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.     

A tale of urban forest patch governance in four eastern US cities

Urban forests are important components of societal interactions with nature. We focused on urban forest patches, a distinct and underexplored subset of the urban forest that spans land uses and ownerships, and requires silvicultural practices to address their unique biophysical characteristics and management regimes. Our goal was to elucidate multi-scalar urban forest patch governance arrangements as they translated to on-the-ground management in four urban areas (Chicago, New York City, Philadelphia, and Baltimore) within the eastern United States. A transdisciplinary knowledge co-production framework was used to guide identification of the prominent management challenge or dilemma motivating change to forest patch management in each location, and to describe the dynamic interplay of decision-making and governance processes across locations as they advanced toward desired forest conditions. A common management goal existed across all four locations: multi-age, structurally complex forests dominated by regionally native species. Ecological and social concerns affected by local context and city capacity served as starting points prompting management action and new collaborations. Disparate governance arrangements including top-down municipal resources, regional conservation facilitated by landowners, and grass-roots community-driven stewardship led to diverse support-building processes and innovative strategies that served as forces initiating and shaping new management actions. Science and iterative learning and adaptation influenced change in all locations, reinforcing new management arrangements and practices. Among the four study areas, the earliest management of urban forest patches started in the 1980 s, historically lacking embeddedness in urban forest management more broadly, and experiencing challenges with integration into existing governance infrastructure. Ultimately, new management and governance approaches to urban forest patches in all four study areas have evolved uniquely and organically, driven by place-based historical legacies and ongoing socio-ecological feedbacks. The generalization of findings for broader urban forest management guidelines, such as for trees and park, would lead to misguided outcomes.     

Estimating the alignment of tree species composition with foraging practice in Philadelphia's urban forest: Toward a rapid assessment of provisioning services

Urban greenspaces (UGS) are increasingly recognized for their potential to provide provisioning services to residents foraging for food and other plant materials. The alignment of tree species composition with foraging practices in cities, and the provisioning services harvesters derive, in UGS remains less well studied. To address this gap, we draw on existing tree species data and forager practices in the City of Philadelphia to estimate the alignment between tree species composition and foraging in the city. Our approach uses an existing forest inventory, an international online database of useful species, online information for residents about useful species found in the city, and novel data about forager practices. By considering these datasets in tandem, we are able to identify useful tree species, species likely of interest to foragers, and species actively foraged, and estimate the relative abundance of species in each category. Our results suggest that managers may be able to analyze proxy data, through use of online quality ratings, to rapidly identify and assess forager interest in species found in their urban forests.     

Quantifying green cover change for sustainable urban planning: A case of Kuala Lumpur,Malaysia

Despite the numerous benefits of urban green cover, urban land development has led to its destruction and degradation, including in Malaysia. In this study, time series Landsat satellite imagery were used to monitor green cover changes in Kuala Lumpur (KL), the largest and capital city of Malaysia. An advanced satellite image processing technique that considers the mixed-pixel problem was employed to determine the fraction of green cover in each Landsat pixel. Results show that the total green coverage in Kuala Lumpur decreased by 3% over the first study period, from 6564 ha in 2001–5,891 ha in 2013. However, it increased by 4% in the second, from 6215 ha in 2014–7,310 ha in 2016, and now green cover is 30% of the total land area of KL. These periods were selected to observe the changes in green cover before and after implementation of the “Greening KL” program, which was aimed to plant 100,000 trees in KL by year 2020. Most of the increase in green cover was contributed by trees planted along streets and in recreational parks. Other findings include a loss of ∼9% of green cover in two public parks compared to their total gazetted area, and a loss of green area in other forested parts of KL. Focus group discussions and structured interviews with public, private and non-governmental organizations indicate that green-cover losses can be partly attributed to weak regulations and their poor enforcement. Opportunities to protect and increase green cover in KL are also explored in this study. Such approaches are urgently needed before most of the green areas disappear from the landscape of KL, exacerbating the existing environmental problems in the city.     

Estimation of broad-leaved canopy growth in the urban forested area using multi-temporal airborne LiDAR datasets

Inter-annual canopy growth is one of the key indicators for assessing forest conditions, but the measurements require laborious field surveys. Up-to-date LiDAR remote sensing provides sufficient three-dimensional morphological information of the ground to monitor canopy heights on a broad scale. Thus, we attempted to use multi-temporal airborne LiDAR datasets in the estimation of vertical canopy growth, across various types of broad-leaved trees in a large urban park.The growth of broad-leaved canopies in the EXPO '70 urban forest in Osaka, Japan was assessed with 19 plots at the stand level and 39 selected trees at the individual-tree level. Airborne LiDAR campaigns repeatedly observed the park in the summers of 2004, 2008, and 2010. We acquired canopy height models (CHMs) for each year from the height values of the uppermost laser returns at every 0.5 m grid. The annual canopy growth was calculated by the differences in CHMs and validated with the annual changes in field-measured basal areas and tree heights.LiDAR estimations revealed that the average annual canopy growth from 2004 to 2010 was 0.26 ± 0.11 m m⁻² yr⁻¹ at the plot level and 0.26 ± 0.10 m m⁻² yr⁻¹ at the individual-tree level. This result showed that growing trends were consistent at different scales through 2004 to 2010 despite uncertainty in estimating short-term growth for small crown areas at the individual-tree level. This LiDAR-estimated canopy growth shows a moderate relation to field-measured increase of basal areas and average heights. The estimation uncertainties seem to result from the complex canopy structure and irregular crown shape of broad-leaved trees. Challenges still remain on how to incorporate the growth of understory trees, growth in the lateral direction, and gap dynamics inside the canopy, particularly in applying multi-temporal LiDAR datasets to the large-scale growth assessment.     

Assessment of spatial equity of urban park distribution from the perspective of supply-demand interactions

Urban parks have been widely recognized for the critical functions they provide in enhancing health and wellbeing. However, parks are known to be inadequately provided and non-uniformly distributed in cities, leading to an increasing interest to examine spatial equity of park distribution. Such studies have mostly focused on the distributional attributes of park supply in determining spatial equity, while the role of residents’ demand is usually ignored or not adequately assessed. In addition, people’s preferences for park use were normally ignored and nearest parks were assumed as supplier of park services. Moreover, even though equity assessment is scale-dependent, few studies adopt a multi-scale assessment. We report on a study to address these gaps. A multi-scale Supply-Demand Equity Index (SDEI) was developed to assess spatial equity of park distribution from the perspective of supply and demand interactions, and data were collected at a fine scale of neighborhood level. Residents’ accessibility to their most often used parks and nearest parks were used to assess and compare supply level; while residents’ perceptions obtained from surveys and population density were used to assess and compare demand level. Results showed that supply measured by accessibility to most often used park more accurately reflects supply, and demand assessment on the basis of perception could reflect variations among different social groups and reveal otherwise hidden patterns of spatial inequity. It was also shown that SDEI could identify areas where mismatch between supply and demand occurs. We demonstrated in a single study that different definitions and approaches of quantifying spatial equity can lead to distinct conclusions, therein highlighting that the complex nature of equity requires nuanced approaches and providing a broader view of equity assessment. In addition, the implications of this study for urban park planning and management were highlighted.     

Defining urban forestry – A comparative perspective of North America and Europe

Urban forestry is generally defined as the art, science and technology of managing trees and forest resources in and around urban community ecosystems for the physiological, sociological, economic, and aesthetic benefits trees provide society. First mentioned in the United States as early as in 1894, the concept underwent a revival during the 1960s as a comprehensive and interdisciplinary approach to the specific challenges related to growing trees in urban environments. Later, urban forestry evoked the interest of scientists and practitioners in other parts of the world. However, harmonization of urban forestry terminology has been complicated by, for example, the involvement of different disciplines and translation difficulties. In many European languages, for example, the direct translation of ‘urban forestry’ relates more to forest ecosystems than to street and park trees. Efforts in North America and Europe defining ‘urban forest’, ‘urban forestry’ and related terms are introduced. A comparative analysis of selected urban forestry terminology in both parts of the world shows that urban forestry has a longer history in North America, based on traditions of shade tree management. Moreover, urban forestry has become more institutionalized in North America. Urban forestry in Europe has built strongly on a century-long tradition of ‘town forestry’. In both parts of the world, definitions of urban forestry and urban forest have become more comprehensive, including all tree stands and individual trees in and around urban areas. Agreement also exists on the multifunctional and multidisciplinary character of urban forestry. These similarities offer opportunities for international harmonization of terminology.     

Updating urban forest inventories: An example of the DISMUT model

Canberra is a unique city in Australia where the trees on public land that dominate the urban forest were planned for at the city's inception. In the mid-1990s, a 100% census of street and park trees was completed, and together with simple health, growth and yield models, this database formed the basis of a decision information system to support the management of the urban trees – DISMUT. The accuracy of the models was evaluated in a study in 2005 where models to predict total tree height were found to be unbiased and precise, tree crown dimension were under-estimated for small trees, and tree health was over-estimated. The over-estimate of health may be due to the relatively poor rainfall conditions over the past 10 years while the biases in crown dimension predictions are more likely due to a too simple model form. However, the existence of DISMUT predictions over all streets and parks in Canberra means that statistically efficient two-phase sampling approaches can be used to correct for any bias in the mean estimates of tree numbers and size, and also to predict the mean value of other environmental, economic or social parameters of interest that are correlated to tree size.     

Uncertainty in urban forest canopy assessment: Lessons from Seattle,WA, USA

Increasing urbanization around the globe is leading to concern over the loss of tree canopy within cities, but quantifying urban forest canopy cover can be difficult. We discuss methods of assessing canopy cover within cities, and then use a case study of Seattle, WA, USA to examine issues of uncertainty in canopy cover assessment. We find that uncertainty is often not reported, and when reported, may be biased. Based on these findings, we provide a list of recommendations for those undertaking canopy cover assessment in complex urban environments.     

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.     

Fine-scale characterization of bird habitat using airborne LiDAR in an urban park in Japan

Birds are ecosystem service providers and excellent urban ecosystem indicators because they are sensitive to habitat structure. Light detection and ranging (LiDAR) technology is a promising tool in bird habitat characterization because it can directly acquire fine-scale 3-D information over large areas; however, most of past avian ecological studies using LiDAR were conducted in North America and Europe, and there have been no studies in Asia. The robustness of LiDAR data across different habitat types remain problematic. In this study, we set 13 plots having different canopy area percentages in a large-scale urban park in Japan, and examined the usefulness of airborne LiDAR data in modeling richness and diversity of forest bird species and the abundance of Paridae species that play an important role in the urban food web. Bird surveys were conducted eight times at each plot during the birds’ breeding season, and the results were estimated using generalized linear models. In consequence, all of the response variables were explained by one or a few LiDAR variables, and the 1 × 1 × 1-m voxel-based variables were especially robust estimators. When targeting only densely-forested plots having more than 60% canopy area, the LiDAR data efficiency declined in estimation of the richness and diversity of whole forest bird species, whereas a laser penetration rate was efficient for estimating the Paridae species abundance. These results implied that the LiDAR data are useful in habitat characterization of forest birds, and even when targeting only dense forests, some LiDAR variables are effective for habitat estimation of birds preferring specific forest structures. In the future, application of LiDAR across a variety of ecosystems will greatly serve to develop adaptive conservation and management planning for urban forests.     

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.     

Modeling the effects of forest harvesting on landscape structure and the spatial distribution of cowbird brood parasitism

Timber harvesting affects both composition and structure of the landscape and has important consequences for organisms using forest habitats. A timber harvest allocation model was constructed that allows the input of specific rules to allocate forest stands for clearcutting to generate landscape patterns reflecting the look and feel of managed landscapes. Various harvest strategies were simulated on four 237 km² study areas in Indiana, USA. For each study area, the model was applied to simulate 80 years of management activity. The resulting landscape spatial patterns were quantified using a suite of landscape pattern metrics and plotted as a function of mean harvest size and total area of forest harvested per decade to produce response surfaces. When the mean clearcut size was 1 ha, the area of forest interior remaining on the landscape was dramatically reduced and the amount of forest edge on the landscape increased dramatically. The potential consequences of the patterns produced by the model were assessed for a generalized neotropical migrant forest bird using a GIS model that generates maps showing the spatial distribution of the relative vulnerability of forest birds to brood parasitism by brown-headed cowbirds. The model incorporates the location and relative quality of cowbird feeding sites, and the relation between parasitism rates and distance of forest from edge. The response surface relating mean harvest size and total area harvested to the mean value of vulnerability to cowbird brood parasitism had a shape similar to the response surfaces showing forest edge. The results of our study suggest that it is more difficult to maintain large contiguous blocks of undisturbed forest interior when harvests are small and dispersed, especially when producing high timber volumes is a management goal. The application of the cowbird model to landscapes managed under different strategies could help managers in deciding where harvest activity will produce the least negative impact on breeding forest birds.     

Impacts of land use and topography on the cooling effect of green areas on surrounding urban areas

Few studies have examined the influence of land use and terrain on the cooling effect of green areas on surrounding urban areas. We investigated the spatial distribution of the cooling effect of green areas on surrounding urban areas in Heiwa Park, Nagoya, central Japan, by applying surface temperature (T_s) information obtained from Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) image data. The cooling effect was found to extend in many directions into the urban areas. The spatial distribution of T_s showed that commercial areas interrupted the flow of park cooling, whereas other types of urban areas expanded park cooling more effectively. We hypothesise that this was the result of differences in geometric and thermal properties and anthropogenic heat release between commercial and other areas. The spatial distribution of T_s also reflected the effects of topography on park cooling. The green area at our study site was located on a hill, and the downward slope and valley terrain inside the park increased the cooling effect towards the surrounding urban areas. To improve the thermal environment of urban areas and the comfort levels of residents, effective utilisation of the cooling effect of green areas should be incorporated into urban designs that consider the effects of land use and topography.     

Remote sensing for the assessment of ecosystem services provided by urban vegetation: A review of the methods applied

The study and assessment of ecosystem services through remote sensing has increased substantially over the last two decades, as evidenced by the publication of studies that have applied it. The technological development of satellite images has improved in terms of spatial, spectral, radiometric, and temporal resolution, allowing the space-time observation, classification and monitoring of vegetation on the surface of the Earth. However, there are remaining methodological challenges for assessing ecosystem services due to the diversity of applications, the resources used, and its study in complex environments such as cities. This systematic review is based on identifying and analysing the variety of methods concerning the application of remote sensing for the assessment of ecosystem services provided by vegetation in cities, through a classification of these methods according to the data collection source (passive sensors, passive and active sensors and the fusion of other data sources with sensors). The classification of methods has been applied to a selection of existing articles in indexed scientific databases based on a non-statistical meta-analysis that make a direct reference to the topic of interest. The results show the approaches found in every method classified, their relationships with the geographical scale and the image resolutions used, and the advantages and limitations from the data processes that comprise remote sensing. We conclude from this analysis with three key factors to consider in the selection of remote sensing methods for the assessment of ecosystem services provided by urban vegetation: the definition of the approach(es), the urban scale to be assessed, and the image resolution available.     

Effect of urban green patterns on surface urban cool islands and its seasonal variations

Urban green spaces often form urban cool islands (UCIs), which are important for human health and urban sustainability. Previous studies have emphasized the cooling effects of urban green spaces on their surrounding areas at landscape level. Less attention, however, has been directed to effects of urban green space patterns on their own UCIs at patch level. In this study, we focused on the effects of spatial patterns of urban green patches on their own surface UCIs. The urban green spaces of Beijing, China, were extracted from one QuickBird image and were classified as Trees, Shrubs, Grass, Crops, River and Lake. Land surface temperatures (LSTs) were derived from four Landsat images, each in one season. The UCI was represented by the minimum LST of each urban green patch. Results showed spatial patterns of urban green patches had significant effects on their UCIs in four seasons. In detail, the size, edge and connectivity of urban green spaces all affected the UCIs negatively, and the influence was stronger in warm seasons. Shape of urban green space also had effects on UCIs, but the effects were stronger in cool seasons. Great differences were found between predictive values of metrics for different green types. Shape metrics were more important for indicating UCIs of River, Trees and Crops than were patch size and connectivity. However, patch size and connectivity metrics were more effective in determining UCIs of Shrubs, Grass and Lake than were shape metrics. Further, among shape metrics, only shape index was a good indicator of UCIs. The results of this study suggest that a combination of specific urban green types and pattern metrics are a prerequisite for analyzing the influence of urban green patterns on UCIs and for urban green design.     

The temporal trend of urban green coverage in major Chinese cities between 1990 and 2010

Information on changes in urban green spaces and the causes of these changes is important for urban planning. In this study the trends of urban green coverage (UGC) between 1990 and 2010 in 30 major Chinese cities were studied using classified Landsat satellite images. Associations between the trends and natural and socio-economic variables were analyzed using the maximum information-based nonparametric exploration method. The results showed that, overall, the studied cities have become greener over the past two decades. Greening in old city districts and expanded built-up areas (BUAs) led to the increase of urban green coverage at a mean annual rate of 1.51%. However rapid urbanization also caused a dramatic turn-over in vegetation covers. On a regional scale, around 46.89% of original vegetation cover was converted to other land cover types. The trends of UGC cannot be attributed to any one of natural or socio-economic variables alone. The combined influences of economic growth, climate change, and urban greening policies are the most likely causes behind the detected trend. One lesson from this study is that the preservation of existing vegetation cover must be a priority in urban greening programs.     

Evaluating the supply-demand relationship for urban green parks in Beijing from an ecosystem service flow perspective

The mismatch between the spatial patterns of urban green parks (UGP) and population in urban areas is a common phenomenon in Chinese cities and elsewhere. Whether and to what extent such mismatch may impact the realization of Ecosystem Service (ES) provided by the former remain unclear. Stemming from the Ecosystem Service Flow (ESF) perspective, this paper argues that the distance-decay effects and spatial heterogeneity in the propagation process of the ESF with different conveyors may render the various types of ES demonstrating different location sensitivity in both provision and realization terms. We then present an “is-ought” framework for analyzing the supply-demand relationship of ES, which features deductively obtained ES provision potential and empirically observed ES realization, both are spatially explicitly mapped. Refined ontological and distance-decay modeling methods and mobile signaling data were introduced to implement the framework taking Beijing as a case. For the two typical types of ES in urban environments, the recreational and thermoregulating services, we find that there indeed exists under- or over-supply of ES along the center-periphery gradient of the city. The findings have policy implications for the planning and management of UGP.     

Private residential urban forest structure and carbon storage in a moderate-sized urban area in the Midwest,United States

In conjunction with urbanization and its importance as a major driver of land-use change, increased efforts have been placed on understanding urban forests and the provisioning of ecosystem services. However, very little research has been conducted on private property and little is known about the structure and function of privately owned urban forests. This research examines the structure of and carbon storage services provided by private residential urban forests in a moderate-sized Midwestern city. The primary research questions are as follows: What is the structure of private urban forests, and how does it vary across parcels? How much carbon is stored in tree and soil pools of private urban forests, and how does carbon vary across parcels? Ecological inventories were conducted on 100 residential parcels within 14 Neighborhood and Homeowners Associations of varying size and development age. Tree species richness, diversity, density, and diameter distribution were determined on a per parcel basis and for the entire tree population sampled. Further, tree and soil carbon storage were determined for each parcel. Results of this research demonstrated large variability in per-parcel tree metrics. Twelve of the parcels sampled had two or fewer trees, while eleven had greater than 50 trees. Further, tree carbon storage ranged from no carbon to 11.22 kg C m^?2. Alternatively, soil carbon storage was less variable and averaged 4.7 kg C m^?2, approximately 1.9 times higher than the average carbon stored in trees (2.5 kg C m^?2). Management efforts aimed at maintaining or enhancing carbon storage and other ecosystem services should focus on both soil protection and maximizing services in living biomass. Our results demonstrate that sustaining tree-produced ecosystem services requires maintenance of large old trees and species diversity, not only in terms of relative abundance, but also relative dominance, and in combination, species–specific size distributions.     

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.