Displaying all posts in the Things You Can Do category.

Transplanting Large Caliper Trees in Goderich, Ontario

The original article was written by Michael Ormston-Holloway BSc, MScP, GDHort, MLA, ASLA, CNLA, ISA Certified Arborist of The Planning Partnership (TPP) for Cabbagetown ReLeafMichael is a Partner at The Planning Partnership (TPP) and works in both landscape and urban ecology. In addition to his work at TPP, he lectures at the University of Toronto in the Daniel’s Faculty of Architecture, Landscape and Design, the University of Waterloo in the School of Planning division of the Faculty of Environment, the University of Guelph, and OCAD University.

Mature trees provide ecosystem benefits that help reduce pollution, lower energy costs, increase property values and reduce stormwater runoff. Moving large trees can be a good strategy for building momentum around an urban forestry project and for preserving large trees that would otherwise be removed due to development. Unlike mature trees, young specimens take years to reach a size that would provide equivalent ecosystem benefits to those of a large canopy tree.

Moving a large beech tree (1850)

Moving a large beech tree (1850)

People have been moving large trees since the 1850s, if not earlier, in fact, there is evidence of the ancient Egyptians transplanting large trees almost 4000 years ago. More likely than not, the Egyptians discovered that to transplant a tree, the size of a tree’s root ball must correspond to the caliper of the tree. Larger trees require a larger root ball in order to transplant. With that said, the physiological changes that affect a tree during transplant are similar regardless of the size or age of the tree.

Moving a tree (1930)

Moving a tree (1930)

A tree that has been planted for three or more years has roots that extend well beyond the drip line of the tree. Generally, 60 to 75 percent of an established tree’s root biomass is outside the drip line, meaning that a fully grown tree has roots branching out in diameter equal to two to three times its height.

During transplant, roots are often purposely trimmed back to lateral roots.  In response to this pruning, the tree produces more roots and root hairs, increasing the total size of the root ball. Thus, the process of root pruning helps increase the integrity and volume of the root ball, and helps the tree better acclimate to new surroundings, however, root pruning is more widely used on smaller trees. Since roots provide water, minerals and physical support for a tree, problems can arise when the root system of a tree, particularly a large tree, is improperly cut during prior to transplant.

AmericanHort (formerly the American Nursery and Landscape Association) set standards for root ball moving. In general, needled evergreens require a minimum of eight inches of root ball for each inch of trunk caliper and deciduous trees require nine inches of root ball per inch of caliper. After determining the root ball diameter, digging, balling and burlapping by hand help ensure the root ball remains intact.

Hand burlapping and balling large trees in preparation for tranplant in Goderich, Ontario.

Hand burlapping and balling large trees in preparation for transplant in Goderich, Ontario.

The Planning Partnership (TPP) is a leading expert in large-tree transplanting methods and has worked with various tree contractors throughout Southern Ontario to move trees 60 ft in height and greater. They worked with the Town of Goderich to redesign and replant their town square park following the F3 (on the Fugita scale) tornado that hit in August, 2011. Goderich, located on the eastern shore of Lake Huron, is home to fewer than 10,000 residents. The 2011 tornado was the strongest tornado Ontario had seen in more than 15 years with wind speeds at 280 kmh (174 mph). While the tornado only lasted 12 seconds, buildings were leveled and trees uprooted or split, leaving the town with $130 million in damages. It’s estimated the town lost more than 90 percent of it’s total tree canopy.

Transplanting a large Metasequoia in Goderich.

Transplanting a large Metasequoia in Goderich.

Following the tornado, the town worked with TPP to develop a master plan to combat lost tree canopy on public land. As part of their redesign of the central square, TPP transplanted more than 150 (44 small, 93 medium and 20 large) mature trees from around the region. The transformation of the town center following the tornado included the planting of 60′ tall trees with 30′ canopies. In addition to donations from the community, the trees came with an unusually long warranty, which was critical to the Town’s ability to afford mature trees. The successful transplant of the trees was just the first step to ensuring they thrived in their new home. The Town was committed to helping the trees adapt to the new environment through consistent fertilizing and soil treatment.

Did you recently transplant a tree in your town or city? We’d love to hear about it. Send us your story at opentreemap@azavea.com.

Additional resources on transplanting trees:

American Standard for Nursery Stock

Colorado Master Gardener Notes on Tree Planting

Clemson Cooperative Extension: Transplanting Established Trees & Shrubs

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.

Recorded Webinar: Tracking Your Green Infrastructure

This week we hosted a webinar with TreeKIT on tracking and measuring the impact of green infrastructure with OpenTreeMap. As climates change and more regions face severe heat and drought, tracking green infrastructure is a necessary first step to measuring its impact and identifying the best locations for additional green infrastructure resources. With OpenTreeMap, you can increase public awareness of the value of green infrastructure and promote community stewardship. For users that provide local data and calculations, OpenTreeMap can also measure the money and water your green infrastructure saves each year.

As part of this webinar, we explored how:

  • OpenTreeMap can be used to gather and maintain data related to rain barrels, bioswales and other features
  • To increase public education of the benefits of green infrastructure
  • To promote installation and stewardship of green infrastructure

Click here for more information on the Green Infrastructure module and sign-up for your 30-day free trial today. You’ll find the full webinar recording below. We’ve also made the slides available on Slideshare. You can reach us at opentreemap@azavea.com with any questions. We hope you’ll join us for future webinars.


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.

Trees, You, and the Urban Heat Island Effect

It’s Memorial Day weekend, and across the country people are headed outside with shorts, sunscreen, towels, and coolers to mark the start of summer. As temperatures rise, you may be taking steps to keep cool like cranking your AC unit or bringing out a box fan. The summer heat can be brutal no matter where you are, but if you live or work in a large city, you may be facing higher temperatures due to a phenomenon called “the urban heat island effect”.

What is the urban heat island effect?

In cities with populations of 1 million or more, the annual mean air temperature can be 1.8-5.4 °F higher than the surrounding countryside. At night, temperature difference between urban and rural areas can be as much as 22°F apart. Man-made materials such as concrete and metal hold heat and and repel moisture. In the summertime, conventional rooftops may be up to 90*F hotter than the air temperature, and pavements may reach 120-150°F. When many buildings are placed together, an urban heat island is formed.

Heat islands are not only uncomfortable, they are harmful to people and the planet! Energy usage goes up as we try to stay cool. This energy is usually produced from fossil fuels that increase pollution and greenhouse gases. Higher temperatures increase reactions with chemicals found in industrial emissions, car exhaust, and other solvents to create ground-level ozone, which exasperates health problems like asthma.

How can cities combat the urban heat island effect?

There is no single solution to the urban heat island effect. Sustainable energy sources, better building materials, and green design can all help—but in our biased opinion, trees are one of the best answers.

If you’ve ever searched a parking lot for a spot under a tree, you know that shade can make a drastic difference in the heat. In fact, 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. Of course, there are many other benefits trees provide as well, such as raising property values and improving air quality. Planting trees is one of the best ways individuals and communities can address the problem.

Before heading out to buy a tree, however, we advocate contacting a local organization that can help you choose the correct tree and correct planting site. Many trees are placed too close to buildings for their adult size and have to be removed. Other times, trees are ill-suited to the soil and environment and fail to thrive. Your local forestry community can provide you with the resources to make the best choices, and they may even provide or plant your tree for free!

Stay cool this summer.


Recorded Webinar: Growing Your Urban Forest – Using the OpenTreeMap Bulk Uploader

On Thursday, April 16, we hosted “Growing Your Urban Forest – Using the OpenTreeMap Bulk Uploader,” a webinar on using the bulk uploader tools to import existing tree inventories and customize the species list on your tree map.

Every OpenTreeMap subscription includes access to the tree inventory and species import functionality at no additional charge. By uploading existing tree inventories and a custom species list, your tree map can become the place for users to update previous tree records, view inventories from a variety of organizations, search for trees using a species list that aligns more specifically with the trees in your region, and more.

As part of the webinar, we explored how:

  • Map owners can upload existing tree inventories and species lists
  • Uploads can be customized to meet the needs of your organization
  • Importing inventories can assist with collaboration between groups and encourage additional data collection

A recording of the webinar is available below and on YouTube. We’ve also made the slides available on Slideshare. If you have any questions, please contact us at opentreemap@azavea.com. We hope you can join us for a future webinar!


3 “Grown-Up” Ways to Celebrate Arbor Day


Arbor Day has a long tradition of children’s activities and celebrations, ever since President Roosevelt issued the “Arbor Day Proclamation to the School Children of the United States” in 1907. Tree planting ceremonies are taking place across the country in schools and parks. But if you’re stuck in an office and feeling a little left out this Arbor Day, the OpenTreeMap team has 3 “Grown-Up” ways for you to celebrate. Trees are for everyone!

1. Reduce Your Paper Trail

How much junk mail did you throw away last week? The average American household receives over 800 pieces of junk mail each year. Junk mail not only wastes your time and clutters your coffee table (admit it), but it also accounts for millions of tons of landfill waste. The good news is: you can significantly cut the amount of junk mail you receive, for free!

The Fair Credit Reporting Act gives you the right to opt-out of having your credit information shared for the purpose of pre-screened credit and insurance offers. You can opt-out online here.  You can opt-out of many other unsolicited mailings through the Direct Marketing Association’s Mail Preference Service.

2. Adopt a Bonsai Tree

If you don’t have the space to plant a tree, consider purchasing a Bonsai tree for your home or office space. Bonsai trees are miniature trees grown in a container. The Japanese tradition dates back over 1000 years and emphasizes creativity and patience. Bonsai trees can be a low maintenance decoration or a complex and time consuming hobby. Either way, indoor plants have been shown to increase productivity and reduce stress. They also improve air quality and reduce noise, just like their outdoor counterparts. You don’t need a full-sized tree to reap the benefits!

3. Make a Local Donation

While there are a plethora of national organizations dedicated to the planting and preservation of trees, there are even more working in local communities to care for the trees and land you see every day. This Arbor Day, take the time to learn about the neighborhood associations, non-profits, government departments, and other groups local to you that promote tree stewardship. You may be surprised to find that one or more of your local organizations offers free trees for your property.

Of course, no matter what day it is, trees are worth celebrating! Consider giving back by making a monetary donation, attending an event, or volunteering with an organization in your community.

Happy Arbor Day from the OpenTreeMap team!

Love and Share Your Trees With Social Media Friends and Followers

Want to tweet about stewardship activities or pruning you just did on the large maple tree outside your office or post a photo on Facebook of the gorgeous oak tree in your backyard, and share the love you have for the trees you care for with your friends and followers on social media?  Now you can!  We are pleased to announce that you can now use Twitter and Facebook to post all your favorite trees to your heart’s delight.  Below is a GIF showing how to use the social media features in OpenTreeMap.

Enjoy and spread the word about your urban forest and all you do to care for it through your favorite social media networks!

Social Media


Create a “Favorites” List of Trees

In addition to being able to tweet, use Facebook and Google+ to promote your community engagement and urban forestry programs, you can now create a “Favorites” list of trees.  You can “favorite” a tree on your own tree map or on any public map.  As you mark trees as favorites– by clicking on the star next to the name of a tree on its “Tree Information” page– they are placed in your “Favorites” list.

This will make it easy to quickly navigate to your favorite trees and add stewardship activities or to respond to comments from other people in your community.  You can see the GIF below on how to “favorite” a tree and find your “Favorites” list in your account.

favorite a tree

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