Complex sentence: The urban area has grown outward so quickly that it is beginning to run into Bureau of Land Management holdings along its edges, increasing land values enough that medium-and high-density development is beginning to occur closer to the core.
Split into simpler sentences: The urban area has grown outward so quickly that it borders Bureau of Land Management holdings along its edges. This has led to an increas in land values such that medium-and high-density development is occurring closer to the core.