Old growth red pine forests (Pinus resinosa) cover less than 1% of their originalrange in North America and are essential for maintaining biodiversity at stand and landscapescales. Despite this, the largest remaining old-growth red pine forest in the world, the Wolf LakeForest Reserve, is currently threatened by mining claims in Northern Ontario and has beenreceiving considerable media and public attention in recent months. We provide a timely reviewof how large old growth red pine forests maintain biodiversity at several taxonomic levels (with a focus on trees and plants) through heterogeneous partitioning of limiting resources such aslight and nitrogen, formation of complex habitats through increased accumulation of coarsewoody debris, and the maintenance of natural disturbance-driven succession. These processesshape the overstory community, allowing for the regeneration of pines, coexistence of earlymid successional shade intolerant species and cross-ecotonal establishment of late successionaltree species in response to regional warming over the past three decades. Using Wolf Lake as acase study, we review legislation and policy complexities around this issue and provide scientific arguments for the preservation of this forest. We invoke recent insights into the ecological role of refugia, the development of criteria for assessing endangered ecosystems, and thechallenges of conservation in the face of climate change and disturbance regimes. These forestsare ecologically important and provide a scientifically irreplaceable system for assessingbaseline ecosystem function, processes and services. As the largest remaining old-growth redpine forestin the world, Wolf Lake Forest Reserve deserves intensive study, monitoring and fullprotection from future development.