ARIZONA — Frustrated Arizona loggers aired a few complaints about the way the Forest Service handles thinning contracts in Arizona, especially when it relies on out-of-state contractors unfamiliar with the ecology of Arizona’s ponderosa pine forests. …The Forest Service is experimenting with a new, high-tech method of marking trees for cutting in restoration timber sales. That includes using computer tablets synced to aerial LiDAR surveys so loggers can determine which trees to cut without the Forest Service marking each tree by hand. …A century of logging, cattle grazing and fire suppression has increased tree densities on millions of acres from less than 100 per acre to more than 1,000 per acre. Now a high-intensity fire can climb up into the lower branches of the tallest trees. …The 4FRI aims to dramatically reduce tree densities across millions of acres in Northern Arizona, making it the most ambitious forest restoration project in the country.