Our spring weather has stressed your trees; here's how to help them through summer

Because of an unusual spring, some of you may have noticed some alarming leaf and needle death in your trees. Here is what is going on. 

When a certain number of winter/spring days average above a temperature threshold, plants and insects will begin developing for the upcoming season. We call thpis Growing Degree Days. (click here to learn more). Our unusually warm winter and spring triggered this development earlier than usual. For trees, this process entails transforming stored carbohydrates into a more consumable sugar. The tree then uses these sugars to start foliate and elongate branches. New foliage is full of sugar and water, making it exceedingly vulnerable to freezing. Not all foliage is equally delicate however. Some trees like Ash, Oak, and Kentucky Coffee are more susceptible to freeze damage, while other trees like crabapples, chokecherries and serviceberries are not. This has to do with their evolved phenological strategies – the timing of biological life-cycle events such as flowering, lea

fing and fruiting. 

This spring many of our susceptible trees were hit by a late freeze, which killed the delicate leaf tissue. Luckily, there are more stored carbohydrates in the tree and the tree is able to push a new flush of foliage. However, each flush of new foliage is using up stored carbohydrates. Eventually, the tree will be depleted of all its stored resources, and it will die. A tree can push out and then freeze foliage as many as three times before it gives up. It all depends on how much stored sugar the tree started with. 

Once your tree finally puts out viable foliage, it will begin making and storing energy for next spring. This is why it is important to make sure your tree has what it needs to maximize its energy production at this point. Let’s make sure your tree has what it needs to not just survive, but thrive. 

— Woodchip mulch is crucially important for your trees. See our blog post about the benefits of woodchip mulch for drought conditions. 

— Water is probably the most important factor to tree survival. Automate your irrigation system. Consider having one of our certified arborists come see if this is possible for your home. 

— Finally, trees can be limited by soil fertility. As science learns more about the ecosystem of the soil, we continue to learn the important of soil health, including the arthropods and microbes that reside therein. We need to feed them as much as we do the trees. 

If you are concerned about your soils, we can help kickstart the soil microbiome for you by adding compost, mulch and a soil inoculant. Contact one of our certified arborist for more details.