Managing forward while looking back: reopening closed forests to open woodlands and savannas

Abstract

Ecosystem management, community restoration, and managing for climate resilience have become major priorities of land management in recent decades. For woodlands and savannas (i.e., “open forests”), this transition has meant moving fire-deprived, closed-canopy forests to structures and compositions characteristic of natural communities that are rare today: open-grown, wide-spreading trees, and endemic flora and fauna associated with frequent, low to moderate intensity fires. Open forest restoration is complex; its approach and operational prescriptions are dependent on a multitude of factors. Reopening forests to achieve ecological objectives associated with open forests is hampered by site histories, novel species compositions, and structures that resist fire. Fire histories shed light on fire regimes that promote open forests, informing prescriptions at stand and landscape levels, but due to many social and environmental factors, managers are challenged to recreate those fire regimes. As fire was removed from these ecosystems, successional processes led to changes in species compositions concomitant with changes in woody structure and fuel complexes further inhibiting restoration without active management. As active management aims to transition residing fine fuels from mesophytic hardwood-shrub litter to herbaceous dominant fuels with canopy openness, fire effects, and prescriptions also change. Silvicultural prescriptions have been developed to aid in the process of transition but maintaining mature, continuous canopy open forests through the regeneration and recruitment phase of predominantly shade intolerant of oaks and pines remains speculative. Further, as a legacy of woody densification, contemporary fire practices may result in undesirable increases in sprouting woody species impacting objectives for herbaceous cover and diversity. Invasive plants and depauperate seed banks may further limit successful outcomes. Even with these formidable challenges, transitioning closed forests to open structures and compositions is critically important for wildlife that depend on them, especially at the size, scale, and connectivity necessary to sustain their populations. Many birds and pollinators of conservation concern require open forests and early successional forests may not serve as surrogates for mature, open forest habitat. In this review, we outline the advances, challenges, and importance for reopening closed canopied forests to open forests in the central and midsouth, USA. Further, we set the stage for new approaches and learned outcomes from the papers of the 7th Fire in Eastern Oak Forests Conference in Tyler, TX, included in this special collection of Fire Ecology.