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Snags are an important component of beech forests that promote biodiversity. However, their occurrence is completely marginal in managed stands. Creating snags in these stands would greatly enhance biodiversity. We investigated whether snag dimensions were important for saproxylic beetle richness since they were easily transferable parameters to forest management and assessed the presence of other snag microhabitats affecting beetle communities. Data collection was performed using passive flight traps placed on thirty snags in a recent beech reserve. A total of 6706 adults belonging to 231 saproxylic species (53 Red List species, 23%) were captured. The results showed that the most important snag parameters were the diameter (thickness) and canopy openness of the surrounding stands. The occurrence of Fomes fomentarius, the volume of snag and decay class 3 were marginally significant in terms of the preference of all saproxylic species. Alpha diversity was reduced by an advanced degree of decay and a surprisingly deep stem cavity. After dividing snag thickness into categories (<35 cm; 35-70 cm and >70 cm DBH), we found that categories with snag diameter greater than 35 cm showed little differences in all saproxylic and Red List species richness and diversity indices and exhibited the highest similarity in beetle communities. Regarding recommendations to forest managers in terms of optimization and simplification of practical procedures, we suggest actively creating high stumps to act as snags greater than 35 cm in DBH diameter to promote biodiversity in beech management stands. [ABSTRACT FROM AUTHOR]

Highlights • We examined survival of created snags 18 years after topping, Oregon, USA. Diameter at breast height (DBH) and distance between snags were associated with survival. • Median survival was 21 and 13 years for Douglas-fir and hemlock, respectively. Abstract Structural enrichment in commercial tree plantations is a potential tool to increase snag numbers but relatively little information is available about how species, size, and spatial distribution of created snags are associated with longevity of these structures. We created 1197 snags in 31 harvest units from 1997 to 1999 in the Cascade and Coast Ranges, Oregon, USA, by topping live trees with harvesting equipment. We used an experimental design to distribute created snags at three densities and as either single or clumped created snags. We fit Weibull and log-logistic Accelerated Failure Time models and found that the median failure time was insensitive to the choice of distribution. We found a small positive effect of diameter at breast height (DBH) and a slight negative effect of increasing distance between created snags on survival. Assuming Weibull and log-logistic distributions at mean observed values of DBH and distance between snags, median survival times for Douglas-fir (Pseudotsuga menziesii) were 21.0 (95% confidence interval: 19.3, 22.8) years and 21.2 (19.7, 22.8) years, respectively. For western hemlock (Tsuga heterophylla), median survival times were 13.0 (11.9, 14.2) years and 12.5 (11.4, 13.7) years, respectively. Although the two failure distributions had similar median failure times, the log-logistic implies a higher survival probability over time for snags that remained standing at the end of the study period. Created snags can be a useful supplement for harvest units rotated at ∼45 years and Douglas-fir will be available for longer as standing structures. For example, under the log-logistic model, a predicted 5% of Douglas-fir snags are retained to rotation age, so that 40 snags per hectare would be required at harvest to maintain 2 snags per hectare through stand rotation. Snags created from western hemlock will provide an early rotation pulse but are unlikely to last longer than 20 years. Our results suggest that longevity can be increased by maximizing the snag size within the safety constraints of harvesting equipment. Scattering of snags may have a slightly negative effect on snag survival but this outcome should be weighed against potential ecological benefits of variation in snag distributions. [ABSTRACT FROM AUTHOR]

ABSTRACT: Snags are important habitat features for many forest‐dwelling species, so reductions in the number of snags can lead to the loss of biodiversity in forest ecosystems. Intentional snag creation is often used in managed forests to mitigate the long‐term declines of naturally created snags, yet information regarding the use of snags by wildlife across long timescales (>20 yr) is lacking and prevents a complete understanding of how the value of created snags change through time. We used a long‐term experiment to assess how harvest treatment (i.e., small‐patch group selection, 2‐story, and clearcut) and snag configuration (i.e., scattered and clustered) influenced nesting in and foraging on 25–27‐year‐old Douglas‐fir (Pseudotsuga menziesii) snags by cavity‐nesting birds. In addition, we compared our contemporary measures of bird use to estimates obtained from historical surveys conducted on the same group of snags to quantify how bird use changed over time. Despite observing created snags for >750 hours across 2 consecutive breeding seasons, we found limited evidence of nesting activity. Only 11% of created snags were used for breeding, with nesting attempts by 4 bird species (n = 36 nests); however, we detected 12 cavity‐nesting species present on our study sites. Furthermore, nearly all nests (94%) belonged to the chestnut‐backed chickadee (Poecile rufescens), a weak cavity‐excavating species that requires well‐decayed wood for creating nest cavities. Our surveys also recorded few observations of birds using created snags as foraging substrates, with only 1 foraging event recorded for every 20 hours of observation. We detected 82% fewer nests and recorded 7% fewer foraging observations during contemporary field work despite spending >7.5 times more effort observing created snags relative to historical surveys. We conclude that 25–27‐year‐old created Douglas‐fir snags provided limited opportunities for nesting and foraging by most cavity‐nesting birds, and that the period of greatest use by this group occurred within 5–15 years of creation. © 2018 The Wildlife Society. [ABSTRACT FROM AUTHOR]

Fault arrays typically include a wide range of fault sizes and those faults may be randomly located, clustered together, or regularly or periodically located in a rock volume. Here, we investigate size distribution and spatial arrangement of normal faults using rigorous size-scaling methods and normalized correlation count (NCC). Outcrop data from Miocene sedimentary rocks in the immediate upper plate of the regional Buckskin detachment—low angle normal—fault, have differing patterns of spatial arrangement as a function of displacement (offset). Using lower size-thresholds of 1, 0.1, 0.01, and 0.001 m, displacements range over 5 orders of magnitude and have power-law frequency distributions spanning ∼ four orders of magnitude from less than 0.001 m to more than 100 m, with exponents of −0.6 and −0.9. The largest faults with >1 m displacement have a shallower size-distribution slope and regular spacing of about 20 m. In contrast, smaller faults have steep size-distribution slopes and irregular spacing, with NCC plateau patterns indicating imposed clustering. Cluster widths are 15 m for the 0.1-m threshold, 14 m for 0.01-m, and 1 m for 0.001-m displacement threshold faults. Results demonstrate normalized correlation count effectively characterizes the spatial arrangement patterns of these faults. Our example from a high-strain fault pattern above a detachment is compatible with size and spatial organization that was influenced primarily by boundary conditions such as fault shape, mechanical unit thickness and internal stratigraphy on a range of scales rather than purely by interaction among faults during their propagation. [ABSTRACT FROM AUTHOR]

The 2002 Hayman Fire burned with mixed-severity across a 400-ha dry conifer study site in Colorado, USA, where overstory tree and surface cover attributes had been recently measured on 20 0.1-ha permanent plots. We remeasured these plots repeatedly during the first post-fire decade to examine how the attributes changed through time and whether changes were influenced by fire severity. We found that most attributes were temporally dynamic and that fire severity shaped their dynamics. For example, low-severity plots experienced a modest reduction in live overstory density due to both immediate and delayed tree mortality, and no change in live overstory basal area through time; in contrast, high-severity plots experienced an immediate and total loss of live overstory density and basal area. Large snag density in low-severity plots did not vary temporally because snag recruitment balanced snag loss; however, in high-severity plots large snag density increased markedly immediately post-fire and then declined by about half by post-fire year ten as snags fell. Mineral soil cover increased modestly immediately post-fire in low-severity plots and substantially immediately post-fire in high-severity plots, but changed little in ensuing years for either severity class. By incorporating pre-fire and repeatedly-measured post-fire data for a range of severities, our study uniquely contributes to the current understanding of wildfire effects in dry conifer forests and should be of interest to managers, researchers, and others. [ABSTRACT FROM AUTHOR]

Standing dead trees, or snags, represent post-disturbance biological legacies in forest ecosystems, and intentional creation of new snags is increasingly common during forest treatments. The abundance, volume, size, and distribution of snags can affect wildlife communities and stand-level biological diversity. Characteristics such as the wood properties of different tree species, environmental conditions, and cause of tree death (e.g., insects, disease, senescence, wind, fire) can influence decomposition and subsequent use of snags by wildlife. The objectives of this study were to characterize decay patterns in jack pine ( Pinus banksiana ) snags that had been killed by prescribed fire, topping, and girdling and determine the effects of these treatments on subsequent snag use by subcortical insects and primary cavity-nesting birds. The prescribed fire, topping, and girdling treatments were implemented in 2003, 2004, and 2007, respectively; bird excavations were quantified in 2014 and insect activity was measured in 2016. One-way analysis of variance tests were used to examine any differences among treatments in snag characteristics, decay characteristics, past insect activity, and past use by birds. An information theoretic approach to model selection was then used to rank potential predictors of bird foraging activity and cavities. The topping treatment had unique decay characteristics relative to the other two treatments; topped snags had the highest levels of past insect colonization, were softer, and had higher proportions of loose bark remaining on the boles. Trees killed by prescribed fire had the greatest number of foraging excavations and cavities. Girdled snags had the lowest evidence of past insect colonization and showed different levels of decay and insect use at different vertical positions on the snag bole. Comparison of candidate models showed that a model containing treatment type alone was the highest ranked when predicting foraging by birds, while snag diameter was the highest ranked when predicting the presence of cavities. A model containing treatment and snag density was also a highly ranked for predicting cavity presence. Our findings suggest that different jack pine snag treatments result in unique decay trajectories that may influence snag use by an array of wildlife taxa. Our characterization of three snag creation treatments can also inform options for generating snags, depending on the desired outcome, when management for biological legacies and wildlife habitat is of interest within mixed-pine forests of the Great Lakes region. [ABSTRACT FROM AUTHOR]

Standing dead trees (or snags) are an important component of forest ecosystems, especially for tree cavity-nesting vertebrate species, but their prevalence in South African forests remains under studied. Consequently, we investigated forest structure, and the presence and abundance of snags in six southern mistbelt forests in the Eastern Cape, South Africa. These forests have had varying levels of timber extraction over the past 150 years or more. We found snags were relatively rare in all six forests (<4.3% of trees sampled). Mean diameter at breast height (dbh) of snags ranged from 52 to 82 cm across the forests, with smaller snags in Kologha Forest and larger snags in Tyume Forest. A bimodal distribution of snag successional stages was found, with frequencies peaking at early and late stages, and few in the intermediate stages. Tree species diversity in the forests was relatively low (twelve-nineteen species across forests; only 28 species in total). There was no significant difference in dbh of trees between forests, with most occurring in the 20-29-cm dbh size class. Future studies are required to identify trees that most likely support suitable cavities for tree cavity-nesting bird species, and to determine cavity-nester assemblage requirements in southern African forests. [ABSTRACT FROM AUTHOR]

Snags provide essential habitat for numerous organisms and are therefore critical to the long-term maintenance of forest biodiversity. Resource managers often use snag creation to mitigate the purposeful removal of snags at the time of harvest, but information regarding how created snags change over long timescales (>20 y) is absent from the literature. In this study, we evaluated the extent to which characteristics of large (>30 cm diameter at breast height [DBH]) Douglas-fir ( Pseudotsuga menziesii ) snags created by topping had changed after 25–27 y. We also tested whether different harvest treatments and snag configurations influenced present-day snag characteristics. Of 690 snags created in 1989–1991, 91% remained standing during contemporary surveys and 65% remained unbroken along the bole. Although most snags were standing, we detected increased bark loss and breaking along the bole relative to prior surveys conducted on the same pool of snags. Although snag characteristics were not strongly influenced by snag configuration, we found that snags in one harvest treatment (group selection) experienced less bark loss and had lower evidence of use by cavity-nesting birds (as measured by total cavity cover) relative to snags created with clearcut and two-story harvest treatments. Our results indicate that Douglas-fir snags created by topping can remain standing for long time-periods (≥25 y) in managed forests, and that the influence of harvest treatment on decay patterns and subsequent use by wildlife is an important consideration when intentionally creating snags for wildlife habitat. [ABSTRACT FROM AUTHOR]

Stand dynamics in the boreal forest are driven by wildfire, and many think that emulating forest fire patterns during harvesting will adequately preserve biodiversity. We tested this hypothesis by examining saproxylic beetle assemblages from a chronosequence of aspen forest stands originating after wildfire or harvest across several age classes (1–2, 14–15, 28–29 years old) as well as from mature (60–80 years old) and overmature (>120 years old) stands of pyrogenic origin. Using window-traps attached to standing dead snags we collected over 6300 saproxylic beetles representing 310 species. Saproxylic beetle assemblages collected immediately post-fire and post-harvest differed significantly; however, by 30 years post-disturbance beetle assemblages had begun to converge with some general similarities evident among stands that were 28–29 years old. Beetle catch and richness was not greatly affected after fire; however, immediately following stand harvest there was a spike in species richness and beetle catch followed by a significant decrease in both metrics in the 29 year old stands. Cluster analysis and non-metric multidimensional scaling ordination indicated that assemblages from stands regenerating 1–2 years after fire and harvest were dissimilar from those of the other stand ages, and that samples from the burned stands tended to be more variable in composition than those from the harvested stands until our last sample 29 years post-disturbance. Saproxylic beetle assemblages were dominated by mycophagous and predatory species, with different species represented in stands regenerating after fire and harvest. Although the saproxylic beetle fauna of the western Canadian boreal forest seems reasonably resilient to disturbance in the present landscape context, retention of large-diameter coarse woody material in a variety of decay classes and selective burning of some residual woody material should facilitate recolonization by saproxylic species by retaining important microhabitat features that are rarefied by harvest. [ABSTRACT FROM AUTHOR]

The Indiana bat ( Myotis sodalis ), a species that is federally endangered in the U.S., is being impacted by white-nose syndrome and habitat loss across much of its range. A better understanding of summer roost ecology of the species will enable us to develop management strategies that promote summer survival for breeding adult females and their pups. We conducted a 5 year investigation of Indiana bat roost habitat selection and roosting behavior in a large (>250,000 ha) forested area of the southern Appalachian Mountains and compared our results to populations in different landscapes across the species’ range. From May to August 2008–2012, we attached radio transmitters to 50 adult females, 3 juveniles, and 7 adult males captured at sites on the Cherokee and Nantahala national forests and Great Smoky Mountains National Park. We radiotracked bats to 95 roosts and measured characteristics of trees, 0.1 ha plots, and landscape attributes for 69 of these roosts and associated random trees. We used an AIC approach to compare 14 candidate conditional logistic regression models. The only plausible model, which carried 95% of total model weights, had 3 important terms. Indiana bats showed strong selection for yellow pine ( Pinus subgenus Diploxylon ) snags that were significantly taller than random trees and in areas with a greater number of snags within 0.1 ha. During this study, tree and stand structure were more important for roost selection than larger scale factors and Indiana bats responded to a pulsed and highly ephemeral resource, dead yellow pines, which were a significant component of the large forest tracts. Roosting behavior differed from what has been observed for Indiana bats in other parts of the eastern U.S.; maternity colonies tended to be smaller (<25 bats, but as large as 75 bats prior to pups being volant) and bats were more nomadic, using each roost tree for only 2–3 days on average and rarely for more than one year. The differences we observed in roosting behavior in the southern Appalachians suggest it would be wise to consider the broader landscape context when evaluating the roosting ecology of Indiana bats, as local forest types and disturbance events will affect stand structure and roost tree availability. Stand- and landscape-scale management practices that create or preserve large pine snags, such as prescribed fire, coupled with natural or manmade pulsed disturbances, should aid in the management and recovery of the Indiana bat in this region. [ABSTRACT FROM AUTHOR]

Tree microhabitats (cavities, conks of fungi, bark features) play an important role for both rare and specialized species biodiversity; their preservation should therefore be targeted by biodiversity-friendly forest practices. However, when compared to other old-growth characteristics like deadwood or large trees, tree microhabitats have only recently been studied so related scientific knowledge is still relatively limited. Defining target values for microhabitat densities in managed forests is mostly based on expert knowledge rather than quantitative empirical data. We compared the densities of microhabitat-bearing trees between managed forests, where wood is still harvested, and strictly protected forest reserves, where harvesting has been abandoned, in 17 French forests (222 plots) located in both lowlands and mountain regions. We found that microhabitat densities are generally higher in strict forest reserves than in managed forests and that this difference is mainly driven by standing dead and large living trees. Though scarce, standing dead trees over-contribute to the difference observed while large trees played a lesser but significant role. In addition, contrary to results obtained for other old-growth characteristics (such as deadwood volumes), the difference between managed and strict forest reserves was higher in mountain than in lowland forests. For individual microhabitats, five out of eleven microhabitats in mountains and only one in lowland (woodpecker cavities) were significantly more numerous in strict forest reserves than in managed forests. Finally, total microhabitat density and density of specific microhabitats such as cavities and bark features increased with time since the last harvest. This increase was also mainly supported by standing dead microhabitat-bearing trees. Compared to previous studies in comparable contexts, the densities we estimated were generally higher; however, such comparisons could only be made for the most documented microhabitat types. Our results support the idea that management abandonment favours the abundance and diversity of microhabitats. However, microhabitat dynamics remain poorly known and only long-term monitoring will help understand underlying mechanisms of recruitment. In the meantime, our results may inspire forest managers in their application of daily biodiversity-friendly practices. [ABSTRACT FROM AUTHOR]

Snags receive special management attention as important components of forest systems. We used data from the US Department of Agriculture (USDA) Forest Service Forest Inventory and Analysis Program, collected during two recent time periods (1995 to 1999 and 2001 to 2010), to evaluate trends in snag populations in two forest types in Arizona. Densities of snags ≥4 in. dbh increased by 21 and 72% between these time periods in mixed conifer and ponderosa pine (Pinus ponderosa) forest, respectively. Proportions of plots meeting USDA Forest Service guidelines for density of large snags (defined as snags≥18 in. dbh and≥30 ft tall) increased between time periods in both forest types (from 19 to 45% in mixed conifer and from 5 to 17% in ponderosa pine forest), but large snags remained relatively sparse, especially in less productive ponderosa pine forests. More than 50 and 75% of sampled plots lacked large snags entirely in mixed conifer and ponderosa pine forest, respectively. [ABSTRACT FROM AUTHOR]

Beavers are ecosystem engineers that modify and maintain a range of special habitat types in boreal forests. They also produce large quantities of deadwood that provide substrate for many lignicolous organisms such as calicioid fungi (Ascomycota). We studied how calicioid diversity differed between boreal riparian forests with and without beaver activity. The results show that calicioid diversity were significantly higher at beaver sites compared to the other two forest site types studied. The large quantity and diverse forms of deadwood produced by beavers clearly promotes calicioid diversity in the boreal landscape. The specific lighting and humidity conditions within beaver wetlands could be the reason why they promote the success of certain calicioid species. [ABSTRACT FROM AUTHOR]

Retention of snags (standing dead trees) is considered to have important effects on saproxylic species conservation in plantation forests because snags would provide vertically stratified deadwood habitats. However, the vertical distribution of saproxylic insects within snag trunks is still unclear. We felled 33 naturally occurring snags of Todo fir Abies sachalinensis in plantation forests and extracted insects from 99 logs sampled from three vertical positions of the snag trunks (basal stem: <2.5 m, lower trunk: 2.5-5 m and upper trunk: >5 m). The mean number of species that emerged from a single log was only 2.69, but we identified 51 morphospecies of saproxylic beetles in total. The total number of species that emerged from the basal stem (34 spp.) was greater than those that emerged from the lower trunk (25 spp.) or the upper trunk (30 spp.). However, rarefaction-extrapolation analysis did not demonstrate a significant difference in species richness among the log positions. Beetle assemblages were separated into two groups by constrained correspondence analysis; one group emerged only from lower and upper trunk logs, while another emerged mainly from basal stem logs. Additionally, vertical position had a significant effect on the distribution of the five main species. Our results show that beetle assemblages within snags in the plantation forests were highly variable, and retaining a sufficient number of high stumps may be important for saproxylic beetle conservation in plantation forests. We propose 'retention thinning' as an appropriate method to combine efficient timber production with biodiversity conservation in plantation forests. [ABSTRACT FROM AUTHOR]

Escalating wildfire in subalpine forests with stand-replacing fire regimes is increasing the extent of early-seral forests throughout the western USA. Post-fire succession generates the fuel for future fires, but little is known about fuel loads and their variability in young post-fire stands. We sampled fuel profiles in 24-year-old post-fire lodgepole pine ( Pinus contorta var. latifolia) stands ( n = 82) that regenerated from the 1988 Yellowstone Fires to answer three questions. (1) How do canopy and surface fuel loads vary within and among young lodgepole pine stands? (2) How do canopy and surface fuels vary with pre- and post-fire lodgepole pine stand structure and environmental conditions? (3) How have surface fuels changed between eight and 24 years post-fire? Fuel complexes varied tremendously across the landscape despite having regenerated from the same fires. Available canopy fuel loads and canopy bulk density averaged 8.5 Mg/ha (range 0.0-46.6) and 0.24 kg/m3 (range: 0.0-2.3), respectively, meeting or exceeding levels in mature lodgepole pine forests. Total surface-fuel loads averaged 123 Mg/ha (range: 43-207), and 88% was in the 1,000-h fuel class. Litter, 1-h, and 10-h surface fuel loads were lower than reported for mature lodgepole pine forests, and 1,000-h fuel loads were similar or greater. Among-plot variation was greater in canopy fuels than surface fuels, and within-plot variation was greater than among-plot variation for nearly all fuels. Post-fire lodgepole pine density was the strongest positive predictor of canopy and fine surface fuel loads. Pre-fire successional stage was the best predictor of 100-h and 1,000-h fuel loads in the post-fire stands and strongly influenced the size and proportion of sound logs (greater when late successional stands had burned) and rotten logs (greater when early successional stands had burned). Our data suggest that 76% of the young post-fire lodgepole pine forests have 1,000-h fuel loads that exceed levels associated with high-severity surface fire potential, and 63% exceed levels associated with active crown fire potential. Fire rotations in Yellowstone National Park are predicted to shorten to a few decades and this prediction cannot be ruled out by a lack of fuels to carry repeated fires. [ABSTRACT FROM AUTHOR]

Snags are used as habitat by several organisms, including bark- and wood-boring beetles, which contribute to snag decomposition and facilitate subsequent snag colonization by other organisms. However, snags seldom occur in young managed forests. This study examines how snag characteristics and spatial arrangement affect bark- and wood-boring beetle colonization and survival in spruce plantations subjected to commercial thinning, thinning with biomass removal and thinning with snag creation where a few clumps of trees were girdled. To this end, we documented the volume of snags, their characteristics and the number of beetle emergence holes in their basal section. Beetle colonization and survival to adulthood in snags was ~33 times greater when expressed per unit area in plantations supplemented with clumps of girdled trees than in other thinning regimes where low densities of beetle emergence holes per hectare were documented. Snag diameter at breast height, snag species and thinning treatments influenced the number of emergence holes per snag. Positive spatial autocorrelation between the abundance of emergence holes per snag was detected but no other spatial effect was noticeable. This work suggests that vertical deadwood is a limiting factor for bark- and wood-boring beetle colonization within plantations and challenges current thinking about the effect of thinning on beetle communities that was developed from window trap studies. These results underline the importance of large diameter snags for beetle conservation within managed forests and demonstrate that tree girdling during thinning entries is a viable method for creating snags to enhance beetle colonization and survival. [ABSTRACT FROM AUTHOR]

We investigated two methods to create white pine and red maple snags in a forested setting. The first involved injecting trees with ethanol at two times (single Ethanol (ETOH) and double ETOH injections) to increase attractiveness to insects and elicit attacks on trees. The second method was unique to white pines and involved both injection treatments in combination with baiting trees with Ips-specific pheromones. Three of five white pines from the double ETOH treatment died in the second year. Species including Ips pini (Say), Ips grandicollis Eichhoff, Orthotomicus caelatus Eichhoff, Crypturgus borealis Swaine and Monochamus notatus (Drury) responded more strongly to at least one of the treatments over control trees. However, there were no differences found in individual Scolytinae or Cerambycidae species response to treatments in red maple. Fitness (FV/FM) and vitality (PIabs) were both significantly reduced in both ETOH treatments compared to controls in white pine. In red maple, fitness was reduced in the double ETOH treated trees but the final mean FV/FM values were within the approximate optimal of health. Ethanol injections, in combination with Ips-specific semiochemicals, show promise for creating standing coarse woody debris (CWD) in white pine. Injecting ethanol was not effective for stressing red maple. [ABSTRACT FROM AUTHOR]

This study examines the habitat suitability for the downy woodpecker (Picoides pubescens) for a parcel of land in Gourdneck State Game Area (GSGA), Kalamazoo County, Michigan. Land within GSGA has undergone habitat restoration from forest and shrub to savanna and prairie, intentionally excluding two parcels. This study took place on one of the excluded parcels. We used the Habitat Suitability Index Model created by the Fish and Wildlife Service to determine suitability. We measured basal area and number of snags in 0.4 hectares to determine the food and reproduction life requisites that are the basis of the Habitat Suitability Index Model for the downy woodpecker. Results revealed that the study site is ideal for the reproduction life requisite but the food life requisite could be improved with habitat management. While the study site is not optimal for both variables, we suggest that management could cull some snags that would make this site more suitable for the downy woodpecker. [ABSTRACT FROM AUTHOR]

Although tool usage in adult birds is well documented, we have not found reports of juvenile birds using tools other than a few observations of individuals held in captivity. Here we describe the first observations of tool usage by juvenile birds in the wild. We observed juvenile Sitta pusilla (Brown-headed Nuthatch) using tools similar to those used by adults as early as 2 months post-fledging. We also observed juveniles attempting to use novel objects as tools, suggesting tool usage in this species may have both innate and learned components. Tool usage also takes place in 2 closely related nuthatch species and may be more common in this family of birds than currently known. [ABSTRACT FROM AUTHOR]

Effective strategies for bat conservation require knowledge of species-specific roost ecology. Thus, conservation planning is difficult for species with poorly understood roost use, such as the federally endangered Eumops floridanus (Florida Bonneted Bat). Prior to this study, only 1 active natural roost had been documented throughout the Florida Bonneted Bat's geographic range. Search efforts to locate new roosts using several techniques have been unsuccessful. Here we present a simple methodology that we successfully implemented to locate a second Florida Bonneted Bat natural roost. Using acoustics, cavity searches, and emergence observations, we documented a colony of Florida Bonneted Bats roosting in a Pinus elliottii (Slash Pine) snag in Florida Panther National Wildlife Refuge in Collier County, FL. Our discovery highlights the importance of snags, and provides additional details to state and federal agencies tasked with species recovery. [ABSTRACT FROM AUTHOR]

In areas where fire regimes and forest structure have been dramatically altered, there is increasing concern that contemporary fires have the potential to set forests on a positive feedback trajectory with successive reburns, one in which extensive stand-replacing fire could promote more stand-replacing fire. Our study utilized an extensive set of field plots established following four fires that occurred between 2000 and 2010 in the northern Sierra Nevada, California, USA that were subsequently reburned in 2012. The information obtained from these field plots allowed for a unique set of analyses investigating the effect of vegetation, fuels, topography, fire weather, and forest management on reburn severity. We also examined the influence of initial fire severity and time since initial fire on influential predictors of reburn severity. Our results suggest that high- to moderate-severity fire in the initial fires led to an increase in standing snags and shrub vegetation, which in combination with severe fire weather promoted high-severity fire effects in the subsequent reburn. Although fire behavior is largely driven by weather, our study demonstrates that post-fire vegetation composition and structure are also important drivers of reburn severity. In the face of changing climatic regimes and increases in extreme fire weather, these results may provide managers with options to create more fire- resilient ecosystems. In areas where frequent high-severity fire is undesirable, management activities such as thinning, prescribed fire, or managed wildland fire can be used to moderate fire behavior not only prior to initial fires, but also before subsequent reburns. [ABSTRACT FROM AUTHOR]

Mixed-severity fires are increasingly recognized as common in Pseudotsuga forests of the Pacific Northwest and may be an important mechanism for developing or maintaining their structural diversity and complexity. Questions remain about how tree mortality varies and forest structure is altered across the disturbance gradient imposed by these fires. Therefore, we sampled live and dead trees at 45–1.0 ha plots, each with four 0.10 ha nested subplots, stratified across an unburned, low, moderate and high-severity fire gradient. Burned plots were primarily sampled 10 and 22 years post-fire, except three plots sampled four years post-fire. We estimated probability of mortality for fire-tolerant (Douglas-fir, incense-cedar, sugar pine) and fire-intolerant (western hemlock, western redcedar, true fir) trees from 5079 samples. The probability of mortality varied across all species and fire-severity classes, but the greatest difference was observed between fire-tolerant and fire-intolerant functional groups. Probability of mortality decreased with increasing DBH for all species except western hemlock that did not increase its fire resistance with increasing size. Some large, fire-tolerant trees survived high-severity fire but only in 31% of our plots. Snag fall and fragmentation was estimated for trees killed by the fire from 2746 sampled snags and logs 10 and 22 years post-fire. The proportion of snags fallen decreased with increasing DBH for all species, and was positively correlated with fire severity, except for Douglas-fir that had a higher proportion felled following low-severity fire. Snag fragmentation rates were positively correlated with DBH and fire severity for all species. Individual tree and snag estimates were scaled to plot-level structural attributes and contrasted by their coefficient of variation within- and among-plots from unburned to moderate-severity, as well as across all sampled conditions. Structural attributes varied more within- than among-plots, likely a result of patchy mortality that increased with fire severity. Although vertical and horizontal structural diversity increased at sub-hectare scales, the highest variability occurred for all structural attributes when compared across all sampled conditions. We conclude that the range of fire effects imposed by mixed-severity fire is important in creating structural diversity in Pseudotsuga forests of the Pacific Northwest and should be promoted through progressive fire management programs aimed at maintaining this forest’s fire regime now and in the future. [ABSTRACT FROM AUTHOR]

Old living oaks ( Quercus robur) are known as a very species-rich habitat for saproxylic beetles, but it is less clear to what extent such veteran trees differ from an even rarer feature: downed trunks of large oaks. In this study, we set out to sample this habitat, using window traps, with two aims: (1) to describe the variation of assemblages among downed trunks of different type and (2) to compare beetles on downed oaks with data from veteran standing trees. The results showed that trunk volume and sun exposure better explained assemblages as well as species numbers on downed trunks than did decay stage. Furthermore, species classified as facultative saproxylic species showed weak or no differentiation among downed trunks. Species with different feeding habits showed no apparent differentiation among downed trunks. Furthermore, species composition on dead, downed oak trunks differed sharply from that of living, veteran oaks. Wood or bark feeders were more common on veterans than downed trunks, but there was no difference for those species feeding on fungi or those feeding on insects and their remains. In conclusion, for a successful conservation of the saproxylic beetle fauna it is important to keep downed oak trunks, and particularly large ones, in forest and pastures as they constitute a saproxylic habitat that differs from that of living trees. [ABSTRACT FROM AUTHOR]

Snag retention is increasingly being incorporated into forest management guidelines. Questions remain, however, in northern hardwood systems regarding factors affecting retention in actively managed stands, the effectiveness of snag creation, and the net effects of snag creation and timber harvesting on snag numbers and sizes. To address some of these questions, we examined the dynamics of natural and created snags within mature, even-aged northern hardwood forests under seven different management scenarios: three Harvest Only treatments, three Harvest Plus (created) Snags treatments, and one untreated Control. We found tree diameter, tree species, and stand treatment status (i.e., managed or Control) to be related to the retention of natural snags, created snags, or both. Snags were less likely to remain standing if they had smaller diameters, were species with relatively rapid decay rates, or were found in stands that had been logged. We found girdling trees to be an effective method of dead wood creation, although trees took longer to die than we expected. At least 84% of girdled trees had died in most stands within 4.5 years of girdling, and 30–77% of girdled trees were still standing 5.5 years after treatment. Comparison of net effects of snag creation and timber harvesting among treatments showed that managed stands, on average, experienced net snag losses compared to untreated Controls. These losses were statistically significant for all snag sizes, but not for large snags alone (i.e., dbh ⩾25.4 cm). Active management prescriptions that included snag creation demonstrated the potential to mitigate snag losses, with the extent of mitigation varying with the type of management. Surprisingly, mitigation was primarily driven by significantly greater natural snag recruitment in Plus Snags treatments, potentially due to competition from girdled trees that had not yet died. Our results may help inform the development of snag management guidelines in even-aged, second-growth northern hardwood systems for forest managers who are interested in enhancing the structural complexity of these forests. [ABSTRACT FROM AUTHOR]

ABSTRACT Snags (standing dead trees) are important components of forests that provide resources for numerous species of wildlife and contribute to decay dynamics and other ecological processes. Managers charged with managing populations of snags need information about standing rates of snags and factors influencing those rates, yet such data are limited for ponderosa pine ( Pinus ponderosa) and especially mixed-conifer forests in the southwestern United States. We monitored standing rates of snags in 1-ha plots in Arizona mixed-conifer ( n = 53 plots) and ponderosa pine ( n = 60 plots) forests from 1997 through 2012. We used the Burnham live-dead, mark-resight model in Program MARK and multimodel inference to estimate standing rates during 5-year intervals while accounting for imperfect detection. Because snag standing rates may be influenced by plot characteristics, we used plots rather than snags as sampling units and conducted bootstrap analyses (500 iterations per model) to resample plots and estimate standing rates and associated parameters. We modeled standing rates in 3 discrete steps. First, we selected a parsimonious base model from a set of models including snag species, and then we evaluated models created by adding snag and plot covariates to the base model in steps 2 and 3, respectively. Snag standing rates differed among snag species and 5-year sampling intervals. Standing rates were positively related to snag diameter, negatively related to snag height, and were lower for snags with intact tops than for broken-topped snags. Standing rates also were positively related to topographic roughness, elevation, tree density, and an index of northness, and negatively related to slope and relative topographic exposure. Our results provide comparative data on standing rates of multiple species of snags based on a large and spatially extensive sample and rigorous analysis, and quantify the relative importance of several snag and plot characteristics on those rates. They indicate that modeling snag dynamics is complicated by both spatial and temporal variation in standing rates and identify areas where further work is needed to facilitate such modeling. Published 2015. This article is a U.S. Government work and is in the public domain in the USA. [ABSTRACT FROM AUTHOR]

Key message: More than half of the dead trees fell down within decade. Besides, DBH effect on snag longevity varied by tree species and was not detected for some species. Management of long-lived snags in temperate mixed forests should be reconsidered. Context: Snags (standing dead trees) provide essential habitats for many species. Those with large diameter at breast height (DBH) are prioritized for retention; one of the reasons is that snag longevity (recruitment to falling down) increases with increasing DBH in conifer-dominated forests. Despite its importance, the DBH effect on hardwood snags is inadequately understood. Aims: The aim of this study is to investigate whether and how the DBH effect varies by tree species in mixed conifer-hardwood forests. Methods: We checked the current status (standing or falling) of dead trees that had been recorded in 37 permanent plots and applied a generalized linear mixed model. We used tree species, time since death, DBH, and interaction terms as variables. Results: Half of the dead trees with a DBH of 25 cm were estimated to have fallen down within 1-6 years for most of the species. While snag longevity increased with increasing DBH in Abies sachalinensis and Phellodendron amurense, we detected no such effect in Picea and three hardwood species. Conclusions: For highly decayed or long-lived snags, retaining large snags is not always effective. Managers of species-rich mixed forests should consider the variability of the DBH effects and management of dead wood before and after tree mortality. [ABSTRACT FROM AUTHOR]

The ability to estimate and monitor standing dead trees (snags) has been difficult due to their irregular and sparse distribution, often requiring intensive sampling methods to obtain statistically significant estimates. This study presents a new method for estimating and monitoring snags using neighborhood attribute filtered airborne discrete-return lidar data. The method first develops and then applies an automated filtering algorithm that utilizes three dimensional neighborhood lidar point-based intensity and density statistics to remove lidar points associated with live trees and retain lidar points associated with snags. A traditional airborne lidar individual-tree detection procedure is then applied to the snag-filtered lidar point cloud, resulting in stem map of identified snags with height estimates. The filtering algorithm was developed using training datasets comprised of four different forest types in wide range of stand conditions, and then applied to independent data to determine successful snag detection rates. Detection rates ranged from 43 to 100%, increasing as the size of snags increased. The overall detection rate for snags with DBH ≥ 25 cm was 56% (± 2.9%) with low commission error rates. The method provides the ability to estimate snag density and stem map a large proportion of snags across the landscape. The resulting information can be used to analyze the spatial distribution of snags, provide a better understanding of wildlife snag use dynamics, assess achievement of stocking standard requirements, and bring more clarity to snag stocking standards. [ABSTRACT FROM AUTHOR]

The 2-years production dynamics of major taxa (family/order) and functional feeding groups was synthesised from detailed production analyses previously published for all major invertebrate species/genera (retained by a 100 μm sieve) found on snags (submerged wood) in a sixth-order south-eastern U.S. Coastal Plain river., The trophic basis of this production and annual consumption of six food types were quantified. Invertebrate production (148 and 203 g dry mass m−2 year−1 of snag surfaces for the 2 years) was among the highest ever measured for a specific habitat in non-polluted or unregulated rivers and was still relatively high when converted to overall area of the river bed (48 and 70 g m−2 year−1). Snag production constituted 73% of total main-channel production (production from snag and river bed combined). Chironomidae (40-44% over the 2 years), Ephemeroptera (14-21%) and Trichoptera (25-31%) together represented the majority (88-93%) of the putative production of primary consumers on snags., Functional group analysis showed that fine filterers (26-36% over the 2 years), gatherers (36-44%) and macro-filterers (21-25%) represented the majority of total invertebrate production. Production of predaceous insects (mostly Plecoptera, Odonata and Megaloptera) represented only 5-7% of the total., Production of the three major taxa and three major functional groups was remarkably consistent over 2 years of monthly sampling, despite strong seasonal variation in discharge/light/temperature and production of individual genera and families., Seventy-nine per cent of production by primary consumers was supported by microbially enriched amorphous detritus, the major component of seston originating primarily from floodplain forests. Invertebrates consumed ˜ 357 g AFDM m−2 (river bed) year−1 of seston, 325 g m−2 year−1 of amorphous detritus and 20 g m−2 year−1 of diatoms. Dividing seston consumption by seston transport indicated that ˜ 67% of seston was consumed over 100 km of river length., Consumption was higher than autochthonous net primary production, supporting other evidence that terrestrially derived dissolved organic matter, incorporated via the microbial loop, is the main trophic basis of this riverine food web. Macro-filtering hydropsychid caddisflies were omnivorous with > half their production from carnivory. Snag predators, including hydropsychids, consumed ˜60% (29 g m−2 year−1 of river bed) of invertebrate production (assumed to be from snags), leaving the remainder for emergence, downstream transport and consumption by fish. [ABSTRACT FROM AUTHOR]

The article describes horizontal structure of the tree layer, natural regeneration, snags and crown projections of natural beech stands on three permanent research plots in the wide altitudinal range in the Krkonoše Mts (Czech Republic). The spatial structure was classified from 1980 to 2010 and subsequently the prediction of spontaneous development with an outlook for 30 years (to 2040) was done by growth simulator. Hopkins-Skellam index, Pielou-Mountford index, Clark-Evans index and Ripley's K-function were calculated. Further, the vertical structure and total diversity index was evaluated. The horizontal structure of individuals in the tree layer had not changed significantly during the monitored years. Tree spatial pattern of the lowest altitude lying herb-rich beech forest was mostly regular to random, in acidophilous mountain beech forest predominantly random and in fragments of beech groups around the timberline aggregated. Juvenile growth on all investigated plots was distributed aggregated and snags randomly. The horizontal structure of crown projection centroids had always higher values toward the regularity than tree layer and was random to regular. The result of principal component analysis also confirmed that spatial pattern was dependent on the altitude, but also on the number of trees. [ABSTRACT FROM AUTHOR]

It has been suggested that a latitudinal gradient exists of a low density of snags and high density of naturally-formed tree-cavities in tropical vs. temperate forests, though few cavities may have characteristics suitable for nesting by birds. We determined snag and cavity density, characteristics, and suitability for birds in a tropical dry forest biome of western Mexico, and evaluated whether our data fits the trend of snag and cavity density typically found in tropical moist and wet forests. We established five 0.25-ha transects to survey and measure tree-cavities and snags in each of three vegetation types of deciduous, semi-deciduous, and mono-dominant Piranhea mexicana forest, comprising a total of 3.75 ha. We found a high density of 77 cavities/ha, with 37 cavities suitable for birds/ha, where density, and characteristics of cavities varied significantly among vegetation types. Lowest abundance of cavities occurred in deciduous forest, and these were in smaller trees, at a lower height, and with a narrower entrance diameter. Only 8.6% of cavities were excavated by woodpeckers, and only 11% of cavities were occupied, mainly by arthropods, though 52% of all cavities were unsuitable for birds. We also found a high density of 56 snags/ha, with greatest density in deciduous forest (70 snags/ha), though these were of significantly smaller diameter, and snags of larger diameter were more likely to contain cavities. The Chamela-Cuixmala tropical dry forest had the highest density of snags recorded for any tropical or temperate forest, and while snag density was significantly correlated with mean snag dbh, neither latitude nor mean dbh predicted snag density in ten forest sites. The high spatial aggregation of snag and cavity resources in tropical dry forest may limit their availability, particularly for large-bodied cavity adopters, and highlights the importance of habitat heterogeneity in providing resources for primary and secondary cavity-nesters. [ABSTRACT FROM AUTHOR]

Snags are standing dead trees that are an important component in the nesting habitat of birds and other species. Although snag availability is believed to limit populations in managed and non-managed forests, little data are available to evaluate the relative effect of stand conditions and management on snag occurrence. We analyzed point sample data from an intensive forest inventory within an 80,000 ha landscape for four major forest types to support the hypotheses that routine low-intensity prescribed fire would increase, and thinning would decrease, snag occurrence. We employed path analysis to define a priori causal relationships to determine the direct and indirect effects of site quality, age, relative stand density index and fire for all forest types and thinning effects for loblolly pine and longleaf pine. Stand age was an important direct effect for loblolly pine, mixed pine-hardwoods and hardwoods, but not for longleaf pine. Snag occurrence in loblolly pine was increased by prescribed fire and decreased by thinning which confirmed our initial hypotheses. Although fire was not important in mixed pine-hardwoods, it was for hardwoods but the relationship depended on site quality. For longleaf pine the relative stand density index was the dominant variable affecting snag occurrence, which increased as the density index decreased. Site quality, age and thinning had significant indirect effects on snag occurrence in longleaf pine through their effects on the density index. Although age is an important condition affecting snag occurrence for most forest types, path analysis revealed that fire and density management practices within certain forest types can also have major beneficial effects, particularly in stands less than 60 years old. [ABSTRACT FROM AUTHOR]

Highlights: [•] Snags/logs and diverse vegetation characterizes early seral pre-forest in the PNW. [•] A number of plant and animal species, some rare, reach peak abundance in this stage. [•] Early-seral forest supports a similar proportion of state-listed species as older forests. [Copyright &y& Elsevier]

Highlights: [•] Sirex grey- and lightning-damaged pine snags were distinguished. [•] The performance of random forest and support vector machines classifiers was compared. [•] The dimensionality of AISA Eagle hyperspectral data was reduced. [•] The performance of random forest and support vector machines classifiers was not significant. [•] Relatively higher overall classification accuracy and less total disagreement were obtained. [ABSTRACT FROM AUTHOR]

Snags and downed logs are substantial components of the detrital carbon pool in boreal forests. Effects of their decomposition on chemical and physical characteristics of the forest floor remain relatively unknown. The main objective of this study was to characterize chemical transformations of decaying logs and snags of common tree species in the boreal mixedwood forest. Logs and snags from a wide range of decay classes were sampled and analyzed by solid-state 13C nuclear magnetic resonance spectroscopy and by near-infrared spectroscopy. Little or moderate chemical changes appeared in fresh and moderately decayed snags and logs, but in well-decayed logs, substantial degradation of carbohydrates and increases in lignin concentrations occurred. Deciduous species had initially more carbohydrates than coniferous species, but decomposition narrowed their differences, and in well-decayed logs, species differed mainly in terms of their lignin concentrations. Well-decayed deciduous logs reached very low wood densities, and their integration into the forest floor and long-term preservation remains questionable. In contrast, chemical composition of well-decayed coniferous logs resembles that of lignic forest floor (i.e., forest floor originating from deadwood decomposition), with preserved lignins, carbohydrates, and alkyl carbon compounds. Decomposed coniferous wood thus contributes to chemical heterogeneity of the forest floor, possibly promoting diversity of decomposers as well as carbon retention in soils. [ABSTRACT FROM AUTHOR]

A 14-year study of snag characteristics was established in 41- to 44-year-old loblolly pine ( Pinus taeda L.) stands in southeastern USA. During the initial 5.5 years, no stand manipulation or unusually high-mortality events occurred. Afterwards, three treatments were applied consisting of trees thinned and removed, trees felled and not removed, and artificial creation of snags produced by girdling and herbicide injection. The thinned treatments were designed to maintain the same live canopy density as the snag-created treatment, disregarding snags that remained standing. We monitored snag height, diameter, density, volume, and bark percentage; the number of cavities was monitored in natural snags only. During the first 5.5 years, recruitment and loss rates were stable, resulting in a stable snag population. Large snags (≥25 cm diameter) were common, but subcanopy small snags (10 to <25 cm diameter) dominated numerically. Large natural snags survived (90% quantile) significantly longer (6.0-9.4 years) than smaller snags (4.4-6.9 years). Large artificial snags persisted the longest (11.8 years). Cavities in natural snags developed within 3 years following tree death. The mean number of cavities per snag was five times greater in large versus small snags and large snags were more likely to have multiple cavities, emphasizing the importance of mature pine stands for cavity-dependent wildlife species. [ABSTRACT FROM AUTHOR]

Snags (dead-standing trees) are biological legacies that remain after disturbances in forests. We enhanced the ecological underpinnings of snag management within the context of mixed-pine forest restoration in the northern Lake States by quantifying characteristics of live trees and snags within eighty-five 500-m2 plots at Seney National Wildlife Refuge (NWR) in eastern Upper Michigan. Study plots represented reference conditions (i.e. no past harvesting, relatively unaltered fire regime) and altered (i.e. harvested, altered fire regime) conditions. We also compared three treatments for creating snags from live trees. Snags were found in 87% of the reference plots and 85% of the altered plots. The only snag variables that differed between plot types were mean snag basal area, which was greater in altered plots (Student's t-test, p = 0.04), and mean percent total basal area of snags (greater in reference plots, p = 0.06). The composition of snags differed only in the 10- and 25-cm diameter classes (Multi-Response Permutation Procedure, p < 0.10). The percentage of snags that developed into the most advanced decay class (DC) differed among treatments after 4 years ( χ2 = 16.49, p < 0.01), with 26% of girdled trees, 3% of prescribed fire trees, and zero topped trees reaching DC5. Logistic regression illustrated that the influence of predictor variables on DC development varied by species and treatment. The findings from this study, past studies, and ongoing projects at Seney NWR are directly applicable to innovative management of snags in mixed-pine forests. [ABSTRACT FROM AUTHOR]

Alaskan spruce forests are exposed to both fire and spruce beetles [Dendroctonus rufipennis(Kirby)]. To understand the influence of spruce beetles on the process through which fire affects ecosystem function, we developed a reconstruction technique to measure prefire damage to trees caused by the spruce beetle. We validated our evaluation of prefire tree conditions using a high-resolution multispectral satellite image by comparing our results with a postfire ground survey. The prefire tree conditions determined by the two methods coincided well with each other. This result suggests that combining high-resolution multispectral imaging and postfire ground surveys of spruce beetles on snags is a powerful tool to determine the prefire condition of a forest in a changing boreal forest ecosystem. [ABSTRACT FROM AUTHOR]

Standing dead trees (snags) are an important component of forest ecosystems, providing foraging, nesting, and roosting substrate for a variety of vertebrates. We examined the effects of four forest regeneration treatments on residual snag density and compared those with densities found in unharvested, naturally regenerated forests (controls) during the second, fourth, and sixth year after timber harvest in mixed pine-hardwood forests of Arkansas and Oklahoma. Regeneration treatments were clearcut with snag creation, shelterwood, single-tree selection, and group selection. Density of large snags (≥25.0 cm DBH) differed only during the sixth year after harvest, with shelterwoods having a lower density of large snags (1.0 snags/ha) than the control or group selection stands (4.0 and 4.2 snags/ha, respectively). Density of small snags (10.0-24.9 cm DBH) mirrored residual basal area, with controls and group-selection stands having the greatest snag densities. Creation of snags in clearcuts by injection with herbicides caused initial snag density in these areas to be greater than other treatments, but density in clearcuts declined sharply by 6 years after harvest. In the absence of snag creation, treatments such as shelterwoods that remove most trees may have snag densities below that required to address some management objectives without additional snag creation. [ABSTRACT FROM AUTHOR]

Within young pine (Pinus spp.) plantations, coarse woody debris (CWD) and green trees are important habitat structures that may be impacted by the production of biofuel feedstock. Therefore, we compared site preparation procedures associated with switchgrass (Panicum virgatum L.) intercropping to determine effects on CWD and green trees in stands (n = 24) site-prepared for intercropping, with switchgrass only, or pine plantation in Mississippi, USA. Following site preparation, CWD dispersal or volume did not differ between intercropped and control stands. Intercropped stands had significantly fewer retained trees and snags. Switchgrass monocultures had no retained trees or piles and significantly fewer pieces and less volume of CWD than the other treatments. Our results suggest switchgrass intercropping may provide similar habitat quality to traditional pine plantations for wildlife species using these areas in the year following disturbance, but may provide a less suitable habitat for species that require snags. However, the relationship between snag reduction and wildlife population response in an intercropped setting is not clear and should be further investigated. Regardless, if retaining snags is a desired outcome, site preparation for switchgrass should be restricted to the interbed area where it will be cultivated as opposed to extensive debris removal from the entire site. [ABSTRACT FROM AUTHOR]

Abstract: In a study of post-fire logging effects over an 8year period at Blacks Mountain Experimental Forest, salvage logging was conducted at varying levels of intensity after a 2002 wildfire event. In a designed experiment, harvest prescriptions with snag retention levels ranging from 0% to 100% in 15 experimental units were installed. Observations of standing snags and surface fuels were made 2, 4, 6, and 8years after the fire. Fire-killed snags fell rapidly over time, leading to elevated surface fuel levels in areas where no salvage logging was done. The 1000h and larger surface fuels were strongly related with basal area retention level, with values ranging from 0–60Mgha−1 by year eight. However, when expressed as a percent of standing retained biomass, surface fuel accumulation was not related to treatment. In year 8, surface fuel was 81% of retained bole biomass. The retention of snags after this wildfire event provided snags for wildlife foraging and nesting habitat, however most of these snags were lost within 8years after the fire. White fir snags were more stable than pine and appeared to be used with greater frequency than pine for cavity excavation. [Copyright &y& Elsevier]

The article offers information on the estimation of snag carbon transfer rates by ecozone and lead species for forests in Canada. It states that dead trees and downed woody debris have substantial effect on the carbon budget of forest in Canada. It further mentions that appropriate calculation of the carbon transfer rates (CTRs) from snags to downed woody debris is important for carbon dynamics models in forests of the country.

Estimating the amount of standing deadwood in forests is crucial for assessing wildlife habitat and determining carbon stocks. In this analysis, snags (standing dead trees) in various stages of decay were inventoried across eight silvicultural treatments in eastern spruce-fir forests in central Maine nearly 60 years after treatments were initiated. Several modeling strategies were developed to estimate number of snags per hectare in various stages of decay. An unmanaged reference area displayed the highest basal area and volume of snags (5.4 ± 3.1 m2·ha-1 and 29.4 ± 23.6 m3·ha-1, respectively, (mean ± standard deviation)), while the lowest basal area and volume (0.9 ± 1.0 m2·ha-1 and 3.1 ± 5.2 m3·ha-1) were observed in selection system with a 5-year cutting cycle. Models indicated that snag abundance was related to stand density, depth to water table, and the average harvest interval of the treatment. At a fixed stand density, approximately 140% more snags were predicted to occur in treatments with an average harvest interval of 55 compared with 5 years. An index of error reflecting the number of snags found in certain decay classes was reduced by 40% when predictions from count regression models fit with a mixed modeling strategy were used over ordinal regression. Results from these analyses can help to reduce the disparities between observed and modeled snag stocking levels and further our understanding of the relationships between live and standing dead trees inherent to eastern spruce-fir forests. [ABSTRACT FROM AUTHOR]

• Aims: Six sampling alternatives were examined for their ability to quantify selected attributes of snags and hardwoods in conifer-dominated riparian areas of managed headwater forests in western Oregon. • Methods: Each alternative was simulated 500 times at eight headwater forest locations based on a 0.52-ha square stem map. The alternatives were evaluated based on how well they estimated the number of hardwoods and snags per hectare and their basal area per hectare using root mean square error and percent bias. • Results: In general, 3.6-m wide systematic strips oriented perpendicular to the stream outperformed the other alternatives. However, the variance of all six sampling alternatives was quite high and further research is needed to determine an optimal sampling method for quantifying hardwood and snag attributes in forests dominated by live conifers. • Conclusion: When sampling snag and hardwood as a minor component of the overall forest composition within a riparian area, we suggest using 3.6-m strips perpendicular to the stream. [ABSTRACT FROM AUTHOR]