Environment - Climate Change

April 1, 2020 Published by Toronto and Area Chapter - By Linda Hawkins

Climate Change and Your Trees

From the Spring 2020 issue of the CCI Toronto Condovoice Magazine.

"Unless Someone Like You Cares a Whole Awful Lot, Nothing is Going to Get Better. It's Not."

We know climate change is one of the hot button issues of our time. It is constantly in the news as natural disasters occur more frequently and world leaders struggle to come to a consensus on how to address the issue. Of course, climate change affects our environment on an ongoing basis as well. Let's explore some of the ways that climate change affects trees in the urban environment.

Have you noticed that over the past couple of summers we have been experiencing long periods of drought followed by large amounts of rain? This inconsistent rainfall can be very stressful for trees. Through the hot, dry periods it is very important to water your trees. Unfortunately, irrigation systems are designed to water grass, flowers, and small shrubs. These plants need moist soil to help keep them green and hold their flowers. Most condominiums' systems provide small amounts of water daily or every other day to keep the soil moist. Trees and shrubs have roots that grow deeper in the soil. They cannot access the small amount of water placed on the surface by a standard irrigation set up. Trees rely on rainfall to apply more water that penetrates deeper into the soil. If your condominium has an irrigation system, ask your irrigation company to set up one day per week with a longer watering period for your trees. Often, watering by hand once a month or every two weeks is sufficient. You can lay a hose at the base of the tree with a trickle of water for the afternoon—just don't forget to turn it off after a couple of hours! You can also check out a new water management system called Hydrawise. It connects to your phone to help your condominium manager manage the buildings watering system more effectively. Lastly, if you are considering redesigning your landscape, there is a new trend called fusion landscaping. Fusion landscaping is the responsible management of water around your property and landscape to alleviate the stress on storm water systems. Fusion landscaping utilizes the techniques such as permeable stones or paving, rain gardens, and redirection of downspouts can also help with waste water management.

Like inconsistent rainfall, heavy wind and down bursts are also increasing lately. Trees can withstand an incredible amount of environmental stress. Just imagine a 100-year-old oak tree that has stood outside from sunrise to sunset and endured weather ranging from –30 °C to 45 °C for 36,500 days, not including leap years, of course. Trees are remarkably tough while remaining flexible, allowing them to move with the wind and withstand heavy loading of wind and snow. They have incredible structure and strength where their branches attach. These unions are so incredibly engineered that they are studied in aerospace when engineers are designing planes and attaching wings. As resilient, flexible, and incredibly well-engineered as trees are, the amount of force exerted on an urban tree is increasing as they experience more down bursts, heavy rainfall, and an increased potential for ice storms. As arborists, we always want to ensure a tree is healthy and people are safe. Reducing the amount of weight of the overall size of the canopy is the ideal method of pruning. Reducing a tree's canopy by approximately 5% to 10% can reduce the forces by upwards of 30%. If your tree hasn't been pruned to reduce weight or the overall size of the canopy, consider having a consultation with a certified arborist assess the potential need.

Rapidly changing seasons and temperatures have also become more common. Our seasons change from cold winter to hot summer with very little spring or fall weather. These changes push our trees to bud and flower quickly and we can expect to see less flowering and fruiting in some seasons where a late frost will damage the delicate buds as they are unfolding. Short spring seasons also impact the overall health of trees, as the time to take up the spring moisture is shorter and the summer heat is stronger. Drastic swings of cold and warm weather can confuse trees and start early sap flow in late winter. This can cause frost cracks in the main stem, and fewer nutrients for the eventual bud break. The rapid change from cold to warm is very hard on soil biology that cycles nutrients and allows trees and shrubs to thrive.

As we take on the challenge of climate change, everyone needs to do their part. If you haven't watched the movie The Lorax with your children yet, we at Shady Lane would highly recommend that you make time for it soon. Dr. Suess was an insightful man. In 1971 he wrote, "Unless someone like you cares a whole awful lot, nothing is going to get better. It's not."