Forest trees display a perennial growth behavior characterized by a multiple-year delay in flowering and, in temperate regions, an annual cycling between growth and dormancy. We show here that the CO/FT regulatory module, which controls flowering time in response to variations in daylength in annual plants, controls flowering in aspen trees. Unexpectedly, however, it also controls the short-day...

In this study, we set up a wood decomposition experiment to i) quantify the percent of mass remaining, decay constant and performance strength of aspen stakes (Populus tremuloides) in dry and moist boreal (Alaska and Minnesota, USA), temperate (Washington and Idaho, USA), and tropical (Puerto Rico) forest types, and ii) determine the effects of fragmentation on wood decomposition rates as relat...

Trembling aspens (Populus tremuloides) are among the world’s most remarkable trees, forming vast clones that can live an improbably long time. These clones share a common root system, from which new trees arise, cover up to 43 hectares and persist up to a million years. The vigor of these ancient plants belies their years, leading to speculation that they defy aging or senescence. But demonstra...

By the early 1900s, Euro-Americans had extirpated gray wolves (Canis lupus) from most of the contiguous United States. Yellowstone National Park was not immune to wolf persecution and by the mid-1920s they were gone. After seven decades of absence in the park, gray wolves were reintroduced in 1995–1996, again completing the large predator guild (Smith et al. 2003). Yellowstone’s ‘‘experiment in...

ECOPHYS is a complex computer model that simulates the growth of hybrid poplar and aspen trees. Its primary purposes are to identify major physiologically-based factors that influence tree growth and to predict how interactions among them and with the external environment will affect growth (Isebrands et al., 2000). ECOPHYS' capabilities and submodels of various tree ecosystem processes continu...

The removal of conifers through commercial timber harvesting has been successful in restoring aspen, however many aspen stands are located near streams, and there are concerns about potential aquatic ecosystem impairment. We examined the effects of management-scale conifer removal from aspen stands located adjacent to streams on water quality, solar radiation, canopy cover, temperature, aquatic...

The recent occurrence of large fires with a substantial stand-replacing component in the southwestern United States (e.g., Cerro Grande, 2000; Rodeo-Chedeski, 2002; Aspen, 2003; Horseshoe 2, Las Conchas, and Wallow, 2011) has raised questions about the historical role of stand-replacing fire in the region. We reconstructed fire dates and stand-replacing fire patch sizes using four lines of tree...

In order to avoid carbon dioxide (CO2) built up in the atmosphere, the major source of global warming, CO2 capture must be applied to large point sources including natural gas processing. Membrane process, a relatively new technology among other available techniques, can be used for the purpose of CO2 capture from natural gas. Over the decades, the membrane performance has been described by dif...