500 research outputs found
Stem and soil CO2 efflux responses of Pinus radiata plantations to temperature, season, age, time (day/night) and fertilization
Stem CO2 efflux is a highly variable component of the carbon budget of forest ecosystems. It reflects the balance between the CO2 respired by the living stem tissues, less the CO2 dissolved in the xylem sap moving upward in the transpiration stream, plus the CO2 transported from the roots and released at the stem. Although knowledge about such fluxes at different spatial and temporal scales has markedly increased, knowledge of the effects of silviculture treatments, such as fertilization, on stem CO2 effluxes are still limited, particularly when connecting above- and belowground processes. Using measurements obtained from twin plots (one control, one fertilized) installed in five-, 12- and 23-year-old stands of Pinus radiata, the objective of this study was to examine the influence of the temperature, stand age, fertilization, season and time of measurement (day/night) on the stem CO2 efflux, soil CO2 efflux and their ratio. There was a strong significant positive relationship between the stem CO2 efflux and temperature. The slope between these two variables declined as the stand age increased and was higher for nighttime than daytime measurements. The stem CO2 efflux was higher in the fertilized plots compared with the unfertilized (control) plots for the 5- and 12- but not the 23-year-old age classes. In contrast, the soil CO2 efflux was largely unaffected by the temperature, time of measurement (day/night), fertilization and stand age; however, significantly higher values of soil CO2 efflux were measured during spring than during the other seasons. Given the relative invariance of the soil CO2 efflux to the temperature and treatment effects, the ratio of the stem:soil CO2 effluxes was affected by the same factors as the stem CO2 effluxes. These results suggest that fertilization would increase wood production and wood CO2 efflux without changing the soil CO2 efflux, thus most likely proportionally increasing aboveground C partitioning and decrease belowground C partitioning, with this effect being enhanced at younger ages.El flujo de CO2 desde los fustes es una componente altamente variable en el balance global de carbono en ecosistemas forestales. Refleja el balance entre el CO2 respirado por los tejidos vivos del fuste, menos el CO2 disuelto en la savia del xilema que se mueve hacia arriba como resultado de la transpiración, más el CO2 transportado desde las raíces y liberado en el fuste. Aunque el conocimiento acerca de estos flujos a diferentes escalas espaciales y temporales ha aumentado marcadamente, los efectos de tratamientos silviculturales, tales como la fertilización, en la respiración de los fustes es aún limitada particularmente al conectar procesos arriba y abajo del suelo. Usando medidas en parcelas gemelas (una parcela testigo, una parcela fertilizada) instaladas en rodales de 5,12 y 23 años de edad de Pinus radiata, el objetivo del estudio fue examinar la influencia de la temperatura, edad, fertilización, temporada y tiempo del día (día/noche) en los flujos de CO2 desde los fustes, desde los suelos y la razón entre ellos. Se encontró una fuerte relación positiva entre el flujo de CO2 desde los fustes con la temperatura de los mismos. La pendiente entre estas dos variables declinó con la edad, siendo superior durante la noche que durante el día. El flujo de CO2 desde los fustes fue mayor en las parcelas fertilizadas que en las testigo en los rodales de 5 y 12 años pero no en el de 23 años. En contraste, los flujos de CO2 desde los suelos fueron mayoritariamente invariantes a la temperatura del suelo, al tiempo de medición (día/noche), fertilización y edad de los rodales; aunque dichos valores fueron significativamente mayores durante la primavera comparado con las otras temporadas. Dada la relativa invariabilidad de los flujos de CO2 de los suelos a la temperatura y a los efectos de los tratamientos (fertilización, edad, día/noche), la razón de los flujos de CO2 entre fustes y suelos fueron afectados por los mismos factores que afectaron los flujos de CO2 desde los fustes. Estos resultados sugieren que la fertilización temprana aumenta drásticamente la producción y flujos de CO2 de los fustes, sin cambiar los flujos de CO2 desde los suelos; o en otras palabras, asignando proporcionalmente más carbono arriba del suelo y menos abajo del suelo, con este efecto decreciendo con la edad de la plantación
Mapping and explaining the productivity of Pinus radiata in New Zealand
Mapping Pinus radiata productivity for New Zealand not only provides useful information for forest owners, industry stakeholders and policy managers, but also enables current and future plantations to be visualised, quantified, and planned. Using an extensive set of permanent sample plots, split into fitting (n = 1,146) and validation (n = 618) datasets, models of P. radiata 300 Index (an index of volume mean annual increment) and Site Index (an index of height growth) were developed using a regression kriging technique. Spatial predictions were accurate and accounted for 61% and 70% of the variance for 300 Index and Site Index, respectively. Productivity predicted from these surfaces for the entire plantation estate averaged 27.4 m³ ha⁻¹ yr⁻¹ for the 300 Index and 30.4 m for Site Index. Surfaces showed wide regional variation in this productivity, which was attributable mainly to variation in air temperature and root-zone water storage from site to site
Modeling spatial variation in radiata pine slenderness (height/diameter ratio) and vulnerability to wind damage under current and future climate in New Zealand
Wind is a significant disturbance agent in forests that is likely to become more prevalent as plantation forests are increasingly grown at high stand density to maximize yields and carbon sequestration. Although research has used models to characterize plantation wind risk at discrete sites, little research has regionally scaled these predictions under both current and future climate. Stem slenderness, or height/diameter ratio, has been found to be a useful proxy for stand stability in the widely grown species, radiata pine (Pinus radiata), which constitutes 90% of the New Zealand plantation area. Stands with a slenderness that exceed 80 m m–1 are likely to be at risk when exposed to strong winds. In this study, slenderness was derived from 4,004 radiata pine permanent growth monitoring plots, that covered the spatial distribution of the species, and matched with stand density, age and key climatic and edaphic variables derived from surfaces. Using these data, the objectives of this study were to (i) develop a model to predict slenderness using machine learning and partition the impacts of key factors on slenderness, (ii) use this model to spatially predict slenderness throughout New Zealand for three contrasting silvicultural regimes, under current and future climate, and (iii) identify any regions that may be particularly vulnerable to wind risk. The final model of slenderness developed using the random forest algorithm included, in order of importance, stand density, stand age, mean annual air temperature and total annual rainfall. Predictions made on a withheld independent dataset (n = 401) were both unbiased and accurate (R2 = 0.85). Spatial predictions of slenderness under current climate showed wide regional variation with mean slenderness at age 30 years increasing from 62.1 m m–1 for low stand density clearwood regimes to 73.5 m m–1 for medium stand density structural grade regimes and 79.5 m m–1 for high stand density carbon regimes. Mean changes in slenderness were relatively low to 2040 and 2090 within the North Island. In contrast, within the South Island there were moderate increases in slenderness for the three silvicultural regimes that were markedly higher for 2090 than 2040
Mapping the productivity of radiata pine
Forest owners, investors and policy makers all want to know the spread and productivity of New Zealand’s current and future radiata plantation. David Palmer, a geo-spatial analyst at Scion, has combined advanced statistical techniques with mapping technology to predict radiata 300 Index and Site Index for any location in New Zealand. The 300 Index is an index of volume mean annual increment, and the Site Index is for height and growth. The map of Site Index and 300 Index was built using growth measurement data from trees in 1,146 radiata pine permanent sample plots, planted between 1975 and 2003. The data was combined with a number of climate, land use, terrain and environmental variables to predict forest productivity under a range of conditions
Pd(II)-Catalyzed [4 + 2] Heterocyclization Sequence for Polyheterocycle Generation
A new Pd(II)-catalyzed
cascade sequence for the formation of polyheterocycles,
from simple starting materials, is reported. The sequence is applicable
to both indole and pyrrole substrates, and a range of substituents
are tolerated. The reaction is thought to proceed by a Pd(II)-catalyzed
C–H activated Heck reaction followed by a second Pd(II)-catalyzed
aza-Wacker reaction with two Cu(II)-mediated Pd(0) turnovers per sequence.
The sequence can be considered a formal [4 + 2] heterocyclization
Palladium(II) Catalyzed CH Functionalization Cascades for the Diastereoselective Synthesis of Polyheterocycles
Remote sensing-based assessment of mangrove ecosystems in the Gulf Cooperation Council countries: a systematic review
Mangrove forests in the Gulf Cooperation Council (GCC) countries are facing multiple threats from natural and anthropogenic-driven land use change stressors, contributing to altered ecosystem conditions. Remote sensing tools can be used to monitor mangroves, measure mangrove forest-and-tree-level attributes and vegetation indices at different spatial and temporal scales that allow a detailed and comprehensive understanding of these important ecosystems. Using a systematic literature approach, we reviewed 58 remote sensing-based mangrove assessment articles published from 2010 through 2022. The main objectives of the study were to examine the extent of mangrove distribution and cover, and the remotely sensed data sources used to assess mangrove forest/tree attributes. The key importance of and threats to mangroves that were specific to the region were also examined. Mangrove distribution and cover were mainly estimated from satellite images (75.2%), using NDVI (Normalized Difference Vegetation Index) derived from Landsat (73.3%), IKONOS (15%), Sentinel (11.7%), WorldView (10%), QuickBird (8.3%), SPOT-5 (6.7%), MODIS (5%) and others (5%) such as PlanetScope. Remotely sensed data from aerial photographs/images (6.7%), LiDAR (Light Detection and Ranging) (5%) and UAV (Unmanned Aerial Vehicles)/Drones (3.3%) were the least used. Mangrove cover decreased in Saudi Arabia, Oman, Bahrain, and Kuwait between 1996 and 2020. However, mangrove cover increased appreciably in Qatar and remained relatively stable for the United Arab Emirates (UAE) over the same period, which was attributed to government conservation initiatives toward expanding mangrove afforestation and restoration through direct seeding and seedling planting. The reported country-level mangrove distribution and cover change results varied between studies due to the lack of a standardized methodology, differences in satellite imagery resolution and classification approaches used. There is a need for UAV-LiDAR ground truthing to validate country-and-local-level satellite data. Urban development-driven coastal land reclamation and pollution, climate change-driven temperature and sea level rise, drought and hypersalinity from extreme evaporation are serious threats to mangrove ecosystems. Thus, we encourage the prioritization of mangrove conservation and restoration schemes to support the achievement of related UN Sustainable Development Goals (13 climate action, 14 life below water, and 15 life on land) in the GCC countries
Comparison and relative utility of inequality measurements: as applied to Scotland’s child dental health
This study compared and assessed the utility of tests of inequality on a series of very large population caries datasets. National cross-sectional caries datasets for Scotland’s 5-year-olds in 1993/94 (n = 5,078); 1995/96 (n = 6,240); 1997/98 (n = 6,584); 1999/00 (n = 6,781); 2002/03 (n = 9,747); 2003/04 (n = 10,956); 2005/06 (n = 10,945) and 2007/08 (n = 12,067) were obtained. Outcomes were based on the d3mft metric (i.e. the number of decayed, missing and filled teeth). An area-based deprivation category (DepCat) measured the subjects’ socioeconomic status (SES). Simple absolute and relative inequality, Odds Ratios and the Significant Caries Index (SIC) as advocated by the World Health Organization were calculated. The measures of complex inequality applied to data were: the Slope Index of Inequality (absolute) and a variety of relative inequality tests i.e. Gini coefficient; Relative Index of Inequality; concentration curve; Koolman and Doorslaer’s transformed Concentration Index; Receiver Operator Curve and Population Attributable Risk (PAR). Additional tests used were plots of SIC deciles (SIC10) and a Scottish Caries Inequality Metric (SCIM10). Over the period, mean d3mft improved from 3.1(95%CI 3.0–3.2) to 1.9(95%CI 1.8–1.9) and d3mft = 0% from 41.1(95%CI 39.8–42.3) to 58.3(95%CI 57.8–59.7). Absolute simple and complex inequality decreased. Relative simple and complex inequality remained comparatively stable. Our results support the use of the SII and RII to measure complex absolute and relative SES inequalities alongside additional tests of complex relative inequality such as PAR and Koolman and Doorslaer’s transformed CI. The latter two have clear interpretations which may influence policy makers. Specialised dental metrics (i.e. SIC, SIC10 and SCIM10) permit the exploration of other important inequalities not determined by SES, and could be applied to many other types of disease where ranking of morbidity is possible e.g. obesity. More generally, the approaches described may be applied to study patterns of health inequality affecting worldwide populations
Protocol for the Foot in Juvenile Idiopathic Arthritis trial (FiJIA): a randomised controlled trial of an integrated foot care programme for foot problems in JIA
<b>Background</b>:
Foot and ankle problems are a common but relatively neglected manifestation of juvenile idiopathic arthritis. Studies of medical and non-medical interventions have shown that clinical outcome measures can be improved. However existing data has been drawn from small non-randomised clinical studies of single interventions that appear to under-represent the adult population suffering from juvenile idiopathic arthritis. To date, no evidence of combined therapies or integrated care for juvenile idiopathic arthritis patients with foot and ankle problems exists.
<b>Methods/design</b>:
An exploratory phase II non-pharmacological randomised controlled trial where patients including young children, adolescents and adults with juvenile idiopathic arthritis and associated foot/ankle problems will be randomised to receive integrated podiatric care via a new foot care programme, or to receive standard podiatry care. Sixty patients (30 in each arm) including children, adolescents and adults diagnosed with juvenile idiopathic arthritis who satisfy the inclusion and exclusion criteria will be recruited from 2 outpatient centres of paediatric and adult rheumatology respectively. Participants will be randomised by process of minimisation using the Minim software package. The primary outcome measure is the foot related impairment measured by the Juvenile Arthritis Disability Index questionnaire's impairment domain at 6 and 12 months, with secondary outcomes including disease activity score, foot deformity score, active/limited foot joint counts, spatio-temporal and plantar-pressure gait parameters, health related quality of life and semi-quantitative ultrasonography score for inflammatory foot lesions. The new foot care programme will comprise rapid assessment and investigation, targeted treatment, with detailed outcome assessment and follow-up at minimum intervals of 3 months. Data will be collected at baseline, 6 months and 12 months from baseline. Intention to treat data analysis will be conducted.
A full health economic evaluation will be conducted alongside the trial and will evaluate the cost effectiveness of the intervention. This will consider the cost per improvement in Juvenile Arthritis Disability Index, and cost per quality adjusted life year gained. In addition, a discrete choice experiment will elicit willingness to pay values and a cost benefit analysis will also be undertaken
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