Why is there so little research into the cell biology of the secondary vascular system of trees?

Despite new techniques for studying the cell biology of plant development in recent years, the secondary vascular system has been neglected. Why is this? Here it is argued that some of the barriers that have prevented more widespread study of the tree secondary vascular system are no longer valid. Some of the more intriguing aspects of the secondary vascular system include the recent discovery of a putative plant muscle and identification of a cytoskeleton-facilitated three-dimensional symplasmic transport pathway that permeates the tree. There are great merits in the recently adopted model tree species, poplar, and a new model system - wood formation in Arabidopsis. The time is now right for much greater exploitation of the possibilities that exist for study of the secondary vascular system of trees.