Red maples, botanically known as Acer rubrum, are a great northeastern shade tree for many reasons. In spring before they leaf out (March into April) red maples produce great looking clusters of red flowers (click here for image of flowers). That in combination with the smooth gray bark was how I was able to identify the tree above when we moved across the street last winter. Our new neighbors talked about the amazing red fall color and just recently we got to see for ourselves.
These shots are of some red maple cultivars up at the new York Botanical Garden. You can see here the difference in the leaf. When people think of maples they tend to think of that quintessential 5-pointed or 5-lobed leaf silhouette. Here you can see that red maples, though they still have five lobes, tend to look more like a leaf with only three points. This can help you identify them in the summer when most maples are rich green in color and not so easy to tell apart. But then in fall of course we are further clued in as to why they are called red maples. As far as your standard list of maples often used in the northeast Norway maples (invasive bastards!) have a bright yellow fall color. Sugar maples can be every fall color imaginable but end up showing mostly oranges. But the red maples will always get this real intense red to scarlet coloration when they change in early November.
Younger trees have a smooth gray bark that helps you to identify them in the woodlands. They are also sometimes called swamp maples and as the name might suggest they do really well in a more wet situation. Often in a forest setting you will find them naturally living down closer to the stream edge or in lower, soggier areas. As the trees mature the bark transforms from being smooth to having these long vertical ridges and furrows, still a nice light gray. This mature specimen is located in the old growth forest up at NYBG.
There are of course a gazillion cultivars of red maples out there so you want to check your local nurseries and do your research before buying. I remember back when I was in the nursery trade we sold a lot of 'October Glory' and 'Red Sunset' but gosh, that was a good ten years ago.