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Forests in the Himalayas are a major carbon store, but are under threat due to changes in precipitation regime. To simulate a precipitation decline, throughfall-exclusion (TFE) shelters were applied during three consecutive monsoon seasons in an oak forest (2.650 m a.s.l.) and a conifer-dominated forest (3.260 m a.s.l.) in central Bhutan. Leaf water potentials, tree mortality, stem increment, soil CO2 efflux, litterfall and fine root dynamics were assessed. TFE significantly and consistently decreased topsoil (0–30 cm) moisture and leaf water potentials of Quercus lanata and Quercus griffithii (lower elevation), and to a lesser extend those of Tsuga dumosa and Quercus semecarpifolia, (higher elevation). TFE did not impose tree mortality. Stem increment remained unaffected until the second TFE year, but showed reductions during the third year with Tsuga dumosa being most severely affected (-60%). Standing fine root biomass stocks were hardly affected by TFE. Increased root necromass and faster fine root growth in the lower elevation forest suggest that the oak trees increased C allocation below ground. Soil CO2 efflux sharply declined during all three TFE years in both forests. Above ground litter input was unaffected by TFE until the second treatment year. Overall, both forest ecosystems appeared highly resistant to the imposed soil drying, with no signs of tree mortality and stable living root biomass stocks., Agricultural and Forest Meteorology, 336, ISSN:0168-1923, ISSN:1873-2240

We present the results of a study on the climate forcing effects of replacing coal for power generation in the United Kingdom (UK) with wood pellets produced in northern Ontario, Canada. Continuous wood pellet production from two biomass sources were considered: fiber from increased harvesting of standing live trees (stemwood scenario) and from harvest residue provided by ongoing harvesting operations (residue scenario). In both scenarios, biomass was collected from harvesting operations in two forest management units (FMUs) with contrasting harvest residue treatments: natural decay of slash piles in the Hearst FMU and slash pile burning in the Kenora FMU. Life cycle emissions associated with wood pellets were assessed for production, transportation, and combustion to replace coal at a hypothetical power generating station in the UK. Greenhouse gas (GHG) emissions and removals in wood pellet and coal scenarios were assessed using two methods: global warming potential (GWP)-based mass balance and dynamic life cycle assessment (LCA) approaches. In the stemwood scenario, climate change mitigation from replacing coal with wood pellets was not achieved within the study timeline (2020–2100). In the residue scenario, immediate climate change mitigation was achieved with fiber sourced from the Kenora FMU where the current practice is to burn slash piles; for the Hearst FMU, where slash is allowed to decompose in the forest, climate change mitigation occurred 11.6 and 3.1 years after biomass collection began, as assessed by the mass balance and dynamic LCA methods, respectively. Factors affecting mitigation potential in the studied scenarios are discussed.

Calculations of the carbon storage capacities of forests have become increasingly important all over the world. International institutions that make carbon notifications want the amount of carbon stored in forest ecosystems to be determined fully and precisely based on the inventory. In order to determine the carbon stock in forest areas of the whole country, it is necessary to determine locally the amount of biomass accumulated by each tree species in different habitats and the amount of carbon they have bound. In this study, above- and below-ground biomass equations were developed for young red pines belonging to pure red pine stands in Mersin-Kozağacı Forest Planning Unit. In the study, wood density ratio and needle dry weight ratio (LDMC) were also determined for red pine., Ormanların karbon depolama kapasitelerine ilişkin hesaplamalar tüm dünyada giderek daha önemli hale gelmiştir. Karbon bildirimlerinde uluslararası kurumlar, orman ekosistemlerinde depolanan karbon miktarlarının envantere dayalı olarak, tam ve kesin olarak belirlenmesini arzu etmektedir. Tüm ülkenin ormanlık alanlarındaki karbon stokunun belirlenmesi için, her ağaç türünün farklı habitatlarda biriktirdiği biyokütle miktarının ve bağladıkları karbon miktarının yöresel olarak belirlenmesi gerekmektedir. Bu çalışmada genç kızılçamlar yöresel olarak dikkate alınarak, Mersin Kozağacı Orman İşletme Şefliği içerisindeki saf kızılçam meşcerelerine ait toprak üstü ve toprak altı biyokütle denklemleri geliştirilmiştir. Çalışmada ayrıca kızılçam için odun yoğunluk oranı ve ibre kuru ağırlık oranı belirlenmiştir.

Cost-effective monitoring of forest carbon resources is critical to the development of national policies and enforcement of international agreements aimed at reducing carbon emissions and mitigating the impacts of climate change. While carbon monitoring systems are often based on national forest inventories (NFI) utilizing a large sample of field plots, in remote regions the lack of transportation infrastructure often requires heavier reliance on remote sensing technologies, such as airborne lidar. The challenge motivating our research is that the efficacy of estimating carbon with lidar varies across the various carbon pools within forest ecosystems. Lidar measurements are typically highly correlated with aboveground tree carbon but are less strongly correlated with other carbon pools, such as down woody materials (DWM) and soil. Field measurements are essential to both (1) estimate soil and DWM carbon directly and (2) develop regression models to estimate tree carbon indirectly using lidar. With limited budgets and time, however, decision makers must find an optimal way to combine field measurements with lidar to minimize standard errors in carbon estimates for the various pools. We introduce a multi-objective binary programming formulation that quantifies the tradeoffs behind the competing objectives of minimizing standard errors for tree carbon, DWM carbon, and soil carbon. Using NFI and airborne lidar data from a remote boreal forest region of interior Alaska, we demonstrate the operational feasibility of the method and suggest that it is generalizable to other carbon sampling projects because of its generic mathematical structure.

Fossil-based emissions can be avoided by using wood in place of non-renewable raw materials as energy and materials. However, wood harvest influences forest carbon stocks. Increased harvest may reduce the overall climate benefit of wood use significantly, but is widely overlooked. We reviewed selected simulation studies and compared differences in forest carbon and amount of wood harvested between harvest scenarios of different intensities for three different time perspectives: short- (1–30 years), mid- (31–70 years), and long-term (71–100 years). Out of more than 450 reviewed studies 45 provided adequate data. Our results show that increased harvest reduces carbon stocks over 100 years in temperate and boreal forests by about 1.6 (stdev 0.9) tC per tC harvested (referred to as carbon balance indicator (CBI)). CBI proved to be robust when outliers explicitly influenced by factors other than changes in the harvest rate, such as fertilization or increase in forest area, were removed. The carbon impacts tend to be greatest in the mid-term, but no significant difference in was found for average values between short and long time-horizons. CBI can be interpreted as carbon opportunity costs of wood harvest in forests. Our results indicate that even after 100 years, CBI is significant compared to the typical GHG credits expected in the technosphere by avoiding fossil emissions in substitution and increasing carbon stocks in harvested wood products. Our estimates provide typical values that can directly be included in GHG balances of products or assessments of mitigation policies and measures related to wood use. However, more systematic scenarios with transparent information on influencing factors for forest carbon stocks are required to provide better constrained estimates for specific forest types.

Carbon sequestration and storage are important areas of scientific research. Despite this importance, the current approach to carbon mass estimates consists primarily of estimating wood volume, multiplying that volume by a species average wood density value to obtain biomass, then multiplying biomass by 0.5. Alternatively biomass may be estimated from allometric equations and then converted to carbon with the same 0.5 carbon conversion value. This approach is fundamentally inaccurate. This dissertation presents three improvements in carbon mass estimation that are critical to moving the science forward. In the first chapter I explore the importance of utilizing carbon fraction measurement methods that are capable of capturing the volatile component of tree tissues. I demonstrate a novel method that captures an additional 1.10% - 2.21% carbon mass in tree tissues. This increase is equivalent to “finding” an additional 16 Pg of carbon at a global scale. In the second chapter I explore the variation in measured carbon fractions, wood densities, and carbon densities within tree boles of seven major conifer species. I determine the importance of accounting for this variation, and discover negative correlations between wood density and carbon fractions within trees suggesting that the current approach of studying these characteristics as two independent properties is potentially biased. Applying the carbon fraction measurements at the whole tree level led to increases in carbon mass estimates of between 3.6% to 10.6% compared to carbon mass estimates that used a carbon fraction of 0.5. These values point to a systematic bias in current carbon mass estimation protocols. In the third chapter I develop carbon mass prediction models for five conifer species that capture some of the variation determined in chapter two. The models developed are the first vertically integrable conifer tree models to be based on accurately measured carbon fraction data paired with wood density measurements. The models are validated with an independent database and applied to the whole tree level demonstrate that accounting correctly for carbon leads to carbon mass estimates that are between 98.4% and 109% of the carbon mass estimated using standard approaches. The data presented makes a strong argument for the need of models that accurately account for variation in and correlation of carbon fraction, and wood density.

The forest sector can help reduce atmospheric CO2 through carbon (C) sequestration and storage and wood substitution of more polluting materials. However, climate change can have an impact on the C fluxes we are trying to leverage through forestry. We calculated the difference in CO2 eq. fluxes between ecosystem-based forest management and total forest conservation in the context of the temperate-boreal forest ecotone of Quebec (Canada), taking into account fluxes from forest ecosystems, wood product life cycle, and the substitution effect of wood products on markets. Over the 2020–2120 period, in the absence of climate change, ecosystem-based forest management and wood production caused average net annual emissions of 66.9 kilotonnes (kt) of CO2 eq. year−1 (relative to forest conservation), and 15.4 kt of CO2 eq. year−1 when assuming a 100% substitution effect of wood products. While management increased the ecosystem C sink, emissions from degradation of largely short-lived wood products caused the system to be a net source. Moreover, climate warming would decrease the capacity of ecosystems to sequester C and cause a shift towards more hardwood species. Our study highlights the need to adapt the industrial network towards an increased capacity of processing hardwoods into long-lived products and/or products with high substitution potential.

The unchecked and unplanned expansion of urban areas has led to the conversion of millions of green areas to gray areas. The recent urban growth patterns of Pakistan’s metropolitan twin cities, Islamabad and Rawalpindi, is a matter of concern for the surrounding green areas. The present study aimed to categorize and quantify the land-use and land-cover change (LULCC) patterns and the corresponding impacts on the forest carbon dynamics around Islamabad and Rawalpindi. Multispectral satellite images for the year 1990 (Landsat 5 TM) and 2020 (Landsat 8 OLI) were used to determine, quantify, and compare the LULCC inside and around the twin metropolitan cities. Field inventory surveys in the reserved forests of Rawalpindi and Islamabad were also conducted to determine the amount of stored carbon in these forests. Our results showed an accelerated annual urban expansion (i.e., an increase in the built-up area) of 16.49% and 26.72% in Rawalpindi and Islamabad, respectively, during the study period. Similarly, the amount of barren land and agricultural land was reduced at an annual rate of 2.08% and 2.18%, respectively, in Rawalpindi and 0.25% and 1.04% in Islamabad. A reduction in the area of barren mountains also occurred at an annual of 2.26% in Islamabad, while it increased by 4.16% in Rawalpindi. The amount of carbon stored in the reserved forests of Islamabad stood at 139.17 ± 12.15 Mg C/ha while that of Rawalpindi was 110.4 ± 13.79 Mg C/ha. In addition, total stored forest carbon was found to have decreased from 544.70 Gg C to 218.05 Gg C in Rawalpindi, while in Islamabad it increased from 2779.64 Gg C to 3548.16 Gg C. Investment in ecological urban planning, sustainable cities, and appropriate land-use planning is recommended to curb the degradation and conversion of the surrounding green areas of Rawalpindi and Islamabad.

Effective initiatives for forest-based mitigation of climate change rely on continuous efforts to improve the estimation of forest biomass. Allometric biomass models, which are nonlinear models that predict aboveground biomass (AGB) as a function of diameter at breast height (D) and tree height (H), are typically used in forest biomass estimations. A combined variable D2H may be used instead of two separate predictors. The Q-ratio (i.e., the ratio between the parameter estimates of D and parameter estimates of H, in a separate variable model) was proposed recently as a measure to guide the decision on whether D and H can be safely combined into D2H, being shown that the two model forms are similar when Q = 2.0. Here, using five European beech (Fagus sylvatica L.) biomass datasets (of different Q-ratios ranging from 1.50 to 5.05) and an inventory dataset for the same species, we investigated the effects of combining the variables in allometric models on biomass estimation over large forest areas. The results showed that using a combined variable model instead of a separate variable model to predict biomass of European beech trees resulted in overestimation of mean AGB per hectare for Q &gt, 2.0 (i.e., by 6.3% for Q = 5.05), underestimation for Q &lt, 2.0 (i.e., by –3.9% for Q = 1.50), whereas for Q = 2.03, the differences were minimum (0.1%). The standard errors of mean AGB per hectare were similar for Q = 2.03 (differences up to 0.2%), and the differences increased with the Q-ratio, by up 10.2% for Q = 5.05. Therefore, we demonstrated for European beech that combining the variables in allometric biomass models when Q ≠ 2.0 resulted in biased estimates of mean AGB per hectare and of uncertainty.

BackgroundIn recent decades the future of global forests has been a matter of increasing concern, particularly in relation to the threat of forest ecosystem responses under potential climate change. To the future predictions of these responses, the current forest biomass carbon storage (FCS) should first be clarified as much as possible, especially at national scales. However, few studies have introduced how to verify an FCS estimate by delimiting the reasonable ranges. This paper addresses an estimation of national FCS and its verification using two-step process to narrow the uncertainty. Our study focuses on a methodology for reducing the uncertainty resulted by converting from growing stock volume to above- and below-ground biomass (AB biomass), so as to eliminate the significant bias in national scale estimations.MethodsWe recommend splitting the estimation into two parts, one part for stem and the other part for AB biomass to preclude possible significant bias. Our method estimates the stem biomass from volume and wood density (WD), and converts the AB biomass from stem biomass by using allometric relationships.ResultsBased on the presented two-step process, the estimation of China’s FCS is performed as an example to explicate how to infer the ranges of national FCS. The experimental results demonstrate a national FCS estimation within the reasonable ranges (relative errors: + 4.46% and − 4.44%), e.g., 5.6–6.1 PgC for China’s forest ecosystem at the beginning of the 2010s. These ranges are less than 0.52 PgC for confirming each FCS estimate of different periods during the last 40 years. In addition, our results suggest the upper-limits by specifying a highly impractical value of WD (0.7 t∙m− 3) on the national scale. As a control reference, this value decides what estimate is impossible to achieve for the FCS estimates.ConclusionsPresented methodological analysis highlights the possibility to determine a range that the true value could be located in. The two-step process will help to verify national FCS and also to reduce uncertainty in related studies. While the true value of national FCS is immeasurable, our work should motivate future studies that explore new estimations to approach the true value by narrowing the uncertainty in FCS estimations on national and global scales.

Forests and wood products, through the mechanisms of carbon sequestration and storage, can slow the rate of global climate change that results from greenhouse gas emissions. In recent years, both natural resource managers and the public have placed greater focus on the role of forests and wood products as a solution to help mitigate the effects of climate change. Little is known about the perceptions and viability of carbon sequestration and storage as a management goal for natural resource managers of public agencies. We explored these perceptions in Minnesota, USA. Minnesota has 7.2 million hectares of forest land managed by a diverse array of landowners, from public agencies (55% of forest land) to private (45%) owners. We sought to (1) understand natural resource managers’ and forest owners’ perspectives on forest carbon opportunities and (2) understand the feasibility of management strategies that could be implemented to increase forest carbon sequestration and storage at a state level. We conducted two focus groups with 15 mid- and upper-level natural resource managers and non-industrial private forest landowners, representing both rural and urban perspectives and a variety of agencies and organizations. Minnesota natural resource managers and non-industrial private forest landowners indicated that they thought managing forests for carbon was compatible with other management goals but nonetheless represented a trade-off. However, they viewed the carbon credit market as the “Wild West” and noted several barriers to entering the carbon market, such as inconsistent carbon accounting protocols and a lack of connection between the price of carbon credits and the cost of managing forest land for carbon sequestration and storage.

West African Sudanian savanna ecosystems greatly contribute to local peoples’ livelihoods and climate change mitigation. Yet, the contribution of these ecosystems to carbon storage remains poorly documented due to the lack of accurate biomass predictive tools. Therefore, biomass allometric models developed at both the species-level and site-level may greatly improve carbon stock estimation. In this study, we developed allometric models for estimating aboveground biomass (AGB) at the tree component-, species- and site-levels in Burkina Faso. Five woody species with high socio-economic significance (Anogeissus leiocarpa, Combretum nigricans, Isoberlinia doka, Mitragyna inermis and Pterocarpus erinaceus) were selected at two forest sites based on their dominance in the savanna ecosystem. A total of 150 trees (30 trees per dominant species) spanning a wide range of diameter at breast height (DBH) were destructively sampled. Models to predict tree component biomass at the species-level were independently built with the Ordinary Least Squares (OLS) technique. Allometric models to predict tree total aboveground biomass (TAGB) for each species and all species were developed using both the OLS technique and the Seemingly Unrelated Regression (SUR) method. Biomass estimates were regressed with DBH as a single predictor, DBH and height (H) as interacted variables, and DBH, H and wood density (ρ) as three independent-input variables. The performance of the validated allometric models were compared with the generalized pantropical equation model for African tropical forests (Chave et al., 2014). The findings revealed that biomass predictors varied between the five species. The goodness-of-fit statistics revealed that both the OLS and SUR methods provide accurate biomass allometric equations, with the SUR method being the most accurate. The developed allometric models provide more accurate estimation of AGB than the pantropical model. Therefore, we recommend the use of these local models to improve the quantification of AGB and carbon stocks in Sudanian savanna ecosystems. Furthermore, the established species-specific and mixed-species allometric equations may constitute a useful tool for the monitoring, reporting and verification of carbon stocks within the REDD+ framework in Burkina Faso.

Tree mortality drives changes in forest structure and dynamics, community composition, and carbon and nutrient cycles. Since tropical forests store a large fraction of terrestrial biomass and tree diversity, improved understanding of changing tree mortality and biomass loss rates is critical. Tropical tree mortality rates have been challenging to estimate due to low background rates of tree death, and high spatial and temporal heterogeneity. Furthermore, the causes of mortality remain unclear because many factors may be involved in individual tree death, and the rapid decomposition of wood in the tropics obscures evidence of possible causes of tree mortality. We present a field protocol to assess tree mortality in tropical forests. The protocol focuses on the rapid, repeatable and inexpensive assessment of individual tree death and damage. The protocol has been successfully tested with annual assessments of >62,000 stems in total in several ForestGEO plots in Asia and the Neotropics. Standardized methods for the assessment of tree death and biomass loss will advance understanding of the underlying causes and consequences of tree mortality.Tree mortality drives forest dynamics, community composition, and carbon and nutrient cycles. We present a field protocol to assess tree mortality in tropical forests. The protocol focuses on the rapid, repeatable and inexpensive assessment of individual tree death and damage. Standardized methods for the assessment of tree death and biomass loss will advance understanding of tree mortality.

This study explored the feasibility of using the terrestrial laser scanner (TLS) and quantitative structure modelling (QSM) to estimate the above-ground biomass (AGB) of individual trees in the tropical rainforest using data from the Ayer Hitam Forest Reserve, Malaysia. We also tested the influence of varying the runs, the cover set’s diameter and nmin values on the ABG derived. To achieve our objectives, we estimated diameter at breast height (DBH) and height of 100 trees from 26 plots using both TLS and QSM, and field measurements then AGB based on both methods. We observed a powerful positive linear correlation between TLS and field-measured DBH (R2 = 0.97) and between TLS and field-measured height (R2 = 0.77), and a moderately strong relationship between TLS and field-based AGB (R2 = 0.56). TLS and QSM overestimated AGB by 30% of field-based estimates. Varying the number of runs had no significant influence on the AGB derived from the TLS and QSM (one-way ANOVA, p > 0.05) while increasing the cover set diameter led to an increase in the derived AGB (one-way ANOVA, p < 0.05). The QSM was very sensitive to variations in the nmin (one-way ANOVA, p < 0.05). Our study has demonstrated that the TLS and QSM can be used for estimation of AGB for individual trees but with varying reliability. Regardless, our study provides yet another non-destructive approach to the suite of methods for estimating carbon of individual trees for various applications, including Reducing Emissions from Deforestation and Forest Degradation. Keywords: 3D reconstruction, allometric equation, forest carbon, point cloud data, REDD+

Recently, the severe intensification of atmospheric carbon has highlighted the importance of urban tree contributions in atmospheric carbon mitigations in city areas considering sustainable urban green planning and management systems. Explicit and timely information on urban trees and their roles in the atmospheric Carbon Stock (CS) are essential for policymakers to take immediate actions to ameliorate the effects of deforestation and their worsening outcomes. In this study, a detailed methodology for urban tree CS calibration and mapping was developed for the small urban area of Sassuolo in Italy. For dominant tree species classification, a remote sensing approach was applied, utilizing a high-resolution WV3 image. Five dominant species were identified and classified by applying the Object-Based Image Analysis (OBIA) approach with an overall accuracy of 78%. The CS calibration was done by utilizing an allometric model based on the field data of tree dendrometry&mdash, i.e., Height (H) and Diameter at Breast Height (DBH). For geometric measurements, a terrestrial photogrammetric approach known as Structure-from-Motion (SfM) was utilized. Out of 22 randomly selected sample plots of 100 square meters (10 m &times, 10 m) each, seven plots were utilized to validate the results of the CS calibration and mapping. In this study, CS mapping was done in an efficient and convenient way, highlighting higher CS and lower CS zones while recognizing the dominant tree species contributions. This study will help city planners initiate CS mapping and predict the possible CS for larger urban regions to ensure a sustainable urban green management system.

Savannahs provide valuable ecosystem services and contribute to continental and global carbon budgets. In addition, savannahs exhibit multiple land uses, e.g., wildlife conservation, pastoralism, and crop farming. Despite their importance, the effect of land use on woody aboveground biomass (AGB) in savannahs is understudied. Furthermore, fences used to reduce human&ndash, wildlife conflicts may affect AGB patterns. We assessed AGB densities and patterns, and the effect of land use and fences on AGB in a multi-use savannah landscape in southeastern Kenya. AGB was assessed with field survey and airborne laser scanning (ALS) data, and a land cover map was developed using Sentinel-2 satellite images in Google Earth Engine. The highest woody AGB was found in riverine forest in a conservation area and in bushland outside the conservation area. The highest mean AGB density occurred in the non-conservation area with mixed bushland and cropland (8.9 Mg ha&minus, 1), while the lowest AGB density (2.6 Mg ha&minus, 1) occurred in overgrazed grassland in the conservation area. The largest differences in AGB distributions were observed in the fenced boundaries between the conservation and other land-use types. Our results provide evidence that conservation and fences can create sharp AGB transitions and lead to reduced AGB stocks, which is a vital role of savannahs as part of carbon sequestration.

Background Forest disturbance induced changes in the coupling of forest carbon and water have important implications for ecosystem functioning and sustainable forest management. However, this is rarely investigated at the large watershed scale with cumulative forest disturbance. We used a combination of techniques including modeling, statistical analysis, and machine learning to investigate the effects of cumulative forest disturbance on water use efficiency (WUE, a proxy for carbon and water coupling) in the 19,200 km2 Chilcotin watershed situated in the central interior of British Columbia, Canada. Harvesting, wildfire, and a severe Mountain Pine Beetle (MPB) infestation have gradually cumulated over the 45-year study period, and the watershed reached a cumulative equivalent clear-cut area of 10% in 1999 and then 40% in 2016. Results Surprisingly, with the dramatic forest disturbance increase from 2000 to 2016 which was mainly due to MPB, watershed-level carbon stocks and sequestration showed an insignificant reduction. This resilience was mainly due to landscape-level carbon dynamics that saw a balance between a variety of disturbance rates and types, an accumulation of older stand types, and fast growing young regenerated forests. Watershed-level carbon sequestration capacity was sustained, measured by Net Primary Production (NPP). A concurrent significant decrease in annual evapotranspiration (ET), led to a 19% increase in WUE (defined as the ratio of NPP to ET), which is contrary to common findings after disturbance at the forest stand-level. During this period of high disturbance, ET was the dominant driver of the WUE increase. Conclusions We conclude that disturbance-driven forest dynamics and the appropriate scale must be considered when investigating carbon and water relationship. In contrast to the stand-level trade-off relationship between carbon and water, forested watersheds may be managed to maintain timber, carbon and water resources across large landscapes.

Background Accurate downed woody debris (DWD) volume or mass estimates are needed for numerous applications such as fuel loading, forest carbon, and biodiversity/habitat assessments. The line-intersect sampling (LIS) method of inventorying DWD is widely used in forest inventories and ecological studies because it is time-efficient and unbiased. Despite its widespread use, the appropriate transect length needed to achieve a desired precision at a particular location has received relatively little attention. Methods We conducted intensive LIS sampling at 33 locations representing eight mature or old-growth forest types in northeastern USA, providing a range of forest conditions and DWD volumes (from 17 to 323 m3∙ha− 1). We used these empirical field data to test, through simulations, the effect of increasing transect length (up to 340 m at each location) on precision of associated LIS volume estimates. Importantly, we used a novel application of copula models to account for within-transect spatial autocorrelation of DWD volumes during our simulations, thereby properly addressing variance estimates. Results As expected, precision consistently improved with increasing cumulative transect length, and locations with lower DWD volumes required longer transects to achieve a given level of precision. We developed models relating precision, transect length, and DWD volume that allows us to gauge a suitable LIS transect length for desired precision levels. Conclusions LIS provides an attractive method for estimating DWD volume for a given localized area of interest. For the forest types sampled here, and for the particular copula model framework employed, transect lengths of ca. 120 m provide a reasonable level of precision, ranging from 18% to 60% coefficients of variation.

Finland has a long tradition of utilizing forest-based biomass for energy and industry purposes and the use has steadily increased in the past decade due to changes in international and regional energy policies. Intensive harvesting practices, in which a larger proportion of the woody biomass is removed from the forest stand, are becoming more common. The objectives of this study were (i) to evaluate the spatial and temporal extent of soil surface disturbance caused by stump-root system harvesting and (ii) to quantify how much biomass and nitrogen is removed from the stand in stump and coarse root harvesting. The extent of surface disturbance was assessed in three clear-cut Norway spruce ( Picea abies , (L . ) Karst.) stands in southern and central Finland, differing in time since harvest. To determine the biomass distribution of the stump-root system, stumps and coarse roots were excavated at one of the experimental stands. Across all age classes (time since harvest) less soil surface had remained undisturbed at the stump harvesting sites (52%) than at the sites where only mechanical site preparation (28%) had been carried out. Thus, the findings of this study indicate that soil disturbance caused by stump harvesting can exist on forest soil surface for more than a decade following harvest. The total biomass of the stump-root system in the stand was estimated to 39.3 Mg ha −1 and 79% of this biomass was removed during stump harvesting and consequently, 8.3 Mg ha −1 of stump-root biomass remained in soil. The stump-root system accounted for 17% of the whole-tree biomass, and coarse roots and fine coarse roots represented a significant portion of it (73%). Thus, the stump-root system represents a large biomass component in boreal forest stands. However, forest management utilizing stumps may result in carbon losses from the stand.

Background: Wildfire is known to reduce forest carbon stocks, but the influence of antecedent disturbance on wildfire related carbon stock losses is not as well understood. Disturbances such as logging and wildfire may increase the vulnerability of remaining carbon stocks to subsequent wildfire. Conversely, these disturbances may reduce the impact of subsequent wildfire, resulting in lower carbon stock losses. Methods: We measured above ground carbon stocks in productive resprouting Eucalypt dominated forests before and after a mixed severity fire that burned during the 2019/20 ‘Black Summer’ fire season in south-eastern Australia. The initial surveys were stratified by time since logging and time since wildfire, allowing for an assessment of how these disturbance histories influence above ground carbon stock losses caused by subsequent wildfire. Results: Above ground carbon stock losses varied substantially; however, there was a weak decrease in losses associated with time since logging but not time since wildfire. Variance in carbon stock losses associated with logging were greater than that caused by the severity of the 2019/20 wildfire itself. Carbon losses and predicted effects of disturbance may be underestimated in some cases due to the accumulation of carbon at sites between pre- and post-fire surveys. Conclusions: This study presents the largest published dataset of direct carbon stock changes resulting from wildfire in eucalypt forests. Our findings indicate that logging reduces the stability of above ground carbon stocks in resprouting eucalypt forests. This information will be critical for land managers looking to manage forests for carbon sequestration.

Forest degradation in the tropics is generating large carbon (C) emissions. In tropical Asia, logging is the main driver of forest degradation. For effective implementation of REDD+ projects in logged forests in Southeast Asia, the impacts of logging on forest C stocks need to be assessed. Here, we assess C stocks in logged lowland forests in central Vietnam and explore correlations between logging intensity, soil, topography and living aboveground carbon (AGC) stocks. We present an approach to estimate historical logging intensities for the prevalent situation when complete records on logging history are unavailable. Landsat analysis and participatory mapping were used to quantify the density of historical disturbances, used as a proxy of logging intensities in the area. Carbon in AGC, dead wood, belowground carbon (BGC) and soil (SOC) was measured in twenty-four 0.25 ha plots that vary in logging intensity, and data on recent logging, soil properties, elevation and slope were also collected. Heavily logged forests stored only half the amount of AGC of stems ≥10 cm dbh as lightly logged forests, mainly due to a reduction in the number of large (≥60 cm dbh) trees. Carbon in AGC of small trees (5–10 cm dbh), dead wood and BGC comprised only small fractions of total C stocks, while SOC in the topsoil of 0–30 cm depth stored ~50% of total C stocks. Combining logging intensities with soil and topographic data showed that logging intensity was the main factor explaining the variability in AGC. Our research shows large reductions in AGC in medium and heavily logged forests. It highlights the critical importance of conserving big trees to maintain high forest C stocks and accounting for SOC in total C stock estimates.

One of the most proposed climate change mitigation strategies is carbon sequestration by vegetation. This depends on the rate of carbon uptake and transformation in biomass, the rate of release through respiration, and the stability of the stocks to disturbances. Forest diversity influences these factors, in a degree that varies according to certain functional characteristics. The Dry Chaco is the largest dry forest in the world, and one of the regions with the highest deforestation rates of the planet. Our aim was to geographically describe three carbon stock attributes from forest communities of the Dry Chaco Forests in Argentina at the landscape scale: wood density, tree height and annual carbon increase in aboveground biomass, as proxies of forest stability and carbon long-term persistence. In addition, we evaluated the relationships between these attributes and climate features, in the search of potential climate controls. Higher precipitation during the growing season and low mean annual temperature benefited the combination of these three treats related to C storage persistence. The distribution of the most favorable states of the three attributes is centered at the northwestern area of the Dry Chaco. Our geographic description of carbon stocks attributes can contribute to more suitable conservation planning and allows forecasting potential shifts in forests due to climate change. Fil: Powell, Priscila Ana. Universidad Nacional de Tucumán. Instituto de Ecología Regional. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Ecología Regional; Argentina. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Cátedra de Ecología General; Argentina Fil: Nanni, Ana Sofía. Universidad Nacional de Tucumán. Instituto de Ecología Regional. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Ecología Regional; Argentina Fil: Nazaro, María Gabriela. Universidad Nacional de Tucumán. Instituto de Ecología Regional. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Ecología Regional; Argentina Fil: Loto, Dante Ernesto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones y Transferencia de Santiago del Estero. Universidad Nacional de Santiago del Estero. Centro de Investigaciones y Transferencia de Santiago del Estero; Argentina. Universidad Nacional de Santiago del Estero. Facultad de Ciencias Forestales. Instituto de Silvicultura y Manejo de Bosques; Argentina Fil: Torres, Ricardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; Argentina. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Museo de Zoología; Argentina Fil: Gasparri, Nestor Ignacio. Universidad Nacional de Tucumán. Instituto de Ecología Regional. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Ecología Regional; Argentina. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo; Argentina

The proper estimation of above-ground biomass (AGB) stocks of managed forests is a prerequisite to quantifying their role in climate change mitigation. The aim of this study was to analyze the spatial variability of AGB and its uncertainty between actively managed pine and unmanaged pine-oak reference forests in central Mexico. To investigate the determinants of AGB, we analyzed variables related to forest management, stand structure, topography, and climate. We developed linear (LM), generalized additive (GAM), and Random Forest (RF) empirical models to derive spatially explicit estimates and their uncertainty, and compared them. AGB was strongly influenced by forest management, as LiDAR-derived stand structure and stand age explained 80.9% to 89.8% of its spatial variability. The spatial heterogeneity of AGB varied positively with stand structural complexity and age in the managed forests. The type of predictive model had an impact on estimates of total AGB in our study site, which varied by as much as 19%. AGB densities varied from 0 to 492 &plusmn, 17 Mg ha&minus, 1 and the highest values were predicted by GAM. Uncertainty was not spatially homogeneously distributed and was higher with higher AGB values. Spatially explicit AGB estimates and their association with management and other variables in the study site can assist forest managers in planning thinning and harvesting schedules that would maximize carbon stocks on the landscape while continuing to provide timber and other ecosystem services. Our study represents an advancement toward the development of efficient strategies to spatially estimate AGB stocks and their uncertainty, as the GAM approach was used for the first time with improved results for such a purpose.

Forest management choices offer significant potential to mitigate global climate change and biodiversity loss. To illuminate tradeoffs relevant to policymakers, forest sector stakeholders, and consumers of forest products, we utilize three Key Performance Indicators&mdash, average carbon storage in the forest and wood products, cumulative timber output, and discounted cash flow&mdash, to compare four alternative management scenarios for Douglas-fir forests on 64 parcels across western Oregon and Washington. These scenarios are designed to meet one of two alternative management objectives: (i) maximize Net Present Value, or (ii) maximize sustained timber yield, according to one of two alternative sets of forest practice constraints: (i) compliance with minimum Oregon/Washington Forest Practices Act (FPA) rules, or (ii) two key requirements (increased green tree retention and wider riparian buffers) of Forest Stewardship Council (FSC) certification. Improved performance in terms of carbon storage for these alternatives generally also corresponded with reduced Net Present Value and timber yields. The gap between FSC and FPA performance indicators was wider in Oregon than Washington, which is primarily attributed to the higher level of stream protection required under Washington versus Oregon FPA rules. We observed consistently higher average carbon storage per cumulative timber output among FSC scenarios relative to business-as-usual, indicating FSC-certified wood carries an embedded carbon benefit. Our findings highlight options for targeted policies to incentivize management that increases carbon storage and minimizes disruptions in timber output, as well as for narrowing the financial gap (or opportunity cost) that would be involved in a transition away from contemporary common practice on industrial timberlands in the coastal Douglas-fir forests of the Pacific Northwest.

To be successful, actions for mitigating climate change in the forest and forest sector will not only need to be informed by the best available science, but will also require strong public and/or political acceptability. This paper presents the results of a novel analytical-deliberative engagement process that brings together stakeholders and Indigenous Peoples in participatory workshops in the interior and coastal regions of British Columbia (BC) to evaluate a set of potential forest carbon mitigation alternatives. In particular, this study examines what objectives are prioritized by stakeholders and Indigenous Peoples when discussing forest carbon mitigation in BC’s forests, as well as the perceived effectiveness of, and levels of support for, six forest-based carbon mitigation strategies. We start by describing the methodological framework involving two series of workshops. We then describe the results from the first round of workshops where participants identified 11 objectives that can be classified into four categories: biophysical, economic, social, and procedural. Afterwards, we discuss the second series of workshops, which allowed participants to evaluate six climate change mitigation strategies against the objectives previously identified, and highlight geographical differences, if any, between BC’s coastal and interior regions. Our results effectively illustrate the potential and efficacy of our novel methodology in informing a variety of stakeholders in different regions, and generating consistent results with a surprising degree of consensus on both key objectives and preference for mitigation alternatives. We conclude with policy recommendations on how to consider various management objectives during the design and implementation of forest carbon mitigation strategies.

Woody biomass from the southeast United States is expected to play an important role in meeting European Union renewable energy targets. In crafting policies to guide bioenergy development and in guiding investment decisions to meet established policy goals, a firm understanding of the interaction between policy targets and forest biomass markets is necessary, as is the effect that this interaction will have on environmental and economic objectives. This analysis increases our understanding of these interactions by modeling the response of southern US forest markets to new pellet demand in the presence of sustainability sourcing or harvest criteria. We first assess the influence of EU recommended sustainability guidelines on the forest inventory available to supply EU markets, and then model changes in forest composition and extent in response to expected increases in pellet demand. Next, we assess how sustainability guidelines can influence the evolution of forest markets in the region, paying particular attention to changes in land use and forest carbon. Regardless of whether sustainability guidelines are applied, we find increased removals, an increase in forest area, and little change in forest inventory. We also find annual gains in forest carbon in most years of the analysis. The incremental effect of sustainability guideline application on forest carbon and pellet greenhouse gas (GHG) balance is difficult to discern, but results suggest that guidelines could be steering production away from sensitive forest types inherently less responsive to changing market conditions. Pellet GHG balance shows significant annual change and is attributable to the complexity of the underlying forest landscape. The manner by which GHG balance is tracked is thus a critical policy decision, reinforcing the importance and relevance of current efforts to develop approaches to accurately account for the GHG implications of biomass use both in the United States and European Union.

The commercial asset value of sequestered forest carbon is based on protocols employed globally; however, their scientific basis has not been validated. We review and analyze commercial forest carbon protocols, claimed to have reduced net greenhouse gas emissions, issued by the California Air Resources Board and validated by the Climate Action Reserve (CARB-CAR). CARB-CAR forest carbon offsets, based on forest mensuration and model simulation, are compared to a global database of directly measured forest carbon sequestration, or net ecosystem exchange (NEE) of forest CO2. NEE is a meteorologically based method integrating CO2 fluxes between the atmosphere, forest and soils and is independent of the CARB-CAR methodology. Annual carbon accounting results for CAR681 are compared with NEE for the Ameriflux site, Howland Forest Maine, USA, (Ho-1), the only site where both methods were applied contemporaneously, invalidating CARB-CAR protocol offsets. We then test the null hypothesis that CARB-CAR project population data fall within global NEE population values for natural and managed forests measured in the field; net annual gC m−2yr−1 are compared for both protocols. Irrespective of geography, biome and project type, the CARB-CAR population mean is significantly different from the NEE population mean at the 95% confidence interval, rejecting the null hypothesis. The CARB-CAR population exhibits standard deviation ∼5× that of known interannual NEE ranges, is overcrediting biased, incapable of detecting forest transition to net positive CO2 emissions, and exceeds the 5% CARB compliance limit for invalidation. Exclusion of CO2 efflux via soil and ecosystem respiration precludes a valid net carbon accounting result for CARB-CAR and related protocols, consistent with our findings. Protocol invalidation risk extends to vendors and policy platforms such as the United Nations Program on Reducing Emissions from Deforestation and Forest Degradation (REDD+) and the Paris Agreement. We suggest that CARB-CAR and related protocols include NEE methodology for commercial forest carbon offsets to standardize methods, ensure in situ molecular specificity, verify claims of carbon emission reduction and harmonize carbon protocols for voluntary and compliance markets worldwide.

Reducing emissions from deforestation and forest degradation in developing countries, and the role of conservation, sustainable management of forests, and enhancement of forest carbon stocks in developing countries (REDD+) is a potentially powerful international policy mechanism that many tropical countries are working towards implementing. Thus far, limited practical consideration has been paid to local rights to forests and forest resources in REDD+ readiness programs, beyond noting the importance of these issues. Previous studies have shown that community members can reliably and cost-effectively monitor forest biomass. At the same time, this can improve local ownership and forge important links between monitoring activities and local decision-making. Existing studies have, however, been static assessments of biomass at one point in time. REDD+ programs will require repeated surveys of biomass over extended time frames. Here, we examine trends in accuracy and costs of local forest monitoring over time. We analyse repeated measurements by community members and professional foresters of 289 plots over two years in four countries in Southeast Asia. This shows, for the first time, that with repeated measurements community members’ biomass measurements become increasingly accurate and costs decline. These findings provide additional support to available evidence that community members can play a strong role in monitoring forest biomass in the local implementation of REDD+. Reducing emissions from deforestation and forest degradation in developing countries, and the role of conservation, sustainable management of forests, and enhancement of forest carbon stocks in developing countries (REDD+) is a potentially powerful international policy mechanism that many tropical countries are working towards implementing. Thus far, limited practical consideration has been paid to local rights to forests and forest resources in REDD+ readiness programs, beyond noting the importance of these issues. Previous studies have shown that community members can reliably and cost-effectively monitor forest biomass. At the same time, this can improve local ownership and forge important links between monitoring activities and local decision-making. Existing studies have, however, been static assessments of biomass at one point in time. REDD+ programs will require repeated surveys of biomass over extended time frames. Here, we examine trends in accuracy and costs of local forest monitoring over time. We analyse repeated measurements by community members and professional foresters of 289 plots over two years in four countries in Southeast Asia. This shows, for the first time, that with repeated measurements community members’ biomass measurements become increasingly accurate and costs decline. These findings provide additional support to available evidence that community members can play a strong role in monitoring forest biomass in the local implementation of REDD+.

Forests play a key role in the global carbon cycle, and programs aimed at mitigating greenhouse gas emissions through the protection and enhancement of forest carbon stocks are growing in number. Adding greenhouse gas mitigation as a management objective presents managers with a considerable challenge, because data and guidelines are scarce. Long-term inventory datasets have the potential to serve as a useful resource, providing data on carbon accumulation over time, as well as offering insight on strategies for managing forests for the objective of climate mitigation in the face of changing climate and disturbance regimes. We present long-term estimates of carbon accumulation developed from biometric measurements from two northern hardwood forests in the northeastern USA. The Bartlett Experimental Forest in central New Hampshire, USA, stored an estimated net average annual 0.53 tC/ha/yr between 1932–2001, for an increase of 50% in carbon stock per unit area; there were significant differences in accrual rates between age classes (38% for old unmanaged stands and 78% for younger unmanaged stands). The Kane Experimental Forest in northwestern Pennsylvania, USA, exhibited a 140% increase in carbon stored per unit area between 1932 and 2006, with an average annual accumulation rate of 0.89 tC/ha/yr. While both forests have experienced management activity and natural disturbances and differ in species composition, the average age of the forests is an important factor driving the differences in net accumulation rates.

The moist forests of the Pacific Northwest United States (PNW) are among the most naturally carbon rich ecoregions in the world. However, regional in-forest carbon storage levels are currently well below ecological potential. Recent climate policy proposals have renewed and deepened debates over forest sector climate strategies. This paper begins with a review of regionally applicable forest carbon life cycle assessments (LCAs) in an effort to provide some clarity around how these studies are conducted, and why their results may vary. The review highlights the importance of assumptions made during carbon accounting across the wood product lifespan and how the inclusion or exclusions of variables, such as product substitution and leakage, influence study results and subsequent management recommendations. Next we discuss the influence of climate change on forest management and planning. We conclude with a review of regional-specific factors to consider when developing optimal forest climate strategies in the moist forests of the PNW. These strategies include, but are not limited to; extending harvest rotations, shelterwood and select tree harvests (in lieu of full harvest), and managing forests for increased structural, age, and species complexity.

International audience; Abstract• Key messageSimulated and observed carbon stocks in Scots pine forests varied considerably with stand age. The contribution of biomass to the total forest carbon stocks increased and that of dead organic matter decreased with increasing stand age.• Context Understanding changes in forest carbon stocks over time is important to estimate carbon inventory. Although Scots pine (Pinus sylvestris L.) is a main species in Turkey, studies on such changes are still lacking.• Aims We aimed to estimate the changes in carbon stocks, with stand age, of Scots pine stands in Turkey using field work data and a forest carbon model (FBDC model).• Methods Biomass and dead organic matter carbon stocks were investigated to adjust the forest carbon model and to verify the model estimates. Forest carbon stocks with regards to stand age were simulated.• Results The simulated carbon stocks were generally in clear agreement with the observed values on a stand scale. Changes in simulated and observed carbon stocks of biomass and dead organic matter varied with stand age. The contribution of biomass to total forest carbon stocks increased, and that of dead organic matter decreased, with increasing stand age.• Conclusion We found that the carbon stocks in each pool and their contribution to the total forest carbon stocks varied with stand age. Our results are expected to contribute to the understanding of annual changes in the carbon stocks of Turkish forests.

The objective of this transport component of the broader Africa Climate Business Plan (ACBP) is to begin to mainstream climate benefits into the World Bank’s transport program for Sub-Saharan Africa, the better to assist African countries in bringing their climate change efforts to scale. It is a first step towards mainstreaming responses to the climate challenge into transport programs in Africa, and it represents the first time the Transport & ICT GP has produced a work plan for its investment and technical assistance operations that takes into account the content of countries’ Nationally Determined Contributions (NDCs) and attempts to align World Bank support to the goals stated therein. The transport work plan under this Africa Climate Business Plan will consist of up to $3.2 billion in investments and technical assistance over the 2016-2020 period – including $2.8 billion in World Bank funds. Those investments will help to make progress on two strategic objectives: (1) improving the resilience of African transport infrastructure to climate change by defining four pillars of resilient transport; and (2) improving the carbon-efficiency of transport systems in Sub-Saharan Africa.