We've always used a sky dish on a tripod, and generally can get a clear view of the Astra satellite.
However, trees can be a problem......the signal will come through trees but you'll never get a picture on the telly....
I noticed some people on various sites had overcome this by rigging a pole which clamps to the jockey wheel. After a bit of investigation, I found one on Ebay and invested some of Mrs Bugs money in one.
Here's a link to the seller I bought from, but there are others....shop around!!