Many forests of eastern North American are undergoing a species composition shift in which maples (Acer spp.) are increasingly important while oak (Quercus spp.) regeneration and recruitment has become increasingly scarce. This dynamic in species composition occurs across a large and geographically complex region. The elimination of fire has been postulated as the driver of this dynamic; however, some assumptions underlying this postulate have not been completely examined, and alternative hypotheses remain underexplored. Through literature review, and a series of new analyses, we examined underlying assumptions of the “oak and fire” hypothesis and explored a series of alternative hypotheses based on well‐known ecosystem drivers: climate change, land‐use change, the loss of foundation and keystone species, and dynamics in herbivore populations. We found that the oak–maple dynamic began during a shift in climate regime‐from a time of frequent, severe, multi‐year droughts to a period of increased moisture availability. Anthropogenic disturbance on the landscape changed markedly during this same time, from an era of Native American utilization, to a time characterized by low population densities, to Euro‐American settlement and subsequent land transmogrification. During the initiation of the oak‐maple dynamic, a foundation species, the American chestnut, was lost as a canopy tree across a broad range. Several important browsers and acorn predators had substantial population dynamics during this period, e.g. white‐tailed deer populations grew substantially concurrent with increasing oak recruitment failure. In conclusion, our analyses suggest that oak forests are reacting to marked changes in a suite of interlocking factors. We propose a “multiple interacting ecosystem drivers hypothesis”, which provides a more encompassing framework for understanding oak forest dynamics.

The purpose of this Delphi study was to develop a consensus listing of those characteristics that comprise an effective agriculture teacher. Panel members consisted of agriculture teachers, county-level administrators, state FFA supervisory staff, and university faculty in agricultural education. The panel identified 40 characteristics of an effective agriculture teacher that were categorized into the areas of instruction, FFA, SAE, community relations, marketing, professionalism/professional growth, program planning/management, and personal qualities. Characteristics identified in the “personal qualities” category that are requisite for effective teachers warrant examination and possible remediation by current teacher education programs.

One of the most pressing issues facing agricultural education as a profession is the shortage of qualified teachers to fill existing and future secondary agricultural education vacancies. To date, the agricultural education profession has been only moderately effective in recruiting and retaining teachers (Camp, Broyles, & Skelton, 2002). The purpose of this study was to develop a consensus listing of the major problems facing beginning agricultural education teachers. By gaining a better understanding of the major problems beginning agricultural education teachers face, pre-service teacher education programs can better prepare potential teachers to deal with these obstacles. Likewise, professional development programs for current teachers could be established and/or modified to address these problems. This study utilized the Delphi method to develop this listing of major problems. An expert panel of teachers with three or fewer years of experience was established. This panel identified 11 major issues facing beginning agriculture teachers. The top five, as rated by the panel members, were: organizing an effective alumni chapter, organizing an effective advisory committee, organizing and planning FFA chapter events and activities, the management of student discipline in the classroom, and recruiting and retaining alumni members.

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In humid, broadleaf-dominated forests where gap dynamics and partial canopy mortality appears to dominate the disturbance regime at local scales, paleoecological evidence shows alteration at regional-scales associated with climatic change. Yet, little evidence of these broad-scale events exists in extant forests. To evaluate the potential for the occurrence of large-scale disturbance, we used 76 tree-ring collections spanning ;840 000 km 2 and 5327 tree recruitment dates spanning ;1.4 million km 2 across the humid eastern United States. Rotated principal component analysis indicated a common growth pattern of a simultaneous reduction in competition in 22 populations across 61 000 km 2 . Growth-release analysis of these populations reveals an intense and coherent canopy disturbance from 1775 to 1780, peaking in 1776. The resulting time series of canopy disturbance is so poorly described by a Gaussian distribution that it can be described as ''heavy tailed,'' with most of the years from 1775 to 1780 comprising the heavy-tail portion of the distribution. Historical documents provide no evidence that hurricanes or ice storms triggered the 1775-1780 event. Instead, we identify a significant relationship between prior drought and years with elevated rates of disturbance with an intense drought occurring from 1772 to 1775. We further find that years with high rates of canopy disturbance have a propensity to create larger canopy gaps indicating repeated opportunities for rapid change in species composition beyond the landscape scale. Evidence of elevated, regional-scale disturbance reveals how rare events can potentially alter system trajectory: a substantial portion of old-growth forests examined here originated or were substantially altered more than two centuries ago following events lasting just a few years. Our recruitment data, comprised of at least 21 species and several shade-intolerant species, document a pulse of tree recruitment at the subcontinental scale during the late-1600s suggesting that this event was severe enough to open large canopy gaps. These disturbances and their climatic drivers support the hypothesis that punctuated, episodic, climatic events impart a legacy in broadleaf-dominated forests centuries after their occurrence. Given projections of future drought, these results also reveal the potential for abrupt, meso-to largescale forest change in broadleaf-dominated forests over future decades.