Drought, not smoke, stressing out Saskatchewan trees

With the season of autumn and back to school arriving, a certain amount of stress and browning leaves on the ground is to be expected.

However, trees shouldn’t be shedding their leaves as early as they are in Saskatchewan — and it’s because trees in the province are feeling stress from this summer.

While wildfire smoke has hung in the Saskatchewan air for much of the spring and summer, there’s another stressor that seems to be weighing down trees in the province.

Rick Van Duyvendyk, manager and owner of Dutch Growers and host of Garden Talk on 650 CKOM and 980 CJME in Saskatchewan, said ongoing drought conditions deserve much of the blame.

“Smoke has maybe something to do with it,” Van Duyvendyk shared, saying many trees are under tension right now. “(But) the smoke probably affects us more than it does the plants.”

The plant expert attributed dry conditions and a lack of rain to symptoms trees are experiencing in Saskatchewan now, like leaf scorching when the top of a tree’s leaves will die. This especially hurts trees without irrigation underneath them or big elm trees, like those lining many Saskatoon streets and boulevards.

Harmful insects are also attracted when trees are strained. Bark beetles, which can carry Dutch elm disease, are one such species.

Van Duyvendyk pointed to the numerous trees in Saskatoon’s Sutherland area that have been taken down this year because they were infected by Dutch elm disease.

The Emerald Ash Borer is another harmful insect that has been moving across Canada and is presently as close as Winnipeg.

“It’s coming our way and stressed trees just attract insects. It’s just the way nature takes care of things,” Van Duyvendyk said.

He pointed to places like Regina and the Qu’appelle Valley where natural elm trees grow without much pruning.

In cities, trees are pruned around once every seven years to take out dead wood, which can help trees stay healthier and protects the inventory of trees, which Van Duyvendyk called “so valuable” to cities.

Smoke can still have a negative effect on tree health, when it’s heavy and prolonged, as well as on vegetable gardens. Van Duyvendyk said the pores on leaves that help with photosynthesis — taking in carbon dioxide and turning it into oxygen — can get clogged with smoke and make that process more difficult.

Much like smoking meat, it can make a vegetable more smoky.

Van Duyvendyk preached a simple, overarching solution to help trees and vegetables with these problems — as well as combat the symptoms of drought stress: Watering.

Sprinklers and morning watering — to prevent mildew by leaving vegetables wet overnight — can help clear pores.

People need to start watering trees, too, Van Duyvendyk said.

“We haven’t had rain … In downtown or in some of the older neighbourhoods, the roots go a long ways,” he shared. “They go underneath the pavement so they need a lot of rain to be able to penetrate and get the groundwater up.

“It doesn’t matter where that tree is, whether it’s in your yard or on the boulevard. We need to take care of the trees because they are a part of our legacy.”

With groundwater very low right now, Van Duyvendyk said problems can come as trees without enough water start searching for it in places like city sewers.

Once a month, Van Duyvendyk said to use a gardening hose to not just water the grass, but to leave out to dribble for up to six hours to give a tree a good soaking. Outer parts of branches that would normally receive rain should be watered to ensure feeder roots are wet.

He also recommended a root feeder that can be stuck in the ground and left at a spot for three hours at a time in one spot.

On top of watering, Van Duyvendyk said trees need fertilizer once a year, regardless of their age, because yard waste is cleared away, removing natural fertilizer from yard plants.

Friday marked the end of the tree pruning ban in Saskatchewan.

In Saskatoon last month, as many as 31 trees elm trees had to be removed because they were infected with Dutch elm disease. That took place in the north section of the Forest Grove shelterbelt.

Currently, the city is still awaiting results to see if more trees have to be removed because of Dutch elm disease.

The city noted it’s continuing to monitor the situation, but said it has given consideration to reducing or scraping the dumping fees for elm wood as a measure to encourage proper disposal and reduce the spread of Dutch elm disease.

A statement from the city said they will be launching a pilot project in October to waive disposal fees for elm wood at the landfill during the month. More details are expected to be made available in a few weeks.