Is shortleaf pine regeneration declining under the current forest fire regime?

Abstract

Shortleaf pine (Pinus echinata Mill.) has one of the widest geographic ranges of all pine species in North America and provides habitats for a large number of species. Shortleaf pine has decreased over time, and much of the decline has been considered recent and aligned with wildfire suppression. Shortleaf pine's decline within a relatively short ecological timeframe results in rapid losses of habitats and puts stress on the associated species to adapt to emerging habitats. Increasing interest is shown in the restoration of shortleaf pine, and a first step in restoration planning would be to understand its population dynamics. We provided a comprehensive evaluation of the spatio-temporal dynamics of shortleaf pine regeneration, indicative of its future population trajectories, across its broad range under the current forest fire regime using large time-series regeneration and forest fire data. Shortleaf pine regeneration was found to be largely stable across its approximate geographical range in the past two decades, contrary to the commonly perceived declining trend. Shortleaf pine regeneration increased in burned areas compared to unburned areas, but such increases gradually diminished over time. The following general recommendations would help forest policy makers and conservation practitioners incorporate science- and data-driven solutions into restoration plans.

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  The return interval probably should be shorter than ∼15 years if prescribed fires are to be used to promote shortleaf pine regeneration;
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  Planting enables prompt restoration of shortleaf pine even in regions where it is currently rare or absent, but requires careful planning and application;
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  Thinning may be a viable solution to restore shortleaf pine in forests where it is a minor component, but may need to be accompanied by prescribed fire.