were significantly lower in the buffer than in the mid-hillslope. Daily Ts varied by zone and ranged from 10 to 93 liters in the dry year and 9 to 122 liters in the wet year. Js responded nonlinearly to VPD in all trees and zones. Annual Tw based on scaled-Js data was 447 mm, 377 mm, and 340 mm for the buffer, mid-hillslope, and upland-hillslope, respectively. We conclude that large spatial variability in Js and scaled Tw were driven by differences in soil moisture at each zone and forest composition. Consequently, spatial heterogeneity of vegetation and soil moisture must be considered when accurately quantifying watershed level ET.


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