Sep 07 2012

Dripping Cones

Published by at 5:25 am under Trees

As I've said before I live in a deciduous place so the ways of conifers are sometimes mysterious.

Take pine sap for instance.   My annual visits to Maine have taught me to check before sitting down under a white pine.  Mainers know that their state flower drips sap (yes, white pine cones are the State Flower of Maine) so they don't put lawn furniture in the drip zone.  I had some unfortunate experiences with pine sap before I learned this.

Only the female cones cause this problem.  Male cones are small pollen-laden structures that appear in the spring at the base of new growth.  They release huge amounts of pollen, then fall off the tree.

The female cones form on the branch tips and capture the wind borne pollen. It takes two years for them to mature into the familiar woody cone that opens when dry to release the seeds.  Along the way they're green and drippy.

Why do immature cones drip sap?

That question spawned this post but I haven't been able to find the answer.

However I have some theories.

  • Theory 1:  The cone has to dry out as it matures. Maybe dripping is part of that process.
  • Theory 2:  Pine sap has insecticidal properties.  Maybe the oozing sap keeps insects away from the developing seeds.
  • Theory 3:  Maybe the sap also keeps squirrels away from the immature cones.

I don't know why they drip, but the sap certainly keeps me away from them.


p.s.  If you know why pine cones drip sap, please leave a comment and let me know. It's driving me nuts!

(photo by Steven J. Baskauf from Vanderbilt University Bioimages)

2 responses so far

2 Responses to “Dripping Cones”

  1. Steve Valasekon 07 Sep 2012 at 9:53 am

    Could the dripping sap from the top of the cone catch pollen (I’m assuming they are wind and not pollinator driven plants) and carry it down the cone to the other parts?

  2. CarrolltonOhon 09 Sep 2012 at 11:08 pm

    I believe you had it correct with both #2 and #3, Kate….it is a repellant to both animal and insect while the seeds develop…
    since it takes over a year for the cones (and seeds inside) to fully mature, it has to keep the pests away from the slow developing seeds until they have matured…
    The seed that fall out of the ripened cone look like little maple “helicopters”…Most have released their seeds in Ohio already and there is a bumper crop of them (and the dried dead cones) from the perfect spring weather conditions back in 2010….

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