Come on, either give me some science or anecdote here. Graft wood is very young and tends to have chlorophyll and therefore stomates. It has no corked bark as older trees do. Chlorophyll dies when deprived either oxygen or light. A tree naturally kills it off as it ages, apparently.
Incidentally paint quickly cracks as soon as trees being to grow, I doubt the smothering affect even lasts for more than a brief time- but I’m just running on imagination here. I don’t think latex paint has much stretch after it dries though.
" The whole tree: branch, stem and roots have specialized groups of cells called lenticels which open the normally impermeable bark and allow O2 to enter and CO2 to exit. The lenticels are attached to ray cells that penetrate deep into the wood. "
That’s a good question, Alan. Honest answer, I dunno! It would be interesting to see exactly how impermeable bark is and how much painting the trunk would affect that, especially considering that you’re probably not getting the same level of coverage painting a tree that you would painting a prepped-and-primered wall.
All that aside, though, flat paint is the cheapest, so if it does the job maybe that’s reason enough?
Yes, I know, but the question is what damage is done if a 2 or 3 ft length of trunk has it’s permeability limited by paint. How long does that limit last once the tree is growing and the trunk is expanding.
Of course. This discussion is academic for me and I don’t think we are talking about anything with meaningful consequences. However a little civil debate is always educational.
i don’t think anyone tried to find an awnser to that question. Since the paint that might damage the trunk is more expensive. And there seems no be no reason to suggest that the more expensive paint has advantages over the cheap one. There might be disadvantages.
This ofcourse is not proof it will not work. But i think there is no awnser to your question. Although at least not a scientificaly vigerously researched one.
Compare it to the question.
Will M26 apples taste better or grow bigger if M26 is grafted to MM111?
Might be, dunno. Don’t think anyone ever had a good reason to justify the expense to reasearch it. Since there seems to be nothing to gain by knowing the awnser. Or at least the anwser does not seem to be worth the hassle.
I would swap the question to you Alan.
Prove that gas impearmeable paint is better, than the “cheap” stuff.
Why would it be “better” ?
How would it “help” the tree. Scientific sources only?
I never suggested glossier paint would be better and I’m not really trying to be the person with the right answer. I run a nursery, manage orchards and have made my living in the dirt for 50 years so I don’t have much to prove.
However, often the cheapest paint is one that has been returned by a customer or something left around in the garage or basement from a paint job where there was some leftover.
My approach is to use the cheapest methods and least labor possible to get more or less the same results- I’m not much of a businessman, but that philosophy has helped me do what I like for a living my entire adult life.
This is hobby time for me and a discussion to help me and others understand the botany of trees better. Also gymnastics for my aging brain.
ah, alan that makes sense. Please let us know if you ever test out some old batch of returned paint that is gloss/high gloss. Im curious about the results to
Alex, what spurred you to use a lime based product vs a “paint based approach”? As the discussion after your post has revealed, it seems that the “rest of the world” generally does not use paint but uses a product like you chose…
So if that’s the case, then I pose the question to @oscar, @alan and others, “if it ain’t broke, why fix it?” As alan mentioned, sometimes the cheapest paint is the one left over from another project (this will be the case for me as well). I also have joint compound left over that will certainly end up drying out and not working properly by the time I would use it for its intended purpose, so I’ll probably try mixing it with some paint. However if you can make a mix that works out of lime (would pulverized lime work with water? A 50 lb bag is $3.49 at tractor supply) and maybe mix that with joint compound, would that be a better solution?
Sure it probably won’t stay on the tree as long as paint, but given the discussion about trunk expansion and the need for bark to breath (to what extent we clearly don’t know), does paint create an impermeable barrier either, and does it matter if it has tiny cracks? Probably not, but I am only speculating.
I am also wondering if the intent to paint is “varmint discouraging”, would a lime mixture be more of a deterrent, and shouldn’t it be just as easy to mix in spicy, rotten egg, or bitter materials to discourage critter munching vs paint?
I have a lot of questions and no answers because I have yet to paint a tree myself, but I’m enjoying the discussion.
Edit: regarding high gloss: wouldn’t mixing a higher ratio of joint compound reduce the “sheen factor” pretty drastically and also allow more gas transfer?
this is exactly my argument. Most people use the cheapest interior wall paint. Which contains
-mostly lime (cheapest filler and whithe pigment, cheaper paints usualy contain more lime)
-some titanium oxide (as a whithe pigment next to the white lime for better coverage, is more expensive)
-some resin to make the paint “stick” (resin again is expensive. so cheaper paints tend to have less of lower quality)
you could also just use lime. (never done it myself, read on why)
But lime is verry caustic. And thus easy to use in an unsafe way. If you can handle lime profesionaly and don’t mind the hassle of PE and how you’d need to use it. It might be the cheapest option. Due to the lack of binder i would expect to have to apply it more often though.
Yeah, we pretty much do because thousands of trees are painted this way in commercial orchards by their keepers, many of whom certainly were able to compare results.
People should relax about having to treat their their trees in the perfect way, IMO. Drives you as crazy as trying to raise your kids that way
The things that usually really matter are for the roots to get adequate air, water and N and that the pH is reasonably adjusted in extreme soils. That and pest control.
i am confused Alan. are you saying thousands of tree’s are painted with outdoor high gloss or high binder paint? or are you saying thousands are painted with lime or lime based flat paints?
Chemical burns in your lungs is nothing to mess around with, that’s for sure. I deal with this kind of stuff at work so it doesn’t scare me (for anyone who takes a powdered lime route to save a few bucks, please wear a high quality, low particle size mask PROPERLY SEALED AGAINST YOUR FACE to protect yourself and try to wet it down gently and quickly to reduce dust exposure).
I think you and oscar are generally on the same page with that, just trying to figure things out!
But as oscar and yourself have come to the conclusion on indirectly, as far as I have seen so far (maybe I missed something) there are few scientific studies showing the “why”, not just that “it works better when you do it this way”.
The only directions given I can find don’t even mention relative gloss so I’m guessing it isn’t a big issue just based on that. I did notice that recs suggest not painting trees until they are over 2 years old.
Wonder if this has to do with having green bark.
I’m thankful for the discussion because somehow I had forgotten that this was done as much to protect from cold injury as sunburn. There are certain red-fleshed J. plum trees and apricots in my nursery that I probably should be painting.
Disclaimer: I didn’t read every post in this thread. This is based on my own past experiences and beliefs, with some basic science mixed in.
Ryan, I went with lime because that’s what my grandpa used back in Ukraine when I was a kid. Painted every trunk every spring, from big old walnuts that were 50 years old to very your apple and stone fruit trees. It washed off in a couple of months. Doesn’t form a film as there is no resin/adhesives added.
For me, the main appeal of the lime is its biodegradability. The cost difference is minimal, but I suspect it is a factor for the “rest of the world”. If you can dig up lime from a quarry outside your village, why pay money?
I couldn’t find the chemical formula for the pulverized lime from Tractor Supply. Basically, you want calcium hydroxide. Over time it reacts with carbon dioxide in the air (a weak acid) to form a relatively insoluble salt of calcium carbonate. For that reason, it can also be used as a binding agent in plasters/putties.
We had a big barrel of lime in the cellar for as long as I can remember, submerged in water to stop the neutralization reaction. Had to top up the water periodically. Then grandpa would make a slurry, scoop it out and use it for painting tree trunks (as well as walls, fences etc).
It is caustic. CaOH2 will eat through the skin, but not as dramatically as NaOH or KOH. Splattering it on your skin accidentally won’t cause any issues but you want to avoid prolonged contact (i.e. wear gloves) and definitely wear eye protection. So, I don’t think the caustic effect is really an issue for a home orchardist.
Edit based on Ryan’s previous post: Inhaling pulverized lime is definitely a very bad thing! With prediluted lime that’s not really an issue.
I suspect latex paint is far more convenient for commercial growers.
May be worth noting that the Tennessee extension guide you cited specifies: “Use only white latex paint, preferably interior grades. While exterior latex may be used, it may present a greater chance of tree damage. Oil base paints should never be used, as they are toxic to the trunk.”
According to this source, the primary differences between interior and exterior paints are in the resins used (resins for outdoor paints are softer, to better handle heat/cold) and the fact that exterior paints outgas to a much greater extent than interior paints.
I’d guess that the greater risk of tree damage and the higher rate of outgas are connected in some way, but that’s an inference on my part.
I was trying to find a Cornell paper I read and posted here sometime ago that debunked any difference as long as the exterior paint doesn’t have certain anti-microbial chemicals in it. Apparently this is more common in exterior paints.
to make it even more confusing there are many different kinds of resin used as bineder. Most outdoor wood paints used to be terpentine or some other solvent based. While nowaday you have water based outdoor paints.
It is also really hard to prove a negative. Proving that ALL paints are safe to use requires testing ALL paints.
It is easier to prove a positive (ie that brand X applied at thicknes Y damages tree aged N of species etc)
I am sure somewhere somehow someone made an interior flat wall paint with enough nasty’s (maybe lead? arsenic?) in it to kill a tree.
However most cheap water based interior wall paint has roughly the same ingredients.
Mostly lime. some binder (although lime also works a bit like a binder. so it might have even left out the binder) somtimes some extra pigment (like titaniumdioxide) and water.
I assume they also buffer the PH. since if never seen interior wall paint with caustic warnings.
In the end the cheap interior wall paint seems like a really cheap convenient and safe way to go. I see no significant reason for a hybbiyst to look for something else.
For an industrial user it might be worth to experiment with other alternatives.
PS: @urbangardener you make an excelent point about biodegradebility. It will probably also matter for organic labeling if your commercial. However handeling lime has to be learned and done safely. It’s not inpossible hard. but it is some hassle id rather go without. And i woulden’t advise “beginners” to go trough. If the alternative is so easy and cheap.
Question - i always thought to go for the cheapest ceiling paint, on the idea that the paint would never cause issues as it was not very sturdy, and cheaper =better all around.
Now, I want to keep the trunk looking browner, more trunk-like, as the neighbors will see them. Can I use brown tinted interior paint with no issues? I certainly don’t want to pay for the brown trunk paint offered. Freecycle paint or what i have is fine.
