Abstract Old-growth forests have been noted for containing significant quantities of deadwood. However, there has been no coordinated effort to quantify the deadwood component of old-growth remnants ...across large regions of temperate deciduous forest. We present results of a regional inventory that quantifies and examines regional and temporal trends for deadwood in upland old-growth forest remnants within Indiana, Illinois, Missouri, and Iowa. From 1992 to 1994, down wood ≥ 10 cm in diameter and standing trees ≥ 10 cm dbh were inventoried on 328 one-tenth ha plots at 12 sites. The mean ratio among the sites by diameter class of the number of standing dead to standing live trees (dead/live ratio) ranged from 0.08 to 0.11 and was consistent for trees ≤ 65 cm in diameter. The dead/live tree ratio was generally greater for old-growth than for mature second-growth forests (70 to 90 yr old). Mean volume of standing dead trees across all old-growth sites was 21.4 m³/ha and down wood was 60.4 m³/ha. However, both standing and down wood volume (total deadwood) increased along a regional gradient of increasing productivity from southwest Missouri to northeast Indiana and also increased with increasing age of dominant and codominant trees. Old-growth forests on high productivity sites averaged more pieces/ha of down wood in all diameter classes and higher volume/ha of down wood in nearly all diameter classes than did old-growth forests on low productivity sites. A chronosequence of forests from 10 yr to more than 200 yr since stand establishment indicated a sharply declining down wood volume from age 10 to 70 yr followed by increasing volume between 80 and 200 yr. For. Sci. 45(2):302-313.
A total of 53 fire-scarred Pinus echinata (shortleaf pine) trees were examined to reconstruct a ridgetop fire chronology of an oak-pine forest in the Ozark Mountains of north-central Arkansas. This ...process yielded 104 fire scars dating to 61 separate fire years. Fire frequency was greatest during the Euro-American Settlement Period (1820–1900), when the median fire interval (MFI) was 1.9 years. Most of the sample trees established during this period. Fire remained prevalent through the Regional Development (1901–1930) and Modern (1931–2003) Periods, when the MFI was 2.1 and 2.6 years, respectively. Palmer Drought Severity Index mean values from 1823–2003 did not differ (p = 0.76) between fire years and non-fire years, suggesting that fires in the study area were predominantly anthropogenic in origin.
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BFBNIB, DOBA, IZUM, KILJ, NMLJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
•We measured carbon pool changes on old-growth sites in the Central Hardwood Forest.•We tested the effect of old-growth forest stand structure on carbon productivity.•Total aboveground carbon had an ...average net gain of 7 % over 20 years.
Managing old-growth forests and promoting old-growth complexity in aging forests for carbon emissions mitigation has become an important component of diversified land management strategies. In the midwestern US, the Central Hardwoods Region (CHR) is the largest continuous deciduous forested area and includes a diverse range of species compositions, forest structures, and topoedaphic environments. Understanding carbon storage potential in old-growth forests across the CHR is important for evaluating climate-adaptive management strategies to increase carbon sequestration in the region’s aging forests. We assessed forest carbon in two time periods (the early 1990s and the 2010s) in ten old-growth forests across a 770 km east-west productivity gradient from Indiana to Missouri. Further, we related anomalies in carbon pools between the two sampling periods to documented or observable disturbances. As expected, old-growth forests on more productive sites in the eastern portion of the study range stored more aboveground carbon (120–177 Mg C ha−1) than less productive sites to the west (93–117 Mg C ha−1). Over the twenty-year period, old-growth forests accumulated 9.2 ± 1.5 (mean ± SE) Mg C ha−1 or a 7 % increase in total aboveground carbon. Further, downed dead wood carbon increased 5 % (0.4 ± 0.7 Mg C ha−1), standing dead increased 7 % (0.3 ± 0.7 Mg C ha−1), live roots increased 4 % (1.0 ± 0.3), and dead roots increased by 68 % (0.3 ± 0.1 Mg C ha−1). However, stochastic disturbances can positively or negatively impact total carbon and carbon pools. Documenting carbon trends and disturbance effects in old-growth forests provides guidance to enhance the representation of structurally complex, late successional forests using active forest management. Old-growth forests are currently rare in the CHR landscape, but the abundance of aging forests in the region provides immense potential to store carbon, particularly when combined with strategies that optimize early- and late-successional habitats for carbon sequestration along with other ecological goods and services.
In central hardwood forests, mean cavity-tree abundance increases with increasing stand-size class (seedling/sapling, pole, sawtimber, old-growth). However, within a size class, the number of cavity ...trees is highly variable among 0.1-ha inventory plots. Plots in young stands are most likely to have no cavity trees, but some plots may have more than 50 cavity trees/ha. Plots in old-growth stands often had 25 to 55 cavity trees/ha, but individual plots ranged from 0 to 155/ha. The Weibull probability density function was used to mathematically describe the variation in cavity-tree abundance for plots in stands of differing size (or age) class. A graph of the cumulative probability of cavity-tree abundance is a particularly easy way for managers to estimate the probability that a stand of a given size class will have any specified number of cavity trees per hectare. Results for individual plots or stands can be combined to estimate cavity abundance probabilities for landscapes. Because the results are presented in terms of plot-size classes (or age classes), this approach to cavity tree estimation is compatible with relatively simple forest inventory systems.
Las especies de madera dura juegan un papel fundamental en los ecosistemas forestales en el sureste de los Estados Unidos. Esto requiere una evaluación de las tendencias de la mortalidad en estas ...especies, así como los factores asociados a éstas. Este estudio evaluó las tendencias de mortalidad para las especies de madera dura utilizando análisis de inventario de bosque ( Forest Inventory Analysis ), datos del Servicio Forestal de los Estados Unidos durante dos ciclos consecutivos de inventario utilizando modelos kernels smoothing y Classification and Regression Tree (CART). El primer ciclo de inventario (2000–2004) revela una tendencia y factores asociados que pueden estar asociados con la disminución de eventos que se han repetido en toda la región, mientras que el segundo ciclo de inventario (2005–2009) exhibe una tendencia diferente en la mortalidad del ciclo uno. Estas diferencias podrían deberse a fenómenos meteorológicos extremos (como huracanes) que afectaron la región durante el segundo ciclo de inventario. Las tendencias de mortalidad y sus factores asociados deben ser monitoreadas con la esperanza de poder desarrollar métodos para mitigar los impactos extremos de estas especies de vital importancia.
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BFBNIB, DOBA, IZUM, KILJ, NMLJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
We examined the structural and spatial distribution of woody biomass in relationship to disturbance in an Indiana old-growth deciduous forest over a 66-yr period. Analysis was done on the core 7.92 ...ha of a 20.6-ha forest in which every tree 10 cm dbh and over has been tagged and mapped since 1926. Five years are compared—1926, 1976, 1981, 1986 and 1992. Dry weight of living biomass for the 7.92-ha area for these 5 yr was 154 Mg/ha, 207 Mg/ha, 220 Mg/ha, 216 Mg/ha and 211 Mg/ha, respectively. Biomass of dead trees was 1 Mg ha−1 yr−1 from 1977 through 1981; 4 Mg ha−1 yr−1 from 1982 through 1986; and 3 Mg ha−1 yr−1 from 1987 through 1992. Biomass of trees that died between 1976 and 1992 was greatest for midseral species. Living biomass of dominant early to midseral species is declining while that of late seral species is increasing. In 1926 biomass of trees 10 to 25 cm diam consisted of 14% Quercus spp. and 12% Acer saccharum. By 1992 biomass in this diameter range consisted of 1% Quercus spp. and 43% A. saccharum. Equilibrium patch size was estimated for biomass at each of the five inventory dates to determine if there was a change. Equilibrium patch size for biomass was estimated to be 0.64 ha during all five inventory dates based on the coefficient of variation (CV) of biomass for 16 different grid cell sizes. Grid cell size refers to the size of adjacent cells in a grid that covered the entire study area. The grid with the smallest cells had cells of 0.01 ha. This grid of 0.01-ha cells was aggregated to 15 additional grid cell sizes, where the largest grid cell size was 1.98 ha. CV for all grid cell sizes was highest in 1926 due to effects of prior grazing. These data indicate an increase in deadwood biomass, a shift in stand composition, recovery from grazing by an increase in small diameter trees and no change in equilibrium patch size over the five inventory dates.
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BFBNIB, DOBA, IZUM, KILJ, NMLJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Abstract Aim Efforts to understand how pollinating insect diversity is distributed across large geographic areas are rare despite the importance of such work for conserving regional diversity. We ...sought to relate the diversity of bees (Hymenoptera: Apoidea), hover flies (Diptera: Syrphidae), and butterflies (Lepidoptera) to ecoregion, landscape context, canopy openness, and forest composition across southeastern U.S. forests. Location Nineteen experimental forests across nine states in the southeastern U.S. Methods We established 5–7 plots on each experimental forest. In each, we sampled pollinators monthly (March–September) using coloured pan traps, and collected data on local forest characteristics. We used the National Land Cover Database (NLCD) to quantify surrounding landcover at different spatial scales. Results Bee richness was negatively correlated with both the amount of conifer (pine) forest and the extent of wetlands in the surrounding landscape but was positively correlated with canopy openness. Hover flies and butterflies were less sensitive to landscape context and stand conditions. Pollinator communities differed considerably among ecoregions, with those of the Central Appalachian and Coastal Plain ecoregions being particularly distinct. Bee richness and abundance peaked 2 months earlier in Central Appalachia than in the Coastal Plain and Southeastern Mixed Forest ecoregions. Main Conclusions Our findings reveal ecoregional differences in pollinator communities across the southeastern U.S. and highlight the importance of landscape context and local forest conditions to this diverse fauna. The closed broadleaf forests of Appalachia and the open conifer‐dominated forests of the Coastal Plain support particularly distinct pollinator communities with contrasting seasonality. Our results suggest pine forests may reduce pollinator diversity in regions historically dominated by broadleaf forests. However, efforts to create more open canopies can help improve conditions for pollinators in planted pine forests. Research exploring associations between forest pollinators and different broadleaf tree taxa is needed to better anticipate the impacts of various management activities.
Oak decline is a process induced by complex interactions of predisposing factors, inciting factors, and contributing factors operating at tree, stand, and landscape scales. It has greatly altered ...species composition and stand structure in affected areas. Thinning, clearcutting, and group selection are widely adopted harvest alternatives for reducing forest vulnerability to oak decline by removing susceptible species and declining trees. However, the long-term, landscape-scale effects of these different harvest alternatives are not well studied because of the limited availability of experimental data. In this study, we applied a forest landscape model in combination with field studies to evaluate the effects of the three harvest alternatives on mitigating oak decline in a Central Hardwood Forest landscape. Results showed that the potential oak decline in high risk sites decreased strongly in the next five decades irrespective of harvest alternatives. This is because oak decline is a natural process and forest succession (e.g., high tree mortality resulting from intense competition) would eventually lead to the decrease in oak decline in this area. However, forest harvesting did play a role in mitigating oak decline and the effectiveness varied among the three harvest alternatives. The group selection and clearcutting alternatives were most effective in mitigating oak decline in the short and medium terms, respectively. The long-term effects of the three harvest alternatives on mitigating oak decline became less discernible as the role of succession increased. The thinning alternative had the highest biomass retention over time, followed by the group selection and clearcutting alternatives. The group selection alternative that balanced treatment effects and retaining biomass was the most viable alternative for managing oak decline. Insights from this study may be useful in developing effective and informed forest harvesting plans for managing oak decline.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Oak regeneration problems have been noted in the Missouri Ozarks an`d elsewhere in the eastern United States. Alteration of disturbance regimes, competition from nonoak species, and high overstory ...stocking are believed to be major barriers that impede oak regeneration. We studied regeneration in upland oak forests that were harvested by both even-aged (clearcutting) and uneven-aged (single-tree selection and group selection) regeneration methods, focusing on differences in oak regeneration among stands that received alternative harvest treatments. Ten years after treatments, the density of oak regeneration generally increased with increased removal of overstory trees, but only the clearcutting treatment resulted in a statistically significant increase in the density of oak seedlings and saplings over that in the no harvest treatment (the control). There were no differences among treatments in the relative proportions of oak seedlings and saplings as a whole or by size classes among the treatments. Successful oak regeneration after removal of overstory trees highly depends on the number and size of advance oak reproduction and is closely related to site conditions such as aspect and bedrock geology. Both site factors and advance oak reproduction must be considered when a regeneration method to promote oak is chosen. Compared with the uneven-aged methods (single-tree selection and group selection), clearcutting favored the red oak species over the white oak species.
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