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The composition and structure of forest stands in the Tatra National Park were examined using data gathered in 2016 and 2017 from 617 circular sample plots (0.05 ha each). The diameter at breast height of all living trees, standing dead trees, snags, and wind throws was measured along with diameters and lengths of fallen logs within the plot boundaries. Tree height was measured for all living trees within the core (0.01 ha) of the sample plots. Using the obtained data, height-diameter curves were calculated for all major tree species and in the case of spruce, the height-diameter relationships were also calculated separately for each of the three elevation zones (up to 1200 m, between 1200 and 1400 m, above 1400 m). For each elevation zone and park protection zone, we also determined the volumes of live and dead trees. The volume of living trees in the Tatra National Park amounted to 259 m3/ha, which was higher than the volume of dead trees (176 m3/ha). Snags constituted the largest part of the dead wood whilst over 97% of the standing dead trees were spruce Picea abies. Among living trees, the share of spruce ranged from 81% in the low elevation zone to 98% in the middle zone. Other significant species in the lower zone were Abies alba (11%) and Fagus sylvatica (4.5%), while in the middle and upper elevation zones only Sorbus aucuparia occurred in significant numbers. Furthermore, in the lower elevation zone, Fagus sylvatica was the only species displaying significantly higher volumes in the ‘strict protection’ zone compared to the other park areas. In the ‘landscape protection’ zone, Picea abies was the most dominant species and the share of other species in the lowest elevation zones calculated based on tree density was smaller than calculated based on tree volume, indicating problems with stand conversion from spruce monoculture to mixed forest.

Highlights • Data on the characteristics of tree stands as well as the birds inhabiting them were collected from a subalpine spruce forest. • The study area exhibited development properties resulting from both biotic and abiotic factors. • Tree stands were characterized in terms of the tree layer, saplings, and deadwood. • The data included bird species composition and pair density in the breeding season or individual bird density in the nonbreeding season., The paper presents data on tree stands located in a subalpine spruce forest in the Gorce National Park (Western Carpathians, Poland) as well as on the birds inhabiting them in the breeding and nonbreeding seasons. The authors conducted stand measurements on a total of twenty-four sample plots, with eight plots established in each of the three studied forest development stages (mature, break-up, and growing-up) representing successive phases of subalpine forest development. The study area designated for each stage was 30 ha. The development properties of each study area resulted from both biotic and abiotic factors. Tree stands were characterized in terms of the tree layer, saplings, and deadwood. The types of deadwood measured were: standing entire dead trees, snags, stumps, and downed deadwood. In the case of birds, the presented data include species composition and pair density in the breeding season and individual bird density in the nonbreeding season. The authors used these data in a paper [1] examining the relationship between forest structural indicators and bird diversity in the three forest development stages. Other researchers can also utilize these data for the purpose of comparison with other areas representing similar forest communities or for studies on stand dynamics, especially in the face of climate change which may substantially affect those phenomena. Furthermore, the presented data may be useful in studies concerning the abundance and dynamics of bird assemblages and other organisms associated with the subalpine zone as well as in research devoted to the diversity of ecological niches. Such investigations may lay foundations for developing conservation guidelines for the ecosystems in question.

In today´s intensively managed landscape, very few forests with old-growth characteristics and little human impact exist. One of the rare exceptions is pine forests on rocky soils, a forest type which has probably escaped extensive human use because of its low productivity. Our objective was to investigate the structure, dynamics, and history as well as the abundance and richness of wood-inhabiting fungi in these types of forest. We chose rocky pine forests situated in the High Coast Region to exemplify this forest type since the regional County Administration had already made surveys of the conservation value in 26 rocky pine forest stands in this region. We investigated the forests by recording tree species and measuring tree size and age in eight of the stands that were ranked with the highest conservation value. We also sampled dead wood to examine time since death and we sampled living and dead trees with fire scars to date fires. In addition, we made an inventory of wood-inhabiting fruiting bodies and took woodchip samples from logs to learn (by DNA analysis) whether five rare wood inhabiting fungi species were present as mycelia in logs. We found that rocky pine forests in the High Coast Region have a multi-sizedand multi-aged structure and old pine trees (approximately 13 ha-1 older than 300 years) are present. Fire has been common (an average of 42 years betweenfires) but they were likely to have been low-intense and small. Although the amount of dead wood is relatively low (4.4 m3 ha-1 on average) compared to many other boreal forests with old-growth characteristics, the share of deadwood of the total tree basal area (18%) was in line with other pine forests with low levels of human impact. The low dead wood volume is therefore likely to be an effect of the low productivity rather than dead wood extraction by humans. We also discovered that dead wood can be present for a really longtime without totally decomposing; we found logs and snags that had been dead for 500 years. This continuity of dead wood might be important for organisms dependent on dead wood as a substrate and even though we found that the species richness of wood-inhabiting fungi was somewhat low, we did find some rare species. Cinereomyces lenis and Hyphodontia halonata were present as fruiting bodies and we also found Antrodia albobrunnea, Antrodiainfirma, Crustoderma corneum and Anomoporia kamtschatica present as myceliain logs. The second part of this thesis reports two systematic reviews studying the effects of active management on the biodiversity in boreal and temperate forests. A systematic review follows certain guidelines and aims to compile the evidence base in well-defined topics, so that managers, researchers and policymakers can gain access to a high-quality compilation of current research. In our systematic map, we found almost 800 relevant papers but the set of papers turned out to be too heterogenic (many intervention types, e.g. thinning, burning, grazing and many types of outcomes) to allow any quantitative analysis. However, this map identified knowledge gaps and several detailed research questions that had sufficient data to provide aquantitative statistical analysis. One of these questions was: What is the impact of dead wood creation or addition on dead wood-dependent species? We focused on three types of interventions: creation of dead wood, addition of dead wood from elsewhere and prescribed burning. The selected outcomes were: saproxylic insects (rareand pest species), saproxylic fungi (rare species), ground-living insects and cavity-nesting birds. There was no significant negative effect on any of the investigated species groups but a positive effect on the abundance and richness of saproxylic insects and fungi. We also found that, although the amount of dead wood created was much less (50%) with prescribed burning, the abundance and richness of saproxylic insects showed similar positive effects to those of other intervention methods. A likely explanation for this is that burning results in a diversity of dead wood of various levels of quality (e.g. dense and/or charred wood), which creates a heterogeneity of dead woodtypes having a positive effect on the diversity of species dependent on deadwood. In summary, active management generally has a positive effect on biodiversity but the choice of management type should always be made carefully, and in consideration of the effect you want to achieve. In addition, there is a need for more long-term primary studies and more species groups in more geographical areas need to be incorporated so that the systematic reviews in this field will be even more informative in the future. Vid tidpunkten för disputationen var följande delarbeten opublicerade: delarbete 1 (manuskript), delarbete 2 (manuskript), delarbete 4 (inskickat).At the time of the doctoral defence the following papers were unpublished: paper 1 (manuscript), paper 2 (manuscript), paper 4 (submitted).

The finer pitch of 10 µm and below is currently explored by Microdisplays and Imaging industries. There are many contenders for achieving assembly at this pitch e.g. Cu-diffusion, Microtubes[1], and SnAg bumps. Among the contenders, SnAg bumps are tested for larger bumps but their capabilities for the finer pitch are yet to be explored. In this paper, behavior of SnAg for smaller bumps for the finer pitch is studied and compared to the larger bumps. Different reflow conditions such as environment, different type of flux, and temperature profile are examined. During this study, some particular bumps were observed, which we called as hedgehog bumps and their behavior is discussed in this paper. The conclusions drew from the reflow studies have been used to achieve assembly. The behavior of SnAg alloy during the assembly is also explored.

Electromigration failure in flip-chip bumps has emerged as a major reliability concern due to potential elimination of Pb from flip-chip bumps and a continuous drive to increased IO density resulting in a reduction of bump size and pitch. Traditionally, flip-chip interconnects incorporate a high Pb bump soldered with a SnPb eutectic paste to the substrate or another die. However, because of RoHS directives, the industry is responding with Pb free bump development, such as SnAg bump with SAC solder or Cu Pillar with SAC/SnAg solder. Although a number of recent publications deal with electromigration reliability of Pb free and Cu Pillar bumps, a gap exists in terms of their performance comparison with high Pb and SnPb solder on the same bump geometry. The available test data is based on different test vehicles and it becomes difficult to determine the relative performance of these different metallurgies under accelerated test conditions. In addition, not all published data provides the essential parameters of Black's equation to determine the performance and reliability for actual use conditions. This paper attempts to fill this gap by comparing electromigration performance of High Pb, SnPb eutectic, SnAg, and Cu Pillar bumps using the same test vehicle. A special test vehicle was designed with daisy chain structures for electromigration testing and the packages we assembled on test cards. The testing is being done using five (5) stress conditions (combination of current and temperature) to estimate the current density exponent, n, and activation energy, Ea, parameters for Black's equation. The reliability data as well as failure modes for these bump metallurgies will be presented in the paper.

In this paper, extensive testing was conducted to study the effects of Lanthanum (La) doping on the creep and fatigue behavior of SnAg lead free solder alloys. Variables considered in this paper include doping amount, aging temperature, and aging time. The experimental data show that rare earth element (RE) doping increases SnAg solders creep resistance by about 15%. Meanwhile, RE doping does not affect thermal aging behavior of the solder alloy. A microstructure dependent Anand viscoplastic model is proposed to capture the RE doping effect on the creep behavior. Good agreement between the model predictions and experimental data are obtained. In addition, fatigue tests were performed with bulk specimen. It is found that La doping increases the fatigue life by about five times. The optimal doping level for better fatigue performance is around 0.1%.

Four types of coarse particulate organic matter (CPOM), 100 mm and 200 mm lengths of wooden dowel, paper strips and Eucalyptus leaves, were released in either straightened or naturally meandering sections of a third-order stream in lower North Island, New Zealand. The distance travelled until retained and the fate of each CPOM type were recorded over a range of discharges (0.10–0.77 m3 s−1) in stream sections with differing riparian characteristics (forest, willow and pasture). In meanders, CPOM travelled a shorter distance until retention and a higher proportion of released CPOM was retained compared to straightened reaches. CPOM travelled further until retention in pasture sections. Snags (vegetation and debris) were more important than rocks and eddies as retention structures, but more items were trapped by eddies in straightened reaches than in meanders. Leafy CPOM (paper strips and Eucalyptus) were retained more than wooden dowels, with paper strips behaving in a similar fashion to Eucalyptus leaves. Longer dowels were retained more than shorter ones. Changes to the channel form of this stream have significantly affected the rate and nature of CPOM retention which in turn could impact on stream ecosystem structure and productivity. Copyright © 2005 John Wiley & Sons, Ltd.

Conductor and casing systems for subsea wells can be damaged due to excessive loads caused by vessel drift offs and snag loads. These types of accidental loads on the conductor and casing system are uncontrolled in nature and hence difficult to predict. Therefore, designing the system for these types of loads can be very challenging and economically not practical. Additionally, in the event of an incident subsea, a conductor and casing system is permanently installed and cannot readily be retrieved or inspected once the damage is done. The decision to abandon or to produce from a well with a damaged conductor has serious financial and environmental consequences and should be fully understood. Therefore, to make a knowledgeable decision, it is necessary to understand extent of the damage and its implications for future operations by forensic analytical tools. This paper examines the methodology of a conductor and casing system damage assessment in order to support more informed decisions and provides a case example for a typical deepwater subsea well undergone excessive accidental loading. The objective of the assessment is (1) to verify wellhead system integrity and (2) evaluate the effect of any future operations on the integrity of the system. The paper outlines a process, suggested code checks, and analysis techniques which can be implemented to determine fitness for service of an excessively loaded wellhead system.

Failures due to Electromigration (EM) in flip-chip bumps have emerged as a major reliability concern due to potential elimination of Pb from flip-chip bumps and a continuous drive to increased IO density resulting in a reduction of bump pitch and size. Additionally, the rapid development and implementation of 3D IC structures introducing new interconnects (μ-bumps, RDL, microvias, and TSVs) at much finer geometries, raises concerns about electromigration and current carrying capacity of these interconnects. This paper presents the results of multiple EM studies on Cu Pillar, High Pb, SnAg, eutectic SnPb Flip Chip bumps and μ-bumps. A special test vehicle was designed to get a head-to-head comparison of Cu Pillar EM with that of solder bumps. Tests are being conducted using three current levels and three temperatures to estimate Black's Equation parameters. A separate test vehicle is also being tested using 5 combinations of current and temperature to estimate the current carrying capacity of Cu-SnAg-Cu μ-bumps of 25um diameter. More than 8000 hours of testing is completed on flip chip solder bump and Cu Pillar, showing Cu Pillars as having the best reliability amongst the four bump metallurgies. The worst reliability was observed for High Pb bumps followed by eutectic SnPb eut and SnAg bumps. The Cu-SnAg-Cu μ-bump structure has been tested for 5500+ hours without any failures. The paper provides the detailed test matrix, failure data, failure analysis, and an estimation of Black's Equation parameters for some of the above configurations on test.

In this paper, quantitative microstructure studies were performed on multiple length scales to investigate effect of La doping on SnAg lead free solder materials. Variables considered in this paper include doping amount, aging temperature and aging time. It was found that La doping refines the microstructure and reduces microstructure coarsening rate, but the inter-particle spacing remains unaffected. Therefore, higher La doping level leads to higher volume fraction of the eutectic phase due to the increased total number of Ag3 Sn particles.Copyright © 2007 by ASME

The Upper Mississippi River flows approximately 2000 km from Lake Itasca, Minnesota to Cairo, Illinois where it is confluences with the Ohio River to form the Lower Mississippi River. North of the confluence, numerous snags, sand bars, rapids, and other obstructions made the Upper Mississippi River travel difficult. This paper highlights how the geological and landscape resources of the Upper Mississippi River and tributary watershed were responsible for the successful economic development of this historically rich region of North America. Environmental challenges include an attempt to keep invasive species such as the Asian carp out of the rivers and lakes north of the Twin Cities. In an attempt to protect the Mississippi River resource, Environmental and Conservation groups have opposed continued navigation through Minneapolis and St. Paul and the planned Upper Mississippi River navigation infrastructure restoration by the United States Corps of Engineers including the upper and lower St. Anthony locks and dams. These Environmental, Conservation and Save the River groups are attempting to mitigate the historic highest and best use of the Mississippi River and adjacent watershed, navigation, and economic development, by having the urban river restored to the natural state.

Prognostics and Remaining Useful Life (RUL) estimations of complex systems are essential to operational safety, increased efficiency, and help to schedule maintenance proactively. Modeling the remaining useful life of a system with many complexities is possible with the rapid development in the field of deep learning as a computational technique for failure prediction. Deep learning can adapt to multivariate parameters complex and nonlinear behavior, which is difficult using traditional time-series models for forecasting and prediction purposes. In this paper, a deep learning approach based on Long Short-Term Memory (LSTM) network is used to predict the remaining useful life of the PCB at different conditions of temperature and vibration. This technique can identify the different underlying patterns in the time series that can predict the RUL. This study involves feature vector identification and RUL estimations for SAC305, SAC105, and Tin Lead solder PCBs under different vibration levels and temperature conditions. The acceleration levels of vibration are fixed at 5g and 10g, while the temperature levels are 55°C and 100°C. The test board is a multilayer FR4 configuration with JEDEC standard dimensions consists of twelve packages arranged in a rectangular pattern. Strain signals are acquired from the backside of the PCB at symmetric locations to identify the failure of all the packages during vibration. The strain signals are resistance values that are acquired simultaneously during the experiment until the failure of most of the packages on the board. The feature vectors are identified from statistical analysis on the strain signals frequency and instantaneous frequency components. The principal component analysis is used as a data reduction technique to identify the different patterns produced from the four strain signals with failures of the packages during vibration. LSTM deep learning method is used to model the RUL of the packages at different individual operating conditions of vibration for all three solder materials involved in this study. A combined model for RUL prediction for a material that can take care of the changes in the operating conditions is also modeled for each material.

Forest management practices can not only influence the amount of deadwood but also the proportions of particular elements. The goal of the present paper was to compare the amount, number of logs, stumps and snags and their dendrometrical parameters between the protected and managed forests in the Karkonosze Mts after a huge dieback of Picea abies. A massive decline of Norway spruce has been observed since the 1980s. The protected forests belong to Karkonosze National Park and the managed forests are situated in its buffer zone. In total, 1336 elements of coarse woody debris (CWD) were included in the study. They were distributed on 180 study plots (10 m × 10 m) that were randomly selected. Among the deadwood elements, spruce Picea abies dominated (80.3%) followed by beech Fagus sylvatica (14.3%). Logs were more numerous in the protected forest (57.3%) than in the managed forests (42.7%). Snags and stumps were more frequent – 56.9% and 52.8%, respectively, in the managed forests than in the protected forests – 43.1% and 47.2%, respectively. The mean volume of CWD was ca 114 m3 ha-1 in the protected forests whereas ca 70 m3 ha-1 was in managed forests.The mean number of stumps per study plot was higher in the managed forests. The mean volume and mean area of logs were higher in the protected forest as was the mean volume and diameter at breast height, whereas the height of the snags was higher in the managed forests. In terms of differences in the decomposition of deadwood between the two types of forests, the mean weighted degree of decay on a five-degree scale amounted to 2.9 in the protected forests and 2.7 in the managed forests. A larger amount of deadwood as well as a greater volume and surface area are very important for nature conservation because deadwood can function as a niche for many saproxylobiont organisms. The forest management practices and especially the weak conditions of spruce lead to a larger number of snags in a managed forest due to the reconstruction of tree-stands and the removal of deadwood by foresters.

Cu-pillar/SnAg microbumps have been used for the latest 3-D through silicon via chip stacking. This microbumps flip-chip interconnection method can significantly further reduce the dimensions of the package and enhance the electrical performance by reducing interconnection path. As the pitch of the Cu-pillar/SnAg microbumps becomes extremely smaller, nonconductive films (NCFs) have recently been introduced to solve interconnection problems induced by the fine size microbumps. However, the applied pressure and heat during the thermo-compression (TC) bonding processes deform the SnAg solder and cause SnAg solder wetting on the sidewall of the Cu-pillar. The SnAg solder sidewall wetting causes rapid Sn consumption at the interface between the Cu-pillar and solder and decreases the joint gap heights of the SnAg solder joints. In this paper, the effects of the new double-layer NCFs (D-NCFs) were investigated for 40- $\mu \text{m}$ pitch chip-on-chip interconnection. The D-NCFs consisted of two NCF layers. The bottom NCF layer behaves as a conventional single NCF layer, and the top NCF layer, covering the Cu-pillar, prevents the movement of molten SnAg solder to the sidewall of Cu-pillar during the TC bonding process. As a result, the gap height of SnAg solder joints was doubled without SnAg solder sidewall wetting of Cu-pillar using the D-NCFs. SnAg solder joints using D-NCFs showed excellent reliability during thermal cycle tests up to 3000 cycles and pressure cooker test up to 72 h because of the significantly remaining Sn at the SnAg solder joint interface and increased joint gap height.

Primary old-growth forests are rare in the state of Indiana and are found only in small, isolated patches of nature preserves. Recent research underscores the values of large tracts of secondary old-growth (referred to in this paper as “older” forests), including carbon sequestration, forest resiliency, mitigation of climate change impacts, and conservation of biological diversity. Due to historical management, many portions of Indiana state forests are maturing, and yet the “older” successional stage is underrepresented. One of these maturing forests, the site of our study, is in south-central Indiana within the Back Country Area (BCA) of the Morgan-Monroe/Yellowwood State Forest (two state forests, herein called a complex, including parcels in three counties with the largest block of forests spanning Brown and Monroe counties). Our study of the forest structure of the BCA addresses the following questions: (a) Is this mature forest developing ecological attributes of old-growth forests, thus making it a good candidate for an older forest reserve? (b) Does this forest support the plant community characteristic of natural areas of Indiana? We analyzed forest stand metrics, coarse woody debris and snags, age of the largest live trees, and the floristic quality of the herbaceous layer. We then compared these data with published accounts from Indiana nature preserves. Metrics such as tree basal area, number of large-diameter trees, and number of snags are within the range of those measured in existing old-growth forests of Indiana. Analysis of tree cores and log cross-sections shows that 78% of the sample trees were over 100 yr old, with 24% over 130 yr, which is also comparable to old-growth forest nature preserves in the state. The metrics of the Floristic Quality Assessment of the broader plant community of the BCA are comparable to or higher than the metrics from published assessments of Indiana nature preserves. Collectively, the attributes measured indicate that the BCA supports a maturing secondary forest with old-growth characteristics. In the absence of further timber harvest, the BCA as a reserve could reach older forest status within 50 yr. Our study demonstrates that the BCA forest is a prime candidate for an older forest reserve. This study of the BCA could also serve as a model for future assessments of potential older forest reserves in other state forests. Reserves of older forests free from harvest are not incompatible with other management goals and can be a valuable part of a broader-scale management plan. These forest reserves should be promoted across the state to increase the representation within Indiana's state forest system of late-successional secondary forest exhibiting ecological attributes of old-growth forests, thereby enhancing the role of state forests in biodiversity protection and climate mitigation.

Human activities made on land use shows an impact on the land cover spatially and temporarily in the long run on the environment. Amendments made within Land Use/Land Cover (LULC) are anticipated in the direction of the need of increasing population through cultivation step-up for edibles. Perceiving the places, broadcasting of LULC changes is significantly intended for launching associations among leading activities, policy pronouncements, and consequent LULC activities. Change detection is a practice used in funding estimation in which multi-date images are correlated in order to determine the nature and volume of transformation that has occurred. Remote sensing and Geographical Information System (GIS) provide fundamental tools for studying LULC change detection. Reliable data scheduled the grade of nature using diverse techniques is essential in solving ecological snags. The main objective of this paper is to assess land cover changes using Normalized Difference Vegetation Index (NDVI) as well as PCA. Landsat 8, OLI/TIRS images from 2014 and 2020 are used to illustrate the concept of Land Cover Change in Vijayawada, Krishna district, Andhra Pradesh. A total of four LULC classes are identified to harvest the statistics of Dense vegetation, vegetation, water bodies, and urban. Results disclosed that dense vegetation is diminished about 28% where vegetation, built up, and water is improved by 10%, 23%, and 1%, and overall accuracy (OA) and kappa coefficient are increased.

A study of bird remains from the Koziarnia Cave (Poland) revealed the presence of nearly a dozen bony shreds (snags) projecting from the natural canals in bones; the snags were made of a material that accumulated during the Late Pleistocene. This paper describes this phenomenon and determines the most probable agent responsible for its occurrence by utilizing observations of snag microstructure, taphonomic analysis of bird assemblages from Koziarnia Cave, and surveys of collected bird remains (modern and fossilized). The presence of snag may be a good qualitative indicator of an agent responsible for the accumulation of bird bones at archeological sites and could be useful in future taphonomic studies.

In southern Australia, many native mammals and birds rely on hollows for sheltering,while hollows are more likely to exist on dead trees. Therefore, detection of dead trees could beuseful in managing biodiversity. Detecting dead standing (snags) versus dead fallen trees (CoarseWoody Debris&mdash, CWD) is a very different task from a classification perspective. This study focuseson improving detection of dead standing eucalypt trees from full-waveform LiDAR. Eucalypt treeshave irregular shapes making delineation of them challenging. Additionally, since the study area is anative forest, trees significantly vary in terms of height, density and size. Therefore, we need methodsthat will be resistant to those challenges. Previous study showed that detection of dead standingtrees without tree delineation is possible. This was achieved by using single size 3D-windows toextract structural features from voxelised full-waveform LiDAR and characterise dead (positivesamples) and live (negative samples) trees for training a classifier. This paper adds on by proposingthe usage of multi-scale 3D-windows for tackling height and size variations of trees. Both thesingle 3D-windows approach and the new multi-scale 3D-windows approach were implementedfor comparison purposes. The accuracy of the results was calculated using the precision and recallparameters and it was proven that the multi-scale 3D-windows approach performs better than thesingle size 3D-windows approach. This open ups possibilities for applying the proposed approachon other native forest related applications.

A substantial amount of literature on the importance of deadwood in Central European forests has been available providing partial recommendations to enhance deadwood-dependent biodiversity. However, a comprehensive review of science- and forestry experts-based recommendations effectively enhancing deadwood bearing in mind operational implications has not been presented in international literature. Therefore, this paper compiles the key aspects regarding the implementation of deadwood management in managed forests where the aim is to favour biodiversity without compromising or negatively affecting operational and commercial aspects of forest management. Simple deadwood management guidelines rooted in science and forestry expertise aiding decision-making in the efforts to effectively enhance biodiversity without compromising other management objectives are thus provided. Specifically, long-term retention of individual trees or tree groups and the retention of already existing deadwood (e.g. snags, coarse woody debris, uprooted, snapped, and sun-exposed trees) as well as artificial creation of deadwood (e.g. tree girdling) are presented here as we identified them as the key approaches to successful deadwood management. The major advantages and disadvantages of individual deadwood management approaches in terms of biological and operational/commercial aspects are also emphasised in order to assist forest managers in their decision-making. Furthermore, the key factors that should be considered when applying ecologically and economically efficient deadwood management are discussed; i.e. retention of trees with microhabitats, size of retained trees, position and arrangement, and decay stage. The main points regarding these factors are also addressed in the light of supporting realistic implementation of individual deadwood management approaches.

Fungal decomposition of coarse woody debris has an essential role in the biodiversity and carbon and nutrient dynamics in forest ecosystems. However, our knowledge of the effects of fungal species and within-stem diversity on wood decay is limited. In this paper, I described the process of wood decay and fungal succession of pine (Pinus densiflora) snags using chronosequence method. The results showed that the decay process differed between sapwood and heartwood. Sapwood decayed faster than heartwood, despite their initial densities being the same. Sapwood decay occurred in two phases. The first phase involved a typical white-rot process wherein acid-unhydrolysable residue (lignin) and holocellulose decayed simultaneously. White-rot species, such as Trichaptum abietinum and Phanerochaete sordida, were the dominant fungi and were likely the functional decomposers in this phase. The second phase involved selective decomposition of holocellulose. The dominant fungi in this phase included soft-rot species, such as Trichoderma spp., that can decompose holocellulose in wood that was previously delignified by white-rot species. In contrast to sapwood, heartwood experienced less loss of wood density and no clear change in lignocellulose composition, even in later stages of decay. Dominant fungi in heartwood included the latent inhabitants of living pine trees, such as Ascocoryne cylichnium, which is known to reduce colonization and wood decay by strong decomposers. These results suggest that, in addition to decay-resistant chemicals present in heartwood, the differences in the fungal communities present in heartwood and sapwood were responsible for the differences in their decay rates.

Prescribed fire is widely applied in western US forests to limit future fire severity by reducing tree density, fuels, and excessive seedlings. Repeated prescribed burning attempts to simulate historical fire regimes in frequent-fire forests, yet there is limited long-term information regarding optimal burn season and frequency. In addition, burns are operationally feasible only in the spring and late fall, largely outside the historical wildfire season. This study quantifies the effect of seasonal reburns on woody surface fuels, forest floor fuels, and understory tree regeneration abundance in six previously thinned ponderosa pine (Pinus ponderosa Lawson & C. Lawson) stands in the southern Blue Mountain Ecoregion of Oregon, USA. Each stand consisted of an unburned control, and four season by reburn treatments: spring 5 yr, spring 15 yr, fall 5 yr, and fall 15 yr. We evaluated season and frequency of reburn for woody surface fuel (1 hr to 1000 hr), forest floor fuel (litter and duff, undifferentiated), and understory conifer seedling density (regeneration). Burning was initiated in the fall of 1997 and spring of 1998; we present results in this paper through 2014 for fuel, and 2015 for seedlings. All reburn treatments reduced the forest floor depth compared to those areas not burned (controls). Fall burning, regardless of frequency, generated 1000 hr fuel primarily from overstory mortality resulting from the initial entry burns and subsequent snag and branch fall. But, for the other woody fuel types, reburning had minimal impact, regardless of season or frequency. All reburn treatments reduced regeneration survival, but 5 yr fall reburning was most effective in reducing excessive conifer seedlings. Repeated spring or fall reburns following thinning will reduce forest floor depth but, to achieve low woody fuel loads and control excessive conifer regeneration, it may be necessary to conduct reburns using different timing, such as during drier periods when wildfire ignitions by lightning occurred historically.

Despite the potential importance of tree species in influencing the processes of wood recruitment, transport, retention, and decay that control river wood budgets, focus has been relatively limited on this theme within fluvial wood research. Furthermore, one of the least investigated topics is the belowground living wood component of riparian trees. This paper presents observations of the morphology and age of buried stem and coarse root structures of eight Populus nigra individuals located in the riparian woodland of two sites on the middle to lower Tagliamento River, Italy. This species was selected because of its wide distribution along European rivers and its frequent dominance of riparian woodland. Each tree was excavated by hand to expose a minimum of half of the root system with complete exposure of the main axis. Smaller roots were then removed and larger protruding roots cut back to permit access to the main axis. The excavated structures were photographed from multiple angles for photogrammetric modelling; the structure and character of the exposed sediments around the tree's main axis were recorded; and wood samples were taken from the main aboveground stem(s), sections of the main buried axis, and major roots for dendrochronological analysis. Results from these field observations and laboratory dating of the wood samples were combined to describe the belowground morphology of each tree and to draw inferences concerning the impact of fluvial disturbances. Common features of these excavated structures included: (i) rooting depths to below the bar surface where the original tree established, with many young roots also existing at depth; (ii) translocation of the main buried axis in a downstream direction; (iii) a main buried axis comprised mainly of stems that have become buried and then generated new shoots, including multistem patches, and adventitious roots; (iv) the presence of steps and bends in the main buried axis associated with the generation of coarse lateral roots, that reflect the sedimentary structure of the surrounding aggraded bank sediments; and (v) grafting of roots within and between some sampled trees. Overall, the sampled trees possessed extremely complex three-dimensional buried wood structures that permeate bank sediments and tie the tree and aggraded bank sediments to basal gravels. These properties and the considerable amount of underground wood that is present have great significance for anchoring trees and giving uprooted trees and root wads a propensity to snag once they enter the fluvial system. Furthermore, the ability of this underground biomass to sprout suggests that uprooted and remaining components of root networks following tree uprooting may resprout, generating new vegetation canopies that can trap mobile wood. Overall, this underground wood offers many traits that may tighten wood budgets, and it is likely that other riparian Salicaceae species with similar traits may have similar wood budget impacts.