Every article you read about pruning tells you the same things, like 3-step cuts, leaving branch collars, cutting out crossing branches, removing co-dominant leaders, don't cut more than 1/4 or 1/3, don't cut power lines, your finger or your little brother's finger, don't poke your eye out, etc. I aim to tell you about things they DON'T tell you.
The ultimate goal with pruning just about any tree is to make it look like it was NEVER pruned, but rather magically grew with proper balance, branching, shape and taper, all without human intervention, all the while looking informal and not like a lollipop or a mushroom. This achievement of a tree following the rules actually is quite rare in nature, and very, very few people have the skills to make this happen. Almost every tree you'll ever see has issues, no matter who pruned it or how frequently or infrequently. Bonsai experts are great at getting this look, ironically with the challenges of keeping the tree less than two feet tall. Very few tree surgeons, arborists, "expert" pruners or guys that advertise on Craigslist get it just right, usually not even remotely right. The best situation I come across is when I get a tree that's only a few years old that's been almost untouched, granted the growers usually already start it off on the wrong foot. They earlier I get my hands on it, the easier I can train it to look great and stay healthy. Any other condition usually means repairing botched earlier jobs, and a great-looking tree may take years of diligent pruning, but likely will never be close to perfect.
So here are the things almost nobody tells you about good pruning. You should NOT do these:
1. ATTAIN WHORLS & KNOBS. A whorl is a situation when there are more than two branches in one union, or more than one branch coming directly out of the trunk at one point. With a few exceptions where trees have a natural branching pattern of 3 branches that's hard to overcome, like some conifers, Chinese Pistache, Japanese Maples to a degree, etc., you should strive to have no more than 2 tree members in one spot. Each joint should look like a peace sign you make with your fingers, more or less. Plus you look really groovy. A far worse scenario involves leaving knobs or knuckles at the end of a branch. This is the result of repeatedly pruning the tip in the same spot, which led to these ugly monstrosities. They always look terrible and can only be corrected by cutting lower down the branch, which is problematic except in the most vigorous trees. People have commonly, peculiarly, and horribly mistakenly, decided to do this most frequently with Mulberry trees and Crape Myrtles, and it's a real crime. Unfortunately, once a whorl is mature, it's usually better to leave it than remove it, since removal will probably be a permanent, obvious blemish, especially if over 2" in diameter. Sometimes, the decision to remove one or more of the branches is obvious, but often takes great thought. If there's one of several branches on the inside, it's usually the best one to take out, so the scar will be hidden and it will open up the canopy. Liontailing is also to be avoided, where all smaller branches are removed from a larger branch except at the very tip. Not at all sensible. Also, take a look at almost every tree you pass by. You'll see almost without exception, one or more branches coming out of the trunk about 6' off the ground. This is usually done so that people can walk under them, and that's ok, though not always necessary. Problem is, there's almost always more than one branch coming out in the same spot.
This is a clear no-no, and it creates a giant bulge. The opposing branches should be staggered and separated by a discernable distance which varies by the size of the tree, thus avoiding various whorls or a huge swollen lump in that section of the tree. And branches on the same side of the tree should be spaced appropriately, which will also vary. It takes a keen eye to determine the right distance apart. Nature determines much of that by node spacing.
2. LEAVING STRAIGHT, UNTAPERED BRANCHES. Branches in most trees naturally tend to taper noticeably, and usually don't keep going straight, but either curve or branch off in a slight direction, or divide into two or more smaller branches.. A lack of taper doesn't look right, but it also means the branch is probably too heavy at the end, and probaby too big in relation to the scale of the trunk or the overall tree. This is common where someone either removed most of the secondary branches from the larger branch, or just let it grow too long, possibly while cutting some of the upper trunk. Since growth is more vigorous at the tip, it lets girth accumulate faster toward the tip. There's no exact formula, but a guideline is to avoid a branch being more than half the diameter of the trunk at the point of attachment. Taking care of all this takes good diligence and ability to figure out how the tree is likely to grow. Pay attention to oak trees in the wild. They have curving, tapering branches and usually no whorls, and look fantastic. They would l look even better if they were meticulously pruned all their lives.
3. INFREQUENT PRUNING
The best scenario is to do more minor pruning more often, several times per year at crucial points, rather than once every year or every few years. It shouldn't end up being a lot more work in the end, because every cut you make should help avoid multiple problems later. More later....
4. PRUNING THE WRONG TIME OF YEAR
You'll find all sorts of opinions on when to prune this or that. It's seemingly quite complicated, and opinions on all sides are somewhat valid, even at opposite points of view . After extensive research, I determined the only way to figure it out is to look at each specie separately, use a bunch of logic and experience, and determine the actual objective for each pruning session. I'll have another post dedicated to all the specifics, which should clear all the confusion. In any case, probably the worst times to prune are between September and late November/early December, but this can vary with climate, specie, and the objective at hand. More later.....