It's spring. The time of year that trees start to leaf out. I have been watching them, and noticed an interesting pattern. The unhealthy trees of a species leafs out first. I've noticed this especially with the wild black cherries. The hollow and damaged trees and the ones in poor conditions leaf out a week ahead of the good ones. The last ones to leaf out are the strongest in the area. This is not just a casual observation, and I have kept careful track of it. What causes this?

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    $\begingroup$ -1 for use of the ambiguous (and unscientific) term "trashy trees" $\endgroup$ Apr 4, 2012 at 14:55
  • $\begingroup$ The question is not clear. How a species of tree would be better than another? Why would a willow be worst than a oak or a black walnut? I think you're mixing two things: sick vs non-sick trees and trees of different species with different leafing times. $\endgroup$
    – nico
    Apr 4, 2012 at 17:14
  • $\begingroup$ Be cautious about drawing conclusions from casual observation. There may be within-species variability in the timing of leaf-out. It is possible that trees that leaf out first are more likely to be infected (or to have been infected in previous years). $\endgroup$ Apr 4, 2012 at 18:09
  • $\begingroup$ @nico No. My question is Why the softer and lower quality trees, especially of the same species, Leaf out before the healthier trees. I am not asking why they are different. I think many people will agree that an old oak tree is of higher quality than a willow scrub. $\endgroup$
    – J. Musser
    Apr 5, 2012 at 1:18
  • $\begingroup$ I clarified my question for you who didn't get the meaning the first time. $\endgroup$
    – J. Musser
    Apr 5, 2012 at 1:22

1 Answer 1


Trees that have been dormant over the winter exist on nutrients stored in their roots during fall. When a tree has been damaged or diseased, it may not have been able to store enough nutrients before winter, or may not have enough stored to heal the damage/disease. If the damaged/diseased tree has depleted its winter root stores, it must leaf out (earlier than others of its species) and resume photosynthesis in order to have enough energy to attempt healing itself.

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    $\begingroup$ This seems reasonable - do you have any references to support your answer? $\endgroup$
    – Rory M
    Oct 29, 2012 at 16:31
  • $\begingroup$ Agree with @RoryM, it seems a reasonable theory, but I am not at all sure that this is true. It could be just as much about rising sap in the spring, carrying resources, reaching the terminal buds quicker, as there is less distance to travel, and so initiating bud burst earlier. Also trees can't 'heal' themselves, as they grow they may occlude wounds and cavities, and compartmentalise decay to stop it spreading. $\endgroup$ Jul 5, 2017 at 11:26

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