Every February & March St. Paul's Forestry Department prunes in the Japanese Garden. They prune the Austrian pines on a rotating basis (ex. one year they will prune half of the pines and the next year they will prune the other half). The purpose of prunning these pines is partially done for aesthetic reasons, but also for the health of the pine. The lower branches can be shaded out by the branches above and can die as a result. Prunning the upper branches lets more light into the lower branches preventing this from happening. Aesthetically, the pines are pruned according to Japanese Gardening standards. Any new growth is thinned by removing growth upward or downward of the branch. In general the branches fork into two branches and then continue to fork by twos, any growth extra of this is removed. You can see a good picture above of a tree that has been pruned and one that hasn't. The tree to the left of the Forestry employee has been prunned, the tree that the Forestry employee is in has not. 
