dormant spray as you intended and disregard whether you've painted

Harvestman, I haven't done either yet, but last spring was the first for the trees outside. Spring here can be extremely volatile. I ended up putting metallic duct tape on my stone fruits in a panic. I know I will need to spay and paint this year.

What was the metallic duct tape for?

Just to reflect the sun's heat on a warm spring day. It was the only thing I could think of that I had on hand. I don't want to be unprepared this next spring. Colorado weather is wild to say the least.

Most of the cambium killed trees I manage have not been the result of winter temps as far as I can tell and have instead been the result of fluctuating temps in early spring as the cells take in water and become more vulnerable to freeze kill. Sorry, I only have anecdotal observation to go on here.

I think the duct tape was a great idea although foil or white plastic taped on might have been quicker. Not hard to splash on some paint either.

The trees haven't evolved to withstand sunlight? I'm skeptical. Where's the research?

IT, first, why on earth would you make the challenge for research when I specifically stated for clarification that my observations were purely anecdotal. Sounds to me like you're picking a fight more than trying to find out anything.

If you're genuinely curious about the basis for my deduction I will tell you that I've managed thousands of fruit trees for decades now on multiple sights as well as a bearing age fruit tree nursery on my own property and another site.

I haven't observed any correlation of cambium kill to harsh winters and in fact have seen more in the last few years of very mild winters. Often it occurs on sites that are the least susceptible to sudden drops in temp being next to very large bodies of water (the mouth of the Hudson river where even the Atlantic comes into play).

The vast majority of fruit trees we grow here did not evolve in our harsh continental climate, BTW.

I've never encountered genuine scientific research on the causes of cambium kill- maybe you can direct me to some of the literature. I'd appreciate it.

I appreciate the anecdotal observations of contributors here even more. Science based research usually isn't hard to come by. This site is mostly about real life experience with fruit trees. Ya notice?

I have read explanations of the cause of cambium kill just never any research verifying what specific conditions in which it is most likely to occur. Vulnerability depends a lot on the amount of water in the cells which is determined by the level of dormancy in the plant.

I loose much more apricots and certain red J. plums than anything else, and considering that both come out of dormancy early it is a good bet that damage is done in early spring.

You find research in pecan trees new planting for sunscald and rabbit nawing bark off around base tree. Matures that have problem with pecan wevils they painted with chemical kill as climb up trunck tree. The part about 50/50 mix is meth you can nix water in laytex up to 50% so as make more volume.

Borer protection

Voles and rabbits seem a little less likely to chew it (although they still do)

Seals crevices that insects use to lay eggs.

Easier to spot bugs or damage to trunk.

I'd definitely stay away from the metallic duct tape. The main reason latex paint is watered down is so the tree can get some air through the protective layer. Duct tape is impermeable to air and water, so could probably cause all kinds of problems like rot and harboring insect activity.

"The trees haven't evolved to withstand sunlight? I'm skeptical. Where's the research?"

I don't know why Harvestman took your question so personally. I read your comments and his a couple of times and don't understand it, but anyway....

There has been tons of research on the topic(s). If you google 'tree trunk sunscald', you'll get quite a few relevant hits. I will post a few links below that I only very briefly skimmed through. Most of what I found in my very short google search is more of the resulting advice than the actual research, but some do contain direct research results and many of the articles reference their sources if you want to drill down farther.

One big reason that "evolved" resistance to sunlight doesn't apply is because the trees with the most likelihood for damage are those that are recently planted (not natural). Other related issues include sudden, significant foliage removal by pruning (not natural) and grafting (not natural). The problem is common and has been well documented, so that alone proves that natural resistance is not sufficient in the cases we are concerned with.

http://www.caes.uga.edu/Publications/displayHTML.cfm?pk_id=7331

http://www.mdvaden.com/sunscald.shtml

http://plantsciences.montana.edu/horticulture/HighAltitudeLandscapes/sunscald_of_deciduous_trees.htm

http://www.treelink.org/joa/2001/sep/Factors_Predisposing_Urban_Trees_to_Sunscald_roppolo.pdf

http://joa.isa-arbor.com/request.asp?JournalID=1&ArticleID=1857&Type=2

Brandon, do me a favor and don't editorialize on the nature of my comments. It is better if we don't relate personally given our history- I don't think we really understand each other.

I wasn't upset as much as puzzled and I sure don't want you as an intermediary or interpreter.

Incidentally, I wasn't talking about sun scald but about lethal cambium damage which for me is a much more serious issue.

When there is a big crack on the southwest side of a tree, I call that sun scald. In the damage I'm talking about the plants show no obvious damage until they fail to leaf out.

Apricots are notorious for doing this. I've also seen it occur with Elephant Heart plums a lot. Santa Rosa will get cankers from it (not on the southwest side particularly) but usually survive.

"...why on earth would you make the challenge..."

"Sounds to me like you're picking a fight more than trying to find out anything."

Harvestman, you're so right. How could anybody possibly think you're "upset"? Afterall, you're always so easy to get along with! Oh, and BTW, according to what I've read, "By the way, you don't get to post a message and constrict response on a forum."

No, but I can ask. The forum would be better off without us constantly involved in pissing contests and I propose that we just don't interact from here forward- unless this is more fun for you than for me. From my perspective it's really quite pointless. You're never here to discuss fruit trees anyway- I wonder if you even have an orchard- you never discuss your experiences with your own trees.

Brandon, take the personal stuff to e-mail, this a FRUIT FORUM not a PERSONAL FORUM.

Harvestman,

Like some other past contributors (some of which got tired of it and left), I don't participate in this forum as much as many others largely because I'm not fond of hearing your insults and belligerent, uncalled for attacks. You seem, to me, to take EVERYTHING personally even when your name is never mentioned and you weren't addressed. Insipidtoast's post didn't call for your aggressive response.

I do have a personal orchard as a part of my arboretum. The orchard section is somewhere around 2 acres in size. I'd be happy to discuss it, but probably not with anyone more interested in personal attack than pleasant discussion.

Michael,

Michael, I'll direct you to your own post. You are correct, and that is EXACTLY why I said what I said and would do so again without ANY hesitation!

P.S....

Michael,

It's kind of in my nature to take up for the bullied. I'm not trying to assign any bully or victim status here, but just giving you an insight as to why I felt compelled to respond. I've seen quite a few people being responded to inappropriately in this forum, and I don't like it. I believe it hurts us all to have people feel uncomfortable using this forum. I think we should all stick to the subjects and discuss things as neighborly adults. Unfortunately, as it seems was the case above, that is not what often happens. Addressing that issue is appropriate when the problem occurs in the forum.

OK, back to the topic....

A nursery man from KY recently told me that painting the trunks white seems to discourage the deer from rubbing the trees. His theory is that the white trunk just isn't as visible to them. He mixes cheap paint 50/50 with water. I will be trying it on several hundred pawpaw trees.

[[[....The trees haven't evolved to withstand sunlight?...]]]

I'm not being a smart alec, here. I think maybe some people would like to hear the answer to this question.

Our modern fruit trees did not evolve. They were bred and selected for improved fruit. Unless the plant breeding program had sun scald resistance set as one of their criteria, the trees were not bred to be resistant to sun scald.

If trees are protected from sun scald by human intervention, the trees that are susceptible don't have to answer to "survival of the fittest" which is how mother nature "evolves" trees.

There are a lot of varieties of trees that did evolve, answering only to Mother Nature, that get sun scald. Young maple trees get it really badly. That's because they evolved in a forest setting where they grew in shade when they were small.

OK, I'll bite and say, "Is there any research to back that up?" Specifically, are there differences in the non-domesticated relatives of modern fruit trees that, given the same treatment (being transplanted, pruned, grafted, etc), do not show these same signs of damage? If the domestication factor adds a significant reduction in tolerance, wouldn't we see a big difference?

To Insipid Post. Brandon's interpretation of my response to your question was certainly not the intent of my communication, though I can see how it could come across as such- I should have at least edited the "Ya notice".

In rereading it, I don't even think you were responding to my post, it just happened to fall in that order and it was only coincidence that you asked for research based info right after I said my statement was based only on anecdotal observation.

I was mainly trying to explain what my anecdotal observation was based on so you could evaluate its usefulness. I really participate in this forum to help people, free of charge, have successful relationships with their fruit trees. I'm not saying my ego doesn't get tied up into it, of course.

I have no reason to actually think you were offended anyway. Presumably you could speak for yourself if you were.

Since, as far as I know, Brandon, you are the only one who cares. I suggest that you do the research yourself and come back and let us know what you've learned.

Brandon: I have no problem with folks helping the bullied but that is not the function of GW forums. We should stick to our experiences as they relate to the forum in which the post is found +- the wavering that threads take off topic from the OP. Corrections where they appear to be needed and additions to other's statements seem to be how the most educational threads go. Yes, I've seen personality enter comments but 99.9% of the time just let it go because it can be very difficult to communicate accurately in this medium with no benefit of voice inflection, tone and facial expression not to mention body posture. I hesitate to judge what I think someone is communicating here knowing that communication here is so handicapped.

Thank you Michael. As a 58 year old (as in pre-computer) non-professional writer, I can confess to being clumsy at the interpersonal communication of this medium. By nature, I do like to tease people, in person, but with a twinkle in my eye, and I've never been punched in a bar or at a party, I swear! Could be why I don't always get invited back, though.

"Since, as far as I know, Brandon, you are the only one who cares..."

Oh, I figured you might have at least some basis for your opinion. It might be an interesting thought if there were any evidence. Without any evidence, I guess there is no need to pursue the idea further or even believe it's likely the case.

H-man: yer welcome. I barely caught the computer wave back in high school in the 70s, good thing too. Too bad I declined to take HTML classes in 1994 because those wonderful EGA screens at work were burning holes in my eyeballs. I'd have more experience designing web pages than the vast majority of people now, oh well, who'd have thunk the gravity of that decision back then.

Maybe we'd benefit from using those cutesy-pootsy emoticons to aid in communicating better, I won't be any time soon, too cutesy-pootsy for me.

And now back to the topic of trunk painting...

OK, a big part of my business is renovating and then long term management for fruit of great big old apple trees. These trees are really tough but if you take off too much wood during dormant pruning it seems to clearly cause classic sunscald. In this case it is always on the sun exposed large branches that have lost the majority of smaller wood and wood previously in the shade is exposed to direct sunlight.

Old timers used to routinely cut off every smaller diameter branch on such trees to de-elevate them and get them under control. Almost like tearing down a house but leaving the foundation. It was a process known as dehorning.

To protect trees I gather it used to be fairly common to paint the newly exposed wood white. I suspect this had some efficacy because sunscald is so common when trees are treated like this, anecdotal evidence would probably be adequate- like taking aspirin for a headache.

Incidentally, I've found (anecdotally again) that if you do your major structural pruning in very late summer when the sun in in decline you seem to be able to get away with a lot more big wood removal without getting scald. It leaves enough growing days to theoretically send a lot of extra energy to remaining leaf buds.

I theorize, without corraborating research, that trees are often actually scalded in early spring. It seems to be as much about pulling sap for cooling the wood as it is about taking away shade. As trees bud out they need to be pulling adequate water to cool the wood on those first clear warm days of spring after bud break.

Maybe I'm just creating a logical old wives tale, but I think trees can be scalded because too many buds are removed reducing transpiration and natural cooling. If this is the case, paint should help by keeping bark temps lower.

Excellent line of thought H-man. I wonder how much effect region has on your old wives tale if any at all. Used to live near Orchard Mesa, outside Grand Junction, CO, what a unique place to grow fruit; a west facing slope laying below 10,000' elev. Grand Mesa, the world's largest flat top mountain. In addition, it is just above what is in effect a desert valley, talk about intense sunlight and very rapid temperature swings from the intense sun and cold air spilling off the mesa when the sun goes down.

You might enjoy talking to CSU's researchers there at the Orchard Mesa facility about sun scald. Seems to me they have a prime environment for sun scald.

Here is a link that might be useful: Western Colorado Research Center

I think most everything Harvestman said pretty much matches what I've heard/read, except for the thoughts about how late summer versus dormant pruning affects sunscald. That part makes sense though.

Thanks Brandon.

Have you read anything about scald induced by spring temps rather than winter? I will contact Michael's link and see if I can get anything from over there. I'm wondering if white paint is affective at all in preventing this kind of injury because I'm not even sure if it's caused by sudden temp drops. I don't know if what kills apricots is the same phenomena that causes scald on apple scaffolds and I'm not sure if either are caused by sudden temp drops. Actually I believe the cambium is cooked in the case of the apples.

I doubt that painting apricots is highly affective or apricots wouldn't have such a rep as being a fragile tree in much of the country. Just a tree that requires painting.

Sometimes I get around to painting the trunks of susceptible trees in my nursery, sometimes not. Maybe I should start painting half of them. I suddenly feel pretty ignorant about the entire issue. That can be the ultimate problem with anecdotal info, I guess.

I should have said that I'm not at all sure paint helps apricots and sensitive Jap plums. I'm pretty sure it helps with the apples- whether it's from the cambium cooking on clear warm spring days or cells bursting from sudden change from hot to cold, either in winter or spring.

"...scald induced by spring temps rather than winter?"

Yes, scald happens when the cells break dormancy and become active (their chemistry actually changes and they are filled with less "plant antifreeze") followed by freezing temperatures which damage the then-active cells. This is more likely to happen in spring than in winter, not only because of the temperature variation/range, but also because of the plant's "season-sensitive" reaction to the temperature rises.

susceptibility of different types of fruit trees and effectiveness of white paint to solve the scald problem

I don't know that I can add anything useful concerning different fruit tree species susceptibility, except to say that the difference would be due (at least mostly) to the difference in chemistry of the cells (the chemicals involved in the plant cell "antifreeze" actually vary with different species).

I haven't seen convincing data that white paint greatly reduces the problems of sunscald, although it has been anecdotally (Harvestman's favorite word) shown to help in some situations (see DWN's Ed Laivo video linked above, or google 'ed laivo painting trees' if the link doesn't work, which seems to be the case right now for some reason).

Brandon, as I understand it, it's more about water content percentage in cells. The water is drawn out of cells as they harden off and they pull water back in as plants come out of dormancy which makes them more vulnerable to similar temps in spring or late winter. The cells simply burst when they freeze because their walls lack adequate elasticity when water expands as it freezes.

But you'd have to play really close attention to know when precisely damage occurs because trees show symptoms long after injury.

Anyway, the importance of specific chemicals in reducing the point of cell freeze isn't something I've read about- or at least that I remember, except as it applies to leaves. Maybe you could direct me to something that can clarify this further. I may have dated theories in my brain and need a refresher course on this one.

Water in the cell is part of it, but it's more complex. First, the contents of the cell are in solution, and that solution is part of what keeps the cells from freezing or being damaged. I wrote a paper on this a few years back (that contained some summaries and references that might be helpful here), but I'll have to see if I can dig it up. I have a pretty good feel for a lot of what happens, but I'm not sure I could easily spit it all out in a short and easy to understand format right now.

Good, I'd like to see it. The specifics may not affect management of the problem but I do find it very interesting.

For practical purposes, simply running with the water concept is nice and simple for me to hold. I'm not sure I have enough capacity to carry much more than the basics on this one, but I can add some anti-freeze to the water OK. I would like to know what the specific chemical is even though I'll quickly forget it.

What I need to know for sure is if it's worth my time to paint my apricots and certain J. plums white. I have managed trees that came from a commercial grower where the at least 15 year old (yes the customer started with 15 year old trees) Santa Rosa trunks had been painted white. When commercial growers do something that takes time and money, they are likely to have a good reason.

By the way, 10 years later those instant orchard trees are almost dead and need to be replaced. Maybe I should have kept painting the trunks- who knows?

Actually the grower probably got rid of the trees because they were already past adequate productivity and laughed to seem them go for cash.

I think that I have made a mistake on the apple trees that I planted this spring. About a month ago I painted their trunks with a white OIL BASED primer. The good news is that I only painted the 1/2 of the trunk that is exposed to the south. I didn't paint the 1/2 exposed to the north.
I see that everyone here uses latex (waterbase) paint) and many even thin that.

The trees have trunk diameters around 1 inch.

Will there be damage from using the oil base primer? I never did apply actual paint.

Do you paint the entire trunk or just what is exposed to the southern sun?

I'm OK with people's opinions. Your replies don't need to be scientifically proven.

I think I've read that an oil based primer will do no harm but that latex is just cheaper and easier. The latest is that both interior and exterior latex are fine.

I'd recommend painting all the way around but using latex, although there might even be one advantage to the oil. It might protect against Roundup and certain insects better. I wonder if the latex might stretch a bit, giving longer lasting sun protection as the tree grows.

I bet someone else can give you a more definitive answer.

Northernmn,

That's a good point. I've always heard from many sources not to use oil base paint, so I simply repeated it in my post. But now that I think about it, I don't think I've ever read of anyone actually using oil base paint, so I'd be interested to hear what happens to your trees.

The idea behind using latex paint is that it allows the bark to "breathe" where oil base doesn't allow the transfer of gases. But I don't know how critical it is for the bark to breathe.

I've used both 50/50 latex and straight latex paint, and haven't noticed a difference.

I don't think breathing is the issue as much as trapping moisture which is a problem when I put tangle trap over stretch wrap- but the damage is gradual rotting of the bark during the growing season. In this case water won't be trapped and in fact when trees grow in spring the solid paint will be split. Unless there's something phytotoxic in the paint I really would be surprised that even painting all the way around would be noticeably destructive.

I too would be surprised if oil-base were problematic. Latex is a relatively new product, and it seems like the practice of painting trunks goes back well before its common availability. Old timers may have been using milk paint but I suspect white lead was what was getting put down.
In terms of breathing...many studies have shown that over finished goods it takes 3 plus coats of any paint (with the exception of epoxies and shellac) to develop an appreciable barrier to vapor and oxygen transfer. This might not directly transcribe to living tissue but would seem to hint that a single coat of either won't get you in much trouble in that regard. Do we even know how much "breathing" is occuring in this area?
Brandon, I too would be interested in the paper you mentioned. Often cell damage from freezing is not so much bursting...although this certainly happens, but micro punctures to cell walls and internal structures. This gets caused by tiny needle-like ice crystals that form in a "slushy" environment where solid freeze can't. Such damage might explain the more gradual failure Harvestman notes as opposed to rapid and complete collapse that total cell rupture usually causes in herbaceous plants?

No, the gradual decline I mentioned is not really gradual. It's just that the trees can get enough water through the damaged cambium to support flowers and the beginning of leaf growth but as water demand increases the trees are toast. If you cut into the cambium you won't find green tissue.

By the way, I've tightly wrapped trees girdled by deer and livestock with straight plastic- not to help the wound heal but in the hope of reducing evaporation and getting more water above the wounds- and to make a client feel better (I admit it). I would remove the plastic sometime in mid-summer with no damage from having plastic tightly taped all the way around 2 foot of trunk or so. Stretch wrap covered with tangle trap does much worse.

Some nice debate here. I'd be interested to know if we can come to some sort of conclusion. My feel is that some growers don't even know why they put they paint on - like the guy from a Santa Barbara county peach orchard who said he does it for "aesthetics."

I'd like to throw another interesting perspective into the mix:
In mexico many of the street trees have the bases of their trunks painted white. This is commonly seen with Ficus benjamina trees throughout various regions of Mexico, and even with Washingtonia robusta palms in norther Baja. In southern California you never see a Washingtonia's trunk painted white.

Enjoyed the debate. Is the best way to find holes in an argument - all parties can learn if they listen. On the topic of waterflow (sap) in the spring vs. antifreeze, chemically a hypertonic solution (high concentration of salts and electrolytes) freezes at a colder temperature than water. That why the ocean doesn't freeze at the same temperature as fresh water. So the 'antifreeze' is probably in part due to dehydration of the cells when sap flow is low. There's no reason to think that cells couldn't manufacture substances to add to this phenomenon but they may not need to. It takes energy to manufacture such substances, and it's a lot more conservative to simply cut off the flow of sap to the trunk and enter a dehydrated stasis. Pretty smart engineering if you think about it. Trees in warmer climates may not be able to dehydrate as well, or a key to their success in warmer climates may be budding before the bugs can get to them, risky behavior further north.

Last fall I painted the trunks of my new apple trees with white, OIL BASED primer insteaded of latex paint. The trees were only painted where the winter sun would shine on them (northern exposure left unpainted). I posted on this thread at that time: "I am wondering if I have done something really bad" and others on this thread were also curious what would happen.

I'm happy to report that there seems to be no ill effects from the oil based primer. The trees are just starting to leaf nicely this spring (zone 3/4). Hman thought that the oil based paint may be less elastic than latex and would crack sooner. This is probably true because I am already seeing cracked paint that is more than likely from the tree trunks swelling.

Thanks for the report Northernmn,

Your experience suggests the rule to use "only latex paint for the trunk", may well be a myth.

I suppose since trees can take tanglefoot directly on the bark, I can't really think of any reason they wouldn't tolerate oil based paint. I think tree bark many times is tougher than what we give credit.

Many years ago when I started painting I didn't even know
what to use,....have chosen latex because I thought it would
more of a environment friendlier paint.

The trunk-painting tradition in the south long predates latex paint, though a lot of the early practice may have been with whitewash (water based) rather than with white-lead oil paint.

Is it OK to NOT dilute and apply 100% latex paint?

I read halfway through the thread above until the personal stuff started, then skipped down here. Sorry if the answer is above.

I recall a DWN video state the 50/50 dilution of the latex paint was just for "easier application".

Brandon7 >>>> The main reason latex paint is watered down is so the tree can get some air through the protective layer.
Makes me wonder if the thickness of NON-diluted latex paint (or application of a few coats) can cause such issues.

I considered this when one of my dying Fireblighted pears showed rotting just under non-diluted (green) colored paint. As it peeled away, it looked like the latex had sealed in some moisture and kept out air to dry it out. This was only in appearance, I'm sure it wasn't the cause of the trunk problem and I know the trunk was dry when I painted it on.