Tree Glossary Banner

Tree Glossary

With a database including over 200 small, medium and large-sized tree species, the Greening the Canadian Landscape website allows users to quickly input various environmental features of their planting site, as well as a number of key tree characteristics and/or tolerances, to generate a recommended planting list in real-time. It is important to note that planting site categories represent broad categories and not all the species generated from selecting planting site alone may be compatible with the specific conditions present on your planting site. The more criteria you are able to fill out for the Tree Species Selector, the more refined the generated species list will be.

Because most urban and suburban environments have conditions—often related to poor soil quality and health—that make tree growth and survival challenging, we recommend testing the soil at your planned planting site. Soil tests will reveal important information such as soil pH, texture and organic matter content. Having adequate soil organic matter is strongly correlated to soil health indicators such as improved water holding capacity, soil structure, drainage and nutrient cycling. For information on how to collect soil samples and soil testing, click here.

Although soil testing is recommended, if you choose not to test your soil the Tree Species Selector is programmed to exclude certain tree species based on the characteristic stressors of selected planting sites. In addition, any selected environmental features or tree species tolerances will further filter your final list of trees. Many species are not tolerant of very common urban conditions, especially if planting sites have a history of being impacted by construction activities. These include compacted, poorly drained and often alkaline soils (due to leaching from concrete infrastructure). Although this precludes certain drought-sensitive and urban-intolerant species, it helps select for species that will be more successful in urban-impacted sites and soils. Many of these issues can be fundamentally improved with soil remediation and appropriate maintenance. If you choose to use the Remediation Calculator and improve your planting site soil by using our Soil Remediation Protocols, the growth and survival of your planted trees will improve and the number of tree species you can choose from to plant will greatly expand – enriching the diversity of your planting and the urban canopy.

Publication:

McGrath, D. & J. Henry. 2016. Organic amendments decrease bulk density and improve tree establishment and growth in roadside plantings. Urban Forestry & Urban Greening 20: 120-127.

 

The following list explains each term in the Tree Species Selector search field:

Name – Search by either botanical or common name. Multiple common names have been included where applicable. If you are not sure of the entire botanical or common name, try searching for part of the name.

Planting Site
– Select the closest approximation of the category of site you will be planting. You are able to select multiple sites at one time if you are interested in species selections appropriate for multiple sites. By clicking the ‘Select All’ button your search will not be restricted by planting site.

Naturalization - Naturalistic plantings primarily intended to provide wildlife habitat, ecological restoration and ecosystem services. Be mindful of the potential for browsing by deer and any other wildlife damage that may impact the survival and growth of planted trees. 

Parks - Can include commercial, industrial and educational campuses, as well as municipal parks. Typically has unrestricted soil volume and more regular maintenance. Known invasive species have been excluded from this list.

Residential- Wide range of soil volumes, but easier access for maintenance, including watering and addition of soil amendments.

Wide Median - Likely to have limited soil volume, soil compaction, poor drainage and dry soils. Potential for salt and pollution exposure depending on the site.

Restricted Urban Site - Typically less soil volume compared to wide median sites, with comparable levels of compaction, poor drainage and dry soils to wide median sites, which may lead to limited life-span and growth. Potential for salt and pollution exposure depending on the site.

Highway - Typically unrestricted soil volume. Very limited maintenance, potential exposure to salt spray and soil salt depending on set-backs from roadways; compacted soil (construction legacy) and potential for poor drainage and dry soils; potential for high wind exposure. Known invasive species have been excluded from this list.

Select All - Includes all species in the database.

Does your soil quality meet our recommendations?
– If you tested your soil, entered your results into our Remediation Calculator and the calculated compost application depth was 0, your soil quality meets our recommendations. If your calculated compost application depth was greater than 0 (meaning your soil quality is poor), it is recommended that you remediate your soil. If you have remediated, or plan to remediate your planting site, click ‘Yes’. This will expand your list of species that can be planted on any site and increase your success on poor or less regularly maintained sites.
If you choose not to remediate but still want to plant the site, click ‘No’. Planting in poor quality soil restricts the number of tree species that can tolerate these conditions.
If you don’t test your soil, select neither ‘Yes’ nor ‘No’.
Please visit the list of accredited soil testing laboratories in Ontario.

Hardy to Zone
– The USDA (United States Department of Agriculture) plant hardiness zone system is based on extreme minimum temperatures and is the most commonly used system in the United States and Canada. To find your zone based on municipality, click here. By selecting species hardy to your zone you can expect these trees to survive your winters.

Tree Height
– Typical mature tree height ranges to be expected in a landscape setting.

Tree Width
– Typical mature tree canopy widths to be expected in a landscape setting.

Tree Type
– Trees are divided into evergreen (year-round leaves) and deciduous (seasonal leaf-loss) categories. Although some deciduous trees on this list are evergreen in warmer climates, classifications are accurate for eastern Canada and much of the northeastern United States.

Drought Tolerance – Refers to the period of time tree species tend to be able to tolerate dry soils before suffering from drought stress. Along the range, ‘Very High’ drought-tolerant species are able to withstand prolonged periods of dry soil, whereas ‘Moderate’ species can withstand occasional periods and ‘Very Low’ drought-tolerant species cannot withstand even short periods of dry soil.

Shade Tolerance
– Different tree species require varying amounts of sunlight during the growing season. Full sun means that planted trees can tolerate/require at least 6 hours of direct sunlight per day during the growing season; partial shade implies that less than 6 hours of direct sunlight, or filtered light throughout the majority of the day is sufficient, and; full shade means that less than 6 hours of filtered light, or very little to no direct sunlight, is enough.

Poor Drainage Tolerance
– Trees with ‘High’ tolerance of poor drainage can tolerate prolonged periods of flooded or poorly drained soil; trees ranked with ‘Moderate’ tolerance of poor drainage can withstand occasional periods of flooded or poorly drained soils, and; trees with ‘Low’ tolerance of poor drainage cannot tolerate flooded or poorly drained soils.

pH Tolerance
– Soil pH tolerances are categorized broadly into species requiring acid soils (pH 5.0 to 7.0), species tolerating acid to slightly alkaline soils (pH 5.0 to 7.5) and species tolerating acid to alkaline soils (pH 5.0 to 8.0). Due to the alkalinity of many urban soils, chlorosis (a yellowing of leaves, indicating nutrient deficiency) can affect certain tree species that require acidic, or can only tolerate neutral or slightly alkaline soils.

Salt Tolerance
– Soil salt and salt spray tolerance rankings have been assigned where scientific research and extension literature has provided clear and unambiguous results; otherwise, salt tolerance has been recorded as unknown due to either lack of information or conflicting assessments. Unless salt levels are expected to be high at your planting site you may not want to select for high salt tolerance as it will exclude many species for which enough research currently does not exist to support a ranking.

Native
– Classification is based on whether the native range of a species occurs within Ontario or within North America. Only species native to Ontario will be recommended for Ontario-based naturalization plantings, whereas other sites, typically farther removed from natural areas and with more challenging urban environmental conditions, will include native and non-native species. Keep in mind that many Carolinian tree species have relatively small natural ranges within southern Ontario, but can be hardy to more northern regions.

Growth Rate
– Growth rates will vary depending on soil type, use of soil amendments, additional irrigation, the climate in your region and weather year-to-year.

Branch Breakage Susceptibility
– Includes assessments based on ice and wind storm damage susceptibility. Similarly to salt tolerance, rankings have only been provided where scientific research and extension literature has provided clear and unambiguous results; otherwise, branch breakage has been recorded as unknown due to either lack of information or conflicting assessments. Unless this category is of a high priority, you may not want to select for branch breakage as it will exclude many species for which enough research currently does not exist to support a ranking.

Insects and Diseases
– Identifies serious pest insects and diseases in the urban environment, including those that warrant recommendations against planting. Also included are notes on common, but less serious pests and diseases.

Management Notes
– Includes notes on maintenance requirements such as pruning, clean-up of fruit or leaves, safety concerns such as thorns or high susceptibility to branch breakage, and documented invasiveness of non-native species in Ontario (and surrounding regions).

Cultivars
– Cultivars listed include those that tend to be commercially available and/or recommended due to desirable traits. Check your local tree nursery for availability.