Corehead Orchard Tree Establishment and Grazing Damage Survey 2013: Report to the Borders Forest Trust

The research report describes the history of fruit orchards in Scotland and monitoring of efforts to establish a traditional fruit orchard. Comparisons are made of the performance of different fruit varieties during the first two years of growth and the effects of deer browsing are discussed

Sphagnum abundance and photosynthetic capacity show rapid short-term recovery following managed burning

Background: Prescribed burning in peatlands is controversial due to concerns over damage to their ecological functioning, particularly regarding their key genus Sphagnum. However, empirical evidence is scarce. Aims: The aim of the article is to quantify Sphagnum recovery following prescribed burns. Methods: We completed nine fires at a raised bog in Scotland, achieving a range of fire severities by simulating drought in some plots. We measured Sphagnum cover and chlorophyll fluorescence Fv/Fm ratio (an estimate of photosynthetic capacity) up to 36 months post-fire. Results: Cover of dominant Sphagnum capillifolium was similar in unburnt and burnt plots, likely due to its high moisture content which prevented combustion. Burning decreased S. capillifolium Fv/Fm 5 months after fire from 0.67 in unburnt plots to 0.44 in low fire severity plots and 0.24 in higher fire severity (drought) plots. After 22 months, Fv/Fm in burnt plots showed a healthy photosynthetic capacity of 0.76 and no differences between severity treatments. Other Sphagnum species showed similar post-fire recovery though their low overall abundance precluded formal statistical analysis. Conclusions: S. capillifolium is resilient to low–moderate fire severities and the same may be true for a number of other species. This suggests that carefully applied managed burning can be compatible with the conservation of peatland ecosystem function

The impact of muirburning on lichen diversity

The use of fire as a management tool on moorlands is a practice with a long history. Primarily carried out to maintain a monoculture of young, vigorous growth Calluna to provide higher quality grazing for sheep, deer and grouse muirburning has a profound effect on the ecology and species composition of moorlands. The overriding influence on the ecology of heathlands is the life-cycle of Calluna vulgaris from the early pioneer phase through the building and mature phases to the degenerate phase. Lichen diversity is largely controlled by the life cycle of C. vulgaris. The process of burning interrupts the natural life cycle of Calluna preventing it moving into the mature and degenerate phases. From the early building phase onwards Calluna begins to greatly influence the microclimate below it canopy creating darker, moist conditions which favour the growth of pleurocarpous mosses over lichens and sees the latter largely replaced with the exception of a few bryophilous species. Muirburning largely aims to prevent progression to the mature and degenerate phases and thus to period traditionally seen as of high lichen diversity. However it maintains areas free from the overriding influence of Calluna where lichens may be able to maintain higher diversity than beneath the Calluna canopy. One hundred quadrats were completed on the moorlands of the National Trust for Scotland Mar Lodge Estate with the aim of quantifying and explaining changes in lichen diversity. 37 different burns were investigated as well as 26 unburnt sites. Analysis of the data was carried out using regression analysis and DCA. The results indicate that lichen diversity increases following burning but declines underneath the closed Calluna canopy. Mats of pleurocarpous mosses largely replaced lichens in older stands with only corticolous species showing any increase in this phase. There exists however significant differences between different communities with lichens in the second area studied being both more diverse and maintaining their abundance into the building phase, the drier conditions allowing them to fill the niche normally held by pleurocarpous mosses. Key factors in controlling lichen diversity were shown to be the time since fire and soil moisture although the latter may be linked to the changing dominance of Calluna and the influence of its microclimate

Bradda Head Fire 17-19th October 2003: A Report to the Isle Of Man Government Department Agriculture, Fisheries & Forestry

Following a large wildfire on the Bradda Head area of the Isle of Man a site visit and a report on the extent of a damage and necessity of restoration were completed by Penny Anderson Associates (PAA). A brief site visit by this author was made possible by the Isle of Man Government in order to gain further information on the severity of the fire and the area's subsequent regeneration. This report is divided into two parts. The first section gives a brief description of what was observed during the site visit while the second section goes on to describe the lessons to be learnt and recommendations based on the observed impacts and events surrounding the fire

Resilience of temperate peatland vegetation communities to wildfire depends upon burn severity and pre-fire species composition

Peatland ecosystems are of global conservation and environmental importance storing globally significant amounts of ancient carbon, regulating regional temperatures and hydrological regimes, and supporting unique biodiversity. Livestock grazing, land-use change, drainage, nutrient and acid deposition, and wildfire threaten the composition and function of many peatlands including those in the uplands of the United Kingdom. Presently, little is known about either the short- or long-term effects of wildfires within these systems in the UK. Our study aimed to evaluate how plant communities respond to wildfires across a range of vegetation communities, soil types, and burn severities. We evaluated wildfire burn severity using the ground-based Composite Burn Index adapted for treeless peatlands. Using paired burned–unburned plots, we quantified differences in the abundance of plant families and functional groups, vegetation diversity, and community composition. Multivariate differences in composition between burned and unburned areas were used as an index of community resilience to fire. Plots in heathland communities with shallow organic soils burned at the highest severities and had the greatest reductions in plant diversity and richness. There were significant declines in plot-scale species richness and diversity with increasing burn severity. Graminoids were resilient to fire whilst Ericaceae tended to increase with higher severity. Bryophyte composition was substantially altered—pleurocarpous species declined and acrocarpous species increased with greater burn severity. Community resilience was related to ground layer burn severity with higher burn severity driving greater changes in communities. Wildfire effects on temperate peatlands are a function of fire weather and site environmental and ecological characteristics. Management policy should ensure that the risk of severe wildfires is mitigated to protect ecosystem function and biodiversity. This will require system-specific fire management prescriptions across the gradient of peatland soil and vegetation types

Discovery of a nuclear gas bar feeding the active nucleus in Circinus

We report the discovery of gas inflow motions towards the active nucleus of the Circinus galaxy caused by the non-axisymmetric potential of a nuclear gas bar. Evidence for dust associated with the bar comes from the HST/NICMOS H-K color map, whereas the streaming motions along the gas bar are seen in the velocity field of the H2 S(1)(1-0) emission line. The gas bar is about 100 pc long with a visual extinction in excess of 10 mag. Indication for the gaseous nature of this bar comes from the lack of a stellar counterpart even in the K band where the extinction is greatly reduced. We also use the NICMOS emission line images (Pa-alpha, [SiVI], and [FeII]) to study the innermost region of the ionization cones and the nuclear star forming activity. We discuss the possible relationship of these components with the gaseous bar.Comment: 14 pages, 7 figures (3 color plates), accepted for publication in Ap

Unveiling the central parsec region of an AGN: the Circinus nucleus in the near infrared with the VLT

VLT J- to M\p-band adaptive optics observations of the Circinus Galaxy on parsec scales resolve a central bright Ks-band source with a FWHM size of 1.9 $\pm$ 0.6 pc. This source is only visible at wavelengths longward of 1.6 $\mu$m and coincides in position with the peak of the [Si VII]~2.48 $\mu$m coronal line emission. With respect to the peak of the central optical emission, the source is shifted by $\sim$ 0.15\arcsec (2.8 pc) to the south-east. Indeed, it defines the vertex of a fairly collimated beam which extends for $\sim$ 10 pc, and which is seen in both continuum light shortward of 1.6 $\mu$m and in H$\alpha$ line emission. The source also lies at the center of a $\sim$ 19 pc size [Si VII] ionization {\it bicone}. Identifying this source as the nucleus of Circinus, its size is compatible with a putative parsec-scale torus. Its spectral energy distribution, characterized by a prominent narrow peak, is compatible with a dust temperature of 300 K. Hotter dust within a 1 pc radius of the center is not detected. The AGN luminosity required to heat this dust is in the range of X-ray luminosities that have been measured toward the central source. This in turn supports the existence of highly obscuring material, with column densities of $10^{24}$ cm$^{-2}$, that must be located within 1 pc of the core.Comment: 15 pages, 4 figures; To appear in The Astrophysical Journa

Burning increases post-fire carbon emissions in a heathland and a raised bog, but experimental manipulation of fire severity has no effect

Large amounts of carbon are stored in northern peatlands. There is concern that greater wildfire severity following projected increases in summer drought will lead to higher post-fire carbon losses. We measured soil carbon dynamics in a Calluna heathland and a raised peat bog after experimentally manipulating fire severity. A gradient of fire severity was achieved by simulating drought in 2 × 2 m plots. Ecosystem respiration (ER), net ecosystem exchange (NEE), methane (CH4) flux and concentration of dissolved organic carbon ([DOC], measured at the raised bog only) were measured for up to two years after burning. The response of these carbon fluxes to increased fire severity in drought plots was similar to plots burnt under ambient conditions associated with traditional managed burning. Averaged across all burnt plots, burning altered mean NEE from a net carbon sink at the heathland (−0.33 μmol CO2 m−2 s−1 in unburnt plots) to a carbon source (0.50 μmol m−2 s−1 in burnt plots) and at the raised bog (−0.38 and 0.16 μmol m−2 s−1, respectively). Burning also increased CH4 flux at the raised bog (from 1.16 to 25.3 nmol m−2 s−1 in the summer, when it accounted for 79% of the CO2-equivalent emission). Burning had no significant effect on soil water [DOC]