The evergreen in my backyard (Yonge and York Mills area in Toronto) has been shedding more than the usual amount of needles and cones this winter. Some of the branches at the mid and top level are almost bare. What is causing this and what do I need to do to help the tree ? Any advice appreciated and thanks for your help.
Thank you for contacting the Toronto Master Gardeners with your inquiry.
Though pines, spruce, firs, cedars and most other conifers are called evergreens, their needles do not stay alive and green forever. Generally, new needles are produced at the branch tips every spring and summer. Spruce trees hold their needles for about 5-7 years while pine trees hold theirs for only 2-3 years before turning brown and then dropping.
As needles age, they become less efficient at producing food for the tree. They also become more shaded by newer needles. For these reasons, old needles finally turn brown and drop off. This seasonal loss of needles occurs mainly on the inside of the tree. Fall needle drop is usually very noticeable on pines but may go unnoticed on spruce. However, if trees have experienced particular stress such as the drought in Toronto last summer and if the tree did not receive adequate water before the winter freeze, then fall needle drop will be intensified. The browning on your trees may be more noticeable this year for this reason.
So, if one-third to one-fourth of the needles on the inner parts of your evergreen tree are falling off, it is probably just a normal sign of aging. Just rake up the dead needles or better yet, leave them under the tree for a good mulch.
If your tree is losing needles at the branch tips, then the culprit is probably some type of disease or insect.
This article from the University of Saskatchewan on evergreens is quite comprehensive for further reading. Why is my evergreen turning brown?