103,558 research outputs found
Monitoring of forest ecosystems in Ireland : FOREM 9 project : final report
No full textIntensive monitoring has been carried out under EC Regulation 3528/86 (project number
8860 IR 001.0) at Ballyhooly, Co. Cork since 1988. In 1991, three new plots (Roundwood, Cloosh and Brackloon) were established (9060IR0030) to give a more comprehensive network of such plots in Ireland. Monitoring of these three plots continued under project numbers 9360IR0030, 9560IR0030, 9760 IR 0030 9860 IR 0030, 9960IR0030, 2000.60.IR, 2001.60.IR and the current project, focusing on atmospheric inputs and biogeochemical cycling. In 2001, a new plot, Ballinastoe was established, to replace the Roundwood plot, which was due to be clearfelled. This
project, (FOREM9, 2002.60.IR) ran from January 2002 to December 2002. The monitoring is designed to improve understanding of the effects of atmospheric pollution on forest ecosystems, and is based on permanent sample plots located in important forest ecosystems in Ireland. The
monitoring procedures followed those in the previous projects and closely follow the ICP Manual (UN/ECE, 1998 and updates). Measurements included: precipitation in an open-field plot; quantitative collection and chemical analysis of forest throughfall and stemflow; collection and chemical analysis of forest soil solution from zero-tension lysimeters below the forest floor, and
from suction lysimeters at greater depths.
The health status of the forests in Ireland is generally good. The Roundwood and
Ballinastoe sites are located in the east of Ireland. As such, they are it is subject to higher levels of atmospheric pollutants than the two sites located on the west coast. If there were to be a deterioration in the health of forests in Ireland due to atmospheric deposition, it would be expected
to first appear on the east coast, where deposition is highest. Thus the Roundwood and Ballinastoe sites are very valuable for the intensive monitoring programme.
Atmospheric deposition in Ireland is dominated by marine ions, notably sodium and
chloride. This is due to Ireland’s location on the western seaboard of continental Europe. However, the country is exposed to pollutants during periods of easterly air flows. Evidence of these is seen
particularly at the Roundwood and Ballinastoe sites, in eastern Ireland. These “pollution events” merit more comprehensive treatment, to ascertain both their frequency and intensity, and to make
some estimation of their potential effects on the forest ecosystem. Soil water sampling is essential to the understanding of these events. Calculation of soil water fluxes carried out in this project, improves our insight into the longer-term environmental impacts of atmospheric deposition on these forests.Not applicableEuropean Commissionti ab SB. 15/10/201
Carbon fluxes in a mature deciduous forest under elevated CO₂
No full textThis PhD thesis addressed several major aspects of the carbon (C) cycle in a c. 100-year-old, mixed deciduous forest under elevated CO₂ with an emphasis on below-ground processes. The aim was to assess the responses of tree fine roots and soil respiration to canopy CO₂ enrichment (? 550 ppm) in this tallest forest studied to date. Furthermore, leaf gas-exchange of the five study species was examined to ascertain the long-term response of photosynthetic carbon uptake to elevated atmospheric CO₂. Investigations at the Swiss Canopy Crane (SCC) experimental site were guided by the following key questions: (1) Does below-ground C allocation to fine root production increase in response to CO₂ enrichment in order to acquire more nutrients to match the enhanced C supply in the forest canopy? (2) Is below-ground metabolism enhanced and therefore forest soil respiration stimulated by canopy CO₂ enrichment? (3) Is leaf-level photosynthesis persistently stimulated by elevated CO₂ in this stand or had these mature broad-leaved trees reduced their carbon up- take by photosynthetic down-regulation under long-term CO₂ enrichment?
Findings from earlier studies at the SCC site, including 13C isotope tracing, all point towards an in- creased flux of C through CO₂-enriched trees to the soil but neither fine root biomass nor soil respiration were stimulated by elevated CO₂. Surprisingly, fine root biomass in bulk soil and ingrowth cores showed strong reductions by ? 30% in year five and six but were unaffected in the following seventh year of CO₂ enrichment. Given the absence of a positive biomass response of fine roots, we assumed that the extra C assimilated in the CO₂-enriched forest canopy was largely respired back to the atmosphere via increases in fine root and rhizosphere respiration and the metabolization of increased root derived exudates by soil microbes. Indeed, 52% higher soil air CO₂ concentration during the growing season and 14% greater soil microbial biomass both in- dicated enhanced below-ground metabolism in soil under CO₂-enriched trees. However, this did not translate into a persistent stimulation of soil respiration. At times of high or continuous precipitation soil water savings under CO₂-exposed trees (resulting from reduced sapflow) led to excessive soil moisture (> 45 vol.-%) impeding soil gas-exchange and thus soil respiration. Depending on the interplay between soil temperature and the consistently high soil water content in this stand, instantaneous rates of soil respiration were periodically reduced or increased under elevated CO₂ but on a diel scale and integrated over the growing season soil CO₂ emissions were similar under CO₂-enriched and control trees. Soil respiration could therefore not explain the fate of the extra C. The lacking sink capacity for additional assimilates led us to assume downward adjustment of photosynthetic capacity in CO₂-enriched trees thereby reducing carbon uptake in the forest canopy. Photosynthetic acclimation cannot completely eliminate the CO₂-driven stimulation in carbon uptake, but a reduction could hamper the detection of a CO₂ effect considering the low statistical power inevitably involved with such large-scale experiments. However, after eight years of CO₂ enrichment we found sustained stimulation in leaf photosynthesis (42-49%) indicating a lack of closure in the carbon budget for this stand under elevated atmospheric CO₂
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Human Impacts on Forest Biodiversity in Protected Walnut-Fruit Forests in Kyrgyzstan
No full textWe used a spatially explicit model of forest dynamics, supported by empirical field data and socioeconomic data, to examine the impacts of human disturbances on a protected forest landscape in Kyrgyzstan. Local use of 27 fruit and nut species was recorded and modeled. Results indicated that in the presence of fuelwood cutting with or without grazing, species of high socioeconomic impor- tance such as Juglans regia, Malus spp., and Armeniaca vulgaris were largely eliminated from the landscape after 50–150 yr. In the absence of disturbance or in the presence of grazing only, decline of these species occurred at a much lower rate, owing to competi- tive interactions between tree species. This suggests that the current intensity of fuelwood harvesting is not sustainable. Conversely, cur- rent grazing intensities were found to have relatively little impact on forest structure and composition, and could potentially play a positive role in supporting regeneration of tree species. These results indicate that both positive and negative impacts on biodiversity can arise from human populations living within a protected area. Potentially, these could be reconciled through the development of participatory approaches to conservation management within this reserve, to ensure the maintenance of its high conservation value while meeting human needs
Height-diameter allometry of tropical forest trees
No full textTropical tree height-diameter (H:D) relationships may vary by forest type and region making large-scale estimates of above-ground biomass subject to bias if they ignore these differences in stem allometry. We have therefore developed a new global tropical forest database consisting of 39 955 concurrent H and D measurements encompassing 283 sites in 22 tropical countries. Utilising this database, our objectives were: 1. to determine if H:D relationships differ by geographic region and forest type (wet to dry forests, including zones of tension where forest and savanna overlap). 2. to ascertain if the H:D relationship is modulated by climate and/or forest structural characteristics (e.g. stand-level basal area, A). 3. to develop H:D allometric equations and evaluate biases to reduce error in future local-to-global estimates of tropical forest biomass. Annual precipitation coefficient of variation (PV), dry season length (SD), and mean annual air temperature (TA) emerged as key drivers of variation in H:D relationships at the pantropical and region scales. Vegetation structure also played a role with trees in forests of a high A being, on average, taller at any given D. After the effects of environment and forest structure are taken into account, two main regional groups can be identified. Forests in Asia, Africa and the Guyana Shield all have, on average, similar H:D relationships, but with trees in the forests of much of the Amazon Basin and tropical Australia typically being shorter at any given D than their counterparts elsewhere. The region-environment-structure model with the lowest Akaike's information criterion and lowest deviation estimated stand-level H across all plots to within amedian −2.7 to 0.9% of the true value. Some of the plot-to-plot variability in H:D relationships not accounted for by this model could be attributed to variations in soil physical conditions. Other things being equal, trees tend to be more slender in the absence of soil physical constraints, especially at smaller D. Pantropical and continental-level models provided less robust estimates of H, especially when the roles of climate and stand structure in modulating H:D allometry were not simultaneously taken into account
Measurement of the ratio of branching fractions B(B0→K∗0γ )/B(B0s→φγ ) and the directCP asymmetry inB 0→K∗0γ
No full textThe ratio of branching fractions of the radiative B decays B0→K⁎0γ and B0s→ϕγ has been measured using an integrated luminosity of 1.0 fb−1 of pp collision data collected by the LHCb experiment at a centre-of-mass energy of s√=7TeV. The value obtained is
B(B0→K⁎0γ)B(B0s→ϕγ)=1.23±0.06(stat.)±0.04(syst.)±0.10(fs/fd),
where the first uncertainty is statistical, the second is the experimental systematic uncertainty and the third is associated with the ratio of fragmentation fractions fs/fd. Using the world average value for B(B0→K⁎0γ), the branching fraction B(B0s→ϕγ) is measured to be (3.5±0.4)×10−5.
The direct CP asymmetry in B0→K⁎0γ decays has also been measured with the same data and found to be
ACP(B0→K⁎0γ)=(0.8±1.7(stat.)±0.9(syst.))%.
Both measurements are the most precise to date and are in agreement with the previous experimental results and theoretical expectations
Branching fraction and CP asymmetry of the decays B+→K0Sπ+ and B+→K0SK+
No full textAn analysis of B+ → K0
Sπ+ and B+ → K0
S K+ decays is performed with the LHCb experiment. The pp
collision data used correspond to integrated luminosities of 1 fb−1 and 2 fb−1 collected at centre-ofmass
energies of
√
s = 7 TeV and
√
s = 8 TeV, respectively. The ratio of branching fractions and the
direct CP asymmetries are measured to be B(B+ → K0
S K+
)/B(B+ → K0
Sπ+
) = 0.064 ± 0.009 (stat.) ±
0.004 (syst.), ACP(B+ → K0
Sπ+
) = −0.022 ± 0.025 (stat.) ± 0.010 (syst.) and ACP(B+ → K0
S K+
) =
−0.21 ± 0.14 (stat.) ± 0.01 (syst.). The data sample taken at
√
s = 7 TeV is used to search for
B+
c
→ K0
S K+ decays and results in the upper limit ( fc · B(B+
c
→ K0
S K+
))/( fu · B(B+ → K0
Sπ+
)) <
5.8 × 10−2 at 90% confidence level, where fc and fu denote the hadronisation fractions of a ¯b
quark
into a B+
c or a B+ meson, respectively
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
PARTICIPATORY FOREST MANAGEMENT IN ANDHRA PRADESH : A Review
No full textThis paper traces the recent emergence of the new participatory forest management regime in AP Joint Forest Management (JFM) and Community Forest Management (CFM). This paper is based on the existing literature on forest policies, the historical context (pre-colonial, colonial and post independent India), and impact studies. The paper considers the contemporary developments in India in shaping the forest policies in AP. At the same time it considers the significant role played by donors and civil society. The process and quality of implementation, and the impact of the programme on local communities and resources are also examined. AP ranks fifth in India in terms of geographical area (275,068 sq km), and third in terms of forestland (63,813 sq km or 6.38 mha (Million Hectares), which constitutes 23% of APs total land area. Some 65% of APs forest area is spread over 8 predominantly tribal districts in the northern part of the state. These tribal populations are particularly dependent on the forest for their livelihoods for forest product collection and cultivation on forestland. Historically the relationship between these tribals and the government agencies, particularly the Forest Department (FD), has been very poor, with numerous uprisings, including the Naxalite movement. Many of these lands are disputed due to inadequacies in the legal processes by which largely tribal lands were declared state forests. Legally podu has de jure status prior to 1980 Act. Post 1980 podu cultivation is illegal and considered as encroachment. De facto podu is considered as encroachment (prior to 1980) as there is no proper settlement, conceptually typical podu practice is seen only in a few pockets in the state, especially in Vishakhapatnam. In 1956, on the formation of AP from Telangana and parts of the Madras Presidency, the pre-existing forest management regimes from the two distinct areas were harmonised by the Law Commission, leading to the AP Forest Act, 1967. Initially the states FD continued with a policy of commercialisation and revenue generation. However, with a growing crisis of forest degradation participatory approaches were introduced. The Government Order (GO) for JFM in AP was issued in 1992, although implementation didnt start until 1994. JFM has built on the roles played by both local forest *Centre for Economic and Social Studies, Hyderabad, India. +Overseas Development Group, University of East Anglia, Norwich, UK. users and the FD staff. Funding to the FD to promote JFM has come from both the World Bank (WB) and from centrally funded schemes, such as the Employment Assurance Scheme (EAS). Formation of Vana Samrakshana Samithies (VSS) began slowly after the GO, although by 2004 the official number stands at 7,245 VSS, managing 1,886,764 ha, (or over 29% of state forest land) and involving 611,095 families. The largest numbers of VSS are concentrated in the tribal areas of Adilabad, Visakhapatnam, and Khammam. The pattern of implementation and the outcomes is extremely complex, partly because of the wide variety of local conditions, ethnic and caste composition and local livelihood uses of forestland. The limited devolution of power which has occurred through VSS formation have however certainly been popular in many areas, because they have given local people endorsement to protect their local forest resources, upon which they depend for their livelihoods. Some employment opportunities have also been provided and some shares of revenues from forest product marketing are promised. Evidence suggests that the VSS have been successful in many areas in terms of regenerating degraded forests between 1993 and 1999. However there have been many criticisms of the JFM programme so far, most fundamentally focussing on the issues of power and land tenure. Because the FD has held almost complete discretionary power over the scheme and its implementation, the JFM process has inevitably reflected their objectives. Whilst many foresters have espoused very progressive ideas and concepts, in practice the implementation of the scheme has often furthered forest management strategy according to silvicultural norms, rather than local livelihood-oriented practices. In the context of a fundamental power asymmetry between the FD and the VSS., there has been little empowerment of local communities to take their own decisions with respect to forest management. This is most obviously seen in forest management plans. Whilst local people would like to see livelihood oriented forest management regime (ie. regular product flows, shorter term rotations, multiple product mixes) the FD has tended to prioritise its conventional forest management practices, often involving long rotation timber stands. The micro-plans commonly fit within wider divisional working plans. Livelihoods security could be increased if the forest resource were under a management plan, which actually prioritised local needs and opportunities. Institutional sustainability is a major problem in AP with many VSS becoming defunct due to conflict, lack of interest, or lack of funds. Where participation has been based on substantial funding flows, when the funds stop the motivation to participate reduces drastically. The institutional linkage between the VSS and the panchayat raj institutions has not been developed, which could ensure not only long-term sustainability, but also empowerment and legal independence of the local institutions. Non-Government Organisations (NGOs) have been largely excluded from the implementation of JFM, despite the fact they have played a major role in formulating the PFM policies at the state level.Forest Management, Andhra Pradesh
How Similar Are Forest Disturbance Maps Derived from Different Landsat Time Series Algorithms?
No full textDisturbance is a critical ecological process in forested systems, and disturbance maps are important for understanding forest dynamics. Landsat data are a key remote sensing dataset for monitoring forest disturbance and there recently has been major growth in the development of disturbance mapping algorithms. Many of these algorithms take advantage of the high temporal data volume to mine subtle signals in Landsat time series, but as those signals become subtler, they are more likely to be mixed with noise in Landsat data. This study examines the similarity among seven different algorithms in their ability to map the full range of magnitudes of forest disturbance over six different Landsat scenes distributed across the conterminous US. The maps agreed very well in terms of the amount of undisturbed forest over time; however, for the ~30% of forest mapped as disturbed in a given year by at least one algorithm, there was little agreement about which pixels were affected. Algorithms that targeted higher-magnitude disturbances exhibited higher omission errors but lower commission errors than those targeting a broader range of disturbance magnitudes. These results suggest that a user of any given forest disturbance map should understand the map’s strengths and weaknesses (in terms of omission and commission error rates), with respect to the disturbance targets of interest
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