•Decay rates of beech wood blocks on the Apennines were relatively high.•Beech deadwood decay was lower in south- than north-facing sites on these Mediterranean mountains.•Soil properties, slope and ...exposure influenced the decay processes in these sites.
Forests contribute to the sequestration of organic carbon (C). A key role in forest C cycling is played by deadwood. While a broad range of literature on deadwood decay (above-ground) exists, the mechanisms occurring in the transition zone from deadwood to the humus are poorly understood. In particular, scarce information is available on the temporal patterns of wood compounds (such as lignin and cellulose) during decay processes.
Our objective was to provide a deeper understanding on deadwood decay in a Mediterranean montane environment by focussing on semi-natural forests of Fagus sylvatica L. (beech). The decay process was studied in a field experiment (in the Majella mountains, Apennine Mountains, Italy) among an altitudinal transect at different climatic conditions. Beech wood blocks (mass, cellulose, lignin) having all an equal in size (5 cm × 5 cm × 2 cm) were placed in soil mesocosms to investigate over one year changes in the overall mass, cellulose and lignin content. The sites were along an altitudinal gradient, reflecting different climatic conditions. The effect of exposure (north- vs. south-facing slopes) was also considered. Deadwood, cellulose and lignin dynamics were related to soil parameters (pH, grain size, moisture, temperature) and climate data. Deadwood decayed very fast and followed an exponential trend. The decay rate constants of the deadwood mass significantly (positively) correlated with air temperature and soil moisture: the lower the temperature, the lower the evapotranspiration, the higher the moisture availability, and the higher the decay rates. Lignin decayed more slowly than cellulose, resulting in average decay rate constants (k) between 0.368 and 0.382 y−1. Soil properties and topographic traits (slope and exposure) strongly influenced the decay processes. At south-facing sites (having an altitude < 1300 m a.s.l., above sea level), decay processes were lower owing, most likely, to drier conditions. The climosequence revealed slower beech deadwood decay processes in south- than north-facing sites of these Mediterranean mountains, owing to the drier conditions. In-field mesocosms were useful to define meaningful indicators of warming-induced changes on the linkages between C storage in beech deadwood and decomposition processes as a function of altitude and exposure.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
•Deadwood volume in protected areas depends on random factors and is difficult to predict.•Deadwood accumulation depends on the vigor of the species comprising the stand.•Silvicultural treatments ...considerably reduce the effects of natural factors.•Deadwood volume increases with site fertility and stand age.•Terrain-related difficulties hindering silvicultural treatments have a positive effect on the amount of deadwood.
In forest management policy, deadwood is regarded as an indicator of sustainable forest management. Dead trees are a key habitat feature for a wide range of organisms. In this study, data from a regular network of nearly 30,000 sample plots (the National Forest Inventory) distributed throughout Poland were used to determine relationships between deadwood volume and thirteen selected natural and human-related factors: forest ownership, protection type, inclusion in the Natura 2000 network, terrain, slope gradient, site fertility, site moisture (water abundance), dominant species, age of the dominant species, stand volume, tree and shrub density, sapling and shrub cover, and stand damage. Analysis of data on deadwood volume was carried out in two steps: univariate analysis was used to determine present-day differences among forests, while a logistic regression model was applied to identify the factors that had the greatest impact on deadwood volume variability on the studied plots. Despite interference from numerous random effects that are difficult to capture and quantify, being often associated with disturbances and differences between the silvicultural approaches of individual forest managers, many of the analyzed factors were found to exert a significant influence. Strong relationships were identified mostly in managed forests (private, municipality-owned, and those managed by the State Forests National Forest Holding). In national parks and nature reserves, the identified effects were less pronounced due to the fact that the examined plots differed in terms of protection type and duration and may have been impacted by different natural disturbances. Indeed, deadwood volume was significantly affected by protection type, with much more deadwood found in strictly protected areas as compared to forests under active protection. Inclusion in Natura 2000 had only a slight effect. On the other hand, a major role was played by difficult terrain accessibility, which impeded silvicultural treatments. More deadwood occurred in the mountains, with increasing slope gradient positively affecting deadwood volume, but only up to a certain point. On the steepest slopes deadwood volume decreased due to the soil and wood sliding to a lower level. Deadwood volume was significantly greater on more fertile and moist sites. In managed forests, both stand age and growing stock volume were positively associated with deadwood accumulation. The species composition of stands, mostly attributable to habitat conditions, was also relevant. The present work identified some significant differences in deadwood volume between stands, and the findings may be useful in developing future management practices with a view to supporting biodiversity.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•Photodegradation significantly accelerated respiration of coarse woody debris (RCWD).•Photodegradation effect further amplified by increasing temperature.•The temperature sensitivity (Q10) of RCWD ...to TCWD was increased by photodegradation.
Enhanced solar radiation (induced photodegradation) is an important driver of global environmental change. Coarse woody debris (CWD) plays a key role in forest carbon (C) dynamics because it contains a sizeable proportion of total forest C. Therefore, understanding the effects and underlying mechanisms of photodegradation on CWD decomposition is critical for the assessment of C storage in forests.
We conducted a field-based experiment to investigate the effects of photodegradation on the respiration of CWD (RCWD) of Cunninghamia lanceolata (CL), Schima superba (SS), and Cinnamomum camphora (CC) over a 24-month period in subtropical China. And we also determined the effects of changes in CWD temperature and moisture content on RCWD of the three tree species. We found that photodegradation significantly accelerated RCWD, with its effect further amplified by increasing temperature. The temperature sensitivities of RCWD to CWD temperature as indicated by Q10 were increased by photodegradation treatments. The CWD temperature can explain over 70% of the variation in RCWD among different tree species and treatments. Our results indicate that the positive effect of photodegradation on CWD decomposition and C cycles could potentially impact C cycling in forest ecosystems. These findings may provide insight on the effects of photodegradation and temperature change on biogeochemical cycling of forest ecosystems under the future global change.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Coarse woody debris (CWD), or fallen logs, is known to be an essential habitat element for many organisms. CWD also supports ecosystem functioning through soil formation, nutrient cycling, and carbon ...storage. For these reasons, accurate assessments of CWD across landscapes are of interest to many ecologists and landscape managers, but traditional field-based measurements can be time-consuming and sampling strategies may not be representative of entire landscapes. Light detection and ranging (LiDAR) technologies may be able to provide a more rapid assessment of the number and volume of CWD across wide areas. However, most research using LiDAR for forest and woodland inventory assessment has focused on standing wood. Detection accuracy of CWD with LiDAR can be impacted by the point density of LiDAR data, ground layer vegetation, and sensor positioning relative to other vegetation or landscape structural features. We used a high-resolution terrestrial laser scanner (TLS), an unoccupied aerial vehicle (UAV) laser scanner (ULS), and a combination of data from both sensors (i.e. fused data, FLS) to estimate CWD in a grassy woodland ecosystem. The study area comprised plots with different types and amounts of vegetation cover and different types of CWD, both naturally occurring and introduced including dispersed, clumped, or a mixture of both types. This enabled a more detailed exploration of model performance across sensor types, vegetation types, and ground cover biomass. A random forest (RF) classification algorithm and noise removing operations on raster imagery were used to classify CWD. Completeness and correctness accuracy with the developed method were highly variable depending on the data and ground vegetation cover and ranged between 20% and 86%, and 12% and 96%, respectively, in comparison with field data. The LiDAR-derived digital surface model (DSM), surface roughness, and topographic position index were important variables for CWD detection. We found that the detection accuracy of CWD varied with the vegetation type, amount of ground vegetation cover, and LiDAR data. Ground cover density had a strong negative impact on accuracy, particularly for TLS and FLS data.
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BFBNIB, GIS, IJS, KISLJ, NUK, PNG, UL, UM, UPUK
Large old trees and decaying logs are key-retained structures for the retention forestry approach, but quantitative estimations of the role of fallen logs in the overall diversity and composition of ...forest vascular species are few and controversial. Particularly for mesic deciduous forests only a small number of such estimates are known. Our study aimed to partly fill this gap using data collected in the Reserve Kaluzhskie Zaseki where large Quercus robur individuals of more than 300 years old and fallen logs are frequent. We found 44 fallen oak logs supporting vascular plants within a 200-ha forest tract. The vegetation in plots of 1 m2 located on the fallen logs and on the forest floor adjacent to the logs was surveyed together with vegetation in fifteen 10 × 10 m plots randomly placed in patches without large fallen logs. NMDS and PERMANOVA were applied to examine differences in composition between fallen logs and forest floor. Generalized linear models were used to examine the relationships between environmental variables and species richness. Additive diversity partitioning was performed to examine differences in species richness and to estimate the contribution of the fallen logs to the general diversity in vascular species. In total, 71 vascular plant species in 108 1 m2-plots were identified. Twenty-five and 16 species were detected only on fallen logs and on the forest floor, respectively. More than 60% of the studied logs were in early stages of decomposition; their mean diameter was 75.4 ± 25.6 cm. Fallen logs significantly affected species richness and composition in terms of both woody seedlings and herbaceous species. The diameter of logs significantly and positively affected species diversity and composition. Large logs with cracked bark at the first two stages of decay were places of successful vascular plant establishment and growth. The abundance and frequency of tree seedlings were higher on the logs than on the forest floor and seven out of ten tree species appeared to be significant indicator species for the log-plots. Illumination varied over the observed sites and directly influenced the richness of herbaceous species and the overall species composition, but had no effect on woody species richness. We conclude that retention of large fallen logs can be an effective tool for maintaining and restoring the vascular species richness and composition in mesic broad-leaved forests.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•183 stands in a managed lowland temperate forest were studied for CWD parameters.•Local demand for specific wood types and their price determine the CWD profile.•Fuelwood collection by residents ...affects the spatial distribution of CWD.•CWD important for saproxylic biota (e.g. hardwood) is rarely left in the forest.•Road and watercourse densities affect CWD removal even in an easily accessible area.
Much is known about the minimum thresholds for dead wood that would ensure the persistence of saproxylic organisms and maintain the overall biodiversity of forest ecosystems, but reaching those thresholds is still a challenge in forests where nature conservation is not the sole goal (e.g., Natura 2000 forests managed for timber). Understanding what determines the quantity and quality of dead wood in managed forests is a prerequisite for developing methods to increase its retention without decreasing a forest’s production. We surveyed the volume, number, stage of decay, and species identity of standing and lying coarse woody debris (CWD) in 183 stands in a complex of lowland Natura 2000 forests in southern Poland, and then determined the relationships between these parameters and tree stand structure, intensity of previous silviculture interventions, accessibility of terrain, and local community impact. CWD volume varied from 0.1 to 66.3 m3 ha−1 (average 6.9 m3 ha−1), which is up to several times less than the recommended thresholds. Large-sized CWD and CWD of species known to support rich communities of saproxylic organisms (e.g., Carpinus betulus) were clearly underrepresented. Wood of economically less valuable species was often left in the forest, which boosted the diversity of CWD microhabitats. CWD quantity and quality was significantly shaped by both natural and human-related factors. Among the latter, harvesting intensity and proximity to human settlements affected CWD negatively, while terrain-related difficulties (distance to roads, watercourse density) affected it positively. Surprisingly, the site accessibility effect was important even though the studied area is level and covered by a dense road network. The results suggest that cost-effective CWD management plans for Natura 2000 forests, or, more broadly, multifunctional forests, should discourage some practices accompanying timber harvesting (e.g., fragmenting of pieces of aged CWD), promote practices that positively affect CWD (e.g., not harvesting low-value timber), and set aside small areas to accelerate CWD retention. These things should be done wherever their effects are unlikely to be reversed, i.e., at sites difficult for forestry vehicles to access and away from human settlements.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
•We tested environmental factors and traits of vascular flora colonising decaying logs.•Decaying logs were colonised by 46 species, that can be classified into six clusters.•Localisation and site ...conditions of logs are more important factor than their traits.•Plants differ in their response to dead wood traits mainly decomposition and log size.•Changes in vegetation along the altitudinal gradient played the most crucial role.
We were interested in which biological attributes and environmental variables enhance the colonisation of vascular plant species on coarse woody debris (CWD) within and among forest communities along lower and upper montane forest belts. The study was carried out in the Sudeten Mts (south-western Poland). A total of 364 decaying logs were studied in terms of their characteristics and the cover of vascular plants colonising them. The three-table ordination analysis (RLQ) revealed that 9 plant traits and 11 environmental variables demonstrated significant associations. Decaying logs were colonised by 46 species, which can be classified into six clusters. The clusters differed in distribution and abundance along the lower-upper montane forest gradient. Annual and autochorous plants as well as herb perennials tended to colonise CWD in the lower montane belt, mainly in beech forests whereas tree seedlings, dwarf shrubs and graminoids prevailed on logs in the upper montane belt – in spruce forests. The localisation and site conditions of logs seemed to be a more important factor than the characteristics of CWD itself. There is a relatively low number of species that are frequently involved in the process of colonisation; however, it can be inferred that they differ in their response to the characteristics of dead wood especially the decomposition stage and the size of a log. Nevertheless, compositional and abundance changes in the vegetation that occurred along the altitudinal gradient played the most crucial role.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
•Timber harvesting negatively affected salamander counts a decade after harvest.•Drought and harvesting together adversely affected salamander counts.•Revegetation and coarse woody debris may protect ...salamanders from these declines.•Harvests that removed less canopy had little impact on salamander counts.•Understanding drought interaction with harvest will be key to future conservation.
Timber harvesting can have strong effects on terrestrial salamanders, which are critical components of forest ecosystems and indicators of environmental change. Effects of harvest methods such as clearcutting have been studied in the short term, but few studies have examined salamander trends throughout the decade following timber harvest. The effects of other harvest methods, such as patch cuts and shelterwoods, also remain unclear. We examined the effects of clearcuts, patch cuts, and shelterwood harvests on salamander relative abundance one year before and up to eleven years after harvest in clearcuts, shelterwoods, and patch cuts at the Hardwood Ecosystem Experiment (HEE). A total of 41,858 salamanders representing ten species were captured under artificial coverboards over this period with eastern red-back (Plethodon cinereus) and zigzag (Plethodon dorsalis) salamanders dominating. No significant declines occurred in the first three years following harvest, but salamander captures declined in the 4–6 and 7–11 year periods in clearcuts and patch cuts, and no signs of post-harvest recovery were found. Rapid vegetation recovery and high volumes of coarse woody debris (CWD) following harvest likely protected the microclimate used by salamanders; when CWD levels dropped 4–6 years after harvest, a corresponding decline in salamander captures occurred. These years also corresponded to a regional drought that likely increased temperature and decreased moisture in harvest openings, further impacting terrestrial salamanders. Neither the first nor second shelterwood harvests produced declines in salamanders, suggesting that canopy retention could prevent declines due to changing microclimate or drought. Our results highlight the need to consider compound effects of disturbances such as drought and canopy loss and the importance of long-term salamander monitoring following timber harvest to capture lagged effects and eventual recovery.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•Scots pine deadwood hosts abundant and diverse mycobiota.•Certain forest practices have small effect on mycobiota in deadwood.•Large-diameter deadwood (logs) is the most relevant for conservation of ...fungi.•Deadwood at later stages of decay supports greatest abundance of fungi.•Deadwood at earlier stages of decay supports greatest diversity of fungi.
Abundance and diversity of wood-inhabiting fungi were studied in managed (sanitation cutting, commercial thinning and timber harvesting) and unmanaged stands in one 85-year-old Scots pine forest in western Poland. Fungi were detected on coarse woody debris collected in each stand in June 2014: logs, fallen branches, standing dead trees and stumps, in the 1st, 2nd and 3rd classes of decay. Fungi were identified after culturing on synthetic media or as fruit bodies. One taxon of Oomycota and 140 taxa of cultured fungi (19 Zygomycota, 108 Ascomycota and 13 Basidiomycota species) were detected in 34 samples of deadwood. Fruit bodies of three species of Ascomycota and 14 species of Basidiomycota were recorded on 33.8% of coarse woody debris in the managed stand and on 20.6% in the unmanaged stand, with 10 species and 15 species in the respective stands. Abundance of cultured fungi was greater and diversity smaller, both non-significantly, in the managed stand. Eighty-six cultured species (55%) occurred in both stands, while 32 (20%) and 39 (25%) species occurred exclusively in, respectively, the managed and unmanaged stands. Communities in different transects within a stand tended to be more similar than communities in different stands, managed and unmanaged. Logs hosted the greatest number of species. Abundance of cultured fungi increased and diversity decreased in more decayed wood. Known wood-decay species were most abundant in the less decayed wood.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Abstract Wildfires have the potential to dramatically alter the carbon (C) storage potential, ecological function, and the fundamental mechanisms that control the C balance of Pacific Northwest (PNW) ...forested ecosystems. In this study, we explored how wildfire influences processes that control soil C stabilization and the consequent soil C persistence, and the role of previous fire history in determining soil C fire response dynamics. We collected mineral soils at four depth increments from burned (low, moderate, and high soil burn severity classes) and unburned areas and surveyed coarse woody debris (CWD) in sites within the footprint of the 2020 Holiday Farm Fire and in surrounding Willamette National Forest and the H.J. Andrews Experimental Forest. We found few changes in overall soil C pools as a function of fire severity; we instead found that unburned sites contained high levels of pyrogenic C (PyC) that were commensurate with PyC concentrations in the high severity burn sites—pointing to the high background rate of fire in these ecosystems. An analysis of historical fire events lends additional support, where increasing fire count is loosely correlated with increasing PyC concentration. An unexpected finding was that PyC concentration was lower in low soil burn severity sites than in control sites, which we attribute to fundamental ecological differences in regions that repeatedly burn at high severity compared with those that burn at low severity. Our CWD analysis showed that high mean fire return interval (decades between fire events) was strongly correlated with low annual CWD accumulation rate; whereas areas that burn frequently had a high annual CWD accumulation rate. Within the first year postfire, trends in soil density fractions demonstrated no significant response to fire for the mineral-associated organic matter pool but slight increases in the particulate pool with increasing soil burn severity—likely a function of increased charcoal additions. Overall, our results suggest that these PNW forest soils display complex responses to wildfire with feedbacks between CWD pools that provide varying fuel loads and a mosaic fire regime across the landscape. Microclimate and historic fire events are likely important determinants of soil C persistence in these systems.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
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