Trends in financial damage related to urban tree failure in the Netherlands

Risk assessments on trees in urban areas and roadside plantings have become common practice and a large body of information exists on qualitative aspects on the risks of tree failure. Quantitative analysis of financial damage due to tree failure is generally lacking. The objective of this paper is to determine the amount of tree failure related property damage and to derive possible trends in the number of cases and monetary claims and compensations. This paper presents the analysis of 1610 observations on urban tree failure in the Netherlands. The data originate from two different sources, i.e. jurisprudence (4% of the data) and 21 municipalities (96%). The data covers property damage in urban areas between the early sixties and 2010. Within municipalities, paid compensations due to tree failure are found to range from €0 to € 49,296 with an average of €2,244 per paid compensation. Results demonstrate a significant annual increase in tree failure as well as in paid compensations.     

Assessing the species diversity and vulnerability of urban tree populations in the London borough of Westminster

The level of tree species diversity in urban tree populations can have serious implications for urban forest resilience and has a direct impact on ecosystem functioning at the local level. Few studies have measured the relationship between tree species diversity and vulnerability in UK urban forests. This study analysed the species composition, species diversity and the vulnerability to pests and diseases of 10,149 public trees in the London borough of Westminster across three land use types: housing, parks, and highways. Tree species diversity was significantly different across these land use types (Shannon’s diversity index (H) was 2.47 for housing sites, 1.63 for parks and 0.83 for highways) and we found that higher diversity appears to result in reduced vulnerability, evidenced by negative correlations between tree species diversity and susceptibility to pests and diseases. A stronger negative correlation was found between vulnerability and species richness than between vulnerability and Gini-Simpson’s diversity index. Our study reinforces the role of biodiversity indices in establishing and monitoring baseline levels of UK urban tree diversity. Our findings may inform future tree planting projects, help to ensure that development does not negatively affect urban tree diversity and inform proactive strategies for urban trees to contribute to wider biodiversity conservation.     

The influence of sidewalk replacement on urban street tree growth

Interactions between tree roots and sidewalks can result in damage to sidewalks and when sidewalk damage is repaired adjacent tree roots are often severed. The objective of this study was to quantify the growth response of urban trees in restricted planting spaces pre- and post-sidewalk construction. The research included four trees species commonly planted along streets in Minneapolis and Saint Paul, Minnesota, USA. Species included were: Acer platanoides, Celtis occidentalis, Gleditsia triacanthos, and Tilia spp. Two street tree populations were sampled: trees adjacent to replaced sidewalk panels (<1.75 m) and trees on streets with sidewalk construction that were greater than 3 m from replaced sidewalk sections. In total, increment core samples from 292 trees were analyzed. Annual rings from each tree were measured and converted to basal area increment (BAI) for analysis. Comparisons of BAI were conducted between the two sample populations to assess differences in tree growth patterns. Pre- and post-sidewalk construction BAI was also evaluated to determine the influence of construction on growth trajectory. Growth response was quantified using resistance, resilience, and recovery indices. Species were found to differ in their response to construction disturbance. Planting space width was also found to influence post-construction growth. Tilia spp. had the highest resilience and fastest overall growth recovery post-sidewalk construction and A. platanoides exhibited the lowest resistance, resilience, and recovery post-sidewalk construction.     

A rapid urban site index for assessing the quality of street tree planting sites

Urban trees experience site-induced stress and this leads to reduced growth and health. A site assessment tool would be useful for urban forest managers to better match species tolerances and site qualities, and to assess the efficacy of soil management actions. Toward this goal, a rapid urban site index (RUSI) model was created and tested for its ability to predict urban tree performance. The RUSI model is field-based assessment tool that scores 15 parameters in approximately five minutes. This research was conducted in eight cities throughout the Midwest and Northeast USA to test the efficacy of the RUSI model. The RUSI model accurately predicted urban tree health and growth metrics (P < 0.0001; R² 0.18–0.40). While the RUSI model did not accurately predict mean diameter growth, it was significantly correlated with recent diameter growth. Certain parameters in the RUSI model, such as estimated rooting area, soil structure and aggregate stability appeared to be more important than other parameters, such as growing degree days. Minimal improvements in the RUSI model were achieved by adding soil laboratory analyses. Field assessments in the RUSI model were significantly correlated with similar laboratory analyses. Other users may be able to use the RUSI model to assess urban tree planting sites (<5 min per site and no laboratory analyses fee), but training will be required to accurately utilize the model. Future work on the RUSI model will include developing training modules and testing across a wider geographic area with more urban tree species and urban sites.     

Modelling the spread of tree pests and pathogens in urban forests

Understanding the potential dynamics of tree pests and pathogens is a vital component for creating resilient urban treescapes. Epidemiologically relevant features include differences in environmental stress and tree management between street and garden trees, and variation in the potential for human-mediated spread due to intensity of human activity, traffic flow and buildings. We extend a standard spatially explicit raster-based model for pest and pathogen spread by dividing the urban tree population into roadside trees and park/garden trees. We also distinguish between naturally-driven radial spread of pests and pathogens and human-mediated linear spread along roads. The model behaviour is explored using landscape data for tree locations in an exemplar UK town. Two main sources of landscape data were available: commercially collated aerial data, which have high coverage but no information on species; and, an urban tree inventory, with low, non-random, coverage but with some species data. The data were insufficient to impute a species-specific host landscape accurately; however, by combining the two data sources, and applying either random or Matérn cluster point process driven selection of a subset of all trees, we create two sets of potential host landscapes. We find that combining the two mechanisms of dispersal has a non-additive effect, with the enhanced linear dispersal enabling new foci of infection to be established more rapidly than with radial dispersal alone; and clustering of trees by species slows down the expansion of epidemics when compared with random distribution of tree species within known host locations.     

Exploring the characteristics of successful volunteer-led urban forest tree committees in Massachusetts

Citizen engagement through urban forest tree committee volunteer service may aid in providing essential experience, ideas, and skills that support municipal tree management. Using semi-structured, research interviews with tree committee (TC) representatives from across the Commonwealth of Massachusetts, this study addresses current knowledge gaps concerning the general composition, processes, and relationships of volunteer-led urban forest tree committees. Our findings indicate that TC representatives are typically motivated, passionate volunteers who generally desire to work cooperatively with the many associations, organizations, and agencies that comprise the local socio-political landscape. Our findings also indicate it is important that TC representatives make a sustained, concerted effort to work collaboratively with their local tree warden to advance the care of their community’s urban trees. Furthermore, it is also essential that municipal managers and decision-makers attempt to provide TC volunteers with appropriate training opportunities, resources, as well as demonstrate appreciation, to further encourage and solidify volunteer-engagement in urban forestry at the local level.     

Allometric equations for estimating the aboveground volume of five common urban street tree species in Daegu,Korea

Quantifying urban tree biomass and carbon (C) storage by using allometric equations is required for various studies such as assessing the inventory, modelling, and measuring ecosystem services of urban trees. However, the lack of urban-specific allometric equations leads to uncertainty when estimating urban tree biomass and C storage. Therefore, we followed a nondestructive approach and developed allometric equations specifically for Acer buergerianum Miq., Ginkgo biloba L., Platanus orientalis L., Prunus yedoensis Matsum., and Zelkova serrata (Thunb.) Makino in Daegu, Korea. Diameter at breast height (DBH)-based and DBH-and-height-based allometric equations were highly accurate at estimating the aboveground volume (R² > 0.92), while the allometric equations for P. orientalis and Z. serrata developed for traditional forests overestimated volume by 68% and 427%, respectively. The addition of a height variable into the DBH-based allometric equations did not increase the reliability of the allometric equations at a local level. The mean aboveground C storage of urban street trees was 24.9 Mg C/ha except for P. orientalis with a mean of 69.7 Mg C/ha, and the total aboveground C storage of urban street trees in Daegu was 10.6 Gg C. Alternatively, a generalized allometric equation which compiled species-specific equations can be applied for large-scale estimation. The generalized equations developed in this study and those found in the literature may suggest a constant value (～2.3–2.4) for the scaling exponent in the generalized equations. Allometric equations developed from natural or artificial stands may overestimate the volume of urban street trees; therefore, estimating urban tree biomass and C storage requires urban-specific allometric equations.     

Branching out to residential lands: Missions and strategies of five tree distribution programs in the U.S

Residential lands constitute a major component of existing and possible tree canopy in many cities in the United States. To expand the urban forest on these lands, some municipalities and nonprofit organizations have launched residential yard tree distribution programs, also known as tree giveaway programs. This paper describes the operations of five tree distribution programs affiliated with the Urban Ecology Collaborative, a regional network for urban forestry professionals. We analyzed the programs’ missions, strategies, and challenges as reported through surveys and interviews conducted with program staff. The programs were led by nonprofit organizations and municipal departments in New York City, NY; Baltimore, MD; Philadelphia, PA; Providence, RI; and Worcester, MA. These organizations focused their tree distribution efforts on private residential lands in response to ambitious tree canopy or planting campaign goals. We assessed these programs through the framework of urban forests as social-ecological systems and discuss the programs’ biophysical, social and institutional contexts. Programs face principle-agent problems related to reliance on individual tree recipients to meet goals; their institutional strategies meant to ameliorate these problems varied. Differing organizational and partner resources influenced the programs’ abilities to perform outreach and follow-up on tree performance. Programs attempted to connect with diverse neighborhoods through free trees, targeting areas with low existing canopy, and forging partnerships with local community groups. Given tree recipients’ demand for smaller flowering or fruiting trees, as well as lack of resources for tree survival monitoring on private lands, program leaders appeared to have turned to social measures of success − spreading a positive message about trees and urban greening − as opposed to biophysical performance metrics. We conclude with suggestions for outcomes monitoring, whether those outcomes are social or biophysical, because monitoring is critical to the sustainability and adaptive management of residential tree programs.     

乡土树种在内蒙古巴彦淖尔市临河区城市绿化中的应用

在巴彦淖尔市临河区的临河区、双河区、朔方区3个主城区各类城市绿地中（公园绿地、生产绿地、防护绿地、附属绿地、其他绿地）,分别选取典型性样地进行调查,主要调查内容有乡土树种的种类、数量、配置形式、观赏特性及生长状况。采用实地调查和系统归纳相结合的途径,采取拍照、特征记录等方法,对所得数据进行整理、比较,分析其应用现状及存在的主要问题,并提出相关建议。     

Perception and preference of trees: A psychological contribution to tree species selection in urban areas

Trees can enhance human mental and physical well-being in urban environments. However, the tree benefits in urban planning are insufficiently recognised, and there is little knowledge on the tree characteristics that are relevant to humans and how they are evaluated. This paper presents perceptual tree parameters and their relation to human preferences. In study 1, participants sorted 24 tree images by perceived similarity. Hierarchical cluster analysis and multidimensional scaling (MDS) revealed the distinction between conifers and deciduous trees, crown shape, the two-dimensional crown size to trunk height ratio and the crown density as important to humans. In study 2, participants rated the trees based on their preferences. Multiple linear regression analyses showed that a high two-dimensional crown size to trunk height ratio and a high crown density predicted deciduous tree preferences. These findings are discussed in light of the savannah hypothesis and the Gestalt grouping principle of closure. In the task of tree selection and placement for urban areas, the identified perceptual tree parameters may allow for achieving a coherent overall picture with a simultaneous increase of tree species richness. Thus, urban landscape planning can apply the presented findings for increasing ecosystem health and residential satisfaction.     

Stemflow chemistry in relation to tree size: A preliminary investigation of eleven urban park trees in British Columbia,Canada

Given increased atmospheric loads in cities, quantification of stemflow chemistry is necessary for a holistic understanding of elemental cycling in urban ecosystems. Accordingly, the stemflow volume and associated solute fluxes (K⁺, Ca²⁺, Na⁺, Mg²⁺) were measured for eleven deciduous trees in a manicured park setting in Kamloops, British Columbia, Canada. Over nine rainfall events from late June to early September 2013, larger trees [diameter at breast height (DBH) > 30 cm] were found to generally produce higher event stemflow volumes but lower funneling ratios than the smaller trees (DBH < 30 cm). The median flux-based enrichment ratio, which compares the solute input of stemflow to that of rainfall on a per unit trunk basal area, also tended to be greater for smaller trees than larger ones. Under all-tree and single-leader tree conditions, significant negative non-linear relationships between tree DBH and mean flux-based enrichment ratios were found for Ca²⁺, Na⁺, and Mg²⁺, but not for K⁺. These preliminary results indicate that urban trees can considerably enrich rainfall that is partitioned into stemflow, and that ion concentrations and enrichment ratios exhibit notably high interspecific variability. In this study, tree size and presence of single versus multiple leaders explained some of this heterogeneity; however, further study into those physical tree characteristics that affect stemflow volume and stemflow chemistry must be carried out if the impact and challenges of urban greening, nutrient cycling, and stormwater management initiatives are to be more fully understood.     

Development of urban forest policy-making toward governance in the Republic of Korea

This research attempts to analyze the emergence and development of urban forest policies at the national and local levels in the Republic of Korea. The Policy Arrangement Approach (PAA) is applied as an analytical frame to analyze changes in the urban forest policies of the central and local governments. The PAA offers four dimensions that can be used to describe and analyze the policy process: actors, power, rules of the game and discourse. The research findings indicate that a discourse on sustainable development in which the social functions of forests are taken into account substantially contributed to the creation of urban forest policies. This discourse contributed to the activities of actors and their power relationships and to the introduction of new rules relating to Korean urban forest management. In addition to public actors, private actors have also participated in creating and managing urban forests. Various partnerships among actors were formed for urban forest management. Civil society exercised its power to design and manage urban forests through increased voluntary participation. The legislation relating to urban forests functioned as a framework for urban forest policies at the national and local levels. Agreements acted as new rules governing the relationships among the actors who were involved in urban forest management. In conclusion, the four dimensions of policy arrangements relating to urban forest policy, and the interconnections among these dimensions, elucidate the emergence and dynamic development of urban forest management in the direction of governance at the national and local level in the Republic of Korea. In particular, discourse about forests was a substantive dimension of policy arrangements, and it influenced changes in the identity of the participating actors and their power. The discourse contributed to the establishment and development of rules for urban forest management. Thus this research provides strong evidence that the PAA helps understand dynamic changes of urban forest policy-making toward governance.     

How different ethno-cultural groups value urban forests and its implications for managing urban nature in a multicultural landscape: A systematic review of the literature

Understanding how different ethno-cultural groups value urban nature is important to understand the role of ethno-cultural diversity in urban ecosystem management. Based on a systematic literature review, this paper summarizes the empirical evidence on how different ethno-cultural groups use, perceive, prefer, and assign meaning to urban nature. I use the urban forest, defined here as all the trees in a city, as a proxy to understand this process. The 31 studies reviewed here differ widely in their lines of inquiry, research methods, urban natural setting, and conceptualizations of ethno-cultural identity. Most studies take place in the US and Europe, where the most common definition of an ethno-culturally diverse group is a person of non-European/non-White background. Most studies focus on what these groups like about a particular urban natural setting, such as an urban park; and whether they like more or less trees in a specific context (e.g. urban park). These groups usually prefer passive and social uses of urban natural areas, and more manicured/functional natural landscapes with less trees. The most common meanings associated with urban natural settings dominated by trees are social interaction and integration. The most common explanations on why these differences occur involve theories on socio-economic marginality, collectivist vs. individualist cultures, urban vs. rural lifestyles, and landscapes of origin. Future research on the topic will benefit by differentiating race from ethnicity, capturing intra-ethnic variation, capturing immigrant identities, exploring the different social, cultural, and economic factors that influence values and/or preferences, and focusing on concrete aspects of urban nature, such as urban forests.     

Strategic planning for new woodlands in the urban periphery: through the lens of social inclusiveness

Current strategies for creating new woodlands in the urban periphery aim to provide as many people as possible with a recreational green space close to where they live. When taking a socially inclusive approach, however, this also involves a number of ‘distributional’ questions. These refer to the kind of people likely to benefit the most from such a plan: urban or suburban residents, low or high-income groups, and so forth. This article presents a GIS-based working method aimed at exploring different options for urban woodland proposals with regard to their positioning in relation to residential areas, as well as the socio-spatial characteristics of those areas. The example of seven possible locations for a new ‘peri-urban forest’ in Antwerp, Belgium was used to demonstrate the method's potential to address relevant questions in socially inclusive planning and hence, to improve strategic planning for new urban woodlands.     

Mapping the urban forest in detail: From LiDAR point clouds to 3D tree models

Trees are an integral component of the urban environment and important for human well-being, adaption measures to climate change and sustainable urban transformation. Understanding the small-scale impacts of urban trees and strategically managing the ecosystem services they provide requires high-resolution information on urban forest structure, which is still scarce. In contrast, there is an abundance of data portraying urban areas and an associated trend towards smart cities and digital twins as analysis platforms. A GIS workflow is presented in this paper that may close this data gap by classifying the urban forest from LiDAR point clouds, detecting and reconstructing individual crowns, and enabling a tree representation within semantic 3D city models. The workflow is designed to provide robust results for point clouds with a density of at least 4 pts/m² that are widely available. Evaluation was conducted by mapping the urban forest of Dresden (Germany) using a point cloud with 4 pts/m². An object-based data fusion approach is implemented for the classification of the urban forest. A classification accuracy of 95 % for different urban settings is achieved by combining LiDAR with multispectral imagery and a 3D building model. Individual trees are detected by local maxima filtering and crowns are segmented using marker-controlled watershed segmentation. Evaluation highlights the influences of both urban and forest structure on individual tree detection. Substantial differences in detection accuracies are evident between trees along streets (72 %) and structurally more complex tree stands in green areas (31 %), as well as dependencies on tree height and crown diameter. Furthermore, an approach for parameterized reconstruction of tree crowns is presented, which enables efficient and realistic city-wide modeling. The suitability of LiDAR to measure individual tree metrics is illustrated as well as a framework for modeling individual tree crowns via geometric primitives.     

Methods for the estimation of sampling sufficiency in urban forest inventories: The case of non-patterned compositions of trees on sidewalks

Sampling inventories are strategies to gather qualified information for managing urban forests, given the scarcity of budgetary resources for a complete inventory and lack of public engagement to reduce costs. However, procedures for testing sampling sufficiency can be unspecified in researches related to urban forest inventories and do not follow any specific pattern. Hence, to determine the sampling sufficiency, we tested different variables related to the trunk, crown, number of trees, and species, focusing on different aims of an inventory of trees on sidewalks. At a level of 10% of the total number of plots, each measuring 50.0 m × 3.0 m, we performed a stratified inventory of a city streetscape whose composition and quality represents most South American cities, with a non-patterned tree compostion. Sampling sufficiency was analyzed considering a limit of error of 10% and 15% by using 12 different variables. The stratification process was necessary for most of the variables analyzed (p > 0.01), with errors ranging from 5.87% to 15.28%. Sampling sufficiency was achieved for 10% of the total population of trees on sidewalks, at a 10% error limit for seven variables: diameter at breast height (DBH), cross-section area, crown diameter, crown area, number of species, and number of species per square meter of sidewalk and per kilometer of the street. However, this result was influenced by the variability of the variables used to estimate sampling sufficiency. As it is not possible to achieve different goals (tree registration, benefits, and diversity) with just one variable like the number of trees per kilometer of street, the sampling sufficiency estimation should be based on the use of at least the DBH, crown diameter, number of trees, and number of species. It would be a better strategy to ensure more reliable data estimations for sampling inventories of trees on sidewalks.     

Comparison of UAV-based LiDAR and digital aerial photogrammetry for measuring crown-level canopy height in the urban environment

Spatial information on urban forest canopy height (FCH) is fundamental for urban forest monitoring and assisting urban planning and management. Traditionally, ground-based canopy height measurements are time-consuming and laborious, making it challenging for periodic inventory of urban FCH at crown level. Airborne-light detection and ranging (LiDAR) sensor can efficiently measure crown-level FCH; however, the high cost of airborne-LiDAR data collection over large scales hinders its wide applications at a high temporal resolution. Previous studies have shown that in some cases, the Unmanned Aerial Vehicle (UAV)-digital aerial photogrammetry (DAP) approach (i.e., UAV-based structure from motion algorithm) is equivalent to or even outperform airborne-LiDAR in measuring forest structure, but few studies have evaluated their performances in measuring FCH in more complex urban environment, across non-ground coverage (including both canopy and building coverage) and topographical slope gradients. Also, the contribution of multi-angle measurement technique from UAV-DAP to FCH estimation accuracy has rarely been explored in the urban environment. Here, we compared the performances of UAV-LiDAR and UAV-DAP approaches on measuring thousands of crown-level FCH at different non-ground coverage and topographical slope areas in an urban environment. Specifically, UAV-LiDAR-based spatial measurements of crown-level FCH were used as the reference after ground-based validation (R² = 0.88, RMSE = 2.36 m). The accuracy of UAV-DAP approach with/without multi-angle measurement in different non-ground coverage and topographical slope areas were then analyzed. The results showed that although the DAP multi-angle-based approach can improve the accuracy of spatial measurement for crown-level FCH in some cases, non-ground coverage (including both canopy and building coverage) was still the main factor affecting the broad applications of DAP approach in measuring urban FCH: at areas where non-ground coverage < 0.95, no matter how topographical slope varied, the accuracy of DAP approach was high (R² = 0.86∼0.94, RMSE = 1.56∼2.93 m); at areas where non-ground coverage > 0.95, except for the case of flat areas (i.e., topographical slope <= 2°), the accuracy of DAP was poor (R² = 0.20, RMSE = 12.34 m). However, using LiDAR-digital terrain model (DTM) instead of DAP-DTM, at areas where non-ground coverage > 0.95, can significantly improve the accuracy of UAV-DAP approach in measuring crown-level FCH (R² = 0.91, RMSE =1.61 m). Our study thus provides a complete guidance on the usage of cost-effective UAV-DAP approach for measuring crown-level FCH in the urban environment, which will be helpful for precise urban forest management and improving the efficiency of urban environmental planning.     

The use of profile diagrams for mixed stands in urban woodlands—the management perspective

In the emerging paradigm of urban forestry objectives are often to develop mixed stands with complex structures. Such stands cannot easily be described in words and numbers. A logical alternative would seem to describe the structure of such mixed stands by use of image-based management tools. However implementing new management goals and using image-based tools challenges professionals, educated and trained within the age-class forestry tradition, to use their knowledge in a creative way. This paper describes how professionals contextualise from hand drawn profile diagrams when planning the management of mixed stands. The appropriateness of profile diagrams in this context is further discussed. The study was carried out as a case study focusing on the planning and development of long-term management goals for two young mixed stands for recreational use. We used explorative, in-depth interviews to identify the perspective on profile diagrams, as experienced by five individuals with different academic backgrounds as well as years of experience. The interviewees revealed that personal experiences and mental images played a key role in order to display an intuitive understanding of the subject stands through the profile diagrams. Further, they recognised this approach themselves often referring to other stands to make comparisons. The types of references used could be divided into three distinct categories: specific, generic and metaphoric. With regard to the ongoing move from age-class forestry to multifunctional management of mixed stands, this aid to dialogue might be the most relevant way in which profile diagrams can contribute to the implementation of new management paradigms.     

Recovering the urban forest: The role of trees,tree culture,and place attachment before and after Hurricane Harvey

Trees can be powerful symbols that contribute to the production and consumption of places. Disaster events, such as hurricanes, alter the physical landscape, causing tree damage and loss. In places with strong tree cultures, the reforestation of damaged landscapes becomes an implicit element of recovery plans; however, less is known about the implications of tree loss to community recovery. In 2017, Hurricane Harvey made landfall near the coastal communities of Rockport and Fulton, Texas. Rockport-Fulton, known for its beach tourism, is home to a remnant live oak (Quercus virginiana) forest shaped by coastal onshore winds. Many of Rockport-Fulton’s windswept oaks were damaged or lost along with native and non-native palm trees. Rockport-Fulton’s history is imbued with stories situated around its oak forest. Drawing from multiple sources and participant observations from repeated site visits, we analyzed references to Rockport-Fulton’s trees in news media, organizational communications, and public exhibits before and after Harvey to understand the area’s tree culture and its associated discourses. We also interviewed tourists, business owners, and community members nine months after Harvey to understand their perceptions of recovery efforts. Our findings show that tree narratives pre- and post-Harvey amplify social-ecological systems definitions of resilience and that tree loss was a dominant theme in the recovery process for all participants. Yet we also found that tourists discussed the damage to palm trees, whereas community members focused on the loss of live oaks. Despite these preferences, trees available through replanting efforts contained few live oak and palm species; furthermore, recovery plans did not amplify trees in recovery strategies. Overall, our findings highlight the importance of replanting trees during the disaster recovery process in a way that not only enhances local biodiversity but also reaffirms place characteristics to meet community members’ and visitors’ expectations.     

Investigating the spatial distribution of urban parks from the perspective of equity-efficiency: Evidence from Chengdu,China

Urban parks play a crucial role in urban public green infrastructure, providing recreational places for urban residents while carrying values of aesthetics, ecology, humanities, economy, life, and society. However, achieving an equitable and efficient spatial layout of urban parks is a challenging task due to limited urban space resources, which requires further exploration. This study employed multisource big data and GIS technology to constructed an indicator system for evaluating the equity-efficiency of urban park spatial distribution. We examined the spatial distribution of 85 parks across 62 sub-districts in the main urban area of Chengdu, the largest city in western China and the first Park City of China. The results demonstrated that equity was polarized, with an indicator value ranging from 0 to 0.77 and an average value of 0.32. The sub-district of Sansheng had the highest equity, while Wenjia and Kanghe had the lowest equity. Twenty-one sub-districts had no parks, and the equity of park spatial distribution in these areas was low. The efficiency indicator ranged from 0.20 to 0.62, with an average value of 0.40. The efficiency of the main urban area was high in the southwest and low in the northeast. The sub-district of Huangtianba had the highest efficiency, while Jinguanyi had the lowest efficiency. In the two-dimensional quadrant of equity-efficiency, 24 sub-districts had high equity and high efficiency, 13 sub-districts had high equity and low efficiency, 4 sub-districts had low equity and high efficiency, and 21 sub-districts had low equity and low efficiency. At the district level, only Chenghua District’s park was spatial equitable and efficient, surpassing the average level of the main urban area. Finally, we discussed the findings in the context of planning policies for Chengdu in recent years. We proposed that strengthening the construction of small urban parks and green spaces, improving park facilities to meet the diverse social needs of people, and enhancing the quality and attractiveness of the parks are crucial for the future development of park green spaces in the main urban areas of Chengdu.