It is definitely NOT A TREE THAT BELONGS NEXT TO A POOL! It is very messy especially when it get a little larger and will be a big pain in the neck for you. It is too bad because it sure looks very healthy and I'm sure you are enjoying it. I would recommend removal and replacement with a large shrub or very small tree that tops out or drastically slows down around the size that tallow tree is currently. That is if you just must have something there. On a different note, your yard looks very relaxing! :) John

You're right - that isn't much to go on! With perhaps 500 named cultivars in commercial trade and many fitting roughly that description, not to mention a few dozen more cultivars of shirasawanum and japonicum that most folks think are also J. maples, any guesses would just be a shot in the dark. Fortunately the Puget Sound area of Washington state is home to dozens of excellent nurseries, many featuring large selections of Japanese and other Asian maples. A number of public gardens and arboreta also have maple collections you can view for comparison. We have just peaked with fall color on most maples in this area and they are starting to drop leaves, so now is perhaps not the optimum time to select based just on fall color. One cultivar you may want to pursue is 'Osakazuki', which is known for stunning fall color. Pretty popular in this area, it will develop a rather horizontal branching pattern and is often sold multi-trunked or with a very low crotch. It will get quite a bit larger than 12-15' in time, ten years being rather young as J. maples go.

Welcome to the forum! Well, the leaf structure is called, "winged petiole", for that small leaf on the petiole (leaf stem). The long thorns would suggest what you've got growing is just rootstock - the cultivar scion having died at sometime in the past, or, being overtaken by rootstock shoots. Please provide some photos of the base of the tree. We need to see where the graft line is on the trunk, where the actual cultivar was grafted to the rootstock, if this was a grafted tree. If you have many shoots emanating from the ground, most certainly just rootstock growth. If you have just one trunk, and there is no graft line, it is possible this is a seedling tree (citrus trees grown from seed also tend to be more thorny). Citrus cultivars with these winged petioles include Yuzu, grapefruits, grapefruit hybrids, pummelos, pummelo hybrids, some sweet and sour oranges, and rootstock with this sort of winged petiole would be citrumelo. If this tree is 15' tall, and has been around a while with no fruit, probably time to dispatch with it, and plant a citrus tree of your choosing that will provide fruit, now. If it is, indeed, rootstock, the fruit will be inedible, so why wait (possibly many more years), to get inedible fruit? Post photos of the trunk of this tree, that will help us quite a bit. Patty S.

It's hard for me to tell from that distance. Can you take a closer photo of the leaf shape? You may be able to ID it yourself by googling images of "Norway maple vs. Sugar maple" or similar. http://oregonstate.edu/dept/ldplants/images/acpl-sa2.jpg http://homepage2.nifty.com/chigyoraku/worldleaf1.jpeg