| 1. |
- Stanaway, Jeffrey D., et al.
(författare)
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Global, regional, and national comparative risk assessment of 84 behavioural, environmental and occupational, and metabolic risks or clusters of risks for 195 countries and territories, 1990-2017: A systematic analysis for the Global Burden of Disease Study 2017
- 2018
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Ingår i: The Lancet. - 1474-547X .- 0140-6736. ; 392:10159, s. 1923-1994
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Tidskriftsartikel (refereegranskat)abstract
- Background The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2017 comparative risk assessment (CRA) is a comprehensive approach to risk factor quantification that offers a useful tool for synthesising evidence on risks and risk-outcome associations. With each annual GBD study, we update the GBD CRA to incorporate improved methods, new risks and risk-outcome pairs, and new data on risk exposure levels and risk- outcome associations. Methods We used the CRA framework developed for previous iterations of GBD to estimate levels and trends in exposure, attributable deaths, and attributable disability-adjusted life-years (DALYs), by age group, sex, year, and location for 84 behavioural, environmental and occupational, and metabolic risks or groups of risks from 1990 to 2017. This study included 476 risk-outcome pairs that met the GBD study criteria for convincing or probable evidence of causation. We extracted relative risk and exposure estimates from 46 749 randomised controlled trials, cohort studies, household surveys, census data, satellite data, and other sources. We used statistical models to pool data, adjust for bias, and incorporate covariates. Using the counterfactual scenario of theoretical minimum risk exposure level (TMREL), we estimated the portion of deaths and DALYs that could be attributed to a given risk. We explored the relationship between development and risk exposure by modelling the relationship between the Socio-demographic Index (SDI) and risk-weighted exposure prevalence and estimated expected levels of exposure and risk-attributable burden by SDI. Finally, we explored temporal changes in risk-attributable DALYs by decomposing those changes into six main component drivers of change as follows: (1) population growth; (2) changes in population age structures; (3) changes in exposure to environmental and occupational risks; (4) changes in exposure to behavioural risks; (5) changes in exposure to metabolic risks; and (6) changes due to all other factors, approximated as the risk-deleted death and DALY rates, where the risk-deleted rate is the rate that would be observed had we reduced the exposure levels to the TMREL for all risk factors included in GBD 2017.
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| 2. |
- Appiah Mensah, Alex
(författare)
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Assessment of vegetation dynamics using remote sensing and GIS: A case of Bosomtwe Range Forest Reserve, Ghana
- 2019
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Ingår i: The Egyptian journal of remote sensing and space sciences. - : Elsevier BV. - 1110-9823 .- 2090-2476. ; 22, s. 145-154
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Tidskriftsartikel (refereegranskat)abstract
- Changing conditions owing to increasing forest fragmentation make land cover and change detection analysis an extremely important consideration for sustainable forest management. This study applied supervised classification using maximum-likelihood algorithm in Quantum GIS to detect land use land cover changes in the Bosomtwe Range Forest Reserve, Ghana from 1991, 2002 and 2017 using Landsat 4 - TM, Landsat 7 - ETM and Sentinel-2 satellite imageries respectively. Based on the results of the study, it is concluded that land use/cover of Bosomtwe Range Forest Reserve have undergone remarkable changes for over the period of 26 years. The current status of forest cover is estimated to be 2995.45 +/- 401.86 ha and 2090.03 +/- 412.78 ha of closed and opened forest canopy respectively. Conversely, built-up areas (1531.68 +/- 487.13 ha) remains virtually high (20%) though it shows a decrease in comparison to the same area in 2002. The land use land cover change map clearly identified probable areas of forest depletion especially in the north eastern and western portions of the reserve. It is recommended that potential spatial drivers of change should be identified to generate suitable image for change modelling of the reserve, coupled with earmarking of degraded areas for reforestation projects to improve upon the forest cover. (C) 2018 National Authority for Remote Sensing and Space Sciences. Production and hosting by Elsevier B.V.
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| 3. |
- Appiah Mensah, Alex
(författare)
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Growth trends and site productivity in boreal forests under management and environmental change: insights from long-term surveys and experiments in Sweden
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Under a changing climate, current tree and stand growth information is indispensable to the carbon sink strength of boreal forests. Important questions regarding tree growth are to what extent have management and environmental change influenced it, and how it might respond in the future. In this thesis, results from five studies (Papers I-V) covering growth trends, site productivity, heterogeneity in managed forests and potentials for carbon storage in forests and harvested wood products via differing management strategies are presented. The studies were based on observations from national forest inventories and long-term experiments in Sweden. The annual height growth of Scots pine (Pinus sylvestris) and Norway spruce (Picea abies) had increased, especially after the millennium shift, while the basal area growth remains stable during the last 40 years (Papers I-II). A positive response on height growth with increasing temperature was observed. The results generally imply a changing growing condition and stand composition. In Paper III, yield capacity of conifers was analysed and compared with existing functions. The results showed that there is a bias in site productivity estimates and the new functions give better prediction of the yield capacity in Sweden. In Paper IV, the variability in stand composition was modelled as indices of heterogeneity to calibrate the relationship between basal area and leaf area index in managed stands of Norway spruce and Scots pine. The results obtained show that the stand structural heterogeneity effects here are of such a magnitude that they cannot be neglected in the implementation of hybrid growth models, especially those based on light interception and light-use efficiency. In the long-term, the net climate benefits in Swedish forests may be maximized through active forest management with high harvest levels and efficient product utilization, compared to increasing carbon storage in standing forests through land set-asides for nature conservation (Paper V). In conclusion, this thesis offers support for the development of evidence-based policy recommendations for site-adapted and sustainable management of Swedish forests in a changing climate.
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| 4. |
- Appiah Mensah, Alex, et al.
(författare)
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Modelling potential yield capacity in conifers using Swedish long-term experiments
- 2022
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Ingår i: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 512
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Tidskriftsartikel (refereegranskat)abstract
- Information on forest site productivity is a key component to assess the carbon sequestration potential of boreal forests. While site index (SI) is commonly used to indicate forest site productivity, expressions of SI in the form of yield capacity (potential maximum mean annual volume increment) is desirable since volume yield is central to the economic and ecological analyses of a given species and site. This paper assessed the functional relationship between SI and yield capacity on the basis of yield plot data from long-term experiments measured over several decades for Norway spruce (Picea abies), Scots pine (Pinus sylvestris), Lodgepole pine (Pinus contorta) and Larch (Larix decidua and Larix sibirica) in Sweden. Component models of total basal area and volume yield were also developed. SI was determined by existing height development functions using top height and age, whereas functions for stand-level (m2 ha- 1) basal area development were constructed based on age, SI and initial stand density using difference equations and nonlinear mixed-effects models. The relation between volume yield (m3 ha- 1) and top height was adjusted with total basal area production through nonlinear mixed-effects models. Species-specific parametric regression models were used to construct functional relationships between SI and yield capacity. The root mean square errors of the species-specific models ranged from 2 to 6% and 10-18% of the average values for the basal area and volume equations, respectively. For the yield capacity functions, the explained variations (R2) were within 80-96%. We compared our yield capacity functions to earlier functions of the species and significant differences were observed in both lower and higher SI classes, especially, for Scots pine and Norway spruce. The new functions give better prediction of yield capacity in current growing conditions; hence, they could later be used for comparing tree species' production under similar site and management regimes in Sweden.
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| 5. |
- Appiah Mensah, Alex
(författare)
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Socioeconomic Indicators of Bamboo Use for Agroforestry Development in the Dry Semi-Deciduous Forest Zone of Ghana
- 2018
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Ingår i: Sustainability. - : MDPI AG. - 2071-1050. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- Bamboo agroforestry is currently being promoted in Ghana as a viable land use option to reduce dependence on natural forest for wood fuels. To align the design and introduction of bamboo agroforestry to the needs of farmers, information on the determinants of bamboo acceptability and adoption is necessary. It is, therefore, the aim of this study to determine how socioeconomic factors, local farming practices and local knowledge on bamboo may influence its acceptability and adoption as a component of local farming systems. Data were collected from 200 farmers in the dry semi-deciduous forest zone of Ghana using semi-structured questionnaire interviews. The results show that farmers' traditional knowledge on bamboo including its use for charcoal production and leaves for fodder are influential determinants of bamboo adoption. Among the demographic characteristics of farmers, age and gender are the most significant predictors. It is also evident that the regular practice of leaving trees on farmlands and type of cropping system may influence bamboo integration into traditional farming systems.
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| 6. |
- Appiah Mensah, Alex
(författare)
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Spatial prediction and mapping of water quality of Owabi reservoir from satellite imageries and machine learning models
- 2021
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Ingår i: The Egyptian journal of remote sensing and space sciences. - : Elsevier BV. - 1110-9823 .- 2090-2476. ; 24, s. 825-833
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Tidskriftsartikel (refereegranskat)abstract
- Estimation and mapping of surface water quality are vital for the planning and sustainable management of inland reservoirs. The study aimed at retrieving and mapping water quality parameters (WQPs) of Owabi Dam reservoir from Sentinel-2 (S2) and Landsat 8 (L8) satellite data, using random forests (RF), support vector machines (SVM) and multiple linear regression (MLR) models. Water samples from 45 systematic plots were analysed for pH, turbidity, alkalinity, total dissolved solids and dissolved oxygen. The performances of all three models were compared in terms of adjusted coefficient of determination (R2.adj), and the root mean square error (RMSE) using repeated k-fold cross-validation procedure. To determine the status of water quality, pixel-level predictions were used to compute model-assisted estimates of WQPs and compared with reference values from the World Health Organization. Generally, all three models produced more accurate results for S2 compared to L8. On average, the inter-sensor relative efficiency showed that S2 outperformed L8 by 67% in retrieving WQPs of the Owabi Dam reservoir. S2 gave the highest accuracy for RF (R2.adj = 95–99%, RMSE = 0.02–3.03) and least for MLR (R2.adj = 55–91%, RMSE = 0.03–3.14). Compared to RF, SVM showed similar results for S2 but with slightly higher RMSEs (0.03–3.99). The estimated pH (7.06), total dissolved solids (39.19 mg/L) and alkalinity (179.60 mg/L) were within acceptable limits, except for turbidity (33.49 mg/L) which exceeded the reference thresholds. The S2 and RF models are recommended for the monitoring of surface water quality of the Owabi Dam reservoir.
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| 7. |
- Appiah Mensah, Alex, et al.
(författare)
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Taller and slenderer trees in Swedish forests according to data from the National Forest Inventory
- 2023
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Ingår i: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 527
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Tidskriftsartikel (refereegranskat)abstract
- Changes over time in annual basal area growth and mean height for Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.) over the period, 1983-2020 were studied using sample tree data from temporary plots recorded in the Swedish National Forest Inventory. The annual basal area growth was derived from the last measured full ring on increment cores. Using 20 to 60-year-old dominant trees, the mean height and annual basal area growth were examined as functions of tree, stand and site conditions, and trends were assessed mainly using residual analyses over time. A significant increase in mean height at a given age was found for both species, but the annual basal area growth level remained stable over the 38-year period. Currently, at a given age of 50 annual rings at breast height, the mean heights of pines and spruces increased on average by 10.1% (i.e. similar to 2 m), compared to 50 year-old pines and spruces in the 1980s, and the increase was similar in the different regions. The results suggest that trees have become taller and slenderer in Swedish forests. Increasing tree height over time at a given age in Northern Europe has been documented in several reports and many causes have been suggested, such as changed forest management, increasing temperatures and nitrogen deposition. We suggest that elevated CO2 in the air and improved water-use efficiency for the trees might also be strong drivers.
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| 8. |
- Holmström, Emma, et al.
(författare)
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The millennium shift: Investigating the relationship between environment and growth trends of Norway spruce and Scots pine in northern Europe
- 2021
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Ingår i: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 481
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Tidskriftsartikel (refereegranskat)abstract
- For boreal forests in colder climates, changes in environmental conditions are hypothesised to substantially affect ecosystem processes. In this study, trends of top height growth of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst) were analysed using permanent sample plot data from more than 300 long-term experimental sites distributed from temperate zones to the boreal forest conditions in Sweden. By regression analyses, the effects of temperature-sum and precipitation-sum on top height growth were assessed in the period 1986-2018. A significant upward temporal trend in height growth was observed for both species, with the trend more pronounced after the millennium shift. The magnitude of the annual relative height growth after the millennium was about 16.92% and 9.54% higher than expected, respectively for Scots pine and Norway spruce. A potential climate response on height growth was found for both species with temperature-sum positively correlated with top height growth. No significant effect of precipitation-sum on height growth was observed for either species. Our results suggest improved growing conditions and forest sites became more productive in response to increasing temperature in the northern temperate and boreal regions. The increasing growth trends may offer shorter rotation periods and increased forest value for Norway spruce and Scots pine, coupled with contributions of boreal forests to the emerging bio-economy and the regulation of global atmospheric carbon.
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| 9. |
- Larson, Johannes, et al.
(författare)
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Tree growth potential and its relationship with soil moisture conditions across a heterogeneous boreal forest landscape
- 2024
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Ingår i: Scientific Reports. - 2045-2322. ; 14
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Tidskriftsartikel (refereegranskat)abstract
- Forest growth varies across landscapes due to the intricate relationships between various environmental drivers and forest management. In this study, we analysed the variation of tree growth potential across a landscape scale and its relation to soil moisture. We hypothesised that soil moisture conditions drive landscape-level variation in site quality and that intermediate soil moisture conditions demonstrate the highest potential forest production. We used an age-independent difference model to estimate site quality in terms of maximum achievable tree height by measuring the relative change in Lorey's mean height for a five year period across 337 plots within a 68 km2 boreal landscape. We achieved wall-to-wall estimates of site quality by extrapolating the modelled relationship using repeated airborne laser scanning data collected in connection to the field surveys. We found a clear decrease in site quality under the highest soil moisture conditions. However, intermediate soil moisture conditions did not demonstrate clear site quality differences; this is most likely a result of the nature of the modelled soil moisture conditions and limitations connected to the site quality estimation. There was considerable unexplained variation in the modelled site quality both on the plot and landscape levels. We successfully demonstrated that there is a significant relationship between soil moisture conditions and site quality despite limitations associated with a short study period in a low productive region and the precision of airborne laser scanning measurements of mean height.
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| 10. |
- Laudon, Hjalmar, et al.
(författare)
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Swedish forest growth decline: A consequence of climate warming?
- 2024
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Ingår i: Forest Ecology and Management. - 0378-1127 .- 1872-7042. ; 565
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Tidskriftsartikel (refereegranskat)abstract
- Following an almost century-long increase, forest growth in Sweden has abruptly decreased during the last decade. Lower than expected forest biomass trajectories threaten national targets for carbon sequestration and bioeconomy. While climate-related drought is the most likely cause, the critical question is whether this recent growth decline is transient, or the beginning of a new normal where conventional management actions may risk further losses of resilience to water stress. We argue that improved mechanistic insights through better integrated research are urgently needed to avoid worsening the situation and further delaying necessary actions.
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| 11. |
- Lozano, Rafael, et al.
(författare)
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Measuring progress from 1990 to 2017 and projecting attainment to 2030 of the health-related Sustainable Development Goals for 195 countries and territories: a systematic analysis for the Global Burden of Disease Study 2017
- 2018
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Ingår i: The Lancet. - : Elsevier. - 1474-547X .- 0140-6736. ; 392:10159, s. 2091-2138
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Tidskriftsartikel (refereegranskat)abstract
- Background: Efforts to establish the 2015 baseline and monitor early implementation of the UN Sustainable Development Goals (SDGs) highlight both great potential for and threats to improving health by 2030. To fully deliver on the SDG aim of “leaving no one behind”, it is increasingly important to examine the health-related SDGs beyond national-level estimates. As part of the Global Burden of Diseases, Injuries, and Risk Factors Study 2017 (GBD 2017), we measured progress on 41 of 52 health-related SDG indicators and estimated the health-related SDG index for 195 countries and territories for the period 1990–2017, projected indicators to 2030, and analysed global attainment. Methods: We measured progress on 41 health-related SDG indicators from 1990 to 2017, an increase of four indicators since GBD 2016 (new indicators were health worker density, sexual violence by non-intimate partners, population census status, and prevalence of physical and sexual violence [reported separately]). We also improved the measurement of several previously reported indicators. We constructed national-level estimates and, for a subset of health-related SDGs, examined indicator-level differences by sex and Socio-demographic Index (SDI) quintile. We also did subnational assessments of performance for selected countries. To construct the health-related SDG index, we transformed the value for each indicator on a scale of 0–100, with 0 as the 2·5th percentile and 100 as the 97·5th percentile of 1000 draws calculated from 1990 to 2030, and took the geometric mean of the scaled indicators by target. To generate projections through 2030, we used a forecasting framework that drew estimates from the broader GBD study and used weighted averages of indicator-specific and country-specific annualised rates of change from 1990 to 2017 to inform future estimates. We assessed attainment of indicators with defined targets in two ways: first, using mean values projected for 2030, and then using the probability of attainment in 2030 calculated from 1000 draws. We also did a global attainment analysis of the feasibility of attaining SDG targets on the basis of past trends. Using 2015 global averages of indicators with defined SDG targets, we calculated the global annualised rates of change required from 2015 to 2030 to meet these targets, and then identified in what percentiles the required global annualised rates of change fell in the distribution of country-level rates of change from 1990 to 2015. We took the mean of these global percentile values across indicators and applied the past rate of change at this mean global percentile to all health-related SDG indicators, irrespective of target definition, to estimate the equivalent 2030 global average value and percentage change from 2015 to 2030 for each indicator. Findings: The global median health-related SDG index in 2017 was 59·4 (IQR 35·4–67·3), ranging from a low of 11·6 (95% uncertainty interval 9·6–14·0) to a high of 84·9 (83·1–86·7). SDG index values in countries assessed at the subnational level varied substantially, particularly in China and India, although scores in Japan and the UK were more homogeneous. Indicators also varied by SDI quintile and sex, with males having worse outcomes than females for non-communicable disease (NCD) mortality, alcohol use, and smoking, among others. Most countries were projected to have a higher health-related SDG index in 2030 than in 2017, while country-level probabilities of attainment by 2030 varied widely by indicator. Under-5 mortality, neonatal mortality, maternal mortality ratio, and malaria indicators had the most countries with at least 95% probability of target attainment. Other indicators, including NCD mortality and suicide mortality, had no countries projected to meet corresponding SDG targets on the basis of projected mean values for 2030 but showed some probability of attainment by 2030. For some indicators, including child malnutrition, several infectious diseases, and most violence measures, the annualised rates of change required to meet SDG targets far exceeded the pace of progress achieved by any country in the recent past. We found that applying the mean global annualised rate of change to indicators without defined targets would equate to about 19% and 22% reductions in global smoking and alcohol consumption, respectively; a 47% decline in adolescent birth rates; and a more than 85% increase in health worker density per 1000 population by 2030. Interpretation: The GBD study offers a unique, robust platform for monitoring the health-related SDGs across demographic and geographic dimensions. Our findings underscore the importance of increased collection and analysis of disaggregated data and highlight where more deliberate design or targeting of interventions could accelerate progress in attaining the SDGs. Current projections show that many health-related SDG indicators, NCDs, NCD-related risks, and violence-related indicators will require a concerted shift away from what might have driven past gains—curative interventions in the case of NCDs—towards multisectoral, prevention-oriented policy action and investments to achieve SDG aims. Notably, several targets, if they are to be met by 2030, demand a pace of progress that no country has achieved in the recent past. The future is fundamentally uncertain, and no model can fully predict what breakthroughs or events might alter the course of the SDGs. What is clear is that our actions—or inaction—today will ultimately dictate how close the world, collectively, can get to leaving no one behind by 2030.
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| 12. |
- Lundblad, Mattias, et al.
(författare)
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Förslag på uppföljning av åtgärder för ökad kolinlagring och minskade utsläpp i LULUCF-sektorn - Beskogning av tidigare jordbruksmark
- 2021
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Genom att aktiviteter inom markanvändning och skogsbruk (LULUCF-sektorn) fått större betydelse i klimatarbetet, såväl internationellt (EU/2018/841) som nationellt (SOU 2020:4) har behovet av förbättrad uppföljning av dessa aktiviteter aktualiserats. Det finns även ett behov av att förbättra bedömningen av potentialen, dvs. effekten på växthusgasbalansen av att åtgärderna införs. I denna rapport analyseras hur kolinlagringen kan öka genom beskogning av jordbruksmark och hur åtgärden kan följas upp. I uppdraget ingår att (i) föreslå hur förändrade utsläpp och upptag kan kvantifieras på objektsnivå i samband med utförd åtgärd, (ii) identifiera tillgängliga datakällor för att följa upp åtgärderna, (iii) föreslå eventuellt ytterligare behov av data för uppföljning av åtgärderna. Eftersom omfattande inventering krävs för mäta effekten av beskogning på plats har vi tagit fram en uppsättning typbestånd för olika trädslag (gran, tall, björk, asp, contortatall, ek, lärk, bok), bördighet (låg, medel, hög), tidigare markanvändning (vallbruk, odling av ettåriga grödor respektive grönträda) för tre regioner (Götaland, Svealand, Norrland), dvs. 216 olika alternativ. Dessutom har vi också tagit fram motsvarande uppsättning för fall där föryngringen är något mindre lyckad. De olika typbestånden simulerades med Heureka Planwise med komplettering av markkolsdata för tidigare markanvändning som simulerades med ICBM-modellen. För att också visa effekten av att välja snabbväxande trädslag som poppel och hybridasp gjordes en litteraturgenomgång som jämfördes med de simulerade bestånden. Det är stor skillnad i utfallet för de olika simulerade beskogningsalternativen. Gran binder i genomsnitt 2,3 ton C ha-1 år-1 över en omloppstid, medan björk binder 0,9 ton C ha-1 år-1 över en omloppstid. Generellt sker ett större kolupptag vid lyckade föryngringar med i snitt 1,4 ton C ha-1 år-1 nettoupptag över en omloppstid vid 2000 stammar vid en återväxtinventering jämfört med 1,1 ton C ha-1 år-1 vid 1000 stammar. Högre bonitet ger i snitt 1,7 ton C ha-1 år-1 jämfört med 0,9 ton C ha-1 år-1 vid lägre bonitet i genomsnitt över samtliga simulerade bestånd. En intressant observation är att det tar ett antal år innan bestånden bidrar som nettosänka (men med stor variation givet variationerna ovan). Detta beror på att nedbrytningen av det gamla kolet i marken inledningsvis är högre än tillförseln av nytt kol. Även om man ska tolka dessa simulerade resultat med viss försiktighet visar det att tidigare markanvändning bör tas i beaktande för var beskogning bör ske och med vilka trädslag. Det finns annars en risk att nyttan med beskogningen begränsas både i total effekt och tidsmässigt för att bidraget ska bli signifikant relativt befintliga klimatmål. Underlagen från de simulerade typbestånden kan användas i kombination med aktivitetsdata, dvs. arealer för aktiv plantering för att beräknas totaleffekt av beskogning. Genomsnitt kan t.ex. tas fram som kan komplettera de utsläpps- och upptagsfaktorer som används i klimatrapporteringen idag i kombination med data från SLU Riksskogstaxeringen (RT), exempel ges i rapporten på regionvisa faktorer. Det är också möjligt att använda typvärden på den aggregeringsnivå som är lämplig givet de aktivitetsdata som finns tillgängliga. Andra källor för aktivitetsdata kan vara den anmälan som görs till Länsstyrelsen när jordbruksmark tas ur bruk eller uppgifter om att jordbruksmarken inte längre ingår i ansökan om stöd inom landsbygdsprogrammet. Om en bra uppföljning ska kunna göras i framtiden behöver ett system som sammanställer den anmälan som görs idag och de ansökningar om stöd som kan bli verklighet om aktiviteten beskogning kommer ges stöd i någon form (antingen genom ett nytt system eller genom att det implementeras i befintliga stödsystem). Uppföljning kan göras genom stickprovsinventering i lämpliga tidsintervall men också genom att markägaren informerar ansvarig myndighet löpande om beståndets utveckling, i.e. i vilken utsträckning beskogningen varit lyckad (kanske vart femte år). Uppgiftslämnarbördan ska dock hållas så låg som möjligt för att inte minska intresset för åtgärden. När det gäller potentialen av beskogning relativt klimatmål till 2030 och 2045 är det uppenbart att bidraget inte hinner bli så stort till 2030 givet att det tar tid innan tillväxten får fart och effekten av att nedbrytningen av markkol är högre än tillförseln av nytt kol initialt. Vi har beräknat ett antal scenarier med stöd av simuleringar av typbestånd. Utgångspunkten har varit dagens beskogningsintensitet och trädslagsfördelning. Den additionella effekten jämfört med det bidrag som aktiviteten beskogning ger idag, hamnar på i storleksordningen 50 kton CO2 år--1 10 år efter att scenarierna startar, men efter 25 år, dvs. runt 2045 kan bidraget bli mer än 1 000 kton CO2 år-1 vid beskogning på 10 kha år-1 i 20 år, dvs. totalt 200 kha. Det är dock stor variation beroende på vilken beskogningsstrategi som väljs. Ett alternativ där andelen löv ökar samtidigt som vi antar att bättre lokaler väljs ger bara ett extra bidrag på drygt 100 kton CO2 år-1 efter 25 år. Kortsiktigt verkar det effektivt att satsa på att plantera snabbväxande trädslag som poppel eller hybridasp, åtminstone på en del av den aktuella arealen. Beskogningen bidrar inte bara med inlagring av koldioxid utan också till produktion av träråvara. Efter 60 år kan bidraget från beskogad mark, dvs. den mark som beskogas i scenarierna bidra med mellan ca 0,4 miljoner m3 sk år-1 (scenario löv) och ca 1,4 miljoner m3 sk år-1 (scenario BAUx2) i gallring. Om utvecklingen följer alternativ Hög kan det handla om uppemot 2 miljoner m3 sk år-1för scenario BAUx2 (som innebär att upp till 400 kha mark tas i anspråk för beskogning). Jämfört med dagens avverkningsnivåer motsvarar detta ca 1-2% av det årliga virkesuttaget. Därtill tillkommer förstås virkesleveranser när bestånden slutavverkas men den kolmängden är inkluderad i nettoupptaget. Potentiellt skulle beskogning och produktion av skogsråvara på nedlagd jordbruksmark kunna frigöra produktiv skogsmark för andra ändamål, t.ex. för ökat bevarande av biologisk mångfald. Hur våra marker utnyttjas i framtiden är dock en svår balansgång, samtidigt som jordbruksmark läggs ner, pekar mycket på dessa arealer kan behövas för livsmedelsproduktion i framtiden. Det är därför rimligt att inte inteckna alltför stor areal för beskogning. Vår bedömning är att de 200 kha som vi använt i denna studie inte i alltför stor utsträckning inkräktar på framtida livsmedelsproduktion eftersom marken i huvudsak redan tagits ur jordbruksproduktion.
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| 13. |
- Murray, Christopher J. L., et al.
(författare)
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Population and fertility by age and sex for 195 countries and territories, 1950–2017: a systematic analysis for the Global Burden of Disease Study 2017
- 2018
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Ingår i: The Lancet. - 1474-547X .- 0140-6736. ; 392:10159, s. 1995-2051
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Tidskriftsartikel (refereegranskat)abstract
- Background: Population estimates underpin demographic and epidemiological research and are used to track progress on numerous international indicators of health and development. To date, internationally available estimates of population and fertility, although useful, have not been produced with transparent and replicable methods and do not use standardised estimates of mortality. We present single-calendar year and single-year of age estimates of fertility and population by sex with standardised and replicable methods. Methods: We estimated population in 195 locations by single year of age and single calendar year from 1950 to 2017 with standardised and replicable methods. We based the estimates on the demographic balancing equation, with inputs of fertility, mortality, population, and migration data. Fertility data came from 7817 location-years of vital registration data, 429 surveys reporting complete birth histories, and 977 surveys and censuses reporting summary birth histories. We estimated age-specific fertility rates (ASFRs; the annual number of livebirths to women of a specified age group per 1000 women in that age group) by use of spatiotemporal Gaussian process regression and used the ASFRs to estimate total fertility rates (TFRs; the average number of children a woman would bear if she survived through the end of the reproductive age span [age 10–54 years] and experienced at each age a particular set of ASFRs observed in the year of interest). Because of sparse data, fertility at ages 10–14 years and 50–54 years was estimated from data on fertility in women aged 15–19 years and 45–49 years, through use of linear regression. Age-specific mortality data came from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2017 estimates. Data on population came from 1257 censuses and 761 population registry location-years and were adjusted for underenumeration and age misreporting with standard demographic methods. Migration was estimated with the GBD Bayesian demographic balancing model, after incorporating information about refugee migration into the model prior. Final population estimates used the cohort-component method of population projection, with inputs of fertility, mortality, and migration data. Population uncertainty was estimated by use of out-of-sample predictive validity testing. With these data, we estimated the trends in population by age and sex and in fertility by age between 1950 and 2017 in 195 countries and territories. Findings: From 1950 to 2017, TFRs decreased by 49·4% (95% uncertainty interval [UI] 46·4–52·0). The TFR decreased from 4·7 livebirths (4·5–4·9) to 2·4 livebirths (2·2–2·5), and the ASFR of mothers aged 10–19 years decreased from 37 livebirths (34–40) to 22 livebirths (19–24) per 1000 women. Despite reductions in the TFR, the global population has been increasing by an average of 83·8 million people per year since 1985. The global population increased by 197·2% (193·3–200·8) since 1950, from 2·6 billion (2·5–2·6) to 7·6 billion (7·4–7·9) people in 2017; much of this increase was in the proportion of the global population in south Asia and sub-Saharan Africa. The global annual rate of population growth increased between 1950 and 1964, when it peaked at 2·0%; this rate then remained nearly constant until 1970 and then decreased to 1·1% in 2017. Population growth rates in the southeast Asia, east Asia, and Oceania GBD super-region decreased from 2·5% in 1963 to 0·7% in 2017, whereas in sub-Saharan Africa, population growth rates were almost at the highest reported levels ever in 2017, when they were at 2·7%. The global average age increased from 26·6 years in 1950 to 32·1 years in 2017, and the proportion of the population that is of working age (age 15–64 years) increased from 59·9% to 65·3%. At the national level, the TFR decreased in all countries and territories between 1950 and 2017; in 2017, TFRs ranged from a low of 1·0 livebirths (95% UI 0·9–1·2) in Cyprus to a high of 7·1 livebirths (6·8–7·4) in Niger. The TFR under age 25 years (TFU25; number of livebirths expected by age 25 years for a hypothetical woman who survived the age group and was exposed to current ASFRs) in 2017 ranged from 0·08 livebirths (0·07–0·09) in South Korea to 2·4 livebirths (2·2–2·6) in Niger, and the TFR over age 30 years (TFO30; number of livebirths expected for a hypothetical woman ageing from 30 to 54 years who survived the age group and was exposed to current ASFRs) ranged from a low of 0·3 livebirths (0·3–0·4) in Puerto Rico to a high of 3·1 livebirths (3·0–3·2) in Niger. TFO30 was higher than TFU25 in 145 countries and territories in 2017. 33 countries had a negative population growth rate from 2010 to 2017, most of which were located in central, eastern, and western Europe, whereas population growth rates of more than 2·0% were seen in 33 of 46 countries in sub-Saharan Africa. In 2017, less than 65% of the national population was of working age in 12 of 34 high-income countries, and less than 50% of the national population was of working age in Mali, Chad, and Niger. Interpretation: Population trends create demographic dividends and headwinds (ie, economic benefits and detriments) that affect national economies and determine national planning needs. Although TFRs are decreasing, the global population continues to grow as mortality declines, with diverse patterns at the national level and across age groups. To our knowledge, this is the first study to provide transparent and replicable estimates of population and fertility, which can be used to inform decision making and to monitor progress. Funding: Bill & Melinda Gates Foundation.
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| 14. |
- Petersson, Hans, et al.
(författare)
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On the role of forests and the forest sector for climate change mitigation in Sweden
- 2022
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Ingår i: GCB Bioenergy. - : Wiley. - 1757-1707 .- 1757-1693. ; 14:7, s. 793-813
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Tidskriftsartikel (refereegranskat)abstract
- We analyse the short- and long-term consequences for atmospheric greenhouse gas (GHG) concentrations of forest management strategies and forest product uses in Sweden by comparing the modelled consequences of forest resource use vs. increased conservation at different levels of GHG savings from carbon sequestration and product substitution with bioenergy and other forest products. Increased forest set-asides for conservation resulted in larger GHG reductions only in the short term and only when substitution effects were low. In all other cases, forest use was more beneficial. In all scenarios, annual carbon dioxide (CO2) sequestration rates declined in conservation forests as they mature, eventually approaching a steady state. Forest set-asides are thus associated with increasing opportunity costs corresponding to foregone wood production and associated mitigation losses. Substitution and sequestration rates under all other forest management strategies rise, providing support for sustained harvest and cumulative mitigation gains. The impact of increased fertilization was everywhere beneficial to the climate and surpassed the mitigation potential of the other scenarios. Climate change can have large—positive or negative—influence on outcomes. Despite uncertainties, the results indicate potentially large benefits from forest use for wood production. These benefits, however, are not clearly linked with forestry in UNFCCC reporting, and the European Union's Land Use, Land-Use Change and Forestry carbon accounting, framework may even prevent their full realization. These reporting and accounting frameworks may further have the consequence of encouraging land set-asides and reduced forest use at the expense of future biomass production. Further, carbon leakage and resulting biodiversity impacts due to increased use of more GHG-intensive products, including imported products associated with deforestation and land degradation, are inadequately assessed. Considerable opportunity to better mobilize the climate change mitigation potential of Swedish forests therefore remains.
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| 15. |
- Petersson, Hans, et al.
(författare)
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Using heterogeneity indices to adjust basal area - Leaf area index relationship in managed coniferous stands
- 2020
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Ingår i: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 458
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Tidskriftsartikel (refereegranskat)abstract
- The structure of contemporary managed forests is complex and deviates from experimental forests which are usually even-aged monocultures and single-storied. To apply theoretical growth and yield functions on managed forests, adjustments are required, especially for leaf area index (LAI) which is a key biophysical variable in process-based growth models. To asses this, the performance of canopy LAI in modelling the basal area (BA) of managed boreal forests dominated by Norway spruce (Picea abies (L). Karst) and Scots pine (Pinus sylvestris L.) was investigated by heterogeneity analysis. The study was based on the assumption that canopy LAI and BA are strongly related and are vital for estimating stand productivity and growth. Managed forests were represented by field data from the 2016 and 2017 Swedish National Forest Inventory (NFI) campaigns. Species-specific LAI conversion parameters were applied on the general plant area index (PAD values from hemispheric fish-eye photos taken from the permanent and temporary NFI sample plots. The heterogeneity analysis was studied in two parts by: (a) ground-based stand structural heterogeneity (SSH) described by species composition, coefficient of tree diameter variation, tree social status and height-diameter ratio, and (b) spectral heterogeneity (SPH) by vegetation and textural indices developed from Sentinel-2. Species-specific final (with heterogeneity metrics) and base (without heterogeneity metrics) models were fitted for BA-LAI and BA-PM relationships by nonlinear least squares and generalised additive regression functions, respectively. The performance of models was assessed by the root-mean-squared error (RMSE, m(2)ha(-1)) and the relative root-mean-squared error (ReIRMSE, %) metrics. For both species, BA-LAI final models (FMs) accounting for heterogeneity resulted in larger explained variance than the base models (BMs). Compared with the BMs, FMs with SSH reduced the variance by 55% in Norway spruce (RMSE = 3.33, ReIRMSE = 15.39) and 43% in Scots pine (RMSE = 3.70, ReIRMSE = 17.38). The fit between BA-LAI with SPH also showed an improvement for Norway spruce (RMSE = 5.56) and Scots pine (RMSE = 5.66) over the BMs, suggesting the potential use of Sentinel-2 in future growth models. The results of the study suggest that in growth models when extrapolating theoretical growth functions to managed forests, there is a need to calibrate the models with the forest structural heterogeneity. This is important for drawing realistic conclusions from growth and yield modelling of managed stands of Norway spruce and Scots pine.
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| 16. |
- Saarela, Svetlana, et al.
(författare)
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Mapping aboveground biomass and its prediction uncertainty using LiDAR and field data, accounting for tree-level allometric and LiDAR model errors
- 2020
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Ingår i: Forest Ecosystems. - : Elsevier BV. - 2095-6355 .- 2197-5620. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- Background The increasing availability of remotely sensed data has recently challenged the traditional way of performing forest inventories, and induced an interest in model-based inference. Like traditional design-based inference, model-based inference allows for regional estimates of totals and means, but in addition for wall-to-wall mapping of forest characteristics. Recently Light Detection and Ranging (LiDAR)-based maps of forest attributes have been developed in many countries and been well received by users due to their accurate spatial representation of forest resources. However, the correspondence between such mapping and model-based inference is seldom appreciated. In this study we applied hierarchical model-based inference to produce aboveground biomass maps as well as maps of the corresponding prediction uncertainties with the same spatial resolution. Further, an estimator of mean biomass at regional level, and its uncertainty, was developed to demonstrate how mapping and regional level assessment can be combined within the framework of model-based inference. Results Through a new version of hierarchical model-based estimation, allowing models to be nonlinear, we accounted for uncertainties in both the individual tree-level biomass models and the models linking plot level biomass predictions with LiDAR metrics. In a 5005 km(2)large study area in south-central Sweden the predicted aboveground biomass at the level of 18 m x18 m map units was found to range between 9 and 447 Mg center dot ha(-1). The corresponding root mean square errors ranged between 10 and 162 Mg center dot ha(-1). For the entire study region, the mean aboveground biomass was 55 Mg center dot ha(-1)and the corresponding relative root mean square error 8%. At this level 75% of the mean square error was due to the uncertainty associated with tree-level models. Conclusions Through the proposed method it is possible to link mapping and estimation within the framework of model-based inference. Uncertainties in both tree-level biomass models and models linking plot level biomass with LiDAR data are accounted for, both for the uncertainty maps and the overall estimates. The development of hierarchical model-based inference to handle nonlinear models was an important prerequisite for the study.
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