DESOTO NATIONAL FOREST, Miss. — When European settlers came to North America, fire-dependent savannas anchored by lofty pines with footlong needles covered much of what became the southern United States. Yet by the 1990s, logging and clear-cutting for farms and development had all but eliminated longleaf pines and the grasslands beneath where hundreds of plant and animal species flourished. Now, thanks to a pair of modern day Johnny Appleseeds, landowners, government agencies and nonprofits are working in nine coastal states from Virginia to Texas to bring back pines named for the long needles prized by Native Americans for weaving baskets. Longleaf pines now cover as much as 7,300 square miles (19,000 square kilometers) — and more than one-quarter of that has been planted since 2010.