1 ) , the stenosis was classified according to the Stanford classification [ 7 ] system into 4 types : ( i ) type I describes a partial obstruction of the SVC ( up to 90 % ) with remaining patency and antegrade perfusion of the azygos vein ; ( ii ) type II shows increasing obstruction ( 90-100 % ) ; ( iii ) type III is complete obstruction with ...
The tulip tree is a deciduous tree with a moderate to rapid growth rate. It has a tendency to produce a strong central leader that forms a tall, straight trunk. When young, this tree tends to have a canopy with an upright pyramidal growth habit, As it ages, the tree becomes columnar or more spreading and open.
The tulip poplar typically grows from a single leader trunk that is usually tall and columnar in form. On mature specimens the lower portion of the trunk is often devoid of any branches. The tree grows relatively fast, with a somewhat oval shape to its canopy that often becomes more irregular as it grows.