Tree root growth rate

I was sitting on my porch (a slab of concrete with steps) having a break... you know, a break from sitting inside. Anyway, I was looking at the trees in front of a large apt. complex that was recently built across the street. The trees are young but look like they might just make it after a shaky start. I was wondering what is going to happen once the trees mature and their root systems spread. From that question came another one: Are there trees where the roots reach a mature level and then do not become any bigger...and by bigger I mean they don't spread any further? I think that would be something to consider when planting a "baby" tree next to a driveway or sidewalk.

I tried to google my question, but I just didn't have the focus to spend much time trying to find the page with the answer. Then I thought...'why not ask on the web...there are lots knowledgable gardeners out there'. Then I needed to decide where to ask the question. Here was the easiest place to ask. It also demonstrates my non-need for an answer.

To tell the truth, if I don't get an answer it won't matter. I'll no doubt forget I even asked the question in an hour or two.

As I peruse many blogs in an attempt to keep from doing anything productive, I've noticed many women say they love gardening...love getting their hands dirty and to watch their 'babies grow'. It sounds lovely but when I try to mentally put myself there...I get a very fuzzy picture full of drops of sweat, painful backs, and sunburned skin. Oh yeah, and very dirty fingernails.

Next time I get an urge, maybe I'll try keeping indoor plants healthy before I try anything outside. I use to always have leafy house plants. When first brought in they would appear green, full, and healthy. After acclimating they seemed to all slim down and lose compactness. They seldom actually died, but they weren't that 'happy go lucky' looking type of plant you see in the nurseries and garden stores.

I have to think about all this. I've spent the last couple of years trying to rid myself of an many responsibilities as I can. Caring the house plants bring some back. I'll have to really give it some thought. Perhaps I'll leave it up to the Universe. If I'm to try it again, caring for something living, then I'm sure a plant or two will come into my life. If anything happens I'll try to remember to post an update. And the operative word is "try".