The scene had a lot of contrast, it was just before dawn but the trees were very dark. In order to have enough detail in lights and shadows I took two shots separated 4 stops of aperture and blended both images following (more or less) these instructions: http://jtrujillo.net/qpix
In short it is about shooting the image twice, one correctly exposed (not burning highlights) and one overexposed so the darker zones are actually captured in the middle luminosity (nothing really new here).
The technique is a method for handling these two images in PhotoShop, so you can blend them and achieve a compound image having the best of each capture in a quite simple way. You can read the whole article at http://jtrujillo.net/qpix