Lichen Growth on Trees
Can you tell me what is causing lichen to grow on all my
tress, from crab apple to spruce, and how can I get rid of it???
"Attempts to remove lichens are rarely successful."
Anthony Brach Ph.D.
The fact that lichen is growing in your area shows
1. there is a source bringing this symbiosis between
an agla (plural algae) and a fungus (plural fungi) in
contact with your trees
2. conditions are good for the growth and development
of the lichen.
I would answer your question with a question: Why do
you want to get rid of the lichen?
There is no real reason to do so....the lichen will
not harm the trees on which it is growing...it is
basically just using the trunk of the tree as a place
to live. The symbiosis of the alga and fungus means
the lichen survives via the photosynthesizing
capability of the alga, and the fungus gets what it
needs from the symbiosis.
I have several trees along the road in front of my
house, and I was observing the lichen growing upon
them the other day. I planted the trees 15 years ago,
and I was pleased to see that what once was a former
farmer's field, then covered with weeds of all types,
was now an environment in miniature.....the lichen had
found a satisfactory place to grow and develop, and
the tree is simply providing a place to do that.
Summarizing, the development and success of an
organism in an area depends first on something
bringing the organism to the area, and secondly, the
provision of a suitable environment for survival. If
the process were to be interrupted (which, again, I
don't recommend), it could be done by stopping one of
these two functions. Adjacent (nearby) forests/trees
where lichen is on the trunks could be leveled and
destroyed. The environment could be altered to make
it less suitable for growth of the lichens; a thinner
canopy with more penetrating sunlight and less
moisture would do the trick. Conceivably, the lichen
could even be removed by abrading it from the trunks
of the trees, but this could certainly damage the bark
and potentially create a infection port for harmful
organisms, namely insects and/or pathogenic
My opinion: leave well enough alone, and enjoy the
development of an environment (the lichen) in an
environment (the tree trunk) in the big environment we
Thanks for using NEWTON!
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Update: June 2012