Displaying all posts in the The OTM Community category.

Community Engagement in Action: A conversation with Greening of Detroit

We recently caught up with the Greening of Detroit to learn how they successfully plant, map and care for thousands of trees each year. In their early days of operation, the Greening planted five to ten trees per event. Over the past two decades, these small planting events have turned into a well-organized operation involving thousands of volunteers, many more thousands of trees and a team of dedicated staff. There are many facets to the Greening’s success, but we wanted to share our five key takeaways.

A strong municipal partnership

The Greening has developed a successful partnership with Detroit’s Forestry Department giving the organization the requisite permits and some financial assistance to fulfill their mission. When they were founded in 1989, the City of Detroit was losing hundreds of thousands of trees to Dutch elm disease, urban expansion and attrition. At the same time, budget cuts forced the city to allocate most of their urban forestry budget towards the removal of hazardous trees. With little money leftover for plantings, they turned to the support of local organizations.

What started as an informal agreement was formalized five years ago when the Greening secured a blanket permit to plant trees along the public right of way. Since then, they’ve been working closely with the City to identify and plant approved species in areas most affected by removal. By engaging volunteers, the Greening can avoid the high labor costs associated with planting and caring for trees to multiply the impact of their investment in urban forestry.

Attention to the details of the volunteer experience

From its inception, the Greening has been committed to providing folks from all walks of life a meaningful volunteer experience. Over the years, they’ve developed relationships with groups – from large corporations to Girl Scout troops – who all share a commitment to giving back to the community.  They take a systematic approach to communicating key information in advance and scheduling the volunteering event to maximize productivity so a lot of the work is done behind the scenes before the day even begins.

Source: The Greening of Detroit

Source: The Greening of Detroit

A commitment to stewardship

The organization is committed to the long-term health of the trees they plant. To reduce tree mortality, the Greening of Detroit cares for trees for the first three years following planting. During the summer, they employ high school students into their youth workforce development program, Green Corps, to water tens of thousand of trees, and maintain city parks and greenways. The 1,600 students that have been involved in the program since inception have also participated in workshops sponsored by the organization on topics like financial literacy, conflict resolution and resume writing.

Source: The Greening of Detroit.

Green Corps getting ready for a day tending to more than 12,000 trees planting by the organization. Source: The Greening of Detroit

Engagement at the local level

Through their Community Planting program, the Greening engages block clubs, schools, faith based and other non-profit organizations in planting events. OpenTreeMap makes it easy for the Greening to showcase the ecosystem benefits a community will garner after a planting event.  An interested group, in conjunction with Greening, works with other local organizations to garner support for plantings among residents. They solicit guidance from residents insofar as where to plant the trees and residents serve as volunteers for the event itself. Following the planting event, the community takes on the responsibility for watering, weeding and mulching the tree for at least three years.

A commitment to data collection

By collecting data on all aspects of their programming, the Greening can improve the volunteer experience and measure their impact. After an event, each volunteer completes a survey, which helps Greening understand which events had the highest satisfaction rates and why. With this information, they can estimate the number of volunteers needed based on trees being planted and better cater the event to the group of volunteers. Additionally, the Greening requires their growers tag trees with genus and species information, making it easier for volunteers to accurately map trees in the field using OpenTreeMap’s mobile application.

The Greening of Detroit has mapped over 15,000 trees on their OpenTreeMap.

The Greening of Detroit has mapped over 15,000 trees on their OpenTreeMap.

The Greening of Detroit didn’t always map their trees. For years, they used a database to track the addresses of plantings. A few years back, the Greening was looking for ways to better engage the community in their planting efforts and to educate citizens on the ecosystem benefits of trees. After researching different mapping solutions, they decided on OpenTreeMap. It was the only platform they found designed specifically for community engagement, and it’s intuitive user interface made training volunteers easy.  They geocoded their address-based inventory and used OpenTreeMap’s bulk uploader tool to add past tree plantings to their map. The Greening of Detroit has over 15,000 trees which equate to more than $85,000 in ecosystem benefits on their map.  

Think we missed a key component of a successful volunteer program? Interested in starting your own OpenTreeMap? We’d love to hear from you!

Uncovering the actionable insights in your tree inventory

We’re excited to see more organizations and municipalities across the country incorporate tree inventories into their urban forest strategic plans. To get the most out of the data you collect in the field, we recommend first identifying your inventory goals. Are you trying to calculate the impact of a program’s ecosystem benefits for grant reporting? Want to track maintenance activities and estimate maintenance costs? Looking to better understand your inventory’s biodiversity to protect against widespread pests and disease? All are important reasons to complete a tree inventory, and will determine what data you collect and in what format.

In many ways, once the tree inventory is completed the work to increase canopy coverage, perform routine maintenance, plant trees in empty planting sites and remove dead trees has just begun. We’ve outlined some easy search queries you can perform to identify the actionable insights hidden within your tree inventory data.

Dale Carlon inventorying trees in the field.

Dale Carlon inventorying trees in the field.

Take Dale Carlon, an OpenTreeMap client and consulting arborist in Reno, Nevada. Dale and his team at Dale Carlon Consulting, Inc. provide clients with comprehensive tree inventories that help them identify hazard trees, allocate resources, maintain key infrastructure and keep residents safe. Dale creates an OpenTreeMap for each homeowners association (HOA) he inventories so his clients can easily update information, budget resources and track maintenance activities.

A map of one of Dale Carlon’s inventories. The map allows property managers to easily identify trees of interest, estimate maintenance costs and plan maintenance activities.

With our new advanced search filter, Dale can search by any custom field he has created. In seconds, he can drill down to the 183 trees – of the nearly 7,000 trees at the HOA depicted above – that are dead or dying and require removal or the 208 trees that have between ¾ and 1 ½ inches in sidewalk damage. With this information, Dale can estimate the costs of required maintenance for his clients and the property manager can require all maintenance work to be logged in the field using OpenTreeMap’s mobile applications. This way, the HOA’s inventory stays up to date and maintenance is tracked and stored on the same place as all other tree information. Technicians see their location on the map, can easily identify the tree of interest and upload photos to create a pictorial timeline of maintenance completed.

Tree People LA uses custom fields to track and report on specific tree planting initiatives.

Tree People LA uses custom fields to track and report on specific tree planting initiatives.

Many of our nonprofit clients must report to funders on ecosystem services, trees planted and volunteer engagement. By creating a custom field for a specific planting program, a non-profit organization like TreePeople LA can quickly identify the 18 plants mapped so far as part of their City Plants program. These 18 trees alone bring over $700 in total annual benefits.

At OpenTreeMap, we will work with you to refine your data collection methodology so you can easily identify and analyze key information of interest. Planning an inventory this Spring? Let us know how we can help. Already have existing geo-coded inventory data? Send it over and we can upload it into OpenTreeMap and bring your tree inventory to life.

After Five Years We Completely Changed Our Pricing—Here’s Why.


Earlier this year, we launched a new “modular pricing” model—the change is significant for several reasons, and it’s worth explaining the observations that led us to totally revamp the way we sell OpenTreeMap. This new direction represents our strong commitment to making OpenTreeMap accessible and affordable for the folks who need it most.

Most Software as a Service (SaaS) companies like OpenTreeMap sell “plans” in monthly or yearly installments. At various points in our history we had between 3-5 plans—each successively more expensive plan came with more capacity for trees and more features. With our most popular plan, customers could upload up to 50,000 trees and could access premium features like our iOS and Android Mobile apps. For many companies, this pricing structure works. It is easy to understand and simple to implement. But at OpenTreeMap, we saw a fundamental problem: urban forestry initiatives can’t simply be boiled down to the number of trees in any given inventory. Every city, non-profit, university and consulting arborist has a different set of priorities and needs. Our pricing model could not accommodate the breadth of applications that our customers found for the software.

Screen Shot 2015-12-30 at 9.03.41 AMTake, for instance, The Greening of Detroit. With a dedicated corps of interns and volunteers, they inventoried nearly 15,000 trees using OpenTreeMap’s mobile apps over the last year alone. The Greening of Detroit continues to be one of the most active and fast-growing tree maps in the country. With our former pricing plan, they had to pay for thousands of additional trees that they had not even mapped. Now, they only pay for the number of trees they need. They’ve been able to reallocate money formerly spent on unused tree capacity to get our Customization module. This way they can customize stewardship activities, user roles, and the mobile app configuration. Now they pay less than they used to and are able to get features previously only available to people with hundreds of thousands of trees.

It’s our sincere hope that the new pricing model will make OpenTreeMap attainable for those groups that have never had access to premium software for collecting, managing, and showcasing urban forest data. It is these groups that benefit most from OpenTreeMap. Small cities with 10,000 street trees and a dedicated group of volunteers now don’t have to pay $40,000 for a basic inventory—they can engage volunteers willing to collect the data instead. And non-profits with hundreds or thousands of trees planted each year can easily report on those plantings to donors and conduct survivability studies with just a few summer interns.

Screen Shot 2015-12-30 at 9.07.48 AMWe’re proud to help clients like Augusta University, who can now afford to use OpenTreeMap to manage an inventory of several thousand trees without breaking their budget and Sustainable JC, who plotted their first several hundred trees in a single weekend. If you aren’t using software to better track and understand what’s happening to your trees, there has never been a better time to try OpenTreeMap. Get started with a 30 day free trial today: www.opentreemap.org/pricing/.

Recorded Webinar: NYC TreesCount! 2015

Coordinating a street tree census in the biggest city in the United States is exciting and challenging. Jacqueline Lu, the Director of Data Analytics at NYC Parks, discusses how NYC Parks developed and conducted TreesCount! 2015. Deborah Boyer from Azavea describes the software used to gather the data and how digital tools can assist with large-scale urban forestry data collection. We received a lot of great questions during the webinar and have compiled answers to some of the most common questions below. 

Is the TreesCount! 2015 software available for other municipalities?

TreesCount! is an open source project and the code is freely available at https://github.com/azavea/nyc-trees. Software development experience will be needed to set up the code, and the mapping process relies on the existence of a file of street block edges for your city or town. For groups without the technical capacity or budget to set up the code, OpenTreeMap may be another solution. OpenTreeMap is a cloud-based platform for helping groups map trees, track stewardship activities, and engage the community around caring for the urban forest. Although it does not include the event management features available in TreesCount!, it does support volunteer mapping as a citizen science initiative.

Why did NYC Parks conduct a volunteer-led tree inventory? Was TreesCount! more expensive than hiring an independent contractor?

NYC Parks’ goal was not simply to collect tree inventory data. From the project’s inception, they also focused on encouraging citizens to engage with the urban forest through the census. If the goal was to get data only, it likely would have been more cost effective to hire contractors to use satellite imagery to plot trees or complete an on-the-ground tree survey. NYC Parks’ focus on citizen engagement was central to the design and functioning of the software Azavea created for them.

Azavea team members volunteering with NYC TreesCount! 20145. Azavea team members volunteering with NYC TreesCount! 2015.

Are ecosystem benefits incorporated into the data?

The TreesCount! software does not calculate ecosystem benefits. After the 2005 census, NYC Parks’ ran the gathered inventory data through the U.S. Forest Service’s iTree Streets (formerly STRATUM) and they plan to complete a similar process with the 2015 data. The software platform for TreesCount! was focused on supporting Parks’ staff, individual volunteers, and partner organizations in their effort to inventory trees. The data was collected so that little manipulation is required for upload into iTree Streets and other analysis tools.

Were there areas that volunteers could not survey due to concerns about personal safety or data quality?

Before sending volunteers into the field, NYC Parks identified block edges where they thought there may be access issues or that would be challenging for volunteers to survey. Challenges included but were not limited to the location of the street, the direction of the street, and the existence of trees in a median. These areas were set aside for volunteers with advanced training or NYC Parks staff. There were also instances where expert surveyors visited a site and determined that the area was too dangerous to survey (example: trees located on a narrow median on a multi-lane street). The project excluded private streets, which fall outside the Parks’ jurisdiction.

How did NYC Parks encourage safety while mapping?

NYC Parks’ encouraged volunteers to map in pairs and groups, and all volunteers wore bright green vests designating them as a volunteer surveyor. Mapping events were often co-sponsored by partner organizations familiar with the area and were generally accessible via public transit.   

How did NYC Parks’ deal with naturally occurring or self-seeding trees?

TreesCount! 2015 was explicitly focused on mapping planted street trees located along street block edges. The surveying methodology worked well for single trees along streets and was not as well suited for gathering data on groups of trees that may appear due to natural regeneration.  

One of the thousands of blocks volunteers inventoried during TreesCount! 2015.

One of the thousands of blocks volunteers inventoried during TreesCount! 2015.

What does the NYC Parks define as a sign of stewardship?

A sign of stewardship is defined as evidence that a tree received tending or maintenance by someone. This can include tree guards, signs of proper pruning, flowers planted in the tree bed, and mulching. These categories of stewardship were taken from a study NYC Parks completed in 2006 on the effect of stewardship on tree growth and mortality. The study concluded that visible more signs of stewardship for a tree often resulted in greater longevity for that tree, especially when the tree was younger or newly planted.

How were volunteers trained?

Before mapping, all volunteers completed an online training and then received field training from NYC Parks staff or a partner organization. Training materials can be viewed online at https://treescount.nycgovparks.org/static/training/TreesCount2015Training.pdf

Urban Forestry Around the World: Urban Tree Management in Epirus, Greece

Recently, the OpenTreeMap team has had the privilege to talk with Mihalis Papakonstantinou and Dr. Grigorios Varras from Urban Tree Management (UTM), an urban forestry project in Greece. Urban Tree Management uses some of OpenTreeMap’s open source code in their project to map urban trees in the region of Epirus. So far, over 8,000 trees have been documented in four cities! Knowing that urban forestry projects face many of the same challenges, I asked Urban Tree Management to share some insight into their success and tell us about their plans for the future.

Karissa: Tell me about how you became part of the Urban Tree Management team.

UTM: Dr. Grigorios Varras (Associate  Professor, Technological Educational Institution of Epirus, Dept. of  Agricultural Technology, Unit Floriculture & Landscape Architecture), who is the academic responsible of Urban Tree Management, is the one that had the idea in the first place. He has been exploring new techniques for urban forestry and its influence on the local environment and as a result came up with the idea of Urban Tree Management.

Karissa:  And why did Urban Tree Management get started?

UTM: This program was based on the idea that green spaces are essential to the urban ecosystem, because trees, parks, urban and peri-urban woods can mitigate temperature, decrease pollution, water run-off and soil erosion, increase aesthetics and quality of places, provide a place for recreation, education and learning. Trees can also contribute by direct and indirect ways to reduce CO2 in the atmosphere and contrast ‘urban heat island’. In order to improve urban landscape using urban forestry, show to the people living in an urban environment its importance, and applying research work in the field, the Urban Tree Management proposal was formed.

Karissa:  What is the urban forestry community like in Greece? How is public awareness of urban forestry issues?

UTM: Urban forestry is practiced usually from foresters-environmentalists, agriculturists, engineers, etc working either in public services such as Green Bureau in Prefecture, in Community etc or in private Bureaus, such as private Consulting Bureaus, landscape architects, environmental research groups, etc. There is also an increasing number of individuals, in the areas of biology, meteorology, and geology over the last years, that tend to practice urban forestry techniques. Also a large part of the Greek urban forestry community consists of Universities, and researchers, like the Urban Tree Management team.

There is a continuously increasing environmental awareness, yet still low, of urban forestry issues either from the local and regional government or from central governance in combination to European Union directives and standards about the well-being of the citizens and the protection of the environment. Generally Greek people and authorities are starting to realize the importance of urban green infrastructures but financing for projects and research on this issue is low.

Karissa:  What challenges did you face when starting Urban Tree Management?

UTM: Challenges faced were:

  • The people’s awareness that was not that high
  • Technical problems to be resolved such as the deficit in rural internet in the research sites
  • Field-data acquisition
  • Compatibility and combination of various technologies that were used as part of the project

Karissa:  What aspects of the project are going well for you, and why do you think this is?

UTM: The project consists of 2 main parts, one of them is the documentation of trees for each of the 4 big cities of Epirus: Arta, Igoumenitsa, Ioannina and Preveza. Besides the geospatial characteristics of each tree, there is a number of data that is stored in our inventory, including height, diameter, stability, etc
The second part of our project is the 12 interactive microclimate maps, for each city that quantify the impact of green areas on the city microclimate. These maps show the values of 6 environmental indicators throughout each of these cities.
We believe that the above data that is stored and shown to the public are the main reason behind its success. Our web based system has shown the public the huge impact of urban forestry and as a result increased awareness and interest of citizens in the importance of green infrastructure in an urban environment.

Karissa:  Are you facing any new challenges now?

UTM: The web-based platform can be used from policy-makers aiming to decide on the proper measures for the management of urban green infrastructure in the interests of public health, quality of life and well-being of the population, so what need to be done is that we need to expand our audience and target-group and to apply our platform to other cities aiming to optimum management of their urban green zones.
Also another challenge that we are facing, has to do with public awareness, which we are trying to increase, in every way we can through our web platform (leave your message initiative, qr codes to be deployed throughout the city).

Karissa:  What are your goals for the future?

UTM: We would like to announce our product to various cities/regions and to teach them how to prepare a tree-registry aiming to incorporate it in our software and finally acquire their own urban tree management system.
We are also on the way of announcing our offline tree inventory app, through which documenting trees will be made much easier.

Karissa: What are your recommendations for someone interested in starting a similar project?

UTM: It is important to set up a team of experts in various disciplines to obtain a total knowledge of the issue, such as environmentalists, foresters, engineers, IT experts, biologists, meteorologists, etc. because the urban tree management issue is a multi-disciplinary topic and it requires a lot of specialized knowledge and expertise.

You can contact Mihalis and Dr. Varras via email at mihalispapak@hotmail.com and grvarras@gmail.com to learn more about the Urban Tree Management project.

If you or someone you know would like to be featured in an OpenTreeMap blog, please contact us at opentreemap@azavea.com.

OpenTreeMap TreeTrip: Finding the Arborist for You

Mike Dunn looks for potential problems while inventorying trees.

You probably know that arborists take care of trees- but do you know when you should call an arborist, or how to find a good one? The OpenTreeMap team was recently able to go “behind the scenes” with one of our clients, Mike Dunn, President of Preservation Tree, to uncover what you need to know about working with an arborist.

It may come as a surprise, but being a tree is tough! Most tree species have lifespans of 100 years or more, and some can live over 3,000 years. We often think of trees as signs of strength and stability that can span many generations. However, in urban areas, over half of all trees die within 20 years of being planted, and an “ideal” lifespan for a city tree is considered 60 years. Trees are sensitive to many environmental factors, but the good news is that they are also resilient. With proper care, your trees can live a long and healthy life!

One of the best times to contact an arborist is before you even have a tree. An arborist can listen to your needs and help you identify the best possible species. An arborist will think about how the tree will look in 30 years, what kind of pests and diseases are common in your region, what kind of weather the tree is likely to face, what risks the tree could cause, and how well the tree will fare in its new planting site. Many tree care issues can be avoided from the start if you choose your tree thoughtfully. Mike’s inside tip about choosing the right tree is to be cautious of native species. While native species seem like an easy, low maintenance choice, climate change and human environmental impact mean that these species may struggle to thrive in areas they were once common.

Once your tree is planted, it’s a good idea to have an arborist visit every 1-2 years for a check-up. During the check-up, your tree should be fertilized and pruned. Pruning creates open wounds on a tree, and can be very stressful. Regular pruning prevents your tree from growing out of control and needing the equivalent of major surgery. Your arborist will also check your tree for signs of pests or diseases. A tree may appear healthy for many years on the outside while slowly rotting away on the inside and posing a great safety hazard. Catching problems early can prevent you from having to remove the tree. Mike’s inside tip about pruning is that a good arborist will try to prune your tree so that you can’t even tell! Just because your tree retains its natural shape doesn’t mean your arborist didn’t do a lot of work.

If you’re committed to caring for your tree, you may now be wondering how to find an arborist to work with. “Anyone with a truck and a chainsaw can start a tree care business,” says Mike. When looking for tree care companies, these four questions can help you narrow down your search:

  • Will a certified arborist physically come to my property? 50% of Mike’s staff are certified arborists, and Mike sends out at least one certified arborist with every crew. However, some tree care companies have only one or two arborists on staff who do not participate in most field work. A good crew may be able to provide excellent routine care but may miss warning signs of disease or pests.
  • Can I see your Workers Compensation Certification and can you tell me about the safety training your workers have? Arborists often work in dangerous conditions with dangerous equipment; workers compensation is costly, but a legal requirement. Any reputable company should be willing to share a copy with you. Mike requires every employee at his company to take first aid and other safety courses on an annual basis, as well as encouraging employees to become Certified Treecare Safety Professionals. Frequent safety training is a good sign that a company won’t cut corners.
  • What certifications and accreditations does your company have? You should expect a reputable company to be accredited by the Tree Care Industry Association (TCIA) and have arborists certified by the International Society of Arboriculture (ISA). Both organizations require members to take continuing education to renew their credentials, so you can be sure to be receiving the best care based off the latest science.
  • Do you have references? A good tree care company takes good care of trees and good care of their customers. Not only should the crew that comes to your property be courteous and professional, but they should be happy to answer your questions and educate you on proper care of your tree.

We had a great day with Mike in the field, and look forward to learning more from him and other arborists in the future. As the OpenTreeMap team grows, we’re working alongside experts to gain a better understanding on their needs and make the best software possible! We’re excited to share what we’re learning with the community, so if you have questions or suggestions, be sure to let us know!

Michael Dunn is the Founder and President of Preservation Tree. Mike is an ISA certified arborist with over 14 years of experience in the Forestry industry, including as a climbing arborist and wildland firefighter for the U.S. Forest Service.

Introducing Joe Morrison: OpenTreeMap’s New Product Specialist

Joe recently joined the OpenTreeMap team in a business development and marketing role. He is a Venture for America fellow, a former small business owner, and an aspiring tree fanatic. Below, he reflects on his first few weeks as a newly minted OpenTreeMapper.

First, a small confession: before joining OpenTreeMap, I never thought of myself as a “tree person.” It’s not that I didn’t care for trees, but they were always just background to me—the nostalgic white noise at the edges of a childhood spent running around the woods. Creaking pines and fragrant Redcedars surrounded my childhood home for miles in all directions, but I can’t say I took time to ponder them. Consequently, I have been frantically trying to acquaint myself with the “arboreal arts”[1] since joining OpenTreeMap. I recently took the first step toward becoming a bona fide “tree person” by signing up for a volunteer training program at the Philadelphia Horticultural Society (PHS). I entered the program as a total novice and emerged a certified “Tree Tender” (a credential that I’m proud to say comes with an official card). And while I’m still unsure of basic topiary topics like the difference between shaggy and exfoliating bark, I think it’s worth reflecting on the experience and the lessons I learned (many of which extend beyond trees).

Fifty total strangers sat at regular intervals around the room, meekly nibbling at their pizza and trying to make small talk. “Let’s each introduce ourselves and say what neighborhood we live in,” suggested Mindy Maslin, Project Manager of the Philadelphia Horticultural Society’s “Tree Tenders” Program. “We’ll start at the front.”

One by one, the strangers obliged—“South Kensington,” “Francisville,” “East Passyunk.” “Cedar Park,” “Society Hill.” Listening to people rattle off neighborhoods was shocking; as I mentally shaded in a map of Philadelphia, I remember pondering the statistical absurdity that so many disparate areas of the city were represented in the room. The din of conversation subsided as each successive volunteer proclaimed their neighborhood with escalating pride. By the time it was my turn to introduce myself, I half-expected trumpets to sound before I bawled, “Old City!”

And with that, we were off. In a whirlwind first day we covered the benefits of trees, their biology, and how to spot signs of stress; we even had local arborists take us outside and apply the concepts we had just learned to the street trees along the side of the building. In that way, the program is simple but effective: over the course of a few weeks, volunteers receive training on an ambitious range of topics and meet experts in many tree-related fields, from agricultural extension to forest pathology. A certified Tree Tender should be able to spot a buried root flare from a block away, prune a stem showing signs of dieback to the closest lateral branch, and enumerate the many benefits of Philadelphia’s urban forest…simultaneously. If you’re reading this and wondering what highfalutin terms like “root flare” and “dieback” mean, then you’re probably a perfect candidate for the program.

Topics vary, as do guest speakers, but the principle is always the same: community forestry begins with community, not forestry. The volunteers who come to be trained at Tree Tenders events often share little in common; they are ministers, landscapers, high school students, young professionals, and retirees. But for such a diverse group, there is one thing that garners absolute consensus: Tree Tender class is a good time. During the nine hours of training I spent learning to plant and care for trees, I think I spent eight of them smiling from ear to ear. Mindy and the team at the Philadelphia Horticultural Society (PHS) are candid, hilarious, and flat-out happy to be there. That kind of positivity is infectious. And truthfully, it’s hard not to have fun when you’re swinging a pickaxe (conspicuously balanced on end in the accompanying picture).

If I had to pick the greatest lesson I have learned as a fledgling Tree Tender, I’d say this: tree people are good people. They’re behind the camera when the tree gets ceremoniously planted, and the only ones who return to (unceremoniously) water it each week. They are patient, humble, and concerned about the future. I’m excited to work on a project like OpenTreeMap that supports groups like PHS across the country in their efforts to improve the quality of life in their cities and neighborhoods. Because when it comes to community forestry, it’s about the people as much as the trees.

[1] Trademark pending

Putting your tree data to work: Key insights from Edmonton

A view of Edmonton's urban forest.

A view of Edmonton’s urban forest. [1]

Urban forests are a critical part of municipal infrastructure. While it’s relatively straightforward to explain why trees are valuable, it’s more difficult to figure out how to manage them in order to maximize benefits and meet strategic goals. Data analysis methods can critically inform tree inventory management decisions and help you answer key questions.

Where should you plant trees to optimize reduction in stormwater runoff?

Which neighborhoods meet your biodiversity goals and which do not?

Which neighborhoods should you prioritize for future plantings?

Edmonton’s trees provide more than $30M in annual benefits. Ecosystem benefits for each tree entered into yegTreeMap, a map maintained by the City of Edmonton in Alberta, Canada, get calculated using regional and species-specific standards set by the USDA Forest Service (iTree). Calculating ecosystem benefits can help justify funding for maintenance and investment in urban trees. However, there are not many tools to model the impact of management decisions in scientific terms or figure out what actions to prioritize.

Edmonton's OpenTreeMap

The City of Edmonton’s tree OpenTreeMap contains over 260,000 trees and planting sites.

In this post, we’ll look at observations that can be deduced from data on tree location, diameter and species, and more specifically how trees are distributed across the city. For our analysis, we used tree data from yegTreeMap, which contains information on over 260,000 trees across 375 neighborhoods, and Edmonton’s Open Data Portal, a free repository of over 500 city-level data sets. In some cases, analysis of urban forestry data can provide opportunities to explore topics like political advocacy and environmental justice in quantifiable terms.

How are trees distributed throughout the City of Edmonton?

One way to answer this question is to break down Edmonton into its constituent neighborhoods and sort them, first by total number of trees and then by density to control for geographic area.[2] As expected, neighborhoods with large public parks dominate the lists for raw number of trees and tree density per square mile. Industrial parks fall out toward the bottom of the list.

Figure 1: Trees with the widest diameter by neighborhood in Edmonton.

Figure 1: Trees with the widest diameter by neighborhood in Edmonton.

In addition to measuring tree density, simple queries of tree inventory data can also reveal more sophisticated insights. We used a similar sorting technique to identify the largest tree of each species in each neighborhood, and plotted the results in an interactive map here (Figure 1). This visualization can indirectly illustrate biodiversity (or lack thereof) by comparing it with the tree density ranking we created earlier. If you have two or more neighborhoods with a similar density, they should theoretically look similar on the map in Figure 1 if biodiversity is uniform across the neighborhoods. But, if one of those neighborhoods only has a few species – even if they have many trees – the map will look comparatively sparse.

For example, the neighborhoods of Ottewell and Clareview Town Centre have almost identical tree densities with 225 and 225 per square kilometer, respectively. Ottewell’s map is speckled with dozens of dots, each representing a unique species. In contrast, Clareview Town Centre shows just nine distinct species (equating to roughly 28% of Ottewell’s biodiversity).

Figure 2: A comparison of species diversity across neighborhoods in Edmonton.

Figure 2: A comparison of species diversity across neighborhoods in Edmonton.

How do you explain the discrepancy? Hundreds of American Elm trees were planted in Clareview, almost to the exclusion of other species creating a concentrated monoculture. This limited biodiversity puts Clareview at a greater risk of losing trees to pests and diseases like Dutch Elm disease. Identifying neighborhoods with lower biodiversity and prioritizing plantings in those areas can avert disaster decades later when a disease or invasive pest attacks one species aggressively.

What variables are related to the distribution of trees throughout Edmonton?

When using analytical methods to better understand tree composition and distribution, the natural impulse is to look for complementary data sets. Establishing a casual connection between tree counts and economic or social variables is nearly impossible. However, correlational data can help explain some of the variation in tree count in geographically similar neighborhoods. In Edmonton, we looked at neighborhood-level statistics for variables ranging from employment to real estate to school enrollment to identify those bore the closest relationship to the number of trees in each neighborhood.

The first level of analysis looks at which variables correlate strongly with higher tree count (i.e. positively correlation) and which correlate with lower tree count (i.e. negatively correlation). Distinctly positive variables included the number of duplex homes, single detached homes and employed people in a given neighborhood, while distinctly negative variables included the number of row homes and whether or not the neighborhood was designated a manufacturing zone.

Those relationships are relatively intuitive, but a second level of analysis, looking at the statistical significance of those relationships, provides more insight. For instance, the number of homemakers in a neighborhood is only 50% significant for predicting the number of trees—a neighborhood with a high number of homemakers is just as likely to have a low number of trees as a high number of trees. Similarly, knowing the number of retirees and unemployed residents is not useful for predicting the amount of trees in a given neighborhood.

Most variables are poor indicators on their own, but we can combine them to get more descriptive models. In Edmonton’s case 40% of the variance in tree count across neighborhoods can be explained by just two variables: the number of employed people under the age of 30 and the number of row homes. The former is positively correlated with tree count, while the latter is negatively correlated.

Looking at more variables provides diminishing returns—our models that used three variables could account for 45% of the variation, four variables for 47%, five variables for 48%, and so on. The complex systems interacting with a large urban forest like Edmonton’s can’t be satisfactorily explained by the relationship among a few variables.

Regression analysis can identify auxiliary data sets that are most closely related to the overall health of the urban forest. In Edmonton’s case, employment numbers and real estate characteristics were inextricably tied to the number of trees in each neighborhood while school enrollment data and residents not in the labor force (homemakers, retirees, etc.) bore little in common with tree count.


Simply knowing the location and species of trees within an inventory can yield worthwhile insights into the strengths and weaknesses of your urban forest. Understanding more about the composition and distribution of trees can inform resource allocation, project prioritization and risk assessments. By combining tree inventory data with other open data sets, analysis can yield richer insights into the impact an urban forest has on its community.

For additional detail on performing your own tree inventory analysis see Loading Spatial Data into PostGIS with QGIS and Analyzing OpenTreeMap Data with PostGIS.

[1] Image Source: http://bit.ly/29tUXET
[2] Edmonton’s neighborhoods are actually standardized geographical territories recognized by the city and are used as census tracts.

Why Are Trees Important?

A few days ago, my colleague Karissa Justice wrote about the urban heat island effect. In her article, she reminds us that “shade can cut surface temperatures by 20-45°F. Strategic planting around buildings to shade windows and roofs can make a big difference in temperatures and energy consumption.” Have you ever had a hard time explaining the importance of urban trees and the importance of your organization’s mission? Take a look at this video and feel free share it broadly. As part of a larger community of tree lovers, we’d love to see the public help you map every single tree in your community; not just street trees but those on private land too. One tree at a time, we can all make our urban forests stronger!


The Tree Inventory of the Future an Interview with an OpenTreeMap Project Lead


“OpenTreeMaps are collaborative, crowd-sourced projects where citizens help inventory urban trees, learn about the environmental benefits trees provide and explore nature in their city. Kelaine Ravdin, owner of Urban Ecos, has worked as the project lead on OpenTreeMap projects across California, including Sacramento, San Francisco, San Diego, and Los Angeles. Kelaine’s work blends a deep understanding of urban forestry with current mapping and data tools.  [Leda Marritz] of Deeproot, a company that builds high-quality tree care and stormwater management tools, spoke to Kelaine about her experience using open data, working with cities, and what tree inventories of the future might look like.”

Read the interview and more about how OpenTreeMap is used in California.

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