Good and Bad Woods for Pressure-Treating

Here's a list of wood species that accept preservative treatments readily, and wood species that don't. July 11, 2013

Question
I have some white pine 6x6 posts that I would like to get pressure treated. Yesterday I heard from a forester that white pine does not lend itself well to pressure treating. Is that correct? If so, why?

Forum Responses
(Sawing and Drying Forum)
From Professor Gene Wengert, forum technical advisor:
Except for the red heartwood and knots (red or black), I also would be interested to hear why it cannot be treated well. In fact, I believe that it might absorb quite a bit of chemical, which is expensive, but provides outstanding protection. Note that for large timbers, only the outside is treated heavily; the core is often not treated much at all.

Here is a list of easy-to-treat species:
basswood
green ash
red oaks
redwood
river birch
slippery elm

white ash
cottonwood
Douglas fir (coast)
eastern white pine
ponderosa pine
red pine
southern pines
sugar maple
western hemlock
yellow birch

Hard to treat:
eastern hemlock
grand fir
hackberry
lodgepole
pine noble fir
spruces
sycamore
western larch
white fir
alpine fir
black locust
Douglas fir (Rocky Mountain)
tamarack
western red cedar
white oaks

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From contributor B:
Eastern white pine does treat quite readily. There are a couple published papers in the literature which document this, and a treater in Maine who used to, and may still, do a fair volume commercially. Be sure the MC is below 25%.