nothing stops growing at some magical height ... and the faster it grows to that height.. the faster it shoots right past it ...

whats important about your 30 foot limitation ....

it might be best to offer us a pic or two ... so we can see the situation ...

also understand ... proper watering is imperative for the first few years with trees .. until they mature the root mass.. so as to develop whatever drought resistance they might have once mature ..

and the bigger the transplant.. the long more important proper watering is ... else it may die before getting the roots it needs ...

if you see some local specimens that seem interesting.. a couple pics here and in the NAME THAT PLANT FORUM.... can get you IDs .... what grows locally is always a good place to start ...

ken

Here's a few to consider:

Ficus nitida

Podocarpus macrophyllus

Quercus tomentella

California pepper tree

Rosewood

Magnolia grandiflora

Honey myrtle

Pittosporum tenuifolium

I would have a look at a mature Fremontodendron if you're interested in them. It is more of a giant shrub than a tree being very broad in the beam. You'd need a large space. Personally, I'm not wild about the shade of yellow either.

Fremontodendron will never hit 30'. Also not considered to be overly drought tolerant. Dislikes routine summer irrigation but can also die if not receiving adequate soil moisture.