Gardens & Trees
Tree Health Data & Monitoring
Contact Us
Katie Mayne
Senior Project Manager
Email [email protected]
Engage Hamilton
Name our talking trees!
Help us name the urban trees that are part of the tree health data pilot. The pilot includes adding data sensors to trees to help monitor tree and soil health.
Hamilton’s trees clean our air, cool our streets, shelter wildlife, and make our neighbourhoods healthier and more beautiful. Yet many trees face challenges from pests, disease, extreme weather, and city growth that often go unnoticed. This pilot project uses technology to gather data and to help residents experience our trees in a new way.
This pilot project supports the Hamilton’s Urban Forest Strategy and Climate Action Strategy and is funded in part through the Climate Change Reserve.
If Trees Could Talk
If Trees Could Talk converts the data gathered into storytelling to help residents see and hear from trees in real time. Strengthening the bond between the community and our neighbourhood trees, helps everyone feel more connected to the tree canopy above us.
Giving trees a “voice” can:
- Show the everyday role of trees in keeping our city livable
- Reveal how climate, weather, and care affect tree health
- Inspire residents to take action—planting trees, watering, and reporting issues
- Provide valuable data to drive research on urban forestry, climate resilience, and sustainability
- Strengthen community support for protecting and planting more trees as part of Hamilton’s Urban Forest Strategy and Climate Action Plan
How It Works
Two native trees in Hamilton are fitted with special sensors that measure:
- Soil health (nutrients, pH, moisture, temperature, oxygen, salinity)
- Stem water potential indicates the amount of water available to the tree by measuring the moisture in the xylem, a direct measure of the tree’s hydration and stress level.
- Bark expansion and contraction (growth patterns)
The data is used to generate short social media posts so the trees can “talk” directly to the community.
Residents can follow along on social media, explore data on a public dashboard, and access the information through OpenData Hamilton for research purposes.
FloraPulse Sensors (Water Potential)
- Measure stem water potential, a direct measurement of how much water in in the trees xylem (water conducting tissue). Stem water potential is a reliable indicator of water stress levels.
- Enable proactive care during drought or changing weather.
- Provide real-time, continuous data to help researchers understand tree responses to environmental conditions.
Soil Life Sensors
- Track soil conditions: pH, salinity, moisture, oxygen, and temperature.
- Soil is a living matrix, and sensors can track the conditions that are essential biological processes vital for tree health, such as nutrient cycling and organic matter decomposition and reveal hidden stressors in urban environments.
- This data can help guide long-term strategies for healthier urban forests.
Dendrometer
- Monitors tiny daily changes in tree trunk diameter and detects early stress before visible symptoms.
- This data can reveal growth patterns and give researchers insight into how environmental factors like moisture, temperature, and relative humidity affects tree health and vitality thereby linking tree growth to climate and environmental conditions.
Relative Humidity
- Weather data will be used to assess how relative humidity affects the tree. Relative humidity is a measure of water vapor in the air relative to the temperature. High relative humidity decreases transpiration, reducing the tree’s ability to transport nutrients and water.
- This data can be integrated with the data generated by the sensors to better understand the trees response to relative humidity. It can also help to predict disease risks, stress, and seasonal growth patterns.
Additional Data
Environmental data such as rainfall, temperature, snow fall, freeze/thaw cycles, and sunlight is available through Environment Canada and can all but used in conjunction with the data collected by the sensors to better understand how environmental changes affect tree health processes.
If Trees Could Talk
Meet the Trees
The project is being piloted on 2 trees in 2 parks:
- Victoria Park (Ward 1, Strathcona Neighbourhood)
- Captain Cornelius Park (Ward 8, Rolston Neighbourhood)
Trees were chosen based on species and existing community partnerships with local schools and neighbourhood programs.
Black Walnut - Juglans nigra
This big old Black Walnut is situated on the edge of a naturalized woodlot adjacent to Captain Cornelius Park. There is ample protection from compaction due to the understory growth, and lack of foot traffic in the immediate area. The woodlot is home to many small animals and birds who benefit from this tree’s fruit and several critters likely call it’s canopy home.
- Size: 68.5 cm diameter. Black Walnut can reach 120 cm, and in some cases more than 240 cm in diameter. They can grow 30–40 meters tall;.
- Age: Based on it’s size and growing environment, our best guess for this tree is that it is between 80 to 100 years old.
- Leaves: Compound leaves with 15–23 leaflets.
- Flowers: long green catkins in spring.
- Bark: Dark, deeply furrowed like “alligator hide.”
- Moisture: grows best in moist soils.
- Shade: intolerant of shade; grows best in full sun.
- Soil: grows best in well-drained, rich soils.
- Nuts: Hard-shelled, edible, but stains when husks are cracked open.
- Wildlife Value: Many birds and small mammals, such as squirrels, eat black walnuts
- Fun Fact: Black Walnuts produce juglone, a chemical that is secreted through the roots and hulls of the walnut seeds. Juglone suppresses growth of nearby plants.
Silver Maple - Acer saccharinum
This Silver Maple is one of the oldest trees in Victoria Park and has lived to see many changes within it’s surrounding neighbourhood (what stories do you think it might tell!?). From pathways to splash pads, this tree has persevered through many construction projects and ongoing compaction from foot traffic likely reduces the water holding capacity of the soil surrounding this tree.
- Size: 85 cm diameter. Silver Maples can reach 35 meters tall; and more than 100 cm in diameter.
- Age: Although the exact age of this tree is unknown, a best guess based on it’s growing environment, is that this tree is approximately 85 to 100 years old. Silver Maple’s can live for up to 150 years in an optimal growing environment
- Leaves: Light green with 5 to 7 lobes; turn bright yellow or to reddish brown in fall.
- Flowers: Small greenish clusters.
- Bark: Smooth and grey when young; dark, shaggy strips as it ages.
- Silver Maple is native to southern Ontario.
- Moisture: grows best in moist soil.
- Shade: slightly shade tolerant but grows best in full sun.
- Soil: grows best in rich soil.
- Wildlife Value: Food for squirrels, and deer; habitat for birds and small mammals.
- Fun Fact: Sometimes older Silver Maple trees develop a hollowed trunk, many wildlife use these spaces for shelter.
Date modified