For a small area like that look for a tree that had 'columnaris' after the name meaning it will grow narrow like a column. There is a Bradford Pear tree with that form and also some small maple trees but in the hot afternoon sun you may want to consider a smoke tree (Cotinus coggygria) as this plant grows rather like a shrub but can be pruned almost to the ground (really, be firm) in the spring if it dares to grow too large. The foliage is amazing and it looks great with sun-loving spiraea 'Magic carpet' and gold and purple barberry plants that come in dwarf and columnaris forms. It would be a symphony of gold and purple foliage and very drought resistant display. Keep growing, Marianne Binetti