Hard pruning of a bonsai tree is a technique that is used to reduce the size and shape of the tree, or to encourage new growth from dormant buds. It involves cutting back the trunk or branches to just above where new growth is desired. Hard pruning should be done in the spring or summer, when the tree is actively growing and can heal faster. Hard pruning can be stressful for the tree, so it should be done with care and not too frequently. Some species of bonsai, such as pines and junipers, require special methods of hard pruning, such as pinching by hand or using concave cutters. Hard pruning can help create a more compact and refined bonsai, but it should always be done with a clear vision and respect for the natural characteristics of the tree .