Fossil charcoal quantification using manual and image analysis approaches

Charcoal particles are evidence of past fire events and macro-charcoal particles have been shown to represent local fire events. There are several methods for the preparation and quantification of macro-charcoal particles, none of which have been universally accepted as standard. Very few studies compare methodological differences and no studies to date compare quantification by mass with quantification by volume using image analysis. Using three cores taken from a peatland located in SE Norway, we compare these two established methods using a generalized linear mixed model (GLMM) and a split-plot ANOVA test. We show that charcoal volume (image analysis method) was a better predictor of charcoal mass than charcoal particle number and the same size classes of charcoal as size class distributions were not spatially and temporally correlated. Although there is still a need for a common and unifying method, our results show that quantification of charcoal particles by image analysis including size (e.g. height in mm) and area (mm2)/volume (mm3) measurements provides more significant results in cross-site or multiple-site studies than quantifications based on particle number. This has implications for the interpretation of charcoal data from regional studies that are used to model drivers of wildfire activity and environmental change in boreal–temperate landscapes during the Holocene. </jats:p

The reconstruction of past forest dynamics over the last 13,500 years in SW Sweden

Evidence for unbroken continuity of tree taxa over the last c. 13,500 years is presented from a biodiversity ‘hotspot’ nature reserve in south-west Sweden.Forest composition, continuity, fire and disturbance events are reconstructed using palaeoecological methods. A lake record reveals that Pinus sylvestris,Betula spp., Salix spp., Populus tremula and Hippophae rhamnoides were the initial trees scattered in a semi-open, steppe environment. This developedinto forest with Pinus, Betula, Corylus, Alnus, Ulmus and Populus with evidence for frequent fires. Deciduous trees became more significant as fires becameless frequent and Quercus, Fraxinus and Tilia expanded. Fire frequencies increased again in the Bronze Age probably associated with anthropogenic useof the forest, and the first Fagus sylvatica pollen was recorded. Burning continued through the Iron Age, but charcoal is briefly absent for a period oftenreferred to as the ‘Late Iron Age Lull’. The forest re-expanded with successions involving Juniperus, but with an altered composition from the earlier mixeddeciduous community, to one dominated by Fagus. This is coincident with the first pollen records for Picea abies. The early Holocene mixed forest withfrequent low-intensity fires is potentially associated with the greatest diversity of red-listed insect species. Forest continuity and the fragmented reservoirpopulations of old deciduous trees in the Fagus-dominated forest today are likely to have been critical in preserving the present-day, species-rich, rareepiphytic flora, wood-inhabiting fungi and invertebrate communities. As many of these forest fragments may become more vulnerable with future climatechange, tree diversity with some disturbance may become essential for survival of the endangered saproxylic species

Millennial-scale fire dynamics in temperate forest of central Europe

International audienc

Vegetation dynamics and Fire History in Färnebofjärden National Park, Central Sweden

Palaeoecological studies can identify past trends in vegetation communities and processes over long time scales. Pollen, plant macrofossils and charcoal analyses are used to reconstruct vegetation over the last 6400 years and provide information about former human impact and disturbance regimes in Färnebofjärden National Park, Central Sweden. Three specific conservation planning topics were addressed: (1) the changing ratio of conifers to broadleaved trees; (2) the origin and history of the river meadows and the biodiverse Populus tremula meadows; (3) the role of fire in the maintenance of biological values. Early diverse mixed broadleaved forest assemblages with pine were followed by significant declines of the more thermophilic forest elements prior to the expansion of spruce in the Iron Age. The rise to dominance of spruce was a ‘natural’ process that has been exaggerated by anthropogenic disturbance to artificially high levels today. The initial river meadow communities were facilitated by fire and frequent flooding events, but subsequent dynamics have more definitely been supported by human activities. Rural abandonment during the last 100 years has led to woody successions. Fire has been a continual disturbance factor with an influence on conservation issues such as Picea abies dominance and the maintenance of diverse, non-forest communities. Present occurrence of fire is unusually low, but natural fire frequencies are increasing in the region

Long-term forest dynamics at Gribskov, eastern Denmark with early-Holocene evidence for thermophilous broadleaved tree species

We report on a full-Holocene pollen, charcoal and macrofossil record from a small forest hollow in Gribskov, eastern Denmark. The Fagus sylvatica pollen record suggests the establishment of a small Fagus population at Gribskov in the early Holocene together with early establishment of other thermophilous broadleaved trees, including Quercus sp., Tilia sp. and Ulmus sp. The macrofossils contribute to the vegetation reconstruction with evidence for local presence of species with low pollen productivity or easily degraded pollen types such as Populus. The charcoal record shows frequent burning during two periods of the early Holocene and from c. 3000 cal. BP to present. The early-Holocene part of the record indicates a highly disturbed forest ecosystem with frequent fires and abundant macrofossils of particularly Betula sp. and Populus sp. The sediment stratigraphy and age-depth relationships give no clear indication of post-depositional disturbance, although a possible short-lived hiatus occurs around 6500 cal. BP. The early pollen record from thermophilous trees could indicate that there may have been some downwash following sediment desiccation through wood peat layers deposited between c. 6500 and 10,000 cal. BP, but the overall biostratigraphy is consistent with other Danish small hollow records

Organisational and extra-organisational determinants of volume of service delivery by English community pharmacies: a cross-sectional survey and secondary data analysis

ObjectivesThis study aimed to identify the organisational and extraorganisational factors associated with existing variation in the volume of services delivered by community pharmacies.Design and settingLinear and ordered logistic regression of linked national data from secondary sources—community pharmacy activity, socioeconomic and health need datasets—and primary data from a questionnaire survey of community pharmacies in nine diverse geographical areas in England.Outcome measuresAnnual dispensing volume; annual volume of medicines use reviews (MURs).ResultsNational dataset (n=10 454 pharmacies): greater dispensing volume was significantly associated with pharmacy ownership type (large chains&gt;independents&gt;supermarkets), greater deprivation, higher local prevalence of cardiovascular disease and depression, older people (aged &gt;75 years) and infants (aged 0–4 years) but lower prevalence of mental health conditions. Greater volume of MURs was significantly associated with pharmacy ownership type (large chains/supermarkets&gt;&gt;independents), greater dispensing volume, and lower disease prevalence.Survey dataset (n=285 pharmacies; response=34.6%): greater dispensing volume was significantly associated with staffing, skill-mix, organisational culture, years open and greater deprivation. Greater MUR volume was significantly associated with pharmacy ownership type (large chains/supermarkets&gt;&gt;independents), greater dispensing volume, weekly opening hours and lower asthma prevalence.ConclusionsOrganisational and extraorganisational factors were found to impact differently on dispensing volume and MUR activity, the latter being driven more by corporate ownership than population need. While levels of staffing and skill-mix were associated with dispensing volume, they did not influence MUR activity. Despite recent changes to the contractual framework, the existing fee-for-service reimbursement may therefore not be the most appropriate for the delivery of cognitive (rather than supply) services, still appearing to incentivise quantity over the quality (in terms of appropriate targeting) of services delivered. Future research should focus on the development of quality measures that could be incorporated into community pharmacy reimbursement mechanisms.</jats:sec

Holocene-scale fire dynamics from spruce-beech temperate forests of central Europe

International audienc