54 PRUNING: ITS ORNAMENT AND UTILITY. 
may have an even surface, without twigs springing from the 
wound, 
All wounds which will not heal in a single season ought to 
be covered with coal-tar containing a small quantity of paraffin. 
This mixture is preferable to paint. Wounds which have not 
been covered absorb moisture, and impart decay to the tree ; and 
although the mark of the cut may be no longer seen from the 
outside, a decayed piece of wood presents itself when the tree is 
sawn up. On the other hand, if the wound is covered with coal-tar 
only a small streak is seen when the timber is cut up after the 
wound is healed over. 
Great diversity of opinion has existed in regard to the proper 
season for pruning. The season in which pruning is performed 
has a deal to do with the healing. Wounds made during the 
winter do not heal so much during the ensuing summer as cuts 
made in the earlier part of summer. Winter pruning gives rise 
to a greater abundance of young shoots than summer pruning. 
In fact, pruning may be performed at any season except during 
late spring. At that season the ascent of the sap is in full play, 
and wounds made then bleed so much that they never heal satis- 
factorily. 
