By David Pearce, Sarah Girard, Jason Henry and Rhoda deJonge
Vineland Research and Innovation Centre
Young tree survivorship in an urban landscape can be a struggle. We’ve all seen it at some point — a row of beautiful (and expensive) trees planted one spring, yet many become dead, dried out sticks a few seasons later. These trees are faced with many challenges, ranging from drought, flooding, unmet maintenance needs, improper planting practices and poor soil quality. There are often also difficulties with matching the correct species to the ideal planting location. A tree that survives best in sandy soil does not have much chance for success in a water-logged clay
planting pit. Thanks to Vineland Research and Innovation Centre’s updated Tree Selection Tool, this last hurdle for tree survivorship — matching of the correct species to a particular site — is now much easier to overcome.
The power of a tree species selection tool
The development of a comprehensive tree species selection tool is advantageous for both seasoned landscapers as well as recreational gardeners. Vineland’s Tree Species Selection Tool streamlines the complex process of species selection while empowering users to make informed decisions to enhance the health and sustainability of their plantings.
With financial support from Tree Fund Canada – Research and Education Endowment and Landscape Ontario, Vineland is proud to launch our Tree Species Selection Tool. This tool builds on over a decade of urban tree and soil research conducted at Vineland and was informed by the advice of many experts in our community, including many volunteers within the Landscape Ontario community.
Key considerations for species selection
When developing our planting lists in the urban environment, we often have to balance competing goals of selecting trees we know will do well in nearly any site, versus the goals for increasing the diversity of our plantings. With the Tree Species Selection Tool. in place, we aim to achieve a greater diversity of plantings, while simultaneously increasing survivorship by matching the correct species to their unique urban environments.
The significance of biodiversity in arboriculture: In the arboriculture community, we have one of the clearest understandings of the importance of avoiding single-species plantings or monocultures. Many of us have spent (and continue to spend) significant time removing the once-dominant green ash (Fraxinus pennsylvanica) and prior to this, the American elm (Ulmus americana). The overplanting of both species led to their eventual fall with emerging pests and diseases.
To prevent a similar fate in the future, our first action is to promote ecosystem resilience through species diversification. Diverse tree planting in turn supports a wider range of wildlife and contributes to healthier environments. We can all plant streets of gingko, honey locust and ivory silk lilac and be pleased with the results of healthy thriving trees, but we’d be putting our canopies at great risk — exactly what occurred with the overplanting of ash and elm. Since different tree species have varying tolerances to temperature and moisture changes, biodiverse plantings can better withstand the impacts of climate change and extreme weather events. A tree selector tool helps us identify species we would have otherwise overlooked or not known about and using them in plantings can now help increase the biodiversity of our plantings.
The impact of planting location: The spatial context of a planting site significantly influences species selection. For example, in residential areas, trees are frequently chosen for their aesthetic appeal and shading capacity. However, how rare it is that those planting the tree can confirm the planting site has the correct amount of soil volume for a tree 30-40 years from now? Will its root systems squeezed into a tiny patch of lawn invariably cause damage to sidewalks or foundations leading to an early tree death by chainsaw? Highway plantings, while providing ample soil volume, present other challenges. Often, these sites necessitate trees that can withstand road salt, compacted soil and salt spray, while also exhibiting resilience to wind. Urban environments present unique challenges, such as high salinity, soil compaction and limited space, but the size of each of these varied challenges can be site-specific, making it essential that we choose species most appropriate for these multiple niche environments.
A user-friendly interface for species selection
The goal of Vineland’s Tree Species Selection Tool is to host a user-friendly interface that provides immediate recommendations for tree species to plant, based on local ecosystem parameters. Users can easily input specific factors such as soil type, moisture levels and climate conditions to receive a list of tree species that are not only likely to successfully establish, but also thrive at that specific site. This list can be input to your planting plan and shared with a nursery or supplier.
Vineland’s Tree Species Selection Tool considers factors such as: sunlight exposure, drainage requirements and hardiness zones. This powerful tool can therefore suggest species that are aesthetically pleasing for residential spaces or even suited to withstand the stresses of highway and urban plantings.
Often, we don’t always know all key parameters of a site. The beauty of this tool is that while adding more information builds you a list with great specificity for your site, you are not required to add all parameters into the tool. You can still create a curated list of trees — even if you are unsure of all the factors at the site that would impact its survival.
Parameters you can input into the tool include:
1. Planting site (residential area, median or boulevard, highway, and so on)
2. Hardiness zone
3. Soil quantity
4. Sunlight availability
5. Canopy requirements (that is, how wide can it be)
6. Drainage
7. Salt tolerance
8. Growth rate
9. Native species option
10. Deciduous or evergreen
11. Watering frequency
12. Soil quality
Vineland’s Tree Selector Tool also includes the option of selecting only trees that are part of a curated list from industry experts at Landscape Ontario that was developed after years of observation in diverse landscapes.
A new tree species selector for eastern Canada
This tool may not be the fanciest interface you’ve ever dealt with on the jobsite, but the goal is to make it functional and as user-friendly as possible.
As we navigate the complexities of planting in various contexts from residential to urban landscapes, it is essential to balance factors for improving establishment while ramping up the diversity of our plantings. We hope this tool can be used by many throughout the industry to address these challenges and allow us to see urban environments with diverse plantings of thriving trees.
