How We Know What We Know

Old Monkey

Treehouser
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Mar 9, 2005
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I find it interesting how many assertions people make are based personal anecdotes and not on some sort of factual evidence. Our pediatrician told us that there is no evidence that milk or dairy increases mucus levels in people and yet I hear that assertion all the time. In our field we have prescribed different treatments and types of pruning that have, later after study, turned out to be false. I am thinking of things like thinning out trees to reduce wind sail, putting dressings on tree wounds and cuts.

Today was the last day of our Idaho Horticultural Exposition and our speaker today muddied up the water on a few things I had been telling my clients. For about a year I have not been recommending amending the native soil when you plant a tree. The thought process explained to me by last years lecturer was that you create two different soil mediums and that the tree roots stay in the nice porous medium and circle around instead of trying to force their way into our native clay soil. Today's lecturer says that amending the soil is beneficial and that the only problem associated with the two different mediums is that water will not pass between the two zones unless saturation occurs. She does say that the roots won't venture out into the native soil if the compaction is too great but seemed to suggest that the composting of the planting hole would give the tree a boost and make it more vigorous before it tries to breach the native soil.

Now I understand the logic to planting bare root in native soil that has been broken up so you have one continuous medium. I also see the logic to what she has suggested. What will I tell my clients? I am not certain. I have planted two trees in my yard by washing all of the planting soil off of their roots and digging shallow and wide for planting. I guess I will have to give this time and see what works for me. Too bad I don't have room enough for a control group.
 
OK THEN .... As far as milk products making mucus... Katy and I and the kids and my siblings and parents all can prove that it does. Katy and I are personally asthmatic and can attest to that very fact ...
As far as trees and roots ...
My past experience has proven to me (no green thumb btw) that if I mulch the soils to be used around the tree roots after I dig a hole that is 2X the box of the root.. they do hella better.
I can also attest... That if I use natural compost (especially red worm) they do better than just straight organics.. I would attribute this to both loose soil for root expansion (I have also added sand in some cases to the clay with the organics to loosen the soil) and nutrients supplied by both the worms and the bacterial necessities the plant or trees need.
Did I mention that we plant in brick grade and pottery grade clay here. ;)
 
There was an article several years ago (In The Journal of Arboriculture I think) with data on planting with large control groups. The conclusion I drew based upon the data was that creating a transition zone from the container grown plant's potting soil to the native clay was beneficial and the creation of "rays" of ammended soil via. a series of trenches radiating from the planting hole was even better for maximum early growth and avoiding girdling root formation.

As for how I know what I know.... it sure helps being a genie ass.
 
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Digging twice as deep as the size of the pot is no longer recommended as you are likely to have settling, resulting in a tree that is planted too deep.

I guess my point is that there is a difference between anecdotally knowing something and being able to prove it through scientific research. We know some things work but we don't necessarily know how or why.

As for your successful plantings have you ever dug them up later to see where their roots are?
 
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There was an article several years ago (In The Journal of Arboriculture I think) with data on planting with large control groups. The conclusion I drew based upon the data was that creating a transition zone from the container grown plant's potting soil to the native clay was beneficial and the creation of "rays" of ammended soil via. a series of trenches radiating from the planting hole was even better for maximum early growth and avoiding girdling root formation.

As for how I know what I know.... it sure helps being a genie ass.

Yeah I have heard the bit about radial mulching too. It wasn't discussed today.

We had a guy earlier in the week discuss decay in trees and tree hazard assessment . At one point he just blurted out that we should ignore the strength figures used to decide the relative strength of hollowed out wood. I think what I need to see is a knock down drag out debate by tree scientist types so we can hash out best practices. I am thinking it could be like a cage match.
 
Darin... I should have clarified... Never twice as deep ... only twice as wide..
I dig maybe 25 percent deeper than the box ( MAX)... On the bottom I mix clay with the mulch and rock for drainage and root growth. This prevents the settling.. As long as you also allow for it on back fill the same 25 percent. Now granted I live in a pretty dry environment.. More moisture I might just stop at box and proper depth to the root. ;)
I have not ever dug up my plantings as they have all done well with this method (and I stress this!) IN MY ENVIRONMENT.
If it ain't broke in 10 years... You damn well don't mess with it ..
Just keep nurturing it and feeding it according to where and what you live in.. ;) If that makes sense........
Environment has to be taken always as a consideration...

I also forgot to mention that we do incorporate our native soil into the plating process even at the potting stage... as we transplant from pot to pot, and then to ground... we assimilate the plant to our environment.... The worm compost is a serious advantage though :D
You should see the difference we have in the green house with the different soil treatments we have tried including the worm composting.. HUGE....
 
Too bad I don't have room enough for a control group.

Remember to blindfold the control group.
True science calls for a "double blind " control group, so maybe you should blindfold yourself, too:D
 
Just because there is no scientific data doesn't mean it isn't factual. It just means no one felt the need to do a proper study.

But I have no scientific evidence to back up my claim.;)
 
Just because there is no scientific data doesn't mean it isn't factual. It just means no one felt the need to do a proper study.

Very true. And, lots of concepts initially supported by science are later proven to be false or only partially supported. Science is great but sometimes it's a mistake to hang your hat on it.

It's seems to me the problem with tree research is that findings are so long in coming... way longer than a masters or PhD project. There's not a lot of funding for 10 or 20 year experiments. Never mind that the financial returns on the research would be considered non-existent by most funding organizations.

We (tree people) just have to do it ourselves and even if we keep better records than a postgrad it will still just be 'anecdotal' since we don't have academic sanction.

To me, one of the best things about tree work is, it still has art to it. In 1987 I got into network datacom... almost nobody was doing it in a business environment short of Sperry and IBM. You had to just know the systems you worked on, all the little environmental quirks, the users, the rev levels, the weak spots in the cabling plant, etc. You had to be on the ground with a particular system to manage it... it was art. Structured datacom in the office was still over a decade away. Computer guys were wiz kids, gurus, blablabla. That's what made it fun, it was virgin ground and we were the ones developing the standards, or... actually the non-standards since no organization sanctioned them. Now it's fairly cut and dried by comparison.

The point is, if there is to be real, long term tree research, it has to be done on the ground by career professional tree people who are in for the long haul and have more to gain from it than money or a sheepskin. Non-scientists are capable of scientific research but we don't have a very good channel for publishing and peer review.
 
Darin, I have been wading or sifting if you will through these dirty issues for some time and the conclusion I came up with is to avoid any extremes.

In these lectures, the examples they usually present are of extremes. For example when they say don't mix amendments they are usually talking about carving a hole in the ground and packing amendments into it.
My practice is to mix smaller porportions, no more than a third for example.

You washing off all the potting soil from the roots prior to installation seems excessive to me.

But I agree with you that there is alot of conflicting information out there.

In the last Sudden Oak Death seminar I attended, the lecturers were all over the map with their information and much of it conflicting.

I understand that often grant money is at stake for these studies and the researchers are working in separate groups, coming up with conflicting results.
It would be helpful to know exactly, but our field is a fairly new one, and much is yet to be learned. Your experience in the field as it pertains to your local area is probably the most valuable for you. As long as you pay attention to what your doing and check up on your results.

Someone told me that in the future, it will be much as it is today, except that things will work better.
example, a cell phone will look the same, but it wont have 'dead areas', computers won't crash, batteries will last and last,
I imagine best plant practices will be the same.
 
I think removing or washing off the soil from the roots will cause more harm than good, since you damage all of the tiny hair roots where transpiration actually occurs. Most transplanted tree deaths occur in the first week. And Frans is correct, avoid extremes. Just because one extreme is not best doesn't make the opposite extreme correct.
 
Eh, I am comfortable in giving a years guarantee. The nursery gives me that.


I am always correct you little skwerl :lol:

It may be different in the PNW but around here, you can plant a tree upside down and it will live over a year. All the nurseries here give a year. Most of the young tree deaths I see are between two and five years old... could be because nobody bothers to call an arborist about a dead sapling though.

Big culprits are SGRs, deep planting and the biggy... wire baskets and non-degradable cords choking the stems. Oy!
 
When I worked at my gummint city job many years ago, we planted about 250 trees every winter. They were planted using 'old school' methods which included bare root and cutting off 90% of the crown "so there would be less volume for the roots to support". About 30% usually died in the first week or two. It would take about 500 trees per year to get 250 that lived. This took an incredible amount of financial resources as we had our own nursury where we grew the trees, we had a water truck so the crew idiot could drive around and water each new tree three times per week, and it took most of the crew the better part of 3 months to dig and plant all those trees. Not to mention many days of pruning and caring for the trees in the nursury.

The last couple years it appears they are now using container grown trees and it looks like their success rate has improved dramatically. I can only hope that a budget cut forced them to use more efficient methods.
 
[...]

The last couple years it appears they are now using container grown trees and it looks like their success rate has improved dramatically. I can only hope that a budget cut forced them to use more efficient methods.

That's pretty funny. I wonder how often government finally gets something right when they're forced to be creative because than ran out of cash.
 
Great subject, Darin.
I've been wanting to make a model out of an old aquarium to demonstrate soil profiles and how watering affects them. It'd be a good learning tool.
What your speaker-lady told you is correct (re.: saturation), but it would've been nice if she could have expanded on it a bit.

Control groups for trees has got to be a tricky thing even on its best day ? Find atleast a dozen trees of the same species, planted in the exact same location, same age, same planting medium, same, same, same... and you'll still get variances that have nothing to do with the actual test.
I agree with the idea of combining field experience with academics & keeping open (cage fighting included) debate alive.
 
Good points on avoiding extremes, amending and blending so there is no interface.

The strength loss formula fight has been fought, and the formula lost.

tried to attach pdf, again, :whine:
 
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Ok so the strength loss formula doesn't work then? I wish the fellow had elaborated. I need to read more trade magazines but they put me to sleep after work.

They are going to do a TRACE class and exam here this year. They have filled their 15 slots for the class and now they are taking names for a waiting a list. If enough folks sign up they will add a second class. I don't think my pathogen identifying skills are up to taking the test and the class is $500 so I am not certain I will take it this time around.
 
Quoted from the Tree Planting BMP's (pg. 20):

"On sites with high-quality soil, the backfill does not require amending. Consider amendments only on sites with poor-quality soil to improve soil structure, water-holding capacity, or drainage. Amending the whole planting site is preferred.
Amending only the backfill soil used in the plantinghole may provide limited benefit but will not cause harm if done properly. Discontinuity of soil properties between amended backfill and site soil has been blamed for inhibiting root growth out of the planting hole. In reality, the roots simply are unable to penetrate the poor quality of site soil outside of the planting hole. It appears the soil transition, rather than the impenetrable clay soil, is responsible."

jp:D
 
Amending the whole planting site is preferred.

Easy for them to say ?!? I've only known of one person (customer) ever to do this. It was hellishly expensive, and I truly didn't see a difference in the health of the trees & landscape plants.
the rest of the info was good... thanks for posting it. :)
 
Yeah, I think the way the writing was worded for that sentence and placement came off as confusing. I interpreted to mean that when the soil is known to be of poor quality (fertility, physical properties, compaction etc.) then the whole planting site should be amended.

Similar to the Fert recommendations: no need unless there is a known deficiency.

jp:D
 
Vineyards are a high dollar crop and they often change the entire soil horizon up to 10-15 feet in vineyards. Often many acres.
But that doesn't happen in our tree world unless maybe it is an arboretum or something like that
 
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