Sap dripping from pine is a sticky
We have a Michigan Pine tree in front of our home. It
was planted about 30 years ago by the previous owner.
Our neighbor alerted us to some white seepage at various
spots on the trunk and limbs. Also, when we had a windstorm this
fall many pine cones came down and he pointed out that they, too ,
We want to have the tree looked at but are not sure how
Michigan's State Tree is the white pine, Pinus strobus.
It has long, soft needles in clusters of five. Like most trees in
its family, it pushes out sap as a defensive move.
Pine resin is an effective insecticide and fungicide. It can
kill or slow the growth of an invading insect or fungus spore.
Sap's not only a chemical shield but can be a physical
deterrent. It can forcefully flood an area to eject insect larvae.
It seals holes as it hardens, shutting out wood-eaters and
There may be tip boring insects attacking the new buds on your
tree, or trying to enter the wood through wounds made by hail or
poor pruning. Sap sucking birds may have made holes in the trunk
that the tree is trying to seal. Squirrel-bitten twigs may be
dripping sap. A fungus may be growing in cracks at bases of
storm-bent limbs. There are other possibilities. Any of them may be
serious enough to warrant treatment or might be minor ills an
otherwise healthy tree can deal with.
So you're right to seek an examination by an arborist -- a tree
care specialist who can diagnose and help treat problems.
Check "Tree Care" in a phone directory for a company which
employs a certified arborist. Call to ask where the arborist's
certification was obtained -- organizations like the International
Society of Arboriculture and National Arborist Association require
that individuals have extensive education and experience to earn
certification, and continue their schooling to keep the
endorsement. Some organizations maintain their own referral lists,
too. For instance, at www.isa-arbor.com, select "Find a Certified
Arborist", enter your zip code and obtain a listing.
An arborist may have a landscape technology certificate from a
Community College or a horticulture degree from a University. These
are all good starts.
Next, do what you would if you were hiring someone to remodel or
repair your home. Ask for references, then follow up to learn about
the experience others have had in working with this individual.
I go one step further before hiring a specialist, which is to
talk to someone who knows about the work I'm looking to hire done.
From my brother the carpenter, for instance, I can get a question
or two to ask to test a potential cabinet-maker's knowledge and
skill. For pine tree care, you've checked with me and can ask, "Why
might sap be dripping from my pine tree?" At least some of what you
hear should be what I've already told you!
Grow all plant-poisoning plants in one
This is what O.L. proposes, after reading here that some
otherwise-desirable plants such as sunflowers, mums, yarrows and
black walnut trees are allelopaths. Such plants are capable of
stunting and killing other plants that share their root space.
It won't work, O.L. These plants share a survival strategy but
they don't all use the same chemical to do their killing. So they
each get along differently with various plant species, including
each other. A killer like buckthorn that can live with black
walnut, another allelopath, may die under the influence of toxins
from sunflowers, barley or rye grass.
Another consideration is that we haven't identified all the
allelopaths yet. Nor do we know which plants may or may not be able
to tolerate a specific killer's presence.
It's a fascinating and important field. To stay abreast, use the
Internet or your local library to follow references to "allelopath"
in the latest scientific publications.
Does construction damage kill red oaks more quickly than
C.R. and others asked for clarification after reading this in my
November 13 column. Answer: No. Construction damage makes no
distinction between oaks.
Oaks in the red oak group (red-, scarlet-, black- and pin oak)
are killed more quickly than oaks in the white oak group (white-,
burr-, swamp- and English oak) by the oak wilt fungus that was the
topic of my November 13 column.
Green thumbs up
to the brilliant red fruit on cotoneaster and barberry bushes. A
little color goes a long way in December!
Green thumbs down
to tiny, dry, white flecks on the needles of a pine, so
noticeable now. These scale insects will begin a new round of
needle-sucking in spring. In some cases they can weaken and
disfigure the plant. Although you can't kill them now, you can mark
your April, 2005 calendar to further evaluate and treat the problem
Originally published 12/4/04