How to Prune Arolla pine?
Keep pruning to a minimum but if dual leaders form on young trees, remove one to produce a single-stemmed tree. Trees may be resinous, any pruning should be carried out from late summer to midwinter

Arolla pine · Pinus cembra
Also known as: Russian cedar; Siberian cedar; Siberian cedar pine; Swiss stone pine
Grow in any well-drained soil in full sun. May be short-lived in shallow, chalk soil. See Trees: buying and planting specimens
Keep pruning to a minimum but if dual leaders form on young trees, remove one to produce a single-stemmed tree. Trees may be resinous, any pruning should be carried out from late summer to midwinter