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I have a young oak tree (ETA: It is a White Oak) that has been in its current location for 7 or 8 years. This year it is very late leafing out. In fact, it has only just started getting leaves in the past week. All of the other trees in the neighborhood (including mature and immature oaks) have been fully leafed out for about 2 weeks now. Reasons I've considered:

  • The tree does not seem to be located in a frost pocket. This is the first year it has leafed out significantly later than the other trees.
  • We did have several late spring frosts/freezes - but again, no other trees in the vicinity seem to have been affected to this extent.
  • When looking at the tree, I see no obvious signs of disease or injury. The bark is intact, I see no damage to the trunk or roots.

What am I missing? Or is the most likely explanation simply that it was more susceptible to the late frost than my other trees?

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    The only bit that surprises me is that this seems the first year. We had two oaks right next to each other and one was always about two weeks later than the other. Plus, one dropped all leaves in fall, the other hung onto them almost until the new growth pushed out. Just an observation, hence only a comment and no answer. Looking forward to whatever comes up in the answers. – Stephie May 23 '16 at 14:43
  • Interesting! I have never noticed that this particular tree leafs out earlier than the others in the neighborhood. It definitely does hold on to its leaves all winter - those just finally dropped about a month ago. – michelle May 23 '16 at 15:07
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Trees vary widely in leaf-out time, oaks are a long-lived species that plays it very safe in order to not die out due to a warm spell.

Factors influencing leaf-out include:

  • Warm, sunny location, such as a south-facing hill (will leaf-out earlier)
  • Cold, shady location (will leaf-out later)
  • White Oak is among the last species to leaf out.

Oak needs a combination of chilling requirement, warm temperatures and a specific sun/day length before it will leaf-out.

Oak, has a “chilling requirement”, (a certain number of cold days between 0 and 10 degrees Celsius or 32 to 50 Fahrenheit) before the buds will break dormancy. The chilling requirement depends both on the tree type and the weather of the preceding growing season. Once the requirement is met, it will break its dormancy at the next significant warming spell.

Oak must also meet the photo-period requirement.

Oak will only leaf out once it gets sunshine for a certain number of hours.

Leaf-out conditions were probably not met for your oak tree, due to one of the above factors. I'm guessing the late frosts were a factor.

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