That is what I like about the new standards, it spells out the goal clearly.. Like so many things it all depends on the tree, location, site, and goal and even weather the day of the work. If I recall Matt's work correctly thinning the ends or outer third of the green while not as effective as drop crotching retained near normal osculation, but the movement was dampened nearly as much as drop crotching.... In my experience end thinning is the best approach for the tree, but short lived results as the tree will quickly put on more.
Thanks for sharing.. word of the day.... osculation.. just texted my GF.. "let's do osculation" ...
While there may be geographic variability in species and conditions there is NFW that thinning a branch tip is going to reduce forces on a bad crotch with included bark anywhere near as well as reduction cuts. I can only speak from experience about eastern hardwoods. Maple, oak, ash, tulip, hickory, cherry, locust, walnut, linden, ginko etc..
You take a tree that has millions of years of evolutionary programming wanting to reach for the sun, because trees evolved to grow in wooded conditions, and put it in a suburban environment where it has wide open skies over the house, pool, road, parking area etc, and especially when there are other trees soaking up the sun in other directions, that tree is going to reach for the sunlight with big heavy horizontal limbs. Quite often, those limbs are going to outgrow their ability to hold themselves up as in the case of storm damage and summer limb drop.
We had an ice storm here in 2014.. the worst any living person could remember. I saw the damage that gets done to these big old trees. MANY times it was a single lowest limb, or just a few of the lowest limbs that failed. They were the biggest horizontal limbs with the most reach because they had been around a lot longer than the upper limbs and because they had to reach away from the tree for the sun as the canopy got taller.
In the case of these big, heavy, reaching, horizontal limbs, it would be completely impractical to thin the tips rather than make one clean reduction cut. Make a 4" cut, taking ten feet of a 35' limb, and what happens? You've removed all that weight from the most leveraged part of the limb. That limb will never fail in a storm... any storm... and it will never have summer limbs drop. In most cases, the limb will recover nicely in its new form. It will put on new growth that looks natural. What you have done is to counteract the negative consequences of putting a tree in an unnatural suburban environment. You'll never get that dramatic effect from thinning the branch tips, so why do it?
The question is how far to take back each limb. When I sell pruning I explain to the customer that each limb will be treated individually, based on its species, size, reach, lean, and condition which considers any defects such as decay and weak branch unions. Those kinds of calls take experience but are generally fairly easy to make. When I pressed the issue, John Ball said the reason he doesn't recommend removing weight from branch tips is because he can't come up with a formula for prescribing how much weight should be taken off. That's pretty lame John. It can't be that hard to figure out. Maybe you can't because you don't know. You're not cutting trees every day for decades.
