Periods of extreme heat will repeat themselves in the coming years and even become more frequent. That's why it's important to remember that, as individuals, we can do our part to make things better, even on a small scale. And if everyone gets involved, it can only help.
This summer, in our greenhouses, it was very hot. We even had to close early one afternoon because it was unbearable. But outside it wasn't much better. What we all wanted was a little freshness. Most of us found ourselves in our air-conditioned homes, windows closed, without hearing the birdsong and without feeling the breeze...
It has been shown that it is cooler in places where there is vegetation than in an area of buildings, concrete and without trees. The difference between a heat island and a cool island could sometimes even reach 10 degrees.
“Trees really have a very, very important impact at the local level. If we go 10 meters further, we feel it less, but when we are really close to the trees, it is a direct impact,” according to Virginie Angers, forestry engineer.
According to the report Measures to combat urban heat islands from the National Institute of Health of Quebec, “ vegetation helps create coolness through different processes, more precisely:
• seasonal shading of infrastructure;
• evapotranspiration;
• minimizing temperature differences on the ground.
Vegetation also offers other interesting and complementary benefits in an urban environment, including:
• improving air quality through the production of oxygen, the capture of CO2, the filtration of suspended particles and the reduction of energy demand linked to air conditioning;
• improving water quality by retaining rainwater in the soil and controlling soil erosion;
• population health benefits, including protection from ultraviolet (UV) radiation, reduction of heat stress, and availability of places for physical activity. »
The trees to favor are those which cast the most shade and those which tend to spread horizontally, such as lime trees ( Tilia ), oaks ( Quercus ) and Norway maple ( Acer platanoides) , but for those which have a smaller plot, Amur maples ( Acer ginnala ) and saskatoon berries ( Amelanchier canadensis ) are excellent choices. The Norway maple produces a lot of samaras and can become invasive, it is worth remembering this.
In our article on planting trees ( here ), we give tips for successful planting ( soil , compost , mycorrhiza , etc.), even in the middle of summer. As you will be able to read among others, the greatest part of your success in watering, because in summer when it is very hot, trees, like us, need water.
Succeed in good watering
To achieve good watering after planting your tree, it is important to take three things into account: 1. gently; 2. long; 3. regularly.
1. Gently
Watering gently allows the water to penetrate deep into the soil and thoroughly soak the roots. This is not the case with high flow watering which tends to run off the surface rather than penetrate the soil. A tip: let a small jet of water run from your garden hose at the base of your tree for at least 30 minutes until it is saturated.
2. Long
This is probably the most important and overlooked step for gardeners. A good way to become aware of how long we need to water is to take the time to dig the soil after watering to see how deep the moisture is. It is quite surprising to note that, most of the time, the wet part is only on the surface! Watering deeply causes the plants' root systems to develop more to draw water from deeper and, in doing so, the plants become more resilient to future droughts.
3. Regularly
Regular watering always pays off in gardening, but one thing to remember is that you need to let the soil dry out before watering again. Gardeners often ask themselves: how many times a week should I water? This question is difficult to answer because many factors can come into play, such as climatic conditions and soil type. Remember that nothing will be more effective than putting your hands in the soil to see if you really need to water!
An absorbent that helps retain water
There is a product to help water retention in the soil: Super Ab Hydrogel granules , which reduces watering frequency by 50%. These potassium-based synthetic polymer granules absorb, retain and release more than 200 times their weight in water. They also improve aeration of the substrate, reduce the leaching of fertilizers and nutrients and allow better cultivation on inclined surfaces.
Planting a tree today may not reduce the temperature in your backyard that much next summer, but it's important to think long term. One mature tree can make a difference, several mature trees can have even more impact. According to some forecasts, average summer temperatures could rise by 3 to 5.8°C within 80 years. It is urgent to think today about the next generations, who will be able to benefit from the actions taken now.
