Why one side of your tree turns brown and how you can prevent it from happening

You may have had the unlucky experience this spring of finding that one side of your pine trees has turned brown, while the rest of the tree has stayed green and looks good. If this change occurred over the winter, and the tree was fine before winter started, then there is a good chance you have a mixture of damage due to wind desiccation and sunscald.

Evergreens, and specifically pines, are more prone to having these two issues together. As small trees, they lack a large and established root system to be able to draw in enough water to keep the whole tree alive through the winter months. You have to keep in mind that pines and all other evergreen trees, like spruce or fir trees, actually do not go dormant like deciduous trees during winter. Instead they just “slow down” their natural processes of drawing in water through their roots and are technically still functioning and completing their natural plant processes.

We live in such a dry arid climate and have dry winds throughout the wintertime. Since they are pulling in water throughout the winter, one side of our trees will often die back. To compound this issue, sunscald can occur during February and March when there is still snow on the ground. There are days where the daytime temperature spikes and the nighttime temperature drops to well below freezing. This can cause the fluids in the bark or needles on the side of the tree that gets the most sun to freeze during the cold of night, damaging the plant cells and killing off that side of the tree.

To help prevent wind desiccation on young pine trees, you will want to protect them from constant winds by putting up a windbreak, (at least during the winter, and while they are young). Next, you want to make sure they are well watered at the end of the growing season and that they go into the winter season well irrigated. This may entail irrigating them with a hose and sprinkler weekly until mid-November, depending upon weather and temperatures.

The other thing you can do is buy smaller evergreen trees rather than larger ones since the ratio of root system size is more in balance than a larger tree with a small root system.

There aren’t many options to manage sunscald on evergreen trees. Wrapping them in burlap during the winter can help prevent temperature fluctuations in the needles or bark. Wrapping them in burlap can also help to stop the wind from drying them out and causing needle desiccation.

For further questions, please call Lance at (208) 624-3102.