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Copyright of Canadian Journal of Forest Research is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Forest Research is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

For millennia, natural disturbance regimes, including anthropogenic fire and hunting practices, have led to forest regeneration patterns that created a diversity of forest lands across the USA. But dramatic changes in climates, invasive species, and human population, and land use have created novel disturbance regimes that are causing challenges to securing desired natural regeneration. Climate is an ever-present background disturbance and determinant of species distribution. Changes in certain other factors such as large herbivore populations, wildfire, and pests modify forest composition and structure, and are common barriers to natural regeneration of desired species. Changes in long-standing disturbance regimes have led to the homogenization of forest landscape composition and structure. Today, forests have low regeneration potential and are low in resilience. They have reduced productivity and are prone to widespread health issues including severe forest mortality. In addition to epidemics of native invasive species due to climate change and availability of habitat at landscape scales, the continued introduction and spread of non-native pests and diseases are causing large-scale forest mortality. These ecological changes have cascading ecological consequences such as increases in severe wildfire, which pose new barriers to natural regeneration. Equally challenging are the barriers to natural regeneration that arise from social, political and economic factors. To address many of these issues requires active management that links all critical stages in the regeneration niche necessary for achieving desired regeneration to sustain forest development and production in a socially acceptable manner and economically viable market system. [ABSTRACT FROM AUTHOR]

Despite their long history as a forest dominant, the importance of Quercus (oak) species is declining under contemporary disturbance regimes in many parts of the world. This is cause for concern considering the great economic and ecological value of this genus. While many chronosequence studies have shown that clearcutting has accelerated the loss of Quercus species in forests of eastern North America, long-term repeated measures studies are needed to understand how topo-edaphic variables and disturbance history influence the persistence of the genus in post-harvest stands. In 1988, a study was implemented on the Hoosier National Forest (HNF) in southern Indiana, USA to examine the fate of Quercus species and their competitors within developing stands following clearcut harvests. Permanent plots were established in six harvest units in Quercus - Carya (oak-hickory) forests using a stratified design to capture a variety of physiographic and edaphic conditions. Pre-harvest plot data were collected in 1988 and plots were resampled in 2011, allowing documentation of shifts in species composition over a 23-year period (1988–2011). Aerial photos from the 1930s were used to determine canopy cover and likely historic land-use within each stand prior to incorporation into the HNF. To characterize edaphic conditions, soil samples were collected and analyzed for chemical characteristics in 2011. Non-metric multidimensional scaling (NMS) and multiple linear regression using fixed and mixed-effect models were used to examine species composition along topo-edaphic and historic canopy cover gradients. We observed drastic declines in the importance of Quercus alba (white oak), Quercus velutina (black oak), and Quercus prinus (chestnut oak) across all stands following harvest. During the same time period, we observed large increases in the importance of other species, with Acer rubrum (red maple) showing large increases on the driest sites and Liriodendron tulipifera (tulip-poplar) displaying the greatest increase across all sites. In pre-harvest stands, Q. prinus was confined to the poorest sites and displayed the strongest association of all species with historically closed canopies in both pre and post-harvest stands. In post-harvest stands, the diminished importance of Q. alba was associated with low soil nitrogen levels and historically open canopies. L. tulipifera and Prunus serotina (black cherry) were associated with more nutrient-rich mesic sites in post-harvest stands. Populus grandidentata (bigtooth aspen) in post-harvest stands was associated with historically closed canopies and low cation exchange capacity. [ABSTRACT FROM AUTHOR]

Guidelines for managing sugar maple-dominated forests by the single-tree selection method are well established and widely adopted. The forests of the Menominee Tribe in Wisconsin provide an opportunity to validate current guidelines by testing tree value and size/age relationships in forests that have substantially older and larger high-quality trees than can be found through the northern region. We harvested grade 1 sugar maple trees across a wide spectrum of ages and diameters, which we then manufactured into veneer, sawlogs, cants, and hardwood/pulpwood bolts to determine tree value. Tree value continued to increase with increasing dbh, but when the effect of tree age on value was discounted, the value of trees older than 100 years dropped precipitously toward zero. Thus, managing trees to maximize diameter and quality within genetic and site potential and harvesting at about 100 years will produce high-value grade 1 trees in the range of 24 to 30 in. dbh. [ABSTRACT FROM AUTHOR]

In burned forestlands, fire scar wounds commonly occur on tree stems as a result of cambial heating. In hardwood forests in particular, wounding can lead to stem decay with the extent of decay being related to scar size and exposure time. Therefore, wound closure rates are important to understand in the context of fire management such that allowing sufficient time for wound closure to occur between fires would enhance wood quality. Conversely, in the context of wildlife management, understanding wound closure rates would improve fire prescriptions needed for creating basal tree cavities as keeping wounds open prior to wound closure could enhance cavity development. The objectives of this study were to quantify growth and wound closure rates of white oaks ( Quercus alba ), one of the most valuable tree species in the central U.S. to both commercial forestry and wildlife. From historically burned, mature, oak-hickory forest site in Missouri, we sampled a wide range of tree sizes, fire scar sizes, and fire scar ages to determine the environmental and tree factors related to closure rates. Dendrochronological techniques were paired with new approaches of digitizing tree rings to capture malformed woundwood areas. The time required for wound closure ranged from 1 to 24 years and was significantly correlated to scar size. Surprisingly, post-fire growth trends were positive following scarring. Growth was positively related to scar and tree size. With this information, we expect that the process of basal wound closure and tree growth can be considered in a quantitative framework and used to guide fire management for wood quality or wildlife tree cavities. [ABSTRACT FROM AUTHOR]

Identification of the primary factors that influence the ecological distribution of species groups is important to managers of lowland-mountain forests in northern Iran. The aim of this study was to identify main ecological species groups, describe the site conditions associated with these species groups and the relationships between environmental factors and the distribution of ecological species groups using multi-variate analysis (Detrended correspondence analysis (DCA) and Canonical correspondence analysis (CCA)). For this purpose, 50 relevés (400 m2 each) were sampled using the Braun-Blanquet method. Vegetation was classified into three ecological species groups using a modified two-way indicator species analysis (TWINSPAN). In each relevé, environmental factors (topographic and soil variables) were measured and analysed using one-way ANOVA and Pearson r statistics. Further, species diversity indices were determined for the identified ecological species groups. Our results show that the environmental factors, e.g. elevation, slope, slope aspect, soil texture, pH and organic matter, were the most important factors explaining the distribution of the three ecological species groups in the study area. The diversity of the ecological species groups decreased with elevation. The results provide an ecological basis for forest management and for developing strategies for forest conservation in the study area. [ABSTRACT FROM AUTHOR]

Armillaria spp. occur widely in Missouri mixed-oak ecosystems. In order to better understand the ecology and management of this pathogen and its effects on oak coppice, we observed a transect of 150 stumps after clearcutting in southeastern Missouri, noting Armillaria infection and oak sprout demography one year and seven years after harvest. Additionally, we visited a 50-year-old clearcut in the same area to sample oak root systems of stump-sprout origin for comparison with the seven-year-old clearcut. One year after harvest, 55% of stumps supported Armillaria infections, while 62% of stumps were infected after seven years. In the 50-year-old clearcut, 21% of examined root systems were infected. Logistic regression analysis of the younger clearcut related likelihood of infection to tree age at time of harvest. Whereas Armillaria infection displayed weak to absent relationships with numbers of sprouts surviving over time, dominant sprout height and diameter on individual stumps—proxies for stump vigor—were positively associated with numbers of survivors. These measures of vigor also had more influence over the magnitude and development of sproutless gaps around the circumference of the stump than did Armillaria infection. Moreover, the random effect of the individual tree on the development of such gaps was large. These results point to an important role for individual stump vigor in regulating sprout self-thinning rates, potentially through compartmentalization of invading Armillaria. [ABSTRACT FROM AUTHOR]

Regeneration failure of Quercus in mature Quercus-dominated forests has been reported throughout the temperate zone. Quercus seedlings are often abundant in these forests, yet frequently fail to recruit to larger size classes despite canopy disturbances. To examine intra-stand patterns of advanced reproduction, competition, and irradiance in an upland Quercus stand, we installed a 2 ha plot that captured the canopy disturbance severity gradient caused by a wind event. To quantify disturbance severity and stand conditions, we inventoried all living and dead woody stems ¥5 cm diameter at breast height (dbh, 1.37 m above the surface) and quantified irradiance in 25 m² quadrats (n = 800) using synchronized ceptometers. To inventory patterns of advanced reproduction within the plot, we recorded the species of every woody stem >1 m in height and <5 cm dbh. We also documented the species and height of every Quercus stem ¥0.5-<5 cm dbh and the species, height, and distance to each stem nearest the focal Quercus stem. At the genus-level, Quercus was the most common nearest neighbor. However, at the species-level, the most common nearest neighbors were Acer saccharum and Ostrya virginiana. Competition index values significantly differed by species (p < 0.01), but did not significantly differ by disturbance severity class and we found no significant interactions between species and disturbance class. Quercus advanced reproduction was significantly clustered through the study plot and cluster locations overlapped with clusters of high irradiance, but these patterns were scale-dependent. Our results indicate that an appreciation for intra-stand heterogeneity may improve forest management planning. [ABSTRACT FROM AUTHOR]

Abstract: The Chilton Creek prescribed burn project was initiated in 1996 by The Nature Conservancy (TNC) to restore native oak woodlands and test the effect of frequent, low intensity surface fires conducted in the dormant season (March–April) on upland oak-hickory forests in the Ozarks of Missouri. Burning treatments on five sites totaling 1000ha were initiated in 1998. The prescribed burn treatments included: annual burns (one site was burned annually) and periodic burns (four sites were burned with a mean fire return interval of approximately 4years). Approximately 3000 stems of advance reproduction with basal diameters ⩽15.0cm were measured in 1997 (pre-burn), and remeasured in 1998, 2001 and 2007 as the prescribed burn treatments proceeded. Mortality and changes in average and aggregate total height between 1997 and 2007 were analyzed for fourteen selected tree species. Over a ten-year period prescribed burning reduced stem density, mean height and aggregate height by 57%, 36% and 67%, respectively. However, individual tree species responded differently to the repeated burns. Oaks exhibited moderate mortality (36–54%) compared to hickories, sassafras and winged elm, all of which experienced relatively low mortality (18–35%). Flowering dogwood, shortleaf pine, blackgum and other minor species incurred higher mortality (60–76%). Oaks generally had slightly lower reductions in mean height and aggregate height than associated species with the exception of shortleaf pine, but the differences were mostly non-significant. Repeated burning tended to favor the white oak species (white oak, post oak, chinkapin oak) more than the red oak species (black oak, scarlet oak), although the differences were minor. Shortleaf pine was the only species to show increases in mean height following the ten-year period of prescribed burning. Effects of repeated burns on mortality of advance reproduction changed with stem size (e.g., basal diameter, total height). A logistic model quantified mortality changes as a function of the ratio between total stem height and the square of stem basal diameter. Based on this model, fourteen species were classified into four groups characterized by model intercept and slope: group 1: high intercept and high slope (shortleaf pine, flowering dogwood); group 2: high intercept and low slope (blackgum, other minor species); group 3: low intercept and low slope (sassafras, winged elm, black and pignut hickories); and group 4: low intercept and high slope (oaks, mockernut hickory). Species in groups 3 and 4 are more resistant to repeated fires than those in groups 1 and 2 as indicated by their lower mortality, particularly for stems with larger basal diameters. Among species in groups 3 and 4, oaks will likely be favored over the long term because of their conservative reproduction strategies as suggested by the significance of the regression coefficients for slope. If large advance reproduction is present, shortleaf pine will likely survive repeated low intensity fires and maintain its height and competitive position due to its ability to avoid shoot dieback. [Copyright &y& Elsevier]

Research on oak (Quercus L.) regeneration has generally consisted of smallscale studies of treatments designed to favor oak, including consideration of site quality and topographic effects on oak regeneration. However, these experiments have not consistently factored in broader-scale ecological differences found in the eastern United States. Oak regeneration experiments should be replicated at appropriate ecological scales to address the similarities and differences in regeneration following prescribed silvicultural treatments among ecological units. Patterns in oak regeneration can be better understood in an ecological context by considering how oak species interact in the differing physical environments and are able to maintain dominance in changing complexes of competing vegetation among the selected eco-units. Our understanding of oak regeneration response to specific silvicultural practices and our ability to model regeneration is improved when we use replication, blocking, or factorial deployment of relatively small-scale (0.5-1.0 ha) treatment plots within an ecological classification system. We present an example of this approach to understanding oak regeneration dynamics in a synthesis of research to regenerate northern red oak (Quercus rubra L.) by underplanting shelterwoods in Arkansas, Missouri and Indiana. We summarize important considerations to guide the design of future research in oak regeneration. [ABSTRACT FROM AUTHOR]

Abstract: The long-standing interest in regenerating oaks stimulated the development of a number of research studies during the past several decades. Most studies have focused on addressing oak regeneration problems and many of these suggested that oak regeneration failures occur where site conditions favor the establishment and growth of competing species that capture the growing space following crown release. Because ecosystem classification regimes incorporate information about site conditions including many of the biophysical factors that largely govern site quality, some forest scientists have proposed that they be used for predicting oak regeneration dynamics. We used a large data set from a replicated landscape-scale experiment comprising nine, 400-ha forest management compartments to systematically examine oak regeneration dynamics following the application of a range of regeneration methods (clearcutting, group and single-tree selection) across differing ecological land types. We found that species of the red oak group appeared to be regenerating successfully only in stands harvested with clearcutting and that regeneration success was greatest in clearcut stands located on ecological land types of lower site quality where the density of competitors was relatively low. In contrast, species of the white oak group were regenerated with clearcutting and with the combination of group and single-tree selection but their regeneration response did not appear to be related to ecological land type. We conclude that an ecological classification framework is valuable for partitioning the landscape into finer-scale land units each having a similar propensity to (1) accumulate red oak reproduction in advance of harvesting and (2) respond to various regeneration methods each in a uniform manner. This framework was less important for examining species in the white oak group, which had similar regeneration dynamics across land types. [Copyright &y& Elsevier]

Copyright of Forestry Chronicle is the property of Canadian Institute of Forestry and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In the Midwestern United States, the General Land Office (GLO) survey records provide the only reasonably accurate data source of forest composition and tree species distribution at the time of pre-European settlement (circa late 1800 to early 1850). However, GLO data have two fundamental limitations: coarse spatial resolutions (the square mile section and half mile distance between quarter corner and section corner) and point data format, which are insufficient to describe vegetation that is continuously distributed over the landscape. Thus, geographic information system and statistical inference methods to map GLO data and reconstruct historical vegetation are needed. In this study, we applied a hierarchical Bayesian approach that combines species and environment relationships and explicit spatial dependence to map GLO data. We showed that the hierarchical Bayesian approach (1) is effective in predicting historical vegetation distribution, (2) is robust at multiple classification levels (species, genus, and functional groups), (3) can be used to derive vegetation patterns at fine resolutions (e.g., in this study, 120 m) when the corresponding environmental data exist, and (4) is applicable to relatively moderate map sizes (e.g., 792 × 763 pixels) due to the limitation of computational capacity. Our predictions of historical vegetation from this study provide a quantitative and spatial basis for restoration of natural floodplain vegetation. An important assumption in this approach is that the current environmental covariates can be used as surrogates for the historical environmental covariates, which are often not available. Our study showed that terrain and soil covariates least affected by past natural and anthropogenic alternations can be used as covariates for GLO vegetation mapping. [ABSTRACT FROM AUTHOR]

• Use of rare long-term data from multiple experimental forests across northeastern U.S. • Of all stand/site factors considered, stocking was most influential in managed stands. • C sequestration was highest a few years after harvest in managed stands. • Uneven-aged management tended to have positive effects on C sequestration in certain conditions. • Showcases the potential use of uneven-aged management regimes in climate mitigation. We compiled data from several independent, long-term silvicultural studies on USDA Forest Service experimental forests across a latitudinal gradient in the northeastern and north-central U.S.A. to evaluate factors influencing aboveground live-tree carbon sequestration and mortality. Data represent five sites with more than 70,000 repeated tree records spanning eight decades, five ecoregions, and a range of stand conditions. We used these data to test the relative influence of factors such as climate, treatment history (uneven-aged or no management), species composition, and stand structural conditions on aboveground live-tree carbon sequestration and mortality in repeatedly measured trees. Relative to no management, we found that uneven-aged management tended to have a positive effect on carbon sequestration at low stocking levels and in areas of favorable climate (expressed as a combination of growing season precipitation and annual growing degree days > 5 °C). In addition, losses of carbon from the aboveground live-tree pool due to tree mortality were lower in managed than unmanaged stands. These findings suggest that there may be conditions at which rate of sequestration in living trees is higher in stands managed with uneven-aged silviculture than in unmanaged stands, and that this benefit is greatest where climate is favorable. [ABSTRACT FROM AUTHOR]

The article focuses on Ecology and silviculture of temperate mixedwood forests. Topics discussed include the ecology and silviculture of these systems has been a consistent area of study given the potential benefits of mixed-species forests in relation to minimizing forest health and climate change impacts; and the occasional higher levels of productivity observed for species mixtures relative to single-species stands.

Miombo woodland (MW) has several multi-purpose forest species, which are over-exploited for agriculture, charcoal and logging. Industrial plantations are among the promising solutions for sustainable management of MW, but high-yielding MW species are still lacking in the forestry sector. In this context, the present study assessed the growth of MW species, with respect to their early (ES) or late (LS) successional status. Seedling development was assessed for eight tree species, which were ES (Combretum collinum, Pterocarpus tinctorius) and LS (Brachystegia boehmii, B. longifolia, B. spiciformis, B. wangermeana, Julbernardia globiflora, J. paniculata), 1, 2 and 4 years after planting. Germination and survival varied in relation to ontogenetic traits of the species, but not the successional status, as was the case for growth and productivity. Seed germination was 60% to 88% for all species (except C. collinum). Seedling survivorship was greater than 70% for most species, except for J. paniculata (36%). ES species have greater growth compared to LS, due to the allocation of biomass to diameter and the length of the root, respectively, from the early stage of seedling development. These two strategies of biomass allocation are positively correlated with height. We further observed two distinct phases of seedling development (0–2 and 2–4 years) for all species. Growth differences among LS species were identified 4 years after planting. Based on seedling biomass, B. spiciformis, C. collinum and P. tinctorius are the most productive potential candidates for reforestation of degraded MW. We concluded that seedling growth and productivity varied according to strategies of biomass allocation that were related to successional status (ES (Chipya group) versus LS (Miombo group)) and to age following planting. [ABSTRACT FROM AUTHOR]

• Woody plant development was monitored in mature, wind-disturbed, and salvaged sites. • Prescribed fire enhanced post-disturbance Pinus palustris woodland recovery. • Salvage-logged sites hosted the greatest Pinus palustris sapling densities. • Low-intensity prescribed fire effects were apparently unaltered by salvage logging. Scientifically informed strategies to manage naturally disturbed forests are critical to support the sustained provisioning of ecosystem goods and services. In fire-adapted ecosystems, catastrophic canopy removal can disrupt surface fuel continuity and challenge the continued use of low-intensity prescribed fire. Although salvage logging is used globally after natural disturbance events, little information is available on how salvage logging interacts with subsequent use of prescribed fire. This study investigated the impacts of operational-scale prescribed fire on Pinus palustris (longleaf pine) stand development in areas differentially impacted by an April 2011 EF3 tornado and a subsequent salvage logging operation. Twenty 0.04-ha nested plots were systematically established in mature, wind-disturbed, and salvage-logged sites (n = 60) to measure seedlings, saplings, woody fuels, organic litter, and mineral soil before and after prescribed fire. Prescribed fire-induced fine fuel consumption, mineral soil exposure, and substantial sapling density reductions were observed throughout the treatment area. Prescribed fire effects were not apparently impacted by salvage logging, which did not alter the amount of fine fuels available for prescribed fire consumption. Despite overall sapling density reductions, fire-resistant P. palustris saplings exhibited increased densities on wind-disturbed and salvage-logged sites. Pinus palustris seedlings, however, exhibited marked post-fire reductions, which contrasted with a strong resprouting response observed among top-killed hardwood species. Concerning woody plant recovery, this study indicated that salvage logging was not detrimental to P. palustris stand development and that prescribed fire effectively enhanced recovery in unlogged and logged wind-disturbed sites. [ABSTRACT FROM AUTHOR]

An abstract of the article "A Stocking Diagram for Midwestern Eastern Cottonwood-Silver Maple-American Sycamore Bottomland Forests," by David R. Larsen, Daniel C. Dey, and Thomas Faust is presented.