In general, to cover all or most hf bands with one wire antenna, you must
have an antenna tuner. Otherwise, you will find the swr will only be
tolerable in the portion of most bands where you either can't work or do not
wish too.

It sounds like you are dealing with very limited space. So, whatever you
install will likely be in an inverted vee configuration. For instance, the
center will be as high as possible up in a tree, while the ends may tie off
to a fence, the garage roof, etc.

Don't worry too much about trees soaking up all the rf from your antennas.
Sure, they will block some of it, but I know too many people whose antennas
are completely hidden in trees who have very good signals, even at the 100
watt level.

My recommendations in order of their simplicity and cost are these:

1. If you only wish to primarily operate on 80, 40, and 20 meters, use an
antenna length of 88 feet. That's 44 feet of wire on each side of the center
insulator. Feed this antenna with 450 ohm ladder line through either a
manual tuner, or through a 4/1 ballun into your rig's automatic tuner with
coax between the rig and the ballun. This antenna works very well,
especially on 40 and 20, and better than you might think on 80. Even with a
ballun, however, some automatic tuners won't handle it on some frequencies.
If you want only 40 through 10 meters, use 22 feet of wire on each side of
center.
Learn more about this antenna at www.cebik.com.

2. The most simple store-bought solution is a G5RV, which has a total length
of 102 feet. Most of the commercially made ones include the ballun and more
than enough coax.

3. You can also buy full size 80 or 40 meter half wave antennas which are
fed with 450 ohm ladder line. These antennas can be forced to work almost
anywhere above their natural resonant point through the use of a tuner.
Again, a ballun will be necessary for use with most automatic tuners.
Visit w7fg.com for examples of this type of antenna.

4. If you can make an antenna fit your space by bending it slightly, or by
otherwise altering its physical shape, just do it, and let the tuner handle
the swr. While it won't be a textbook installation, and while your radiation
pattern may be crazy, somebody somewhere will hear you when you are on the
air! At that point, who cares about radiation patterns anyway?

Mike Duke, K5XU
American Council of Blind Radio Amateurs