Sustainable Timber Production Research Articles

A comprehensive analysis of time investment in skid trail planning for forest access.

Properly planned skid trails form an important basis for sustainable timber production. They affect cost-effectiveness and the environmental impact of the harvesting process to a large extent. Here, we conducted an economic analysis to understand the skid trail planning process and to generate an initial model to estimate the time and costs involved. We investigated in detail how the planning process of skid trails is carried out in practice, what time is required for the planning work, and what factors influence its performance. Through an online survey conducted in 2022, we asked practitioners in Germany and Switzerland about their time and effort required for the planning process and the determining factors, such as the planning method and the terrain and stand conditions. Based on this survey, we calculated statistical indicators of time consumption, considered possible rationalization options, and developed an initial estimation model. The effort required to identify and evaluate skid trails planned for distances of 20 to 40 m amounts to around 3 to 4 hours of productive working time per hectare, with deviations expected depending on the specific situation in the forest. The costs corresponding to this investment amount to less than one euro per cubic meter of harvested timber, depending primarily on the extent of wood use. Our in-depth insight into the planning process enables its economic evaluation and the development of improvements.

Land sharing, land sparing, and Triad forestry: modeling forest composition, diversity, and carbon storage under climate change and natural disturbances

ContextForests are vital renewable resources for timber, while also serving as carbon reservoirs and habitats for many terrestrial species. However, there are tradeoffs between timber production and other ecosystem services, such as carbon storage and biodiversity, highlighting the need for new management strategies that more effectively balance these tradeoffs. This case study models the effectiveness of four such strategies, based on a newly proposed management plan for a state forest in coastal Oregon.ObjectivesWe tested the effectiveness of four landscape-scale forest management strategies designed to minimize tradeoffs between timber production, carbon storage, and biodiversity. These strategies include land sparing (spatially separating timber production from conservation), land sharing (integrating timber production with conservation), and two variants of Triad management (dividing forests into intensive, extensive, and reserve areas). This study assesses the long-term impacts of these strategies on timber production, tree and shrub diversity, and carbon storage, while also evaluating how natural disturbances (i.e. wind and fire) and climate change could affect their relative benefits.MethodsWe used the spatially interactive, raster-based forest landscape model, LANDIS-II, to simulate forest succession, management, windthrow, and wildfire under a range of potential climate futures from 2016 until 2100.ResultsOur results demonstrate that while all management strategies ensured sustainable timber production, land sharing promoted the highest occupancy, Shannon diversity index, and biomass of key early and mid-successional tree and shrub species identified by managers for their conservation value. In contrast, Triad management and land sparing tended to maximize carbon storage. Under extreme climate projections, carbon storage was equally compromised across all management strategies and there was a further shift towards Douglas-fir dominance.ConclusionTo our knowledge, this study represents the first modelled comparison of land sharing, land sparing, and Triad management under climate change and natural disturbance regimes. Management strategies differed in their provisioning of carbon, diversity, and plant biomass, and while the relative differences between these benefits remained consistent, all outcomes were negatively affected by climate change. We demonstrate the use of LANDIS-II in strategic forest planning and highlight the necessity of using spatial models for informed decision-making to simultaneously achieve multiple forest management objectives under climate change and disturbances.

Timber resources and management characteristics of economic forestry management areas and other forests in South Korea: post-reforestation challenges

ABSTRACT Over the past 50 years South Korea has made considerable strides in economic development and reforestation by converting barren land into dense forests. Despite these achievements, the forestry sector still faces significant challenges in economic viability and resource utilization. Economic Forestry Management Areas (EFMAs) were established to enhance sustainable timber production and address these challenges. This study evaluates the effectiveness of EFMAs in comparison to other forest areas, focusing on timber resources and management characteristics. The findings reveal that, although EFMAs show a higher intensity of management operations than other forest areas, improvements in timber quality and productivity remain limited. This highlights an important insight: despite increased management efforts, substantial progress in enhancing the quality and quantity of timber resources has not yet been achieved. This outcome may be attributed to the relatively short time since EFMAs were first established, which has not allowed sufficient time for significant developments in timber resource enhancement. To address these challenges, this study recommends increasing the proportion of economically valuable coniferous species and expanding artificial forest coverage through well-coordinated reforestation and management efforts. Additionally, developing precise, location-specific management data is crucial to avoid overlapping activities and to enhance the efficiency of forest management. These strategic improvements will not only boost the productivity of EFMAs but also support sustainable forestry practices, facilitating South Korea’s transition into the post-reforestation era.

Diameter distribution of Carapa guianensis Aubl. in a managed forest in the Amazon guarantees its continuous production and conservation in the ecosystem

The growth of a population of Carapa guianensis Aubl. was evaluated, based on predictions made in Markov chain on the diametric distribution of the number of trees, after reduced impact logging and application of silvicultural treatments in an Amazonian forest. Monitoring was carried out in 60 permanent plots measuring 50 m x 50 m, in which all trees with DBH ≥ 5 cm were measured. Four treatments and a control area were established (T0 - unlogged area - control; T1 - logged area; T2 - logged area + thinning up to 20.8% of basal area; T3 - logged area + thinning up to 27.6% of basal area basal; T4 - logged area + thinning up to 53.2% of basal area). A Markov transition matrix was constructed to make predictions for the years 1995 and 2011, using the periods 1983-1989 and 1995-2003 as a basis. The efficiency of the method was analyzed using the Kolmogorov-Smirnov test, at a significance level of 5%. The predicted values for the years 1995 and 2011 were statistically similar. The Markov chain was accurate for the first prediction (1995), but it was different for the second (2011). The models generated allow us to estimate values close to those observed in the field. Carapa guianensis can be included in management projects for sustainable timber production, considering that even after logging and thinning operations its population remains abundant and well distributed across diameter classes.

Heterogeneous conservation corridors of remnant vegetation protect biodiversity in South African timber mosaics

AbstractIt is urgent now to place greater emphasis on harmonising conservation of indigenous biodiversity with food and fibre production. This is especially important in countries like South Africa which support high levels of irreplaceable biodiversity. The local timber industry has responded to this challenge by retaining large-scale networks of conservation corridors of historic ecosystems in the forestry landscape. The corridors consist mostly of grassland, with patches of indigenous forest, thickets, wetlands, ponds, and rivers. The motivation is to future proof compositional and functional biodiversity for ecological resilience in these production environments in a rapidly changing world. We synthesise here the substantial evidentiary research on the effectiveness of conservation corridors in plantation forestry-dominated landscapes in the Maputaland-Pondoland-Albany biodiversity hotspot. We focus on six emergent themes: 1. corridor dimensions, orientation, and connectivity, 2. heterogeneity at different spatial scales, 3. maintaining aquatic and terrestrial habitat quality in the conservation corridors, 4. biodiversity value of conservation corridors relative to protected areas, 5. the plantation matrix, and 6. assessment of corridor network performance. Results show the importance of prioritising large, high quality conservation corridors, especially those with a high number of natural features and variety of environmental conditions, both terrestrial and aquatic. Alien clearing, grazing control, and appropriate fire regimes should be prioritised in these corridors. Where possible we need to retain, restore, or replicate the natural ecological regimes. Overall, this conservation approach in commercial forestry landscapes helps to conserve indigenous biodiversity and ecosystem integrity, improves connectivity across afforested landscapes while also having sustainable timber production, thereby safeguarding the resilience of these working landscapes well into the future.

Sustainable timber production in afforestations: Trade-offs and synergies in the provision of multiple ecosystem services in northwest Patagonia

Evaluating ecosystem services (ES) in pine plantations involves a comprehensive analysis of the diverse benefits and drawbacks that these managed ecosystems offer. Such assessments typically consider particularly provisioning, regulating, and supporting services, yet they often overlook important concerns such as biodiversity loss, soil carbon balance, and land-use conflicts. Understanding these dynamics in plantations with different density, age and structure is crucial for sustainable forest management. Our objective was to analyze changes in ES trade-offs and synergies by indirectly quantifying several ES in Pinus ponderosa plantations in a xeric grassland environment in northern Patagonia, Argentina. We assessed changes in soil fertility maintenance, erosion prevention, forage production, firewood production, and timber production across plantation stands under a diverse range of silvicultural managements and the surrounding natural habitat. We found a clear trade-off between indicators of provision services, as increasing timber production diminishes forage and firewood production —two vital land uses in the northern region of Andean Patagonia. Interestingly, we did not observe such trade-offs in supporting services or regulating services, as indicators of soil fertility maintenance and erosion prevention remained stable, without significant declines; higher values were found in intermediate plantation densities and basal area conditions. This suggests that their spatial occurrence does not negatively impact soil nutrient dynamics or the potential for erosion prevention. Conversely, low-density, young, and thinned plantations facilitate coexistence with other land uses such as forage and firewood. Therefore, a strategically planned landscape, incorporating plantations of varying ages and management practices, offers the potential for maximizing all three provision services.

An appropriate combination of a thinning schedule and subsidies to realize sustainable Makino bamboo forest management

ABSTRACT This study addresses the relationship between subsidies and thinning operations in Makino bamboo forests, with implications for sustainable timber production management. Focusing on indigenous lands in Taoyuan, North Taiwan, where 85% of bamboo is cultivated, with a 70% coverage constraint, and the government provides an annual subsidy of NT$30,000 per hectare. Three scenarios, minimizing subsidies, thinning rates, and maximizing profits, are analyzed using linear and multi-choice goal program techniques. Results indicate that a company with 5 laborers can clear-cut 15,000 culms/ha in 22 days, yielding a profit of NT$101,150. Without subsidies, a minimum 34% thinning rate ensures financial viability. Sensitivity analysis reveals that NT$29,345 in subsidies with a 70% thinning rate matches clear-cutting profits, validating the effectiveness of the existing NT$30,000 compensation policy. Recommendations propose a two-phase thinning program for sustainable Makino bamboo forest management. The first phase involves a 70–75% thinning rate in the first year, leaving one-year-old bamboo. The second phase, starting from the fourth year, harvests 3 and 4-year-old bamboo every two years, covering 50% of the bamboo forest. This phased approach, covering 24 hectares, establishes a win-win situation for the Forest Bureau and bamboo forest managers.

Phloem Sap and Wood Carbon Isotope Abundance (δ13C) Varies with Growth and Wood Density of Eucalyptus globulus under Nutrient Deficit and Inform Supplemental Nutrient Application

Eucalyptus globulus, commonly known as blue gum or southern blue gum, is a tall, evergreen tree endemic to southeastern Australia. E. globulus is grown extensively in plantations to improve the sustainability of timber and fibre production across Australia. Sustainable forest management practices necessitate the consideration of ‘off-site’ carbon and ecological footprints. Pursuing optimal supplemental nutrient application and maximum growth rates is therefore critical to the establishment of a sustainable timber and fibre production industry. Biological indicators that can predict growth responses are therefore of extreme value. We investigated the carbon isotope abundance of wood cellulose (δ13Ccel) in E. globulus to determine potential relationships with the carbon isotope abundance of phloem sap (δ13Cphl) where the trees were subjected to different level of nutrient availability. This study also sought to determine the effect of nutrient additions on the growth of the E. globulus and to quantify the relationship between the volumetric growth of wood and δ13Ccel. Phloem sap and wood cores were collected from trees within study plots which were subjected to seven nutrient treatments over a two-year period in a monoculture E. globulus plantation in South Australia. Phloem sap was collected using the razor blade technique and wood cores were collected using a stem borer. The carbon isotope abundance (δ13C) of phloem sap and wood grown in the radial direction of the stem were determined. The basic and dry densities of wood were determined, and their relationships with phloem and wood δ13C were established. The δ13Cphl was significantly correlated with δ13Ccel. The relationship between δ13Ccel and the wood density of the respective wood sections was significant but did not consistently show the same pattern. There was no significant variation in basic density observed along the radial direction of the stem wood of the short-rotation E. globulus trees. A positive correlation was observed between δ13Ccel and the wood basic density, but the relationship was not consistent along the radial direction of the stem. However, positive correlations were observed between δ13Ccel and the air-dry density of respective wood sections. The relationship between phloem and wood δ13C and the relationship between δ13C and wood density along the radial direction of the stem needs to be considered while monitoring forest growth under nutrient- and water-limited conditions.

Evaluation of carbon emission reduction effect of Cryptomeria japonica stand management in Yamagata Prefecture, Japan

Planted forests are in the utilisation phase in Japan, contributing to the increased use of timber and the realisation of carbon neutrality. We simulated and compared the carbon emission reduction effects of three forest management scenarios, including a no final cutting scenario at two geographical scales, in the context of a privately owned Cryptomeria japonica planted forest in Tsuruoka City, Yamagata Prefecture, Japan. We adopted two substitution approaches: the status quo approach and the dynamic approach in line with Japan’s nationally determined contribution. We used hypothetical stands over three rotation periods of 150 years at the stand level, and a harvest schedule of 120 years at the regional level. The harvesting scenarios based on the status quo substitution approach reduced carbon emissions more than the no final cutting scenario for current wood usage at the study site, although those based on the dynamic substitution approach reduced carbon emissions as much as the no final cutting scenario during the first 30 years. Sustainable timber production from forests may reduce carbon emissions as much as unharvested forests until 2050, indicating that the substitution effects of harvested wood products could have a significant impact on the climate change mitigation effect arising from timber.

Integration of Unmanned Aerial Vehicle Imagery and Machine Learning Technology to Map the Distribution of Conifer and Broadleaf Canopy Cover in Uneven-Aged Mixed Forests

Uneven-aged mixed forests have been recognized as important contributors to biodiversity conservation, ecological stability, carbon sequestration, the provisioning of ecosystem services, and sustainable timber production. Recently, numerous studies have demonstrated the applicability of integrating remote sensing datasets with machine learning for forest management purposes, such as forest type classification and the identification of individual trees. However, studies focusing on the integration of unmanned aerial vehicle (UAV) datasets with machine learning for mapping of tree species groups in uneven-aged mixed forests remain limited. Thus, this study explored the feasibility of integrating UAV imagery with semantic segmentation-based machine learning classification algorithms to describe conifer and broadleaf species canopies in uneven-aged mixed forests. The study was conducted in two sub-compartments of the University of Tokyo Hokkaido Forest in northern Japan. We analyzed UAV images using the semantic-segmentation based U-Net and random forest (RF) classification models. The results indicate that the integration of UAV imagery with the U-Net model generated reliable conifer and broadleaf canopy cover classification maps in both sub-compartments, while the RF model often failed to distinguish conifer crowns. Moreover, our findings demonstrate the potential of this method to detect dominant tree species groups in uneven-aged mixed forests.

Comparison of different spectral indices to differentiate the impact of insect attack on planted forest stands

Eucalyptus plantations are an important contributor to the South African economy and are geographically concentrated in the productive Zululand region. However, this area is becoming increasingly vulnerable to various forest disturbances such as insect attacks and drought. Information of the location, extent and duration of insect infestation is therefore crucial for sustainable timber production and forest management planning, and remote sensing approaches have been successful in the retrieval and analysis of such information along with field surveys. Sappi Forests frequently conduct field surveys to establish the nature of disturbances to improve the performance of trees, as these may be difficult to distinguish from other disturbances such as droughts. Great effort has been made to remotely detect the impact of G. scutellatus using single-date high-resolution commercial satellites, whose application is restricted by high costs. Here, we compare the performance of spectral indices for detecting the impact of G. scutellatus infestation in KwaMbonambi plantations using publicly available Landsat data and also apply anomaly detection framework to further test their performance for detecting the impact of insect damage on trees and other disturbances that occurred on the same compartment over time. Our results showed high performance of short-wave infrared (SWIR) band for detecting the impact of insect damage, followed by the normalized difference infrared index (NDII) and normalized difference vegetation index NDVI, when anomaly detection was applied. Without anomaly detection, the spectral indicators showed changes even to drought impact in 2015, which did not when anomaly detection was used. We believe that indices containing the SWIR would perform better for detecting anomalous changes, and further research is required to explore this. Anomaly detection only showed the impact of insect damage and clearcutting as anomalous changes. Overall, we demonstrated the benefit of identifying vegetation anomalies caused by the impact of insect damage and other disturbances using freely available Landsat time-series data, particularly in data-poor regions that have restricted computational resources.

Sustainable Development in Europe: A Review of the Forestry Sector's Social, Environmental, and Economic Dynamics

Despite their resilience, forest ecosystems become increasingly impacted by extreme climatic events, fires, and pathogen outbursts, which have considerable economic repercussions. How forest management solves these difficulties will affect human health, environmental variety, productivity, and forest ecosystem recuperation from exogenic distresses. Assuming forests provide ecosystem services essential to society and humanity along with wood, a better understanding of forest ecosystems seems essential to defining a development policy that meets ecological safeguard and energy and climate goals. According to the UN 2030 Agenda's Sustainable Development Goals, European forest management practices still don't provide a clear picture of ecological conditions, monetary estimate, and biodiversity. In light of the existing research, this article reviews and discusses recent European forestry industry trends and the environmental-economic nexus' complexity. Wood use has social consequences for regions adapting to ecological change, from rising temperatures to landscape modifications. This paper confirms that the technical-economic dimensions of forestry affect short-term economic dynamics, sector growth prospects, supply chain organization, company interconnections, and investment strategies. Forestry practices conserve species and habitats while boosting sustainable timber production. The European Commission's policy direction is to gradually encourage public and private entities to embark on worthy circular economy pathways, which will result in more jobs, material recycling, minimized carbon emissions, and community-added value. Forestry should contribute more holistically to sustainable development at diverse spatial dimensions. This includes focusing on environmental and economic aims in light of the recognition of relevant features that may guide forthcoming research and policy action while enhancing cooperation among member nations and local experts.

The great mistake of plantation programs in cocoa agroforests – Let's bet on natural regeneration to sustainably provide timber wood

Cocoa production has been one of the main drivers of forest loss in West Africa. In the resulting post-forest landscapes, agroforestry has often been recognised as a solution to reconcile the preservation of trees and agriculture. Thus, a large number of tree plantation programs have been carried out in cocoa fields. Despite these major investments, the success of these plantations as a tool for "reforestation" of landscapes and sustainable timber production has never really been evaluated in fields where remnant trees, spontaneous trees and (trans)planted trees coexist. To quantify the current and future timber resource, we inventoried all trees in 150 cocoa fields distributed along the bioclimatic and historical gradients of the cocoa production area of Côte d'Ivoire, the world's leading producer. Our results show that (i) 19.6% of all associated trees are timber species, (ii) in plots where farmers actually introduced trees by planting, only 13.1% of trees have been (trans)planted, (iii) 69.7% of the current timber volume comes from remnant trees and (iv) spontaneous trees constitute 77% of the future timber resource. Based on our results, we propose 23 species along with their cultivation methods for the renewal of timber resource in cocoa fields. Overall, our results show the failure of plantation programs in cocoa fields and suggest to bet on natural regeneration to sustainably provide timber wood. Consequently, private companies supplying trees to farmers should focus on species that are complementary to those already present in natural regeneration. At the landscape level, remnant trees and residual forests should be preserved to maintain propagule sources. Finally, investments in reforestation of cocoa fields should be redirected towards training small farmers in silvicultural management techniques such as assisted natural regeneration and tree pruning.

Artificial intelligence as an alternative modelling strategy for reliable height-diameter predictions of mixed-oaks species

Forest management and sustainable timber production rely on forest measurements that include tree height. However, the fieldwork needed for tree height measurements is time-consuming, and several times, hard to obtain. The solution to this problem is the construction of reliable height-diameter (h-d) models that can provide accurate tree height predictions. To this direction, a modified Gompertz model that included dominant height and diameter at breast height was used to predict tree height. In order to investigate the most promising modelling method, six alternative approaches were evaluated; these involved both regression and artificial intelligence techniques and produced the (i) fixed-effects (FE), (ii) mixed-effects (ME), (iii) three-quantile regression (3QR), (iv) five-quantile regression (5QR), (v) general regression neural network (GRNN), and (vi) support vector regression (SVR) models. The accuracy of the developed h-d models was studied in this work for mixed-oak stands (Quercus cerris L., Quercus petraea (Matt.) Liebl. and Quercus frainetto Ten.) in Türkiye. For this purpose, 1735 trees were measured in 52 sample plots in total. The tree variability among sampling plots was incorporated in the constructed models through the dominant heights and the tree height variance in each sample plot, while the models were localized using one to five oak trees, as calibration samples, per plot. The study showed that the ME constructed model with root mean square value equal to 1.8331 was constantly superior to nonlinear regression methods used, while the GRNN and the SVR models with root mean square values equal to 1.8330 and 1.8279, respectively, showed similar predictive ability with the later to prevail, as compared to the rest of the models tested. Finally, five trees per plot were found to be an acceptable trade-off between sampling cost and predictive capacity and reliability.

Financial Revenues from Timber Harvesting in Secondary Cloud Forests: A Case Study from Mexico

Secondary forests, i.e., those arising after the clearance and abandonment of previously forested land, dominate tropical forest landscapes, rapidly sequester carbon, provide essential ecosystem services and are prone to re-clearance. Secondary cloud forests (SCF) play a particularly critical role for biodiversity and hydrological regulation. To promote their persistence, sustainable management is necessary; however, there is limited information regarding SCF potential for sustainable timber production. We estimated the revenue from selective timber harvesting in a pilot study in a 20-year-old SCF in Mexico. We explored the effect of the harvested timber volume, harvesting costs and price of forest products on the Net Present Value (NPV). Small landowners could only extract 17% of the harvestable standing volume due to a high number of small trees, a high (34%) volume of non-timber species, and their limited capacity to process timber. A third of the income derived from fuelwood, and overall financial returns were negative. A positive NPV may result from a 20% harvesting intensity, a 10% reduction in harvesting costs, or a 20% increase in stumpage price. Our results warrant the development of forest policy instruments and economic incentives for small-scale SCF landowners to alleviate poverty and meet national and global restoration and climate mitigation goals.

Above-ground biomass storage potential in primary rain forests managed for timber production in Costa Rica

Tropical forests play a fundamental role in mitigating climate change through storage of carbon in above- and below- ground biomass. Their mitigation potential is, however, affected by significant greenhouse gas emissions through tropical deforestation or forest degradation. Mitigating degradation caused by conventional logging is therefore an important challenge for silvicultural management, and various reduced impact logging techniques seek to reduce biomass loss and other logging impacts during forest logging activities.Little knowledge exists about the potential of sustainable management for maintaining and restoring the climate change mitigation capacity of tropical forests. Our research contributes to knowledge about this potential, as our aim is to evaluate the above-ground biomass (AGB) stock of tropical forests managed for sustainable timber production and compare it with that of intact primary forests. We also determine the environmental and spatial factors that influence AGB.We estimated the AGB of 141 permanent sampling plots in Costa Rican tropical forests (71 plots set up in areas managed for timber production forests and 70 plots set up in areas with intact primary forests) using data for the 2000–2015 period. We compared the AGB of timber production forests with that of primary forest using linear mixed models and examined the relationship between forest AGB and climate, soil fertility and spatial variables (PCNM eigenvalues) using variation partitioning (VARPART) and multiple linear regression in the mixed model framework.Mean AGB was higher in forest plots set up in areas managed for timber production than in plots set up in areas with intact primary forests. In VARPART, spatial variables had the strongest effect on AGB with a small but significant effect of soil fertility. Regression showed potassium levels in the soil to be positively related to AGB. There was no significant effect of climate, probably because of the short temperature and precipitation gradients.Sustainable forest management in these Costa Rican forests managed for timber production has enabled them to store as much carbon in biomass as primary forests, due to the low intensity logging and sustainability criteria stipulated by the country’s forestry legislation. As a result, sustainable forest management, in addition to providing a sustainable timber ecosystem service, is also a natural climate solution, maintaining the mitigation potential of Costa Rica’s tropical forests in the current climate context.

Sustainability of Brazilian forest concessions

In 2006, the Brazilian Forest Service (SFB) started an ambitious program to establish forest concessions so as to provide a legal framework for long-term sustainable timber production in Amazonian forests. Forest concessions in the Brazilian Amazon currently cover only 1.6 million ha (Mha) but we estimate the area of all potential concessions as 35 Mha. This paper assessed the conditions under which the present and potential concession system can ensure an annual production of 11 Mm3. yr−1 to meet the estimated present timber demand. For this we used the volume dynamics with differential equations model (VDDE) calibrated for the Amazon Basin with a Bayesian framework with data from 3500 ha of forest plots monitored for as long as 30 years after selective logging. Predictions of commercial volume recovery rates vary with location.We tested 27 different scenarios by using combinations of initial proportion of commercial volume, logging intensity and cutting cycle length. These scenarios were then applied to the current area of concessions and to the area of all potential concessions (35 Mha). Under current logging regulations and the current concession area (mean logging intensity of 15–20 m3.ha−1, a harvest cycle of 35 years and an initial commercial timber volume proportion of 20%), timber production can be maintained only for a single cutting cycle (35 years). Only the scenario with a logging intensity of 10 m3ha−1 every 60 years with a 90% initial proportion of commercial timber species can be considered as sustainable. Under this scenario, the maximum annual production with the present concession areas is 159,000 m3 (157–159), or less than 2% of the present annual production of 11 Mm3. When considering all potential concession areas (35 Mha), under current rules, the total annual production is 10 Mm3yr−1 (2–17 Mm3yr−1, 95% credibility interval) but is not maintained after the first logging cycle. Under the most sustainable scenario (see above) and a concession area of 35 Mha, the long-term sustainable annual production of timber reaches only 3.4 Mm3yr−1. Based on these results we argue that the concession system will not be able to supply the timber demand without substantial reforms in natural forest management practices and in the wood industry sector. We argue that alternative sources of timber, including plantations linked with forest restoration initiatives, must be promoted.

Optimizing Strip-cutting Patterns for Sustainable Timber Production Under Spatial Constraints in Okinawa, Japan

Optimizing Strip-cutting Patterns for Sustainable Timber Production Under Spatial Constraints in Okinawa, Japan

Soil Recovery Assessment after Timber Harvesting Based on the Sustainable Forest Operation (SFO) Perspective in Iranian Temperate Forests

Minimizing the impact of timber harvesting on forest stands and soils is one of the main goals of sustainable forest operation (SFO). Thus, it is necessary to make an accurate assessment of forest operations on soil that is based on the SFO perspective. The present study was conducted according to SFO principles to investigate the time required for the natural recovery of soil after disturbance by skidding operations in some Iranian forests. The physical, chemical, and biological properties of soil found in abandoned skid trails from different time periods were compared with undisturbed forest soils. The soil bulk density, the penetration resistance, and the microporosity of a 25-year-old skid trail were 8.4–27.4% and 50.4% greater, and the total porosity, macroporosity, and soil moisture were 1.9–17.1% and 4.6% lower than the undisturbed area. In a 25-year-old skid trail, the values of pH, Electrical conductivity (EC), C, N, available P, K, Ca, and Mg, earthworm density, and biomass were lower than in the undisturbed area, and the C/N ratio value was higher than in the undisturbed area. High traffic intensity and slope classes of 20–30% in a three-year-old skid trail had the greatest impact on soil properties. In order to have sustainable timber production, SFO should be developed and soil recovery time should be reduced through post-harvest management operation.

Estimating Potential Woody Biomass Supply under Sustainable Timber Production from Plantation Forests in a Snowy Mountainous Region of Japan

Numerous woody biomass-powered stations for energy generation have been constructed in Japan since the Feed-in Tariff Scheme was introduced. However, a stable, long-term woody biomass supply from plantation forests is necessary for the construction and operation of such power stations. The logs that are used to produce fuel chips are harvested from roundwood. Thus, the main objective of this study was to estimate the potential supply of woody biomass resources under the condition of maximum sustainable harvesting from privately-owned plantation forests. Another aim was to examine the stability of sustainable harvest volumes from periodical changes. The study focused on privately-owned forests in the Sampoku district of Murakami City in the northernmost part of Niigata Prefecture, Japan. Trees in the studied region are commonly bent during periods of high snowfall, and the current bucking strategy – influenced by the construction of a biomass-powered generation facility – was integrated into the model. The revenues and costs of plantation management and timber production were calculated based on stands’ geographical attributes using a geographic information system. A mixed integer programming model was used to predict the maximum sustainable harvest levels that would provide stable profits. The simulation showed that even though the trees had a unimodal age class distribution, sustainable harvest volumes ensured a sustainable supply of woody biomass over various rotation ages. Extending the range of rotation ages by 20 years dramatically increased the potential supply of woody biomass resources. Fluctuations in each woody biomass resources were mostly less than 20% over the planning horizon. The presented research could be useful to regional forest resource managers and stakeholders involved in biomass-powered energy generation or the purchasing of woody biomass.