Abstract
Many municipalities are working to protect and grow their urban forest, including adopting private tree regulations. Such regulations typically require property owners to apply for a permit to remove trees and, if the permit is granted, plant replacement trees. Even with such regulations, many private trees are removed each year, particularly on residential property. Property-level construction activity, including expanding building footprints, replacing an older home with a new one, and increasing hardscaping, is emerging as a key driver of residential tree loss. This study addresses whether homeowners who receive a permit to remove one or more trees comply with the requirement to plant replacement trees to better understand the effect of private tree regulation. We explore this question through a written survey of homeowners who received a tree removal permit and site visits in Toronto (Ontario, Canada). While 70% of all survey participants planted the required replacement trees 2 to 3 years after receiving the permit, only 54% of homeowners whose permit was associated with construction planted. Additionally, most replacement trees were in good health but were dominated by a few genera. We also found significant differences in replacement planting and tree survival across the city’s 4 management districts. This study highlights that if resources supporting private tree regulations are limited, tree permits associated with construction should be prioritized for follow-up. Additionally, guidance about diverse species to plant should be communicated to ensure that private tree regulations are supporting the long-term protection of the urban forest.
INTRODUCTION
Given the range of ecosystem services provided by urban forests, many cities across North America are working to protect and grow their urban forests over the long term. Part of these efforts include retaining existing trees to ensure the benefits they provide are available now and into the future (Kielbaso et al. 1988; Rines et al. 2011). Efforts are increasingly including privately owned land, as these spaces collectively contain the majority of trees in many cities (Nowak and Greenfield 2020), and private tree benefits often extend beyond the property boundary (Konijnendijk van den Bosch 2016). Thus, protection of private trees is essential to maintain the urban forest as a whole and its associated benefits.
A recent review examining private tree retention highlighted that most case studies in forested ecosystems indicate a loss of canopy on private land over time (Ordóñez-Barona et al. 2021). Property-level construction activity is emerging as a major cause of private tree canopy loss (Croeser et al. 2020), particularly on residential property (Lee et al. 2017; Steenberg et al. 2018). This includes expanding building footprints, replacing an existing house with a new one, and/or adding additional hardscaping (Lee et al. 2017; Morgenroth et al. 2017). Trees are often removed during construction activities so that equipment can more easily access the site (Guo et al. 2018); trees were identified as increasing redevelopment costs by developers and landscape architects surveyed in Tampa, Florida (USA)(Landry et al. 2013). Other trees do not survive the construction phase due to direct damage and/or soil compaction (Koeser et al. 2013). Additionally, expanding building footprints and other impervious surfaces may also reduce the amount of space available for trees, triggering removal of existing trees on a property (Jim 1998; Lee et al. 2017).
While there is a long history of local governments regulating removal of public trees through ordinances or by-laws, recent efforts have expanded to also protect trees on private property (Ordóñez-Barona et al. 2021). Often, local regulations exist to protect private trees during the (re)development process, with a study in Highland Park, Illinois (USA), suggesting such efforts are effective at tree preservation (Pike et al. 2021). Increasingly, blanket private tree regulations have also been adopted in the US and Canada that outline a permit process required of all property owners wanting to remove trees (Hill et al. 2010). Such regulations usually identify the size of regulated trees, criteria for approving a permit, and penalties for removing a tree without a permit (Lavy and Hagelman 2017). Additionally, permits typically require one or more trees to be planted to replace those removed (Coughlin et al. 1988; Conway and Lue 2018).
Recent research suggests that regulation of private tree removal can be effective. Municipalities with private tree protection regulations have more tree canopy cover (Landry and Pu 2010; Sung 2012; Hilbert et al. 2019) and higher average tree heights (Sung 2013) than comparable municipalities without such regulations.
But there are also challenges associated with private tree regulations. Limited enforcement makes it unclear how frequently regulated trees are removed without following the permit process (Conway and Urbani 2007; Landry and Pu 2010). In addition, some permitting regulations may exclude significant numbers of trees or have fines that are low enough, particularly in the context of major construction, that they do not serve as a deterrent to tree removal (Coughlin et al. 1988). In Falls Church, Virginia (USA), Chojnacky et al. (2020) found that the local ordinance requiring 20% property-level canopy cover 10 years after redevelopment often did not force replacement of trees removed during construction because many properties already exceed 20% canopy cover. A final challenge is that removal permits are typically issued with the requirement to plant replacement trees, but that planting may not occur (Conway and Lue 2018). Thus, the number of trees is reduced, and tree canopy extent will likely not recover.
This study examines if the tree replacement requirement associated with a private tree removal regulation is supporting long-term protection of the urban forest through a case study of Toronto, Ontario (Canada). We addressed three specific objectives: (1) measure compliance rates associated with the tree replacement requirement of residential tree removal permits; (2) determine if property-level construction or homeowner characteristics are related to the likelihood that replacement trees are planted; (3) determine the health and species of replacement trees to see if planted trees will contribute to growing a diverse urban forest. These objectives are addressed through an analysis of a written survey of homeowners who received a tree removal permit and follow-up site visits to a subset of survey participants. We end by considering challenges and opportunities for regulating private trees through a permitting process.
METHODS
Study Area
The City of Toronto (Ontario, Canada) serves as a case study to explore homeowner compliance with replacement tree planting associated with a private tree removal regulation. The city is located on the north shore of Lake Ontario, with a population of 2,731,571 (Statistics Canada 2016). Toronto’s canopy cover was between 28% and 31% in 2018, with 55% of trees located on private property (City of Toronto 2018). While a recent city report identified residential property as containing the most planting opportunities, it is also the land use that has added the most impervious surface in the last decade (City of Toronto 2018).
The City of Toronto adopted a private tree by-law in 2004 (Private Tree By-Law, Toronto Municipal Code Chapter 813, Article III) obliging property owners, including residential homeowners, to apply for a permit to remove any tree over a diameter of 30 cm at 1.4 m above the ground. Any tree determined by city staff to be terminally diseased, dead, or imminently hazardous are exempt from the permit process. Moreover, for major construction projects (e.g., constructing a high-rise, multi-unit dwelling), tree retention and planting is often part of negotiations that occur during the planning approval process (e.g., site approval, zoning variances, and building permits) outside the private tree by-law. Thus, this study focused on situations where non-exempt trees were removed on residential property that were not part of major development projects.
The permit process involves an application submitted to the Urban Forestry unit, which must include an arborist report, a replanting plan, and site and elevation plans if the application is related to construction. The application cost is $124 or $370 CAD per tree for non-construction permits and construction-related permits, respectively. A site visit from a municipal arborist may occur after the permit application is submitted. Toronto also requires a (minimum) 14-day period of public notice if the arborist determines the tree is in good health and not a hazard to nearby structures (Private Tree By-Law, Toronto Municipal Code Chapter 813, Article III). While the decision to issue a permit is made by city staff, the local city council member is consulted before a permit is issued. Ultimately, removal permits are granted over 95% of the time (Rider 2016).
When a permit is issued, property owners are required to plant at least one replacement tree for each tree removed. If no suitable planting site is available on the property, planting at another location or a cash in lieu payment may be accepted. Property owners are required to contact Urban Forestry once replacement trees are planted. A fine of $500 to $100,000 CAD per tree can be issued if the permit process is not followed (Private Tree By-Law, Toronto Municipal Code Chapter 813, Article III).
A 2018 Auditor General’s Report focusing on permit issuance and by-law enforcement by Toronto’s Urban Forestry unit found significant flaws in the process. One issue highlighted in the report is the lack of follow-up by city officials to ensure compliance with the replacement tree planting requirement; city staff do not regularly complete site visits, and property owners frequently do not notify the city when they replant (Romeo-Beehler 2018). Additionally, there is no official review of the proposed replanting site and inconsistent recommendations about which species to plant (Romeo-Beehler 2018). Enforcement of required replanting is therefore minimal, and city staff indicate that fines are rarely issued.
Non-compliance with replacement requirements is particularly concerning in Toronto, given the overwhelming percentage of private tree removal applications that are approved at the same time as the city is implementing a long-term strategic management plan to increase total canopy cover and species diversity (City of Toronto 2013). While the rate of permit approval may be high in Toronto, limited enforcement and follow-up of private tree regulations is not unique to the city (Coughlin et al. 1988; Conway and Urbani 2007), so a better understanding of tree replacement can highlight the strengths and challenges of a private tree removal permit process more generally.
Survey and Site Data
In 2019, a total of 1,992 addresses associated with private tree removal permits issued in 2016 and 2017 for residential property were provided by staff in the Urban Forestry unit of the Parks, Forestry, and Recreation Division of the City of Toronto. The 2-year time period was chosen as it is recent enough to reduce the likelihood of a new owner since the permit was issued, but also allows several years for tree removal and replanting to have been reasonably completed by the time of the survey. The addresses received represent a sample of all permits on residential property issued in that 2-year period, stratified by the 4 management districts used by Urban Forestry: 280 in East, 517 in North, 714 in South, 481 in West (Figure 1). In the data provided by city staff, 484 addresses were labeled as tree removal permits associated with construction activity, 1,077 were labeled as non-construction permits, and the permit type was not given for 431 addresses. Of the addresses, 43 were clearly for non-residential properties (e.g., a church, university property), so 1,949 addresses were retained for the study (Table 1).
Percent of surveys mailed with no response, a response indicating tree replacement, and a response indicating no tree replacement, summarized by municipal ward. The size of the pie chart represents the number of surveys.
Surveys mailed and sites visited across the 4 management districts.
In the summer of 2019, a multi-contact approach was used to administer the mail-based survey following standard procedures to generate strong response rates (Dillman et al. 2014). First, information postcards were sent to the addresses, notifying them a survey would soon arrive in the mail or they could complete it online. Within a week, a package that included an information and consent letter, the survey, a stamped return envelope, and a site visit permission form was mailed. Two weeks later, a reminder postcard, followed in two more weeks by a second copy of the survey packet, were sent if a survey for the address had not yet been completed. All survey materials were given a unique code so we could track completed surveys.
The survey began by confirming that the homeowner who applied for the permit still lived at the address associated with the tree removals. Next, there were questions that assessed homeowners’ basic attitudes towards regulation of private tree removal; type of permit issued; status and characteristics of replacement trees, including species and source of any tree(s) planted; and basic socio-demographic characteristics of the homeowners (see Appendix). Permit type included construction permits, necessary when the request to remove trees is related to construction activities such as expanding a house’s footprint or replacing an old house with a new one, and non-construction permits, which are associated with removing a tree due to any non-construction reason.
We sought to reduce any concerns participants may have had about repercussions if they had not planted the required trees by clearly communicating that all responses would remain confidential, and we would not share individual responses with the city. This was stated in the information letter and again as part of the question about replacement trees: “One of the requirements of the City of Toronto Tree Removal Permit is to plant and maintain (a) replacement tree(s). Was a replacement tree (or trees) ever planted on your property? This information will NOT BE SHARED with the City of Toronto.”
We also assessed whether homeowners were more likely to complete the survey or more likely to indicate that they had not planted the required trees if the confidentiality of their responses was highlighted at the start of the survey. To do this, 50% of the surveys had the following anonymity statement in bold at the top of the first page: “DISCLAIMER: All information collected in this survey is reported anonymously. Individual surveys and raw data will not be shared with the City of Toronto. As such, there are no negative repercussions based on survey responses.”
In addition to the written survey, site visits were conducted on properties when the homeowner provided permission to access the property. A total of 174 homeowners agreed to site visits, and 96 of these were completed between July and October 2019 (Table 1). Altogether, 183 replacement trees were evaluated across the properties. In addition to identifying the species, the health status of each tree was assessed using a grading scheme based on the Neighbourwoods protocol (Kenney and Puric-Mladenovic 2014). To analyze the presence of crown defoliation, weak or yellowing foliage, and signs of pathogens on the replacement trees, a value of 0 to 3 was assigned in each category: “0” indicated that there was no presence of a negative health condition, while “3” showed extensive damage visible to over 50% of the tree. Finally, the percent of hard surface (e.g., paved walkways, rock gardens, or any structures) located under the drip line of each tree was visually estimated following the Neighbourwoods protocol.
Analysis
Survey responses were entered into a database, and an error checking procedure was used to ensure accuracy of the data. The data collected during the site visits went through the same process. First, simple summaries of the survey responses and site visit data were completed, including the number of respondents who had planted the required replacement trees.
Second, statistical tests were conducted to see if significant (P < 0.05) correlations existed between survey response rate, replacement planting, presence of anonymity statement on survey, management district, permit type (construction or non-construction), attitudes towards tree regulation, and 3 socio-demographic measures that are often correlated with residential yard tree actions (household income, education level, and age). Cross tabulations were calculated using the chi-square test statistic, Cramer’s V test statistic when comparing categorical variables where at least 1 variable has more than 2 classes, or Fisher tests when smaller and irregular category sizes were present.
We also compared the species homeowners listed as planting in the survey and the species identification of the tree(s) based on the site visits to better understand if homeowners were reliably identifying the replacement tree species. As most homeowners listed the common name at the genus level (e.g., maple), we summarized and compared the tree identification data by genera. For the site visit data, we also examined the percent of native species planted, defining native species as those historically found in the Toronto region (City of Toronto 2010; Farrar 2017). Hybrid species such as the Freeman maple (A. × freemanii) were considered native because its parent species, the red maple (Acer rubrum) and silver maple (Acer saccharinum), are endemic to southern Ontario.
RESULTS
Of the 1,949 surveys mailed, 1,824 were successfully delivered, while 125 surveys were “returned to sender” (i.e., never reached the intended destination). The “returned to sender” number is relatively high given that the mailing label only included addresses and not names; it reflects addresses that do not exist according to Canada Post, rather than a homeowner no longer living at that address, suggesting errors in the City of Toronto’s record keeping. A total of 605 surveys were returned. After filtering for surveys that did not answer yes to the screening question, surveys with missing answers to the tree permit and replacement questions were removed, leaving a total of 429 responses. Thus, the survey response rate is 24%. This is typical for a mailed survey that is not addressed to homeowners by name (Dillman et al. 2014). We found no significant difference in response rate between surveys with (21%) and without (24%) the anonymity protection statement at the top of the survey, although underreporting of permit violations may have occurred, as survey data tends to underrepresent illegal activities (Aday and Cornelius 2006).
The initial 1,949 sample has an uneven spatial distribution, with few permits located in the central and northern part of the East District and the western part of the North District (Figure 1). These areas have relatively low canopy cover compared to the city as a whole, so may have fewer trees that are covered by the private tree by-law. The spatial distribution of survey responses generally follows the same pattern, suggesting that the response group is not spatially biased.
The majority of survey respondents reported income above $120,000 CAD and held a university degree (Table 2), thus respondents were wealthier and better educated than Toronto residents in general. However, there is no demographic data available for homeowners who participate in the permit program, so it is unclear if these characteristics reflect permit holders as a group. The majority of respondents were between 40 and 70 years old, as expected given that all participants are homeowners. No one under 30 responded to the survey.
Basic demographics of homeowners by percent of survey responses.
Tree Removal Permits and Replacement Trees
“Non-Construction” tree removal permits were the most common type of permit obtained by respondents (68%), whereas only 20% of respondents reported obtaining a “Construction” permit (Table 3). Most of the homeowners who checked “Other” for permit type wrote that they did not know what type of permit they received, often noting that the application was handled by a construction contractor or tree professional. Five other respondents indicated that their application was declined or they submitted a tree protection plan rather than a tree removal permit. This later group again suggests that the City of Toronto records have some inaccuracies that include mixing permit types. There are no statistically significant differences in permit type across the 4 districts.
Percent of different types of tree removal permits obtained by survey participants. Percentages based on the number of trees per district.
Of those who completed the survey and received a permit, 70% said they had planted the required replacement tree(s), while 30% had not (Table 4). Eighty-five percent said that the requirement to replace trees removed was clearly communicated through the permit process, including a number who had not planted replacement trees. There was no statistically significant difference in replacement tree planting compliance between respondents with (68%) and without (72%) the anonymity protection statement at the top of the survey. We also did not find any significant difference based on household income, education level, or age of survey respondents.
Number (N = 429) of survey respondents who planted the required tree(s) or did not plant. Percentages based on the number of trees per district.
Overall, attitudes towards private tree regulation were mostly positive, which is not surprising given that everyone in the survey complied with the private tree by-law requirement to obtain a permit to remove regulated trees (Figure 2). There was not a significant difference between attitudes towards regulating tree removal or replacement tree planting and actually planting the required replacement trees, although more people who replanted indicated strongly agreeing with regulating replacement planting as compared to those who did not replant.
Level of agreement with private tree regulation by survey participants who did and did not plant required replacement trees. Regulate removal represents responses to the statement: “Medium and large trees on private property should be regulated through municipal by-laws,” while Regulate replacement planting represents responses to the statement: “Tree planting to replace trees removed on private property should be regulated through municipal by-laws.”
The type of tree removal permit did have a significant relationship with replacing trees, with 76% of non-construction permit holders planting the required tree(s), while only 54% of construction permit holders planted (Χ 2 = 11.408, P < 0.001). Additionally, the replacement compliance level is also significantly different among survey responses across the 4 districts, with 84% of the respondents from the North District replanting following their tree removal, but only 61% in the West District (Table 4).
Replacement Trees’ Source, Health, and Composition
Contractors, which includes landscapers, arborists, and other members of the private sector, planted more of the required replacement trees than any other party (32%), followed by property owners planting the tree(s) themselves (26%). Five percent of the survey respondents received their tree through a regional non-governmental organization that runs a subsidized yard tree planting program (LEAF 2020). Additionally, some survey participants indicated that their multiple replacement trees were planted by more than one party, which was accounted for in the data summary (Table 5).
Source of tree(s) planted to meet replacement requirement. Some survey respondents received their trees from more than one source, and this is reflected in the counts.
The overall survival rate of the 619 replacement trees was high (94%) over the short time period since planting (maximum of 3 years). The survival rate in the West District was significantly lower than the other districts at only 88% (Fisher’s Exact Test for Count Data; P = 0.0419). City-planted trees have a higher mortality rate than other sources, while LEAF-planted trees in our sample experienced no mortality (Table 6), although these differences were not significantly different.
Number of trees that survived by source. Percentages based on the number of trees per source.
Of the 183 trees assessed during the site visits, the majority (73%) of them did not exhibit any signs of crown defoliation, while only 3% were assigned a value that suggests signs of likely not surviving (Table 7). The majority of the assessed replacement trees (78%) also had no signs of weak or yellowing foliage, nor any evidence of pests or disease that may cause serious health issues in the future (92%). Many had no surrounding hard surface (43%), while 50% of the assessed trees had 10% to 30% hard surface in the immediate surroundings. These trees were most commonly planted along fences. Of the 183 trees, 9 had a hard surface of 50% or greater, primarily planted in rock gardens or between walkways and built structures.
Health assessment of 183 trees from site visits.
The most frequently planted genera based on the homeowner survey responses were Acer (40% of all trees reported), Quercus (10%), Fagus (9%), Ginkgo (6%), and Liriodendron (5%)(Table 8). Five percent of survey respondents who indicated they had planted one or more replacement trees were unsure or could not remember the type of tree(s) planted. On the other hand, the most common species identified through the site visits were Fagus sylvatica (23%), Acer saccharum (8%), and Acer × freemanii (7%)(Table 8).
Most common genera based on survey responses and most common species based on site visits.
The differences between the 2 data sets may be partially due to the different sample sizes, as only 22% of the properties with survey responses have site visit data. However, when the site data and survey were both available, 18% of the time the 2 sources were different at the level of genus, and 13% of the properties include some but not all trees differently identified. Of the remaining 68%, the same genera were identical in the 2 data sets, but in many cases the homeowner did not specify the species, or the species information was present but differed. Thus, at least some of the differences in genera frequency between the survey and site data is due to misidentification, likely by homeowners.
Based on the site visit data, the overall number of native and non-native species is roughly equal, but this was highly variable across the 4 districts, with only 26% of trees considered native in the East District and 75% in the West District (Table 9).
Native and non-native species identified through the site visits.
DISCUSSION
The majority of homeowners who participated in the survey complied with the tree replacement requirement of their tree removal permit, and nearly all of the trees planted were in good health 0 to 3 years after planting. Not surprisingly, the survey participants, who all engaged with the permit process, collectively have a more supportive attitude towards private tree by-laws than found in recent surveys of Greater Toronto Area residents (Conway and Lue 2018).
On the other hand, 30% of respondents did not plant the tree(s) required by their removal permit. Given the percentage of respondents who indicated that the requirement to plant replacement trees was clear, many non-compliant homeowners are aware of the requirement but are choosing to violate the terms of the permit. The survey and site data also suggest that replacement trees are dominated by just a few genera. Thus, there is a disconnect between maintaining tree counts, City of Toronto species diversity goals, and actual practices captured in the study.
Although most surveyed homeowners are complying with the replacement tree requirement, key groups have significantly lower rates of replacement planting. Specifically, holders of construction-based tree removal permits were less likely to plant than non-construction permit holders. These findings confirm recent research highlighting the negative impact of property-level construction on tree retention (Lee et al. 2017; Guo et al. 2018) and the potential for cumulative property (re)development-related tree removal to have a substantial impact on neighborhood and city-wide urban forest cover (Steenberg et al. 2018; Croeser et al. 2020).
It is somewhat surprising that relatively low compliance is associated with construction-based removal permits in this case, as everyone included in the survey sample conformed to the by-law by acquiring a tree removal permit. There are a few possible reasons why a homeowner would follow the requirement to obtain a removal permit but not meet the permit requirement of planting replacement trees. First, homeowners may have intended to plant replacement trees, but due to extended construction activities they had not yet had the chance at the time of the survey. However, we sought to minimize this occurrence by surveying people who received removal permits 2 to 3 years prior to the survey. Second, those who received construction-based tree removal permits may have been more likely to pay the fee in lieu of planting replacement trees. We do not have enough information to determine the frequency of this occurrence. Third, non-compliance with the permit may indicate a lack of agency felt by homeowners who did not personally apply for the permit (i.e., a contractor or other service professional applied on their behalf). Finally, those who received construction-based permits may be less willing to plant replacement trees precisely because of the construction on the property.
Previous studies have found that homeowners with higher income and/or education are more likely to remove trees on private property, but also more frequently plant trees and increase overall tree numbers on their property over time (Kirkpatrick et al. 2013; Lavy and Hagelman 2017). On the other hand, older homeowners have been associated with a higher likelihood to remove trees and not plant new ones nor support regulations protecting trees (Kirkpatrick et al. 2013; Conway and Bang 2014).
This survey did not find any relationships between replanting and income, education, or age of homeowners, possibly because the homeowners included in the survey were limited to those who applied for the removal permit in the first place, while homeowners who remove trees outside the permit process may be different in terms of socio-demographic factors, level of engagement with the city, and/or knowledge and attitudes about trees. Additionally, the majority of the surveyed homeowners had relatively high income, post-secondary education, and were in a limited age range. Thus, the homogeneity of the survey population may have muted the socio-demographic effects often associated with costs, knowledge, and attitudes.
Based on the data from the site visits, the species planted were slightly more likely to be non-native than the city’s current species composition on residential property (over 50% native; City of Toronto 2013). Instead, the survey and site data sources suggest that non-native tree species and/or those that were smaller in stature are frequently planted. For example, European beech (F. sylvatica) was planted at several properties to create a hedge, so unlikely to be allowed to grow to a large form.
A broader concern is that homeowner’s reporting was typically limited to common names that could represent native or non-native species (e.g., maple) and often conflicted with the site visit identifications made. This creates uncertainty about species planted, suggesting many homeowners had limited awareness of the trees planted on their property and cannot be relied on to accurately report what species is planted unless an invoice or other documentation is required. Additionally, without clear guidance and follow-up from city staff, it is likely that homeowners will favor trees that are easy to acquire, potentially limiting diversity.
Based on the data collected from the site visits, the overall tree health appears to be very encouraging for the future survivorship, with few signs of crown defoliation, weak or yellowing canopy, or pathogen impact. This bodes well for the future of these trees, considering they are at their most vulnerable in the initial years following planting (Roman et al. 2014a). Furthermore, the majority of replacement trees have little to no hard surface in the immediate surroundings, reflecting that the trees are planted in locations with ample growing space. This is particularly encouraging considering the challenges associated with limited spaces in urban environments.
Trees planted by homeowners had a higher mortality rate compared to other entities providing planting services. Studies have indeed shown that trees planted by homeowners have a higher mortality rate than those planted and maintained by professionals (Roman et al. 2014b; Smith et al. 2019). Ensuring the use of proper planting methods, including encouraging a professional to plant replacement trees, would help promote tree health and survivability during the establishment period (Pauleit et al. 2002).
Variations in replanting rate, percent of native species, and survival also existed between the city’s management districts, with the lowest replacement tree planting rate in the West District. It is unclear why. There was a similar percent of construction-based permits associated with surveys across the districts, and respondents in the West were equally likely to state that the requirement to plant replacement tree(s) was clear. Further investigations are needed to understand why these differences exist in Toronto. More generally, it highlights the challenges of equally implementing a private tree regulation where there is some discretion in permit approval and replacement tree requirements.
Beyond the potential that the level of communication varies across the city, the survey highlighted errors in record keeping, including incorrect mailing addresses linked with approved permits, and incomplete permit records, including missing or incorrect information about the type of permit issued. While staff are supposed to provide a list of approved species for replacement planting, this information was largely absent from the data record provided. Limitation in record keeping was a known issue in Toronto (Romeo-Beehler 2018). This study provides further evidence that monitoring outcomes and enforcement of private tree regulations cannot occur without accurate records.
Toronto and other municipalities have sought to maintain their urban forests, in part, through the regulation of private tree removal. Based on this study, Toronto’s tree removal permit process is falling short of maintaining tree numbers, with construction a particular threat to the long-term protection of the urban forest. Given the high approval rate for tree removal permit applications in Toronto, the permit process is not stopping most removals, making replacement tree planting even more important. But, even in situations where fewer permits are approved, these results indicate not everyone who requests a tree removal permit will comply with its requirements. When limited follow-up and enforcement capacity exists, tree removal permits associated with construction should be prioritized based on the lower replacement tree compliance rates found in this study. Clear direction about diverse species to plant could also avoid homeowners selecting a limited number of species to plant. Collectively, these actions would contribute to a private tree regulation effectively protecting and diversifying a city’s urban forest.
ACKNOWLEDGMENTS
Thanks to the City of Toronto, Parks, Forestry and Recreation Division, Urban Forestry, for providing the tree removal permit data and funding to support the site visits. We also thank Janet McKay for initially encouraging the project and the homeowners who completed surveys and allowed site visits.
Appendix. Survey questions assessing homeowners’ basic attitudes towards regulation of private tree removal; type of permit issued; status and characteristics of replacement trees, including species and source of any tree(s) planted; and basic socio-demographic characteristics.
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- Appendix. Survey questions assessing homeowners’ basic attitudes towards regulation of private tree removal; type of permit issued; status and characteristics of replacement trees, including species and source of any tree(s) planted; and basic socio-demographic characteristics.
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