Developing and Using Fire Scar Histories in the Southern and Eastern United States

Land managers developing fire management plans in the eastern and southern United States lack quantitative information on historic fire regimes. Twelve new fire histories were developed from dated fire scars on trees from regions where no fire scar history data had existed before in the states of Alabama, Louisiana, Kentucky, Iowa, Wisconsin, and Michigan. Sites represent highly variable climates from extreme cold (with long snow cover duration) to subtropical. All sites utilized oak or pine recorder species that were collected from closed forest to open savanna structures. Pre-industrial mean fire intervals ranged from 3 to more than 35 years at sites that typically encompassed less than 2 km2 in area. The most frequent fire regime was found in Louisiana‟s Kisatchie National Forest (MFI = 3 yrs) while the longest fire intervals were at inland sites near the shore of Lake Superior (MFI \u3e 35 yrs) some 1900 kilometers to the north. The subtropical site in Louisiana is perhaps the only site in the U.S. where fires are documented to have occurred more than once a year. The history of fire at sites in Wisconsin, Louisiana, and Michigan showed distinct temporal progressions in changes in fire frequency that we attributed to changing human population. Sites in Wisconsin showed potential for very large fires associated with drought years. Fire history data analyses and summaries were presented at multiple venues (workshops, conferences) and have been published in scientific journals and reports to regional land managers. Fire history data has also been made publicly available through the International Multiproxy Paleofire Databank (IMPD). New fire history data from this project combined with previously collected fire history data from the Missouri Tree-Ring Laboratory and published fire histories in North America were used to parameterize and calibrate a continental fire frequency model based on climate. The most important contribution of this model is towards understanding climate forcing of fire regimes across the continental U.S. We have developed a suite of climate-based fire frequency models for the continental U.S. that show to be highly robust. Models and calibrations were validated with empirical fire history data during pre-industrial periods so to minimize non-climate influences associated with U.S. settlement (land conversion, changing cultures). Fire frequency models follow theoretical concepts from physical chemistry, utilize spatially-explicit fire and climate data, and were parameterized and validated using statistical methods. Data from fire history studies were accumulated from 37 states and include data based on fire scars (n = 168), expert estimates (n = 7) and charcoal (n = 3). Historic mean fire interval (MFI) models were parameterized using mean maximum temperature, precipitation, their interaction, and estimated population density (anthropogenic ignitions). Models are being used to: assess the role of climate in forcing fire frequency, map coarse-scale historic fire frequency for the continental U.S., and assess departures in fire regimes and smoke emissions

Developing and Using Fire Scar Histories in the Southern and Eastern United States

Land managers developing fire management plans in the eastern and southern United States lack quantitative information on historic fire regimes. Twelve new fire histories were developed from dated fire scars on trees from regions where no fire scar history data had existed before in the states of Alabama, Louisiana, Kentucky, Iowa, Wisconsin, and Michigan. Sites represent highly variable climates from extreme cold (with long snow cover duration) to subtropical. All sites utilized oak or pine recorder species that were collected from closed forest to open savanna structures. Pre-industrial mean fire intervals ranged from 3 to more than 35 years at sites that typically encompassed less than 2 km2 in area. The most frequent fire regime was found in Louisiana‟s Kisatchie National Forest (MFI = 3 yrs) while the longest fire intervals were at inland sites near the shore of Lake Superior (MFI \u3e 35 yrs) some 1900 kilometers to the north. The subtropical site in Louisiana is perhaps the only site in the U.S. where fires are documented to have occurred more than once a year. The history of fire at sites in Wisconsin, Louisiana, and Michigan showed distinct temporal progressions in changes in fire frequency that we attributed to changing human population. Sites in Wisconsin showed potential for very large fires associated with drought years. Fire history data analyses and summaries were presented at multiple venues (workshops, conferences) and have been published in scientific journals and reports to regional land managers. Fire history data has also been made publicly available through the International Multiproxy Paleofire Databank (IMPD). New fire history data from this project combined with previously collected fire history data from the Missouri Tree-Ring Laboratory and published fire histories in North America were used to parameterize and calibrate a continental fire frequency model based on climate. The most important contribution of this model is towards understanding climate forcing of fire regimes across the continental U.S. We have developed a suite of climate-based fire frequency models for the continental U.S. that show to be highly robust. Models and calibrations were validated with empirical fire history data during pre-industrial periods so to minimize non-climate influences associated with U.S. settlement (land conversion, changing cultures). Fire frequency models follow theoretical concepts from physical chemistry, utilize spatially-explicit fire and climate data, and were parameterized and validated using statistical methods. Data from fire history studies were accumulated from 37 states and include data based on fire scars (n = 168), expert estimates (n = 7) and charcoal (n = 3). Historic mean fire interval (MFI) models were parameterized using mean maximum temperature, precipitation, their interaction, and estimated population density (anthropogenic ignitions). Models are being used to: assess the role of climate in forcing fire frequency, map coarse-scale historic fire frequency for the continental U.S., and assess departures in fire regimes and smoke emissions

Una aproximación ecológica a la silvicultura del roble:síntesis de 50 años de investigación en ecosistemas de roble en Norteamérica

Oak (Quercus L.) is an abundant and widely distributed genus in eastern North America. A history of periodic ire, grazing, canopy disturbance and timber harvesting has favored oak's dominance. But, changes in this regime toward much less ire or complete ire suppression, and selective cutting are causing the successional replacement of oak. High populations of forest herbivores such as whitetailed deer (Odocoileus virginianus), invasive species such as gypsy moth (Lymantria dispar), or dominance of native lora such as mountain laurel (Kalmia latifolia) can also inhibit oak regeneration and add to its loss within a region. Successful oak regeneration is dependent on having an adequate number of large oak advance reproduction before stand regeneration. However, this prerequisite is often lacking in eastern oak forests. Many oak stands have either few or no oak advance reproduction, and when present, it is small and noncompetitive. These common situations can be addressed through silviculture. The lack of oak seedlings in older, mature stands is addressed with a three-stage shelterwood method that promotes acorn production and site preparatory burning that increases acorn germination success. In younger, i.e., sapling and pole stands, crop tree thinning to release co-dominant oaks promotes crown development and future acorn production. The lack of competitive-sized oak reproduction is addressed with a two ­ or three ­ stage shelterwood sequence because this method is very useful for providing adequate light to foster root development of the shade intolerant oak seedlings. Application of the shelterwood method often includes herbicides or prescribed ire to control competing vegetation either before or after the inal overstory removal. When adequate oak advance reproduction is present, then clearcutting is a viable option, but measures may be needed after harvesting to control competing vegetation. Prescribed ire applied several times after inal removal of the shelterwood, or clearcutting is proving a useful tool to favor oak. These silvicultural practices generally have either no or positive impacts on non-target communities of herbaceous plants, mammals, birds, and herpetofauna.Los encinos constituyen un género (Quercus L.) abundante y ampliamente distribuido en los bosques del este de Norte América. La dominancia de los encinos se debe, en gran parte, a una historia de frecuentes disturbios que incluyen fuegos, herbivoría por mamíferos y explotación forestal. Alteraciones a estos regímenes de disturbios históricos hacia disturbios con menos frecuencia e intensidad, y la supresión de fuego, han ocasionado un remplazo gradual de los encinos. El aumento de poblaciones de herbívoros mamíferos (por ejemplo, Odocoileus virginianus), de insectos invasivos (por ejemplo, Lymantria dispar), o la dominancia de arbustos nativos (por ejemplo, Kalmia latifolia) impiden la regeneración de los encinos y contribuyen a su deterioro dentro de una región. La regeneración exitosa de los encinos depende de obtener un nivel adecuado de regeneración avanzada antes de que se inicien los cortes inales. La producción de bellotas puede incrementarse en rodales jóvenes con la aplicación de raleos para estimular el desarrollo de los doseles, o en rodales maduros utilizando una serie de cortes de protección para estimular la producción de semillas. Los cortes de protección suelen estimular el desarrollo de especies helióilas como los encinos, porque aumentan la luminosidad en el sotobosque. Estos cortes usualmente se aplican en conjunto con procedimientos para controlar la vegetación en el sotobosque que compite con los encinos, como el uso de herbicidas o quemas prescritas. Si existe una cantidad adecuada de regeneración avanzada, el uso de la tala raza es apropiado, pero usualmente requiere el control de la competencia (por ejemplo, de malezas) que puede desarrollarse después de la cosecha. La quema prescrita, aplicada una o varias veces después de los cortes de protección o de la tala raza, es una práctica viable que favorece a los encinos. Todas estas intervenciones generalmente ocasionan una respuesta relativamente neutra o positiva a las comunidades de otros grupos de organismos como plantas herbáceas, aves, mamíferos, y la herpetofauna

Survival of Quercus alba (White Oak) Advance Reproduction in Small Group and Single Tree Openings

Survival probabilities of white oak (Quercus alba) in small circular group and single tree openings ranging in size from 0.001 to 0.175 ha twelve years after opening creation are presented. At the beginning of the study, 3948 advance reproduction white oak trees were measured and tagged to determine survival of each tagged seedling at the end of the study. Logistic regression indicated that variables important in predicting advance reproduction survival included initial seedling basal diameter, aspect, slope, canopy opening size, opening border tree height and treatment for control of understory competition. Survival probability ranged from 10% to 90% depending on the combination of and disposition of variables. For these small openings, the greatest probability of survival of advance reproduction resulted when advance reproduction initial basal diameters were ≥1 cm, when the height of trees bordering the openings were relatively short, with understory chemical competition control, in the largest canopy openings, on 6% slopes, and on southwest and northwest aspects. These criteria can help managers select sites and treatment options for group opening creation that provide optimal conditions for advance reproduction survival

Characteristics and spatial pattern of old-growth forests in the midwest

This research examined old-growth forests in the midwest to determine long-term dynamics, spatial relationships, differences from second-growth forests and to determine characteristics of old-growth in Indiana, Illinois, Missouri and lowa. The first phase examined woody biomass in a midwestern old-growth forest over 270 years. Results indicate two disturbances occurred, one around 1730 and one around 1824. In 1926 the biomass of 10-to-25 cm dbh trees was greater for early seral Quercus species than for Acer soccharum. This relationship reversed by 1992. Equilibrium patch size was estimated to be 0.64 ha. Dry weights of living biomass reached a maximum in 1981 of 220,220 kg/ha and decreased since due to mortality of dominant early seral trees. Based on these mortality rates, this forest could reach a steady-state phase by the year 2070. The second phase examined spatial and temporal relationships of old-growth and secondary forests in Indiana. Reforestation of riparian areas between secondary forests would reduce the number of forest fragments by 62%. All existing old-growth sites were isolated from each other. If current public forest management plans are followed, the area and number of old-growth forests will increase as relative isolation decreases. The third phase dealt with differences in characteristics between old-growth and second-growth forests in Indiana. Significant differences were found for forest structure, depth of soil A-horizon, standing deadwood volume, down deadwood volume and species. The fourth phase dealt with characterization of old-growth forests within Indiana, Illinois, Missouri and Iowa. For sites without recent wind disturbance in Indiana, Illinois and Iowa, basal area values were $\u3e$25 m\sp2/ha. Most Missouri sites had basal areas $\u3c$25 m\sp2/ha. Volume of deadwood, soil phosphorus levels, percent organic matter, soil A-horizon depth and dry weight of forest litter were variable among sites. Percent of cavities in living trees divided by cavities in all trees was 82%, SD = 9.4% among all sites. Age of dominant trees ranged from 75 years for a Missouri site to 336 years at an Indiana site

Characteristics of Dry-Mesic Old-Growth Oak Forests in the Eastern United States

Dry-mesic old-growth oak forests are widely distributed remnants across the eastern U.S. and are expected to increase in number and extent as second-growth forests mature. In this study, we synthesize published and unpublished information to better define the species, structure and extent of these forests. Mean site tree density for trees ≥10 cm dbh ranged from 341–620 trees ha−1. In the eastern part of the region, most stand basal areas were >23 m2 ha−1, compared to ≤23 m2 ha−1 in the westernmost stands. Overall, woody species diversity was relatively low compared to old-growth oak forests on moister sites, with tree species per forest ranging from 5–18. The most common species among the stands were white oak (Quercus alba), northern red oak (Quercus rubra), and black oak (Quercus velutina). Shrub and vine species per forest ranged from 1–10, with common species or genera including Virginia creeper (Parthenocissus quinquefolia), poison ivy (Toxicodendron radicans), Vaccinium spp., and grapevines (Vitis spp.). Within the southern Appalachian Mountains, rosebay rhododendron (Rhododendron maximum) and mountain laurel (Kalmia latifolia L.) were common. Herbaceous species per stand ranged from 4–51, with the highest richness occurring in a southern Appalachian oak-hickory forest. The maximum within-stand age of the large trees ranged from 170 to over 365 years. The mean density of standing dead trees ≥10 cm dbh ranged from 31–78 ha−1 and the volume of coarse woody debris ≥10 cm in diameter averaged 52 m3 ha−1. We more fully describe the characteristics of these forests and fill gaps in the collective knowledge of this increasingly important forest type. However, over the past 20 years, there has been scant research on these forests, and older research studies have used a variety of research plots and methods. A uniform approach to surveying these sites is needed to gain a better understanding of these forests before we are faced with caring for an increase in old-growth forest areas