My Sciadopitys verticillata is rapidly growing upward with very little increase in width. It started as a perfect pyramidal 5' specimen 4 years ago; has since added 14 to 24" height per year with virtually no increase in girth. Started as a potted specimen on our deck but soon grew too tall so is now in the ground. Deck was sunny; area now mostly shade. Should I trim the leader branch so slow vertical growth?