Bonsai For Beginners
This is just a quick note because I have been asked about pruning pines by several people this week, there seems to be some confusion as to what to do with the newly forming candles on most pines at the moment. It is now late spring with some signs of summer coming on in NZ. I had a look on the net and a few of my books and I can see why there is some confusion. They all had different ideas on what should be done.
The buds are the areas where the candles form on the ends of the branch. Ideally you want your branches to divide into two new smaller sub-branches at the end of the main branch. To encourage this remove all but two buds from the tips. Your main objective is to redistribute vigor. On the top more dominant branches remove the large buds leaving the smaller weaker buds, on the lower and weaker branches; leave the larger more dominant buds. Buds continually need to be reduced to two as they appear in autumn and spring.
I think most of the trouble starts when people over think these things and get tied up with details. This should help with the basic principles behind what you are doing.
The key to the whole process is that pines are apically dominant and always want to grow up from the furthest tips of the tree. Everything you do is to try and combat this tendency and redistribute vigor. There are four main techniques for achieving this.
They are, bud selection, candle pinching, needle plucking and shoot trimming.
During the spring the buds that you have kept will elongate into candles, their size will be determined by the vigor of the buds you retained. Your main objective: redistribute vigor. To do this pinch back the candles, the amount each candle is reduced depends on its position within the structure of the tree and its future purpose. Next years buds will form on the ends of these candles. To redistribute vigor reduce the more vigorous areas by more than the weaker inner areas. The timing of pinching makes a difference, pinching before new needles appear will cause buds to form at the base of the candle. Pinching the candles after the needles begin to elongate will cause the new buds to form at the end of the new shoot. Don't pinch all the candles at once, start pinching the weaker areas of the tree first and finish with the strongest areas 2-8 weeks later. Strong areas should be reduced by 1/2 to 2/3, candles in weak areas should be reduced by 1/3.
In late autumn or early winter both old and new needles can be plucked. This will open up the tree and allow airflow but will also help redistribute vigor. Reducing the amount of needles in vigorous areas such as the apex will help stimulate less vigorous areas. The actual number of needles removed will depend on the needs and strength of the tree. Remember this method can only reduce vigor in areas so don't remove so many needles that you weaken the entire tree.
This should not need to be done if correct pinching has been carried out. It is a method to try and stimulate back budding. All shoots should be allowed to grow throughout the growing season. In autumn all the current seasons growth is removed, leaving only the previous years needles. This will cause the tree to produce buds at branch tips and sometimes even on old wood. This technique is quite stressful on your tree and should only be carried out on strong healthy plants.
Five Needle Pine                  Two Needle Pine
There are two main groups of pine, five needle and two needle. There is very little difference in the treatment of these two groups. Some sources recommend that when pinching the candles on five needle pines you should start with the stronger candles instead of the less vigorous ones as in the two needle pines
I hope this helps, if in doubt remember what you are trying to achieve - redistribution of vigor.