resource conservation, ecosystem health, sustainability - How am I going to improve my impossibly stony soil?

There are two approaches you could take. I have tried both, and each have their rewards.

First, you could commit to a long term project, improving the soil in your garden area. Each year, you can add compost, remove some stones, plant something that will tolerate the conditions to bring more humic material into the root zone, and just make the progress you are able to make. My garlic patch began as an extremely stony, mineral subsoil six years ago. I could not even get a shovel or fork more than a half an inch into the ground. My strong, patient, beloved is the one who dug a grave-sized pile of large and small stones out of the 10' by 10' plot so that I could start adding organic materials to it. It is now dark, fertile, crumbly, "this is what garden soil should be" quality. I add some compost and cottonseed meal and ashes each year, and let the worms do most of the work. The garlic gets bigger and more robust each year.

Second, you could decide that you don't want to wait, and don't want to exert the kind of physical effort required. That means you grow in containers or raised beds (which are just large containers, sometimes without bottoms). You make the soil by combining compost with other materials to obtain the characteristics you want. It needs to drain well but hold moisture and nutrients. Peat can be added (I want us to get away from unsustainable materials, but it can be useful - some are trying coconut fiber). Coarse vermiculite helps with keeping good air spaces in the soil. Of course, compost is probably the most wonderful gift you can give your plants. Mel Bartholomew, the engineer who developed Square Foot Gardening, has a recipe for raised bed growing media that works very well. Advantages to this method include the ability to put hardware cloth across the bottom of the container to discourage burrowing pests, and the lack of weed seeds in properly produced compost.