I have a Liquid Amber located in my front yard here in sunny southern California and it has flourished here for 30+ years. Last year I noticed that it was not producing 100% of its leaves and this year it produced close to 1/3 of its average leaves. They are already beginning to wilt and its only late spring. I do not know what to do because it has appeared completely healthy for all the time I have had it up to last year. It is sick tree?
Liquidambar styraciflua (the sweetgum of the eastern U.S. and southern Mexico and mountains of Central America) tends to be a tree of somewhat moist areas. I doubt that you have the species from Taiwan and China, but you might possibly have Liquidambar orientalis, from the eastern Mediterranean--Greece and Turkey. would seem a logical plant to import into California. There's any number of reasons for trees to decline. For you, water could well be critical. Here in Florida, any number of ornamental plants will grow happily for a number of years, then unexpectedly fail.
American sweetgum is the usual one in southern California plantings. It is interesting for bringing eastern North American fall color to the Los Angeles etc. landscape.
American sweetgum is what I saw as street trees in Portland, Oregon. At least in the central and northern Florida part of its range, sweetgum is a big, fast-growing tree with a tendency toward rather weak branches, so it's the sort of tree you'd prefer to see away from houses, cars, and other things that might be damaged if something falls. It seems much better behaved where it's not native. There's a fair number of eastern hardwoods that don't need much winter cold, but sweetgum's fall colors are the best. The public botanical garden in Orlando, Leu Gardens, has a nice Liquidambar formosana, and I suppose it would be cultivated at gardens in the Los Angeles area. Flora of China has photos. None of which has much to do with the troubling problem of seeing a healthy tree decline. I'd suggest irrigation, and UC Davis has a list of potential problems.
