The pruning (cutting the leaves), can be done when we see the old leaves has been grown yellow or looked a little bit dull. We can do it in two ways: shearing or pulling out. The best way is the second one, that is gradually pull out the old leaves. To prevent pulling out the whole group of leaves, use your left hand to hold the lower end of the leaves group, and use your right hand to pull out the old leaves one by one, and leave the young ones. If you prefer the first way, shear the old leaves at about 1 cm higher from the leaf stalk. This is to provoke the new bud from the rest of those old leaves. Unfortunately, shearing will leave brown traces, and these unsightly traces will stay there for months before they disappeared.
To keep the twigs and the leaves short and dense (to avoid disfigured or to keep the good shape), do the following:
1. Gradually pull out the old leaves every year.
2. Cut the twigs, small twigs, and new buds once every two or three years. This is to keep the shape from being undesirable. Two or three new buds usually come up once a year naturally. Cut off the very thriving (big) bud and the very weak (small) bud by shearing from the lowest part. Leave the moderate growing buds until they release their new leaves. Then cut it at the length we intend to. Two weeks later, there will come up the second bud from the trace of cutting. If it is needed, do the same to the second bud, so that we will get the third bud. The second and the third buds will create the short twigs and leaves. This theory is he same with bonsai tree that will have big leaves in the country but after making it bonsai planted on the pot by cutting its leaves several times, the leaves become small such as Sancang (Phemna Microphylla), Beringin Karet (Ficus Ratusa), etc.
3. When the leaves of the new bud have grown, do not cut off too many twigs when the leaves of the new buds has blossomed because in this phase, the trace of cutting will release much turpentine (sap) that will possibly kill the tree. The best time to shape and shear the twigs is when we start to see its old leaves (looks yellow and dull). This shows that this tree is stop growing temporarily and is saving energy before releasing its new buds. It’s the safest time to prune black pine by pulling out or shearing, and cutting the twigs too, because it’s the strongest period of the tree.