Yellow needles won’t have long-term effect

Don’t worry, yellow needles on a pine tree aren’t a sign that the tree is struggling or in danger.

A ponderosa pine tree with frost-damaged yellow needles.
A ponderosa pine tree with frost-damaged yellow needles.

Many people are noticing that many ponderosa pine trees have yellowed tips on last years’ needle growth. In some cases the yellowing is only at the very tip, but sometimes it comprises half or more of the needle’s length.

The damage comes from the abrupt change in temperature last fall, when an extended warm fall was followed by an extreme cold snap in November. Trees respond to a normal decrease in temperatures by hardening off their needles. Trees that have hardened off can withstand very cold temperatures, even those well below zeroFahrenheit, without damage. But with the warm temperatures of last fall, some trees didn’t harden off normally and new needles froze. It’s the abrupt change in temperature, rather than the cold temperatures themselves, that caused damage to tree needles.

The damage to trees will likely be very small over time. Damaged needles are likely to drop off during this growing season and newly emerging needles along with still-healthy older needles will largely compensate. By June, damage will hardly be noticeable.

The damaged needles from a ponderosa pine. The affected trees will drop the damaged needles with long term damage unlikely.
The damaged needles from a ponderosa pine. The affected trees will drop the damaged needles with long term damage unlikely.

Some trees experienced significant damage and needle loss may be extensive such that growth is affected. Almost all trees affected, however, are unlikely to suffer damage at all. No work will be needed to help the trees. If a tree is near a water source and temperatures get high, additional water won’t hurt but isn’t necessary in a tree as tough and resilient as ponderosa pine.

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