Looking for advice on constructing a living fence, using trees or vine

Question

I have a simple, old, rusted chainlink fence at the back of my yard. In the future, we want to replace it. Therefore, we have been looking for ideas. We recently spotted a very interesting fence-like setup in our neighborhood, which uses trees trained along cables (see pictures). It will be a couple years before we do this project, but I would like to do some more research on this idea now. My first inclination is that trees would be a bad choice, ultimately, because they will get too big. Therefore, what would be an ideal plant choice? Maybe a vine? For your information, there is plenty of space on both sides of the fence we want to replace, unlike in the pictures below.

If possible, I would like:
Good foliage all year long (evergreen - zone 6b, Boston), to provide privacy.
Relatively fast growing
Relatively long lived
Friendly to birds (optional)
Flowering (optional)

Any ideas or suggestions would be appreciated.

UPDATE:

After the helpful answer below, I've been able to find many examples of what I'm considering. For those who may be interested, I've found using the general term espalier to helpful when searching. The Belgian fence style is particularly relevant. As to the subject of selecting an ideal plant, I think I can narrow down some of the option.

Most important to me:
Good thick foliage for a good portion of the year
Winter hardiness
Moderate to low water requirements

What I do not want:
No edible fruit bearing plants
No thorny plants

Off the top of my head, I wonder if a holly might be a good choice. I welcome any suggestions for me to explore.

Answer 1

Your photos show a good example of what's known as cordon training - this is a method used mostly for fruiting trees, and it looks as if the trees in the photo may actually be apple, but its hard to be sure. Cordon training requires a basic framework to be in place, and the trees you choose will need regular pruning and tying in, so they must be able to withstand this kind of treatment - not all trees and shrubs will respond well. They don't get too big because you're expected to continue pruning and training (certainly annually, possibly twice a year, depending on growth rate and variety of tree/shrub) as time goes on.

Because this is a relatively time consuming, high maintenance method, and the best subjects for it are fruit trees, and maybe Pyracantha, one or two other large shrubs, and possibly climbing roses, it's likely something you may consider unsuitable, given you really want an evergreen cover and may not have sufficient time. With regard to evergreen vines, there are none that I can think of which are hardy in your area, with the exception of Hedera helix varieties, which won't co-operate with this type of training. It might be better to consider evergreen shrubs or conifers which stand without support rather than a vine/climber.

More info on cordon training below

https://www.rhs.org.uk/advice/profile?PID=87

UPDATE

Following on from your comment, grapevines can be trained into all kinds of shapes. I wouldn't say they have attractive foliage for most of the year though, even in full leaf they're not a thing of beauty. You'd be safer choosing an American grape too, for hardiness reasons, so cultivars of Vitis labruscana. Link below to possible training techniques, but there's loads on the web on this subject, including videos.

http://www.thewinedoctor.com/advisory/technicaltraining.shtml

You could, though choose Pyracantha coccinea - its hardy, technically evergreen, though may be more semi evergreen with your winter temperatures, can be trained in various ways, has flowers around May and berries in Fall

http://www.ilonasgarden.com/how-to-train-pyracantha/