DIRECT ESTIMATION OF ABOVEGROUND FOREST PRODUCTIVITY THROUGH HYPERSPECTRAL REMOTE SENSING OF CANOPY NITROGEN

The concentration of nitrogen in foliage has been related to rates of net photosynthesis across a wide range of plant species and functional groups and thus represents a simple and biologically meaningful link between terrestrial cycles of carbon and nitrogen. Although foliar N is used by ecosystem models to predict rates of leaf‐level photosynthesis, it has rarely been examined as a direct scalar to stand‐level carbon gain. Establishment of such relationships would greatly simplify the nature of forest C and N linkages, enhancing our ability to derive estimates of forest productivity at landscape to regional scales. Here, we report on a highly predictive relationship between whole‐canopy nitrogen concentration and aboveground forest productivity in diverse forested stands of varying age and species composition across the 360 000‐ha White Mountain National Forest, New Hampshire, USA. We also demonstrate that hyperspectral remote sensing can be used to estimate foliar N concentration, and hence forest production across a large number of contiguous images. Together these data suggest that canopy‐level N concentration is an important correlate of productivity in these forested systems, and that imaging spectrometry of canopy N can provide direct estimates of forest productivity across large landscapes

Predicting the effects of climate change on water yield and forest production in the northeastern United States

Rapid and simultaneous changes in temperature, precipitation and the atmospheric concentration of CO2 are predicted to occur over the next century. Simple, well-validated models of ecosystem function are required to predict the effects of these changes. This paper describes an improved version of a forest carbon and water balance model (PnET-II) and the application of the model to predict stand- and regional-level effects of changes in temperature, precipitation and atmospheric CO2 concentration. PnET-II is a simple, generalized, monthly time-step model of water and carbon balances (gross and net) driven by nitrogen availability as expressed through foliar N concentration. Improvements from the original model include a complete carbon balance and improvements in the prediction of canopy phenology, as well as in the computation of canopy structure and photosynthesis. The model was parameterized and run for 4 forest/site combinations and validated against available data for water yield, gross and net carbon exchange and biomass production. The validation exercise suggests that the determination of actual water availability to stands and the occurrence or non-occurrence of soil-based water stress are critical to accurate modeling of forest net primary production (NPP) and net ecosystem production (NEP). The model was then run for the entire NewEngland/New York (USA) region using a 1 km resolution geographic information system. Predicted long-term NEP ranged from -85 to +275 g C m-2 yr-1 for the 4 forest/site combinations, and from -150 to 350 g C m-2 yr-1 for the region, with a regional average of 76 g C m-2 yr-1. A combination of increased temperature (+6*C), decreased precipitation (-15%) and increased water use efficiency (2x, due to doubling of CO2) resulted generally in increases in NPP and decreases in water yield over the region

Measuring Economic Disadvantage During Childhood: A Group-Based Modeling Approach

Recent research suggest that child well-being and subsequent status attainment are influenced not only by the overall magnitude of exposure to family economic disadvantage during childhood, but also by the age of exposure and significant changes in family economic circumstances. Unfortunately, traditional measures of children's economic deprivation, such as permanent and transitory income, persistent or cumulative poverty, and the number and length of poverty spells, fail to differentiate between exposure to disadvantage at different stages in childhood and largely ignore how family economic circumstances are changing over time. In this paper, the authors propose a new method for assessing economic disadvantage during childhood that captures both children's overall levels of exposure to economic disadvantage and their patterns of exposure. This new method, which takes advantage of recent advances in finite mixture modeling, uses a longitudinal latent class model to classify children into a limited number of groups with similar histories of exposure to family economic disadvantage. Using this new methodology, group membership can be related to both family background characteristics and achievement in childhood and early adulthood, making it possible both to assess how family characteristics affect patterns of exposure to disadvantage during childhood and directly test alternative theories about the effect of different patterns of exposure on achievement. In this paper, the relationship between background factors, such as race, parental education, and family structure, and group membership is investigated, as is the association between group membership and achievement in early adulthood. The use of this technique is demonstrated using data from the Panel Study of Income Dynamics (PSID)

Women’s Perceptions of Caesarean Birth: A Roy International Study

The purpose of this Roy adaptation model-based multi-site international mixed method study was to examine the relations of type of caesarean birth (unplanned/planned), number of caesarean births (primary/repeat), and preparation for caesarean birth to women’s perceptions of and responses to caesarean birth. The sample included 488 women from the United States (n = 253), Finland (n = 213), and Australia (n = 22). Path analysis revealed direct effects for type of and preparation for caesarean birth on responses to caesarean birth, and an indirect effect for preparation on responses to caesarean birth through perception of birth the experience

Trends in Causes and Distribution, and Effects of Whitebark Pine Decline on Grizzly Bear Mortality in the Greater Yellowstone Ecosystem

Documented grizzly bear (Ursus arctos) mortalities have been increasing in recent years in the Greater Yellowstone Ecosystem (GYE), due, in part, to increases in bear numbers and range expansion. Previous research has documented that variable seed production of whitebark pine (WBP; Pinus albicaulis), an important fall food, is inversely related to grizzly bear fall mortality.  However, WBP has experienced widespread mortality during the last decade because of mountain pine beetle (Dendroctonus ponderosae) infestations. We investigated trends in causes and distribution of human-caused mortalities for independent-aged (? 2 yrs old) grizzly bears in the GYE during 1975–2012, and the effect of WBP cone production on numbers of fall (> 1 August) mortalities (n = 172) during the period of WBP decline (2000-2012) using Poisson regression. During 1975–1982, 91 percent of mortalities occurred within the Grizzly Bear Recovery Zone and primary causes were poaching/malicious killings and losses related to conflicts with livestock. During the two most recent decades most mortalities were associated with ungulate hunting, usually involving self-defense kills, or anthropogenic sites, and an increasing percentage of mortalities occurred outside the recovery zone. Using predictor variables of cone production, sex, location in or out of the Recovery Zone, and year suggests: 1) annual cone production was still predictive of human-caused fall mortalities, 2) no evidence of a difference in annual numbers of fall mortalities between males and females, and 3) an increase in annual mortalities over the study period, with most of this increase outside the Recovery Zone

Families' social backgrounds matter : socio-economic factors, home learning and young children's language, literacy and social outcomes

Parental support with children's learning is considered to be one pathway through which socio-economic factors influence child competencies. Utilising a national longitudinal sample from the Millennium Cohort Study, this study examined the relationship between home learning and parents' socio-economic status and their impact on young children's language/literacy and socio-emotional competence. The findings consistently showed that, irrespective of socio-economic status, parents engaged with various learning activities (except reading) roughly equally. The socio-economic factors examined in this study, i.e., family income and maternal educational qualifications, were found to have a stronger effect on children's language/literacy than on social-emotional competence. Socio-economic disadvantage, lack of maternal educational qualifications in particular, remained powerful in influencing competencies in children aged three and at the start of primary school. For children in the first decade of this century in England, these findings have equity implications, especially as the socio-economic gap in our society widens

Acute mesenteric ischemia and duodenal ulcer perforation: a unique double pathology

Background: Acute mesenteric ischaemia and duodenal perforation are surgical emergencies with serious consequences. Patients presenting with acute mesenteric ischaemia alone face a high mortality rate as high as 60% whereas those presenting with peptic ulcer perforation the mortality rates range from 6-14%. There are very few reported cases of patients presenting with this dual pathology. Case presentation: We report a unique case of a 53 year old Italian lady who presented with acute mesenteric ischaemia and duodenal perforation. This is the first report of massive bowel ischaemia and duodenal perforation with no apparent underlying common pathophysiology leading to this presentation. Conclusion: Early management in the intensive care unit and appropriate surgical intervention maximised the patient’s chances of survival despite the poor prognosis associated with her dual pathology. The rare pathology of the patient described can be explained by two possible hypotheses: peptic ulcer disease causing duodenal ulceration, which precipitated ischaemic infarction of the small bowel. The second hypothesis is the patient developed a stress related ulcer following ischaemic bowel infarction secondary to arterial thrombosis

Dual isotope analyses indicate efficient processing of atmospheric nitrate by forested watersheds in the northeastern U.S.

Author Posting. © Springer, 2008. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in Biogeochemistry 90 (2008): 15-27, doi:10.1007/s10533-008-9227-2.Nitrogen from atmospheric deposition serves as the dominant source of new nitrogen to forested ecosystems in the northeastern U.S.. By combining isotopic data obtained using the denitrifier method, with chemistry and hydrology measurements we determined the relative importance of sources and control mechanisms on nitrate (NO3-) export from five forested watersheds in the Connecticut River watershed. Microbially produced NO3- was the dominant source (82-100%) of NO3- to the sampled streams as indicated by the δ15N and δ18O of NO3-. Seasonal variations in the δ18O-NO3- in streamwater are controlled by shifting hydrology and temperature affects on biotic processing, resulting in a relative increase in unprocessed NO3- export during winter months. Mass balance estimates find that the unprocessed atmospherically derived NO3- stream flux represents less than 3% of the atmospherically delivered wet NO3- flux to the region. This suggests that despite chronically elevated nitrogen deposition these forests are not nitrogen saturated and are retaining, removing, and reprocessing the vast majority of NO3- delivered to them throughout the year. These results confirm previous work within Northeastern U.S. forests and extend observations to watersheds not dominated by a snow-melt driven hydrology. In contrast to previous work, unprocessed atmospherically derived NO3- export is associated with the period of high recharge and low biotic activity as opposed to spring snowmelt and other large runoff events.This work was funded by an EPA STAR Fellowship (FP-91637501-1) and a grant from QLF/The Sound Conservancy to RTB

Relationship between ecosystem productivity and photosynthetically-active radiation for northern peatlands

We analyzed the relationship between net ecosystem exchange of carbon dioxide (NEE) and irradiance (as photosynthetic photon flux density or PPFD), using published and unpublished data that have been collected during midgrowing season for carbon balance studies at seven peatlands in North America and Europe. NEE measurements included both eddy-correlation tower and clear, static chamber methods, which gave very similar results. Data were analyzed by site, as aggregated data sets by peatland type (bog, poor fen, rich fen, and all fens) and as a single aggregated data set for all peatlands. In all cases, a fit with a rectangular hyperbola (NEE = α PPFD Pmax/(α PPFD + Pmax) + R) better described the NEE-PPFD relationship than did a linear fit (NEE = β PPFD + R). Poor and rich fens generally had similar NEE-PPFD relationships, while bogs had lower respiration rates (R = −2.0μmol m−2s−1 for bogs and −2.7 μmol m−2s−1 for fens) and lower NEE at moderate and high light levels (Pmax = 5.2 μmol m−2s−1 for bogs and 10.8 μmol m−2s−1 for fens). As a single class, northern peatlands had much smaller ecosystem respiration (R = −2.4 μmol m−2s−1) and NEE rates (α = 0.020 and Pmax = 9.2μmol m−2s−1) than the upland ecosystems (closed canopy forest, grassland, and cropland) summarized by Ruimy et al. [1995]. Despite this low productivity, northern peatland soil carbon pools are generally 5–50 times larger than upland ecosystems because of slow rates of decomposition caused by litter quality and anaerobic, cold soils