September 1, 2020
Drip irrigation for challenging tree-planting sites pays off
Idea helps trees succeed
BY DAVE TURNBULL,
Highway of Heroes Living Tribute operations manager
The Highway of Heroes Tree Campaign’s overall goal is to plant 117,000 trees — one for every Canadian soldier who has died defending our freedom from Confederation until the present. Our planting goal this spring was 15,000 trees, on three sites along the Hwy. 401 right-of-way in the Whitby and Oshawa, Ont., area.
A challenging “storm” came across the landscape this past spring, in the form of a hot summer, and Covid-19’s impact on tree supply and contractor installation. We were able to get just over 10,000 trees planted by late June.
Site conditions along the 401 can be absolutely brutal in terms of soil structure, organic matter and fertility. For site preparation, we follow the guidelines developed by Dr. Darby McGrath and her team at Vineland Research and Innovation Centre to improve establishment and survival of these memorial trees.
Watering the newly planted trees can be a challenge, depending on site access and availability of water. For 2020 we decided to install drip irrigation systems at all three planting sites. While it was a big learning curve in terms of installation and operation, given the very dry spring — especially out in the Whitby area — we are glad we made the investment. The drip system improved establishment and survival rates dramatically.
The systems have to be standalone and self contained, since no electricity is available to run the pumps. Components included two 3,000-gal. tanks, portable gas-powered pumps, main lines and drip lines. Water is supplied by custom water hauling companies. Watering frequency varies depending on site and weather conditions, but is generally needed three to five times per week. Each truckload of hauled water costs about $250. The drip lines delivered water extremely efficiently, right where the tree is, and coir mats at the base of each tree effectively conserved moisture.
Overall, drip irrigation cost the Tree Campaign $3-4 per tree. Since each tree costs $60-70 to plant, we have been very happy with the investment. Contractors know the cost to replace trees is even higher; I can certainly see the value of adding this modest line item to a quote to reduce losses and warranty replacements. Water will be available on-site for most contracting jobs, making drip irrigation costs even lower.
Most tree plantings will need drip for one season, or sometimes a second. The systems can be drained and left in place over winter, and are completely transportable.
One challenge we found: rodents seem to like to chew through the lines occasionally. So I walk the lines weekly to ensure the system is intact, and because automation of watering start and stop is not practical for our application.
Looking back on the idea, I am thrilled it paid off in improving our survival rates. Hopefully our experience will help contractors improve rates in their tree installations. Whether the goal is beauty, shade or honouring a fallen hero, let’s help trees survive!