Why is a conservation organization cutting trees?!

Few places on our planet are truly pristine and unaffected by human activities. In many cases, the best care for our preserves requires restoring lost or disrupted ecological processes. Where that is difficult or impossible, we must mimic natural processes with our management techniques. Ecological Management and Restoration is the correct term for this work, a scientific way of saying "healing the land." Ecological Management and Restoration may include such diverse activities as:

planting trees, restoring native prairie or wetland plants
revegetating stream banks to reduce siltation, erosion and nutrient runoff
building exclosures for deer and cattle to protect rare plant populations
controlling invasive exotic species (aka weed control or Weed Busters)
restoring the natural flow of water by removing ditches or culverts (hydrological restoration)
reintroducing a plant or animal that has vanished from the area
conducting prescribed burns
controlling woody vegetation (trees and shrubs) to maintain open habitats

A more familiar term for these activities is "habitat restoration."

"There can be no purpose more inspiring than to begin the age of restoration, reweaving the wondrous diversity of life that still surrounds us." -- E.O. Wilson