Holy cow! Look at my pine tree – it has lots of yellow needles on it! Is that a problem? What’s wrong? These are common questions/comments that we get at this time of year. In terms of the question of “is that a problem?”, it depends on where the needles are and which type of pine/fir/spruce it is.
Let’s start with the – not a problem – answer. If the yellow needles are on the inside of the canopy, or along the middle of the branches, then it’s likely that the tree is simply shedding older needles as Mother Nature had intended it to do. This phenomenon is more visible and pronounced on white pine, as they hold their needles for only 2 years, with approximately half of the needles falling off each autumn. Most others hold their needles for 3 or 4 years.
The other answer, the – it’s a problem – answer, is usually characterized by other symptoms and needle location. If needles are yellow or brown on the newest growth, near the ends of the branches and/or the middle of the branch, then the tree may be suffering from a malady such as girdling roots, compacted soils, or overly frequent watering. If they have spots, lines or other marks on them, then a fungus disease such as Dothistroma needle blight is possible.
Dothistroma Needle Blight
Diplodia Tip Blight
The key to determining which is the causal agent is knowing the tree’s history, the timing of the symptoms’ appearance and the tree species.
