Trees communicates???????

Pedro J. Aphalo aphalo at
Mon Jun 5 02:21:16 EST 1995

In article <h+99NQG.nanharrison at>, nanharrison at 
>Guillaume, some research in Calif shows that Oak trees infested
>with tent caterpillars or some other pest will communicate this
>to other Oak trees.  They will then become more resistant.  No,
>I don't have any references to give you, but I'm just
>suggesting that you are not alone in having heard about this
>kind of phenomenon! A toute a l"heure - Nan in Calif

One recent review on this kind of phenomena is:

Bruin J, Sabelis MW, Dicke M (1995) Do plants tap SOS signals from their 
infested neighbours? Trends in Ecology and Evolution 10: 167-170.

The idea that neighbours "feel" that a tree is cut and respond by 
reinforcing their bark is very unlikely to be true. Above all, because a 
thickening of the bark would take a long time to occur! And also because 
axes and chainsaws have not been around for long enough for such a 
response to evolve!

However, what is the time scale of the supposed response?
In the long term many factors will affect the growth of the remaining 
trees: one of them is release from competition, which could potentially 
lead to thickening of the bark! Also bear in mind that individual trees 
of the same species growing near each other can be connected through 
natural root grafts... and neighbours can "adopt" the roots of the felled 
tree. There are many ways in which plants can interact, so you may also 
want to look at our recent review:

Aphalo,PJ; Ballaré,CL (1995): On the importance of information-acquiring
systems in plant-plant interactions. Functional Ecology 9, 5-14.

I hope this helps.


 Pedro J. Aphalo
 University of Joensuu, Faculty of Forestry
 P.O. Box 111
 FIN-80101 Joensuu, FINLAND
 Internet: aphalo at
 fax: +358 73 151 3590, tel: +358 73 1513623        ,,,^..^,,,

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