•Harvest impacts on stream chemistry greatest in the clearcut, less in selection and shelterwood cuts.•The largest impacts on stream solutes typically short-term, some lasted decades.•Patterns in the ...response reflect change in nutrient demand, sources, and transport.•Cumulative impact of forest harvesting with climate change and acidification recovery.
Previous studies of harvest impacts on stream chemistry from deciduous forests with seasonal snow cover have shown variable responses and recovery times. We hypothesized that this variability in response and recovery was due to the interactive effects of forest harvesting with regional and global environmental changes. We investigated harvest impacts on stream solute (K+, Na+, Ca2+, Mg2+, Cl–, SO42–, DOC, Si, NO3–, NH4+, total P) concentrations, pH and conductivity under clearcut, selection, and shelterwood harvesting using a before-after control-impact experimental approach. The experiment was conducted at the Turkey Lakes Watershed, a shade-tolerant sugar maple forest within the Boreal Shield Ecozone, over a 36 year period (15 year pre-harvest and 21 year post-harvest) that has experienced climate change and acidification recovery. Harvest impacts on stream chemistry were greatest in the clearcut, moderate in the selection cut, and least in the shelterwood cut. The largest impacts on stream solutes typically lasted one to six years following harvest, although some solutes were impacted during the entire 21 year post-harvest period. Different patterns in the response of stream solute concentrations included: initial deviations (increase or decrease) followed by a return to pre-harvest levels within two to four years (Na+, Ca2+, Mg2+, conductivity); initial increase followed by a decrease but still not recovered (K+); initial increase followed by a decrease to below pre-harvest levels (NO3–, Na+, Cl-); sustained elevated concentrations (dissolved organic carbon DOC, Si); and a noisy response (TP, SO42-, pH). The different patterns were consistent with expected changes in nutrient demand, sources, and transport (including changes in hillslope-stream hydrologic connectivity due to harvesting). Comparing harvest impacts to long-term climate change and acidification recovery showed that harvesting had antagonistic (mitigative) effects to environmental changes for some solutes (e.g., cations), while for others (e.g., DOC) harvesting had agonistic (synergistic) effects to environmental changes. These results emphasize the need for long-term monitoring to accurately interpret the consequences of forest harvesting practices on the resilience of forests experiencing environmental change.
El aprovechamiento sustentable de los recursos forestales consiste en utilizarlos para generar riqueza, mejorando indicadores sociales y evitando el desequilibrio ambiental. El objetivo del estudio ...fue determinar la sustentabilidad ambiental de las concesiones forestales en el departamento Huánuco, Perú, mediante el análisis multicriterio basado en el uso de indicadores. Se construyeron indicadores que incluyen la diversidad de macrofauna edáfica evaluada hasta 30 cm de profundidad, como evidencia del estado de conservación y mantenimiento del suelo. Los indicadores fueron estandarizados mediante escala de 0 a 4.0, siendo 4.0 el mayor valor de sustentabilidad; posteriormente, fueron ponderados multiplicando la escala por un coeficiente, según su importancia respecto a la sustentabilidad. Una concesión forestal es ambientalmente sustentable, si el índice de sustentabilidad ambiental (ISA) es ≥ 2.0. La encuesta elaborada se aplicó a titulares y trabajadores de las concesiones forestales. Para conocer si el ISA en 60% de concesiones forestales supera el valor 2.0, se empleó la prueba estadística no paramétrica chi cuadrada; también se realizó entre indicadores, la correlación de Pearson con un 95% de confiabilidad. La prueba chi cuadrada confirma que las concesiones forestales con aprovechamiento forestal manual (60% del total), son ambientalmente sustentables (X2 = 0.056, p-valor = 0.814). Se registró fuerte correlación positiva estadísticamente significativa (r = 0.970, p-valor < 0.05) entre los indicadores “conservación y mantenimiento del recurso suelo” y “conservación de flora silvestre”. El aprovechamiento forestal manual mantiene armonía con el entorno natural, y aunque el aprovechamiento forestal mecanizado sea de impacto reducido, genera daños al ecosistema.
•Streamflow was 50% lower in a 40–43-yr-old plantation relative to 110-yr-old forest.•Summer low flow deficits persisted over six or more months of each year.•Contemporary forestry practices produced ...persistent, large summer low flow deficits.
We examined long-term changes in daily streamflow associated with forestry practices over a 60-year period (1959–2017) in the Alsea Watershed Study, Oregon Coast Range, Pacific Northwest, USA. We quantified the response of daily streamflow to (1) harvest of mature/old forest in 1966, (2) 43- to 53-yr and 48- to 58-yr-old industrial plantation forests in 2006–2009, and (3) logging of the plantations using contemporary forest practices, including retention of a riparian buffer, in 2010 and 2014. Daily streamflow from a 40- to 53-yr-old Douglas-fir plantation was 25% lower on average, and 50% lower during the summer (June 15 to Sept 15 of 2006 to 2009), relative to the reference watershed containing mature/old forest. Low flow deficits persisted over six or more months of each year. Surprisingly, contemporary forest practices (i.e., clearcutting of the plantation with riparian buffers in 2009 and 2014) had only a minor effect on streamflow deficits. Two years after logging in 2014, summer streamflow deficits were similar to those observed prior to harvest (under 40- to 53-yr-old plantations). High evapotranspiration from rapidly regenerating vegetation, including planted Douglas-fir, and from the residual plantation forest in the riparian buffer appeared to explain the persistence of streamflow deficits after logging of nearly 100% of the forest plantation. Results of this study indicated that 40- to 50-yr rotations of Douglas-fir plantations can produce persistent, large summer low flow deficits. While the clearcutting of these plantations, with retention of riparian buffers, increased daily streamflow slightly, flows did not return to pre-first entry conditions. Further work is needed to examine how intensively managed plantation forests along with expected warmer, drier conditions in the future may influence summer low streamflow and aquatic ecosystems.
Governments often subsidize forest stands to ensure a stable wood supply or other environmental utilities. In this situation, efficient forest stand selection for subsidization may be desired for ...efficient use of public funds. In this study, we developed a method that determines the optimal set of forest stands for subsidization using an optimization technique of stand-level forest harvest scheduling. The method numerically determines the minimal subsidy and the optimal forest harvesting (commercial thinning and clearcutting) schedule of each forest stand. Further, based on an assumption that forest stands in a region can be divided into categories such that each category is substantially smaller than the total forest area, a simple sort method for identifying the optimal selection of subsidized forest stands is developed. The subsidized forest stands are determined so that annual government expenditure is minimized under “normal forest” conditions. Finally, an application example using the case of Nagano Prefecture, Japan is presented.
•A method for optimal selection of forest stands for subsidization was developed.•Minimal subsidy and optimal harvesting schedule for each stand are identified.•The use of integer-mixed optimization is avoided with a practical assumption.•A simple sort with an efficiency index provides practically–optimal selection.•Efficient selection of stands for subsidization compared with ordinary method.
•Forest harvest may increase MeHg in streamwaters and aquatic food chain.•Streamwater chemistry and MeHg in biota were studied in a paired-catchment design.•Concentrations of nutrients increased but ...not streamwater MeHg and total Hg.•MeHg in invertebrates was reduced after harvest related to improved nutrient access.
Forest harvesting practices can potentially increase mercury run-off from catchments. A paired catchment experiment was conducted in a boreal forest in southern Norway, to test effects of forest harvest operations on (i) concentrations and fluxes of methylmercury (MeHg), total mercury (HgT), nutrients and dissolved organic matter (TOC), and on (ii) MeHg bioaccumulation in stream foodwebs.
Thirty percent of a catchment was harvested in winter time with snow cover but no soil frost, resulting in wheel tracks and soil compaction. Pre-harvest differences included higher streamwater MeHg, HgT and TOC, and lower pH in the treated catchment compared to the reference.
No significant treatment effects on concentrations of MeHg, HgT and TOC were detected, whereas concentrations of nutrients (ammonium, nitrate, phosphorus (P)) increased significantly. Estimated catchment export of nitrate and ammonium increased fourfold, as a combined effect of changed discharge and concentrations. Export of MeHg and HgT increased weakly, primarily because of an increase in discharge.
Levels of MeHg in stream invertebrates mirrored differences in aquatic MeHg between the two streams, resulting in higher MeHg in biota in the harvest catchment in pre-harvest conditions. After harvest, MeHg levels in primary consumers (herbivorous stoneflies) were no longer different between the two streams, despite continued exposure to higher aqueous MeHg in the harvested catchment. Simultaneously, dietary biomarkers (δ15N signature, lipid- and algal fatty acid content) in the stoneflies had changed significantly, consistent with higher nutrient loadings and associated higher diet availability in the harvested stream.
The results of our experiment do not support that forest management has a strong impact on catchment MeHg production. Catchment disturbance through forest harvesting may decrease MeHg in aquatic biota, because of higher stream productivity and associated higher quality of dietary sources, at least in the short-term. Other studies on catchment MeHg production to disturbance have shown a range in responses, from strong to none. So far, no factor has emerged to explain such range in responses. Predictions of forest management effects on MeHg in streamwater and aquatic food webs are hampered by limited understanding of catchment controls on MeHg production.
SEILAPLAN Bont, Leo Gallus; Moll, Patricia Edith; Ramstein, Laura ...
Croatian Journal of Forest Engineering,
06/2022, Letnik:
43, Številka:
2
Journal Article, Paper
Recenzirano
Odprti dostop
Cable-based technologies have been the backbone of forest management and harvesting on steep slopes for decades. The design of a cable road is a complex task. It essentially comprises the ...identification of the start and end points of a cable road, as well as the intermediate supports. With the aim of simplifying this design process, we developed a semi-automated cable road design tool (QGIS plugin SEILAPLAN) that is easy and intuitive to use. SEILAPLAN is based on mechanical assumptions for the structural analysis that are »close-to-reality«, contains an algorithm that checks all possible intermediate support combinations and automatically identifies the optimal solution, and integrates tools and geodata within a GIS application. We present its main components and present an example of application. The integration into a GIS program, the implemented cable mechanics, and the associated information for the construction of a cable road were highly appreciated by the users.
•Research on impact of selective logging is in increasing trend.•Impact studies are predominantly concentrated in Brazil, Malaysia and Indonesia.•Global environmental discourses and fund flow have ...high influence on impact studies.•Plant species richness, composition and diversity are in the key focus.•Needs, interests and capacity of the selective logging forestry stakeholders are poorly discussed.
Selective logging is the dominant timber harvesting practice in natural tropical forests. Considering its scale and its contribution to forest management outcome, efficient management of selective logging is crucial to address challenges associated with timber demand, carbon sequestration and biodiversity conservation. Ongoing selective logging has been a key reason for forest degradation despite a set of recommended practices such as reduced-impact logging. With the objective of drawing the attention of scholars and policy makers to answer the question why effectiveness of selective logging practice is still an issue, we tracked the trend and pattern of scholarly research related to the impact of selective logging. Using a systematic review of literature, we explored and discussed the possible factors hindering implementation of improved forest harvesting practices and the overall knowledge gaps yet not explored in this field of research. This review found consensus among scholars that implementation of improved forest harvesting is still rare despite the constant efforts made by researchers since the 1970s. Based on the review findings we concluded that concentration of research on specific countries, insufficient coverage of diversified forest dimensions/thematic areas, and higher concerns relating to ecological impacts of forest management are the reasons behind poor adoption of research outcomes of improved logging practices. Likewise, their implementation is further hindered by limited attention to the interests and needs of the forest managers/owners, lack of coordination and collaboration among stakeholders and negligible support to develop stakeholders’ capacity. Our review suggests a broadening of the geographical and thematic focus of the study as well as a consideration of effective engagement and capacity development of the forest managers/owners and stakeholders in selective logging policies and practices.
Is forest harvesting increasing in Europe? There is scientific debate about methodological approach and data regarding clearcut increment in Europe but, besides the discussion, there is a general ...agreement about the need to collect reliable scientifically robust remote sensing data for sound forest policy-making.
•From the seventh year after RIL onwards, recruitment rates were higher than mortality rates.•Harvested wood volumes up to 40 m3 ha−1 under RIL did not promote tree growth.•Highest growth rates in ...diameter were observed five years after RIL.•Tree growth increased proportionally to the tree diameter class.
Forest harvesting causes disturbances in the forest, affecting the dynamics of tree species. In this study, growth, mortality, and recruitment of trees ≥45 cm DBH were assessed in different forests logged along 13 years (2002–2015) in the Eastern Amazon. The data were collected in a control unlogged forest and in four 100-ha working units divided into 20 plots of 5 ha (total of 100 plots in 500 ha sampled) and inventoried at 100% one year before harvesting and again in 2015. A total of 49 species were analyzed in the study. The highest mortality rate occurred in the first five years after harvesting (5.6%), with a reduction from the seventh year (3.2% year−1), a period in which recruitment rate significantly increased for species from all ecological groups. Harvesting reduced both the number of individuals and species in the first five years after logging. Logged areas presented the highest growth rates five and seven years and only stabilized eleven years after logging. Within the range of 3–40 m3 ha−1 of logging intensity no differences were observed in growth rates of remaining trees ≥45 cm DBH. Pioneer, light-demanding, and shade-tolerant species presented higher growth rates in the first five years after logging. From seven years after harvesting, light-demanding presented a higher growth when compared to the shade-tolerant species. Larger diameter classes presented the highest relative growth rates (RGR). All diameter classes increased RGR up to 11 years after logging.
•Paired catchments show effects of forest harvest, regrowth, and conversion.•New nonstationary Bayesian method improves peak flow analysis.•Larger effect of harvesting on large, infrequently ...occurring peak flows.•Forest harvesting can change the season of the annual maximum flow.
Forest harvest, climate change, and their interaction can alter catchment peak discharges, which have ramifications for channel geomorphology and water quality. Catchments in the boreal-temperate transition zone may be especially vulnerable to these factors. We developed a new approach to peak flow analysis using two long-term, paired catchment experiments in that landscape at the Marcell Experimental Forest (MEF) in north-central Minnesota. We investigated how forest cover change affects the magnitude, occurrence probability, event decoupling, and seasonal decoupling of annual maximum peak flows. Event decoupling is when the annual maximum flows on control and treatment catchments occur in response to different events within a given year. Seasonal decoupling is when the annual maximum flows on control and treatment catchments occur in different seasons within a given year. Commonly used statistical methods (e.g., ANCOVA) support inferences only for effects on peak flow magnitude, disregarding effects on event occurrence probability. Statistical stationarity (i.e., time-invariant parameters) is generally assumed within the ANCOVA analysis, despite temporal changes in climatic and land cover controls. Further, use of these methods requires event coupling, which is not always valid for annual maximum flows in catchments with mixed precipitation regimes. To address these limitations, we developed new nonstationary flood-frequency analysis methods with Bayesian parameter estimation to analyze two harvesting experiments, including conversion from deciduous to coniferous species. We compared results from these models to traditional least-squares based methods (e.g., ANCOVA). We assessed event and seasonal decoupling using logistic regression with Bayesian parameter estimation. There was no effect of harvesting on the annual maximum flow according to ANCOVA and generalized least squares models, but these methods were not reliable due to the presence of outliers, and both event and seasonal decoupling. Flood-frequency results from one clearcutting experiment showed increases in the annual maximum flow across nearly all return intervals, with 80–85% confidence for peak discharges between the 10 and 50-year peak flow. The 50-year return interval peak increased from an expected 17 cfs to 34 cfs after harvest. Harvesting induced substantial event decoupling in the catchment pairs, and seasonal decoupling in one catchment pair. As forest cover regenerated, decoupling probability decreased. Our coupling analysis results indicated that control and treatment catchments generated and processed flood peaks differently after harvest, and explained the poor fit of the linear models for which we assumed event coupling. Our study calls into question several key assumptions of traditional linear models in the analysis of paired-catchments given certain conditions. For example, where forest harvesting can affect the season of annual maximum peaks, and thus the phase of the generating precipitation event (snowmelt versus rainfall), it changes the relationship between the catchment pair in a way not accounted for in traditional linear models. We advocate the use of probabilistic methods that can incorporate nonstationarity and are robust to different mechanisms of catchment hydrologic change in response to forest harvest.
PDF
