METHODS FOR THINNING TREES IN SPRING. (April, 2010)
Deciduous trees: After pinching a fully-styled tree (refined trees only), the exterior will become full of leaves. Here are some tips for thinning this new growth:
Japanese Maple: Leave a pair of new leaves at each bud tip after pinching. If the tree is still very full, remove one leaf from each pair. Do not remove leaves from weak or interior branches. (Thinning the leaves is done after the leaves have hardened off.)
Trident Maple: Remove all large leaves and trim elongated shoots. Leave the interior leaves and small; leaves alone. (The leaves should be hardened off also.)
Beech: Check the tree carefully from top to bottom, leaving only three leaves per new bud in strong areas (usually at the tree's apex and exterior).
Pine: Thin pines to balance the growth between strong and weak areas.
White Pine: In the tree's strong zone, break strong shoots leaving about 1/4 of the new needles per candle. In zones of medium strength, leave 1/2 to 3/4 of the new needles. Do not pinch weak areas or small buds. Start by breaking the strongest buds first. Pinching with your finger (see photo). If you want to, you can use two hands. To do so, hold the candle at the base with the thumb and index finger of one hand, then use the thumb and index finger of the other hand to break it.
Black Pine. Break strong candles to about the same length of the rest of the tree's candles. Even if the tree's growth is significantly unbalanced, break only the strongest candles. If the needles have already opened, use scissors to cut 1/4 to 1/2 of the large candles. Note: Photo is not black pine decandle. Decandle will be done in June. This is somewhat like five needle pine technique, but later in June/July, those spring candles will be completely removed.