All of these considerations and any others which occur to you should be carefully evaluated and worked out so that you can make the most intelligent choice possible. Probably you will have to compromise somewhere along the line, for practical considerations must always shape the ideal and will influence the placement, the construction, and the embellishment of the terrace.

. . . terraces on problem sites
Not so long ago terraces were never built on anything but level, flat land, and, if a house had to be built on sloping land, terraces might be considered but they would probably not be built, due to the expense of excavation. Today, however, terraces can be built anywhere and everywhere, even on very sharply sloping hillsides where houses have been perched to take advantage of the view. In such extreme cases the terrace may become a wooden deck built on posts and joists and fitted around existing trees whose branches have been trimmed to the proper level, thus taking advantage of them for shade while opening up enough space for use around them. If the trees are surrounded by the deck on a very high level, sufficient space must be left open around the trunks so that they can sway with the wind without endangering the terrace structure.

On less violent slopes, a terrace can be made by excavating with a bulldozer or by hand (depending upon the extent of the work and the energy of the builder), the excavated soil being used as fill on the downhill side, probably behind a retaining wall. The fill should be well soaked with water, tamped, and allowed to settle for some time before it is finally paved, to avoid cracks and settling. If the uphill side is more than a foot or so high, it may also require a retaining wall where the excavation has taken place. If there are existing trees on the site, the retaining wall may be curved, square, or triangular shaped to save the trees and contain the important roots. It is dangerous to fill in around a tree more than a few inches, for roots need air as well as water. The fill may cut these off and smother and kill the tree. Thus, if your tree is on the downhill side, it would be well to curve the retaining wall around it to leave four or five feet of clear soil at the original level about the trunk.