Here is the article from the Smithsonian that Steve Wilent posted in the SAF Linked-In site..
And here is one from the New York Times..
Swainson’s warbler breeding pairs require large territories of between 10 to 20 acres, which the pine plantations provide. Most warbler territories observed by Graves occurred in plantations planted on sandy loam soil, with normally low water tables, he says. “These pine forests may be creating a microhabitat at ground level where the birds feed on insects in the leaf litter, maintaining humidity and allowing them to live on dryer soils then they have traditionally.” Also, Graves observed, most plantations occupied by Swainson’s warblers had a certain “weediness,” associated with them: namely broadleaf saplings, vines and shrubs growing along the edges of roads and streams crossing the forests.
Covering some 40 million acres in the U.S. today, southern pine plantations are projected to increase to 66 million acres by 2060, Graves points out in his paper. “Given the 25 to 35 year rotation cycles commonly prescribed for private and commercial plantations, and a 7 to 8 year window of habitat suitability for Swainson’s warblers in a typical stand,” roughly one quarter of these pine plantations will be suitable habitat for these birds at any given time, provided that other requirements such as deciduous weediness and soil moisture are met, Graves concludes. “If current distributional trends continue, forestry lands managed for short rotation pine plantations will soon support a majority of the global Swainson’s warbler breeding population.”