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As demand for wood energy rises, it's vital to understand the environmental impact of various harvest types, considering different best management practices (BMPs) and site conditions, for sustainable forest management. This study provides a comparative analysis of postharvest site characteristics between biomass and conventional harvest sites located in the Coastal Plain region of the southeastern US. A total of 30 recently harvest sites (15 each for biomass and conventional) were selected from the Coastal regions of Alabama, Georgia, and Florida. Erosion rates were estimated using the USLE-Forest method and ground cover was assessed as a percentage of the area covered by bare soil, litter, light slash, heavy slash, and piles. BMP implementation (%) was based on state-specific BMP surveys. The findings show that stream management zones (SMZs) and harvest areas were less prone to soil erosion, while forest roads, skid trails, and stream crossings were more prone to erosion, regardless of the harvest type. Conventional harvest sites had an overall weighted average erosion rate of 0.35 Mg/ha/year, with an average BMP implementation of 92.70 %, while biomass harvest sites had an overall weighted average erosion rate of 0.22 Mg/ha/year, with an average BMP implementation rate of 97.91 %. Average erosion rate (Mg/ha/year) from the harvest area (biomass=0.11, conventional=0.06) and SMZs (biomass=0.05, conventional=0.02) were not significantly different (p >0.05). Conversely, average erosion rate from roads (biomass=4.17, conventional=6.44), skid trails (biomass=2.15, conventional=3.73), decks (biomass=0.39, conventional=0.72), and stream crossings (biomass=1.53, conventional=5.31) were significantly higher in conventional harvest sites (p <0.05). BMP implementation rates for roads (biomass=98.09 %, conventional=93.71 %), stream crossings (biomass=95 %, conventional=71 %), and timber harvest (biomass=96.44 %, conventional=93.33 %) were significantly higher in biomass harvest sites, while waste management BMP (biomass=89.91 %, conventional=100 %) was significantly higher in conventional harvest sites. Regarding ground cover, conventional harvest sites had significantly larger areas covered by light slash, heavy slash, and piles than biomass harvest sites, while biomass harvest sites had significantly larger areas covered by green growth. Our research shows a significant negative correlation between overall BMP implementation and erosion rates (r=-0.67, p =0.0002), as well as site size (r=-0.38 p =0.0400), indicating that larger sites tend to have lower BMP implementation and increased erosion risk. In conclusion, biomass harvest sites in our study did not yield higher erosion rates in comparison to conventional harvest sites, provided that the current BMP recommendations were implemented properly and in adequate amounts. This study emphasizes the importance of site-specific management strategies to mitigate erosion in all harvest sites, irrespective of harvest type used. • There is no significant difference in erosion rate between biomass and conventional harvest sites. • Conventional harvest sites exhibit a greater coverage of woody debris than biomass harvest sites. • Proper implementation of BMPs at both conventional and biomass harvest sites underscores water quality protection efforts. • A significant negative correlation exists between BMP implementation and erosion rate. [ABSTRACT FROM AUTHOR]

Highlights • The impact of shelterwood (SW) cutting on understorey diversity was studied. • SW increases the species richness of vascular plants and bryophytes in pine forests. • The responses to different management practices were species group specific. • SW may be a suitable method to sustain the keystone forest floor species bilberry. Abstract Shelterwood (SW) cutting is considered a sustainable harvest method but its impact on understorey diversity of Scots pine (Pinus sylvestris) forests has not been thoroughly studied. Our aim was to clarify how uniform SW cutting in interactions with soil scarification, deposition of logging residues and altered light conditions affects the species richness and composition of vascular plants and bryophytes and how different species groups and individual species vary in their responses to SW practices. We monitored permanent vegetation plots in nine mature pine forests of hemiboreal Estonia before, shortly after and 3–4 years after SW harvesting. The results indicated that the effect of uniform SW harvesting was species group specific as the majority of vascular plant species groups as well as mosses and epigeic bryophytes increased in richness, however, the species richness of epiphytic and epixylic bryophytes decreased. Late-successional species showed two types of responses to SW harvesting: either reduction of cover or reduction followed by a recovery. Soil scarification favoured early-successional bryophyte species as well as the richness of tree seedlings and dwarf-shrubs but diminished the cover of Vaccinium myrtillus , Vaccinium vitis-idaea and Hylocomium splendens. The harvest-induced changes in the species composition were more pronounced for bryophyte communities than for vascular plants. Retention of green trees and dead-wood is important in SW harvesting for sustaining the vulnerable epixylic and epiphytic bryophyte species. To summarise, uniform SW harvesting increases the species richness of vascular plant and bryophyte communities in pine forests - at least in the short term. [ABSTRACT FROM AUTHOR]

As a response to the increased market for biomass for energy in Sweden logging residues such as slash and stumps, previously left in the forest at stemwood harvest, have been targeted as a resource. Negative effects on site and stand productivity have been suggested as unwanted effects of this increased harvest intensity. Slash with its high nutrient content has the potential to impact forest production on nutrient limited northern forest sites. Stumps, with a lower nutrient content, may therefore be more favourable from a production point of view and the additional soil disturbance caused by the harvest may counteract the nutrient loss as a result of stimulated mineralization and reduced competition from the ground vegetation. Seedling survival is another critical factor that could be affected with potential effect on future stand productivity. Here stand and site productivity data from four long-term field experiments planted with, Scots pine (2 sites) and Norway spruce (2 sites) seedlings following (i) conventional stemwood harvest (S), (ii) stem and stump harvest (SS), and (iii) stem, stump, and slash harvest (SSS) is analysed and presented. The statistical analyses based on data from all sites did not reveal any general treatment effects on seedling survival, standing volume (after 24–27 years), basal area growth (between the last two revisions), upper quartile mean height (25% highest trees) after 10 years or top height (after 24–27 years). Analyses at the species level revealed a significant main treatment effect on top height for the spruce sites, with lower top height following SSS (11.6 m) as compared to S (12.9 m). No main treatment effect was detected for the pine sites. Analyses at the site level gave significant but inconsistent results for the least productive site in both pine and spruce, suggesting site and possibly also species-specific responses. Response variables affected by treatments at the pine site were survival rate after 15 years (S < SS), standing volume after 24 years (S < SS and SSS), and upper quartile mean height after 10 years (S < SS and SSS). Response variables affected at the spruce site were standing volume after 27 years (SSS < S and SS), upper quartile mean height after 10 years (SSS < S and SS), and top height after 27 years (SSS < S and SS). Thus, responses on increased harvest intensity were from a forest production perspective positive in pine, whereas the spruce responded negatively – primarily on slash harvest. From a forest production perspective these results suggest that pine forests should be targeted before spruce forests and that stumps should be targeted before slash in spruce forests. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine the effects of different amounts of logging residues on soil properties and growth of Scots pine and Norway spruce seedlings 10 years after clear-felling. The field experiments consisted of two Scots pine and four Norway spruce experiments. The treatments, on three replicate 8 m ∗ 8 m plots in all field experiments, were whole-tree harvesting, i.e. harvesting all the above-ground biomass with no logging residue left on the site (R0), stem-only harvesting, leaving logging residues on the site (R1), and stem-only harvesting with double the amount of logging residues left on the site (R2). In the R1 treatment the amount of logging residue in the spruce stands was 39–54 Mg ha −1 dry mass and in the pine stands, 11–18 Mg ha −1 dry mass. Over all sites, logging residues had no consistent effects on seedling growth, amounts of soil carbon and nutrients or organic matter characteristics. In some spruce experiments, however, logging residues increased the average diameter, height and height growth (last three years), as well as the number of seedlings, stem volume and biomass. In pine experiments, logging residues had no effect on tree or stand characteristics. In one pine experiment the amounts of exchangeable base cations increased, and there were also changes in the quality of organic matter: the C/N ratio decreased, and NH 4 –N, microbial biomass N and C mineralization increased due to residues. In the spruce experiments and the other pine experiment, the effect of logging residues on the soil properties measured was slight. Logging residues did not affect NO 3 –N concentrations or rates of net nitrification, which in most soils were both negligible. Seedling height and height growth correlated strongly and positively with net N mineralization and its ratio to microbial biomass N. All in all, logging residues improved tree and stand characteristics generally in spruce stands, but the effects on soil properties and processes, if any, occurred mostly in one pine stand. This poor correspondence may point to other changes brought on by the logging residues, such as changes in physical environment or decreased competition with ground vegetation, being more important for seedling growth than nutrient status was. [ABSTRACT FROM AUTHOR]

Highlights: [•] We assessed how loads of logging residues altered the microenvironment of seedlings. [•] Soil temperatures decreased with increasing forest logging residue load. [•] Reduction of competing vegetation cover by logging residues was site-dependent. [•] Logging residues had no effect on soil available nutrients. [•] Seedlings showed little growth response to different loads of logging residues. [Copyright &y& Elsevier]

The relative volume growth effects of thinning after whole-tree harvesting (WTH) compared to a conventional stem-only harvest (CH) in young stands of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.) were analyzed, using a series of four pine and four spruce field experiments. The series was established in the years 1972–1977, and thinning was performed only once. Results are shown periodically and cumulatively. All sites were included for 20 (19) years in pine and 25years in spruce. The total experimental period varied between 19 and 35years for individual sites. Four models assuming additive or multiplicative effects gave only slightly varying results. The inclusion of standing volume after thinning as a covariate was effective in spruce independent of whether the covariate was treated as multiplicative or additive. A logarithmic model with a multiplicative effect of the covariate was preferred in further presentations. Results for pine stands after 20years indicated a nonsignificant loss of 5% with confidence limits (p =0.05) of ±6–7%, while the spruce stands showed a significant growth loss of 11% with confidence limits of ±4–5% after 25years. The difference between the species in relative growth effects was significant, and amounted to 8% for a cumulative 20-year period. No indications of trends in response were found during a 20-year period in pine and a 25-year period in spruce. An analysis of growth effects in the first years showed that basal area increment in spruce was significantly reduced already in the first growing season after thinning. [ABSTRACT FROM AUTHOR]

Abstract: Harvesting of stumps and logging residues for bioenergy can be expected to increase in the future. An increased biomass export from the forest will increase the biological acidification, measured as net cation (cations–anions) export. The aim of this study is to estimate the acidifying effect that various levels of harvesting of tree stumps and logging residues will have in Sweden, and compare this with the acidification currently caused by acid deposition. Estimations of yearly logging of Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies (L.) Karst.) and birch (Betula spp.) on county-level were made based on scenario data from forestry consequence analyses and data from the Swedish National Forest Inventory. Data of cation and anion contents in tree parts were used to calculate the net cation extraction per area unit resulting from harvesting of stumps, stem-wood and logging residues, respectively. County-level data were merged into data for three different regions representing a gradient in deposition and climate. Results indicate that harvesting of stumps constitutes 13–24% of total (stumps+stem-wood+logging residues) excess cation extraction, depending on harvest intensity and tree species. Harvesting of logging residues constitutes 27–45% of total net cation extraction. The higher acidifying effect of logging residues can be explained by the higher contents of base cations in needles and branches compared to stem-wood. In a comparison between total net cation extraction by tree harvesting and maximum levels of current acid deposition the acidifying effect of pine harvesting is 57–108% of that of acid deposition, the acidifying effect of spruce harvesting is 114–263% while the acidifying effect of birch harvesting is 60–171%. Concerning the amount of acid input to the soil per unit heating value as biofuel, stump harvesting generates 12–27eqH+ MWh−1 while logging residue harvesting generates 39–66eqH+ MWh−1. Stump harvesting generates a higher heating value per area unit than logging residue harvesting and results in a lower acid input to the soil per unit heating value generated. Thus, from a strict nutrient balance and acidification perspective stump harvesting is a better alternative than harvesting of logging residues. [Copyright &y& Elsevier]

Abstract: The aim of this study was to determine the amount of boron in three Norway spruce (Picea abies (L.) Karst) stands in eastern Finland, where boron deficiency is common. A further aim was to estimate the effects of logging-residue harvest on boron balance and the boron-to-nitrogen ratio on these sites. The data were obtained from a 30-year-old and a 62-year-old healthy spruce stand as well as from a 35-year-old spruce stand with boron deficiency and growth disorders. Altogether 2.1 and 2.4kgha−1 boron, respectively, were bound in trees+organic layer+0–10cm mineral soil layer in the two healthy stands, and 0.9kgha−1 in the boron deficient stand. For the amount of boron in the healthy stands the trees made up 43% and 49%, respectively, and in the boron deficient stand 38%. Stems contained 30% and 40%, respectively, of the boron in trees in the healthy stands and 37% in the boron-deficient stand. Only 11–13% of the tree boron was in the needles. The amount of nitrogen bound in the ecosystem studied was 2.1 and 2.5Mgha−1, respectively, in the two healthy stands and 3.0Mgha−1 in the boron deficient stand. In the ecosystem the trees contained 21–29% of the amount of nitrogen. Stems contained 14–24%, respectively, and needles 26–36%, respectively, of the nitrogen in the trees on the studied stands. In stem-only harvestings, relatively more boron than nitrogen would be removed from a site. In the boron-deficient stand, boron fertilisation for 3years nearly doubled the amount of boron in the ecosystem. Only 38% of the fertiliser boron (2kgha−1) was found in the ecosystem components studied. [Copyright &y& Elsevier]

Abstract: The effects of whole-tree thinning on soil were investigated in 9 Scots pine and 4 Norway spruce experiments in Finland. Three pine experiments had been thinned once, the other experiments twice. Time between thinning and soil sampling varied from 3 to 30years. Amounts of exchangeable base cations, Ca, K and Mg, seemed to have decreased after whole-tree thinning. The larger the amount of removed logging residues, the greater these decreases tended to be. Changes in base cations in soil due to whole-tree harvest were more expected than were changes in the amounts of nitrogen, because, e.g. potassium and magnesium in logging residues of one thinning corresponded, on average, to 60–70% and to 30–40%, respectively, of the total amounts of nutrients in the organic layer, but nitrogen only to 10%. Overall, in the experiments studied, whole-tree harvest induced only slight changes in soil nutrients. The changes would be even smaller if the present motorised whole-tree harvest, in which logging residues are not totally removed, were compared to the present motorised stem-only harvest, in which logging residues are not distributed evenly over the cutting area. [Copyright &y& Elsevier]

Abstract: The aim of this study was to determine the effect of whole-tree harvesting (WTH) on the growth of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.) as compared to conventional stem harvesting (CH) over 10 and 20years. Compensatory (WTH+CoF) and normal nitrogen-based (CH+F or WTH+F) fertilisation were also studied. A series of 22 field experiments were established during 1977–1987, representing a range of site types and climatic conditions in Finland, Norway and Sweden. The treatments were performed at the time of establishment and were repeated after 10–13years at 11 experimental sites. Seven experiments were followed for 25years. Volume increment was on average significantly lower after WTH than after CH in both 10-year periods in the spruce stands. In the pine stands thinned only once, the WTH induced growth reduction was significant during the second 10-year period, indicating a long-term response. Volume increment of pine stands was 4 and 8% and that of spruce stands 5 and 13% lower on the WTH plots than on CH during the first and the second 10-year period, respectively. For the second 10-year period the relative volume increment of the whole-tree harvested plots tended to be negatively correlated with the amount of logging residue. Accordingly, the relative volume increment decreased more, the more logging residue was harvested, stressing the importance of developing methods for leaving the nutrient-rich needles on site. If nutrient (N, P, K) losses with the removed logging residues were compensated with fertiliser (WTH+CoF), the volume increment was equal to that in the CH plots. Nitrogen (150–180kgha−1) or N+P fertilisation increased tree growth in all experiments except in one very productive spruce stand. Pine stands fertilised only once had a normal positive growth response during the first 10-year period, on average 13m3 ha−1, followed by a negative response of 5m3 ha−1 during the second 10-year period. The fertilisation effect of WTH+F and WTH+CoF on basal area increment was both smaller and shorter than with CH+F. [Copyright &y& Elsevier]

Abstract: Machines used for final felling operations are heavy and the risk for rutting and soil compaction can be considerable under unfavourable soil conditions. It is known that slash reinforcements of strip roads reduces rutting and soil compaction, but few studies are after traffic with large forwarders on moist fine-grained soils. An increased interest to utilise logging debris for energy production has made it important to know if and where slash is needed for strip road reinforcement. The aim of the study was to evaluate if slash reinforcement of strip roads influences rutting and soil compaction on a moist fine-grained soil, and to quantify these effects. The study was designed as a factorial experiment with factors slash depth in the strip road and number of machine passages. The effects of 0, 10 and 20cm slash, and one, two and five passages were studied. The first passage was made with a 20.5Mg harvester and subsequent passages by a 37Mg laden large forwarder. Rut depths increased with number of machine passages but were not influenced by slash depth. Slash reinforcement of strip roads significantly reduced changes in soil dry density and soil porosity in the upper 20cm of the soil. An increased number of machine passages increased soil dry density in the upper 20cm and reduced air filled pore volume in the upper 30cm of the soil. In the uppermost 20cm of the soil, observed soil dry density increase after one machine passage on strip roads without slash was higher than after five machine passages where strip roads were covered with 20cm of slash. [Copyright &y& Elsevier]

To optimize the use of resources of Deramakot Forest Reserve, a model area for sustainable management of tropical forests in Sabah, Malaysia, a study on the utilization of hollow logs and other logging residues was initiated. In a pilot study, how much high quality timber can be extracted from trees regarded as hollow by the felling team of the logging contractor was evaluated. The amount of extractable timber considered as timber of low-quality (upper stem parts, top portions, big branches) was also determined. At the same time whether the chain saw method is a reliable method for the detection of hollow stems was tested.Results of the study were as follows:

We used 2 long-term field experiments with Norway spruce Picea abies (L.) Karst. to investigate the influence of lime, acid sulphur compounds, or nitrogen (1 site) on the rate of recruitment of new vascular species after clear-fellings. On the study sites, Farabol in southern Sweden and Fa¨xboda in south–central Sweden, the chemical treatments had been applied before clear-felling and whole-tree harvesting. An additional, post-harvest experiment was conducted at Farabol in which lime, hardened wood-ash, or logging residues were applied. A germination experiment including seven species was carried out in a greenhouse using sifted humus from Fa¨xboda that was sampled 2 years before clear-felling.The clear-fellings resulted in establishment of many ephemeral species. The number of newly established species was greater than the number of disappeared species.There was an overall positive correlation with pH in the humus layer and the number of newly established species. The treatment effects differed between the sites, probably reflecting differences in total dose and initial soil conditions. Farabol is characterised by more acid soils and greater atmospheric deposition of S and N than Fa¨xboda. At Farabol, liming (in total 6000 kg limestone ha−1 distributed over 12 years) resulted in about 20 new species established after clear-felling, four times more species than in untreated, sulphur-treated, or nitrogen-fertilised plots. At Fa¨xboda, where lime (2000 kg dolomite ha−1), sulphuric acid, and elementary S had been applied 16 years before clear-felling, the number of newly established species was about 15, and no effect of the treatments was revealed.The post-harvest treatments at Farabol showed that wood-ash and logging residues had similar effects as lime on the establishment of new species.The pot experiment showed that liming or acidification can affect the germination of seeds. Compared with untreated soil, a greater proportion of seeds of Primula veris (P. veris) and Senecio sylvaticus (S. sylvaticus) germinated in limed soil and the germination of P. veris was lower in acid- or sulphur-treated soils. The germination of Vaccinium myrtillus (V. myrtillus) seeds was negatively affected by liming. No effects of the treatments were discovered on the germination of Deschampsia flexuosa, Calamagrostis arundinacea, Galeopsis bifida (G. bifida), or Poa nemoralis. The soil water in the pot experiment had higher pH, higher concentrations of Ca and Mg, and higher NO3−/NH4+ ratios in limed soil compared with other treatments.Nomenclature of plants follows . [Copyright &y& Elsevier]

• Dynamics of N cycling was studied under spruce logging residues on a clear cut. • Stimulated N cycling processes increased N losses via leaching and N 2 O production. • Amount of residues affected soil N cycling and losses. This study aimed to determine the effects of Norway spruce logging residues on the early-stage dynamics of N cycling processes on a clear cut and how this is related to N losses via leaching or nitrous oxide emissions. We compared N cycling processes in soil under spruce logging residues (fresh residues 40 kg m−2) and in corresponding soil without the residues for four growing seasons on a clear-cut in southern Finland. In addition, two other sites were studied in the same region six years after clear-cutting in plots with three different amounts of spruce logging residues (0, 10, 40 kg m−2). Logging residues strongly stimulated net nitrification within the first three months after the residue treatment, and this stimulation continued over the whole study period, although NO 3 -N concentrations in the soil decreased. Residues increased the pH, rate of net N mineralization and microbial C-to-N ratio. N 2 O production in the laboratory and fluxes in the field were both studied after four growing seasons. N 2 O production was higher in the humus layer under the residues and originated from both autotrophic nitrification and denitrification. N 2 O fluxes in the field were low but were also higher in the residue-containing plots. N concentrations in percolate water were monitored for four years at the same site. Logging residues increased NO 3 -N and NH 4 -N concentrations; the highest concentrations were found during the second and third years after clear-cutting. After that the concentrations of dissolved organic N increased. Both the percolate water study at this site and the N cycling studies at the two other sites six years after clear-cutting showed that the largest amount of residues resulted in the highest rates of net N mineralization and net nitrification and the highest concentrations of mineral N forms in the percolate water. The amount and decomposition stage of the logging residues as well as the development of ground vegetation may together determine the dynamics of soil N cycling processes and losses. [ABSTRACT FROM AUTHOR]