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Sigurd and I passed on the gourmand line-up, stuffed, as it was, with MPW classics. We were in search of the real [Robert Reid], which is not as easy as it should be. There seems far too much of MPW all over this menu, and not nearly enough RR, which seems a pity, as RR is more than able to compose his own twinkling dishes. I was first alerted to this fact some months back by a fabulously good dish of rabbit in its own jelly and loads of baby veg that managed to roll out the flavour of the rabbit without killing the flavour of the vegetables (not always an easy thing). It was a dish of a sophisticatedly sunny aspect, something you can't carry off without care, thought and talent. For this lunch, I decided on a panache of langoustines and pork belly with a puree of celeriac and a sauce made from the langoustines, grilled sea bass with fennel and beurre noisette, and ile flottante with custard. Sigurd was taken by caramelised scallops and calamari with sauce nero from the daily menu, then tranche of salt cod with smoked salmon and sauce \"Reputation\", whatever that might be, and finally the toothsome quiddities of tarte Tatin of pears, a longtime MPW classic, the virtues of which need no extolling here. Actually, the same could be said of the ile flottante, which looked as if part of the massive iceberg that recently broke off Antarctica had floated into the Oak Room on a sea of custard.

Acute Oak Decline (AOD) is complex syndrome affecting Britain’s keystone native oak species, (Quercus robur L. and Q. petraea L. (Matt.) Liebl.), in some cases causing mortality within five years of symptom development. The most distinguishable symptom is weeping stem lesions, from which four species of bacteria have been isolated: Brenneria goodwinii, Gibbsiella quercinecans, Lonsdalea britannica and Rahnella victoriana. We do not yet know where else these bacteria exist, and little is known about the relationship of the wider oak leaf microbiome (phyllosphere) to acute oak decline. Here we investigate whether incidental evidence from a large oak genome re-sequencing dataset could be used to detect these bacteria in oak foliage, and whether bacterial incidence co-varied with AOD status or location. Oak leaves and buds were sampled from 421 trees at five sites in England. Whole genomic DNA from these samples was shot-gun sequenced with short reads. Non-oak reads were extracted from these data and queried to microbial databases. Reads uniquely matching AOD-associated bacterial genomes were found to be present on trees from all five sites and included trees with active lesions, trees with historic lesions and trees without AOD symptoms. The abundance of the AOD-associated bacteria did not differ between tree health categories but did differ among sites. We conclude that the AOD-associated bacteria may be members of the normal oak microbiome, whose presence on a tree is not sufficient to cause AOD symptoms.

Acorn production in oak (Quercus spp.) shows considerable inter-annual variation, known as masting, which provides a natural defence against seed predators but a highly-variable supply of acorns for uses such as in commercial tree planting each year. Anthropogenic emissions of greenhouse gases have been very widely reported to influence plant growth and seed or fruit size and quantity via the ‘fertilisation effect’ that leads to enhanced photosynthesis. To examine if acorn production in mature woodland communities will be affected by further increase in CO2, the contents of litter traps from a Free Air Carbon Enrichment (FACE) experiment in deciduous woodland in central England were analysed for numbers of flowers and acorns of pedunculate oak (Quercus robur L.) at different stages of development and their predation levels under ambient and elevated CO2 concentrations. Inter-annual variation in acorn numbers was considerable and cyclical between 2015 and 2021, with the greatest numbers of mature acorns in 2015, 2017 and 2020 but almost none in 2018. The numbers of flowers, enlarged cups, immature acorns, empty acorn cups, and galls in the litter traps also varied amongst years; comparatively high numbers of enlarged cups were recorded in 2018, suggesting Q. robur at this site is a fruit maturation masting species (i.e., the extent of abortion of pollinated flowers during acorn development affects mature acorn numbers greatly). Raising the atmospheric CO2 concentration by 150 μL L−1, from early 2017, increased the numbers of immature acorns, and all acorn evidence (empty cups + immature acorns + mature acorns) detected in the litter traps compared to ambient controls by 2021, but did not consistently affect the numbers of flowers, enlarged cups, empty cups, or mature acorns. The number of flowers in the elevated CO2 plots’ litter traps was greater in 2018 than 2017, one year after CO2 enrichment began, whereas numbers declined in ambient plots. Enrichment with CO2 also increased the number of oak knopper galls (Andricus quercuscalicis Burgsdorf). We conclude that elevated CO2 increased the occurrence of acorns developing from flowers, but the putative benefit to mature acorn numbers may have been hidden by excessive pre- and/or post-dispersal predation. There was no evidence that elevated CO2 altered masting behaviour.

Chronically overabundant white-tailed deer (Odocoileus virginianus) populations have made it difficult to regenerate desirable woody species throughout much of their range in the eastern United States and southern Canada. Neither silvicultural prescriptions nor deer management alone have resulted in successful forest regeneration. We tallied woody stems (≥1 m tall, <10 cm diameter) on 62 hunted and 46 nonhunted forest stands throughout Connecticut, USA, during autumn 2015 to spring 2018; all stands had a timber regeneration harvest from 2–12 years prior to our study (2003–2016). Our objective was to examine the influence of the combination of deer management and residual stand structure on woody regeneration diversity, density, and composition. After accounting for the influence of stand structures over a range of residual basal areas from 0–23 m²/ha, we found that deer had a negative effect on regeneration diversity, density, and species composition. Moreover, we found that the combination of state-regulated deer hunting and forest-overstory removal resulted in greater woody-plant regeneration rates with increased diversity. Stem densities of oak–hickory (Quercus spp.–Carya spp.), maple (Acer spp.), and minor species, as well as combined species, were greater in hunted versus nonhunted stands, and in clearcuts as opposed to 2-aged and shelterwood stands. American beech (Fagus grandifolia) and shrub species did not differ in stem density regardless of hunting or treatment prescription. Our study indicates that for properties where the management goal is to create dense vegetation with high tree, shrub, and herbaceous species diversity, managers should both encourage hunting to reduce pressure on browse-sensitive species and leave as few postharvest residual trees as possible to maximize growing space for regeneration. A lack of deer harvest and overstory removal in southern New England resulted in low diversity vegetation dominated by lesser preferred species such as birch (Betula spp.) or American beech. The use of hunting as a tool to relieve browsing pressure will improve both woody and herbaceous plant regeneration where light is not limited.

Outbreaks of acute oak decline (AOD) have been documented in England from 2006. Both species of native oaks (Quercus robur and Quercus petraea) are affected. To complement isolation efforts for identification of putative causative biotic agents and increase our understanding of bacteria associated with oak tissue, five sites in England were chosen for this study. Samples of outer bark, inner bark, sapwood and heartwood were taken from healthy oak and trees with symptoms at varying stages of the syndrome. Furthermore, larval galleries attributed to infestation with Agrilus biguttatus were included. After DNA extraction and amplification of the V3–V5 fragment of the bacterial 16S rRNA genes by pyrosequencing, the dataset was analyzed to identify patterns in bacterial communities in oak tissue samples with and without AOD symptoms at each site. The composition of bacterial communities differed greatly according to the site from which the samples were obtained. Within each site, the composition of the bacteria associated with symptomatic tissue varied between advanced stages of the syndrome and healthy tissue. Key players in healthy and symptomatic tissue were identified and included members of the Gammaproteobacteria related to Pseudomonas sp. or Brenneria goodwinii and members of the Firmicutes.

The number of emerging tree diseases has increased rapidly in recent times, with severe environmental and economic consequences. Systematic regulatory surveys to detect and establish the distribution of pests are crucial for successful management efforts, but resource-intensive and costly. Volunteers who identify potential invasive species can form an important early warning network in tree health; however, what these data can tell us and how they can be best used to inform and direct official survey effort is not clear. Here, we use an extensive dataset on acute oak decline (AOD) as an opportunity to ask how verified data received from the public can be used. Information on the distribution of AOD was available as (i) systematic regulatory surveys conducted throughout England and Wales, and (ii) ad hoc sightings reported by landowners, land managers and members of the public (i.e. ‘self-reported’ cases). By using the available self-reported cases at the design stage, the systematic survey could focus on defining the boundaries of the affected area. This maximized the use of available resources and highlights the benefits to be gained by developing strategies to enhance volunteer efforts in future programmes.

An area of ancient and semi-natural woodland (ASNW) has been investigated by applied aerial spectroscopy using an unmanned aerial vehicle (UAV) with multispectral image (MSI) camera. A novel normalised difference spectral index (NDSI) algorithm was developed using principal component analysis (PCA). This novel NDSI was then combined with a simple segmentation method of thresholding and applied for the identification of native tree species as well as the overall health of the woodland. Using this new approach allowed the identification of trees at canopy level, across 7.4 hectares (73,934 m 2 ) of ASNW, as oak (53%), silver birch (37%), empty space (9%) and dead trees (1%). This UAV derived data was corroborated, for its accuracy, by a statistically valid ground-level field study that identified oak (47%), silver birch (46%) and dead trees (7.4%). This simple innovative approach, using a low-cost multirotor UAV with MSI camera, is both rapid to deploy, was flown around 100 m above ground level, provides useable high resolution (5.3 cm / pixel) data within 22 mins that can be interrogated using readily available PC-based software to identify tree species. In addition, it provides an overall oversight of woodland health and has the potential to inform a future woodland regeneration strategy.

We present a millennial long dendroclimatic reconstruction of spring/summer precipitation for southern-central England. Previous research identified a significant moisture stress signal in ring-width data measured from oak trees growing in southern England. In this study, we build upon this earlier work, specifically targeting south-central England, to derive a well replicated oak ring-width composite chronology using both living and historical material. The data-set includes 352 living trees (AD 1629–2009) and 1540 individual historical series (AD 663–1925). The period expressed by at least 50 trees in any year is AD 980–2009. Calibration experiments identify the optimal seasonal predictand target as March–July precipitation (1901–2007: r 2  = 0.33). However, comparison with the long Kew Gardens precipitation record indicates a weakening in tree-growth/climate response from ~1800 to 1920 which we speculate may be related to smoke and sulphur dioxide (SO 2 ) emissions at that time which may have also contributed to a decrease in tree productivity. The time-series derived using the regional curve standardisation method to capture lower frequency information shows a mediaeval period with alternating multi-decade-long dry and wet periods, with AD 1153–1172 being the wettest reconstructed 20-year period in the whole record. Drier conditions are prevalent from ~1300 to the early sixteenth century followed by a period of increasing precipitation levels. The most recent four centuries of the record appear similar to the mediaeval period with multiple decade-long dry and wet periods. The late twentieth century is the second reconstructed wettest period. These centennial hydroclimatic trends are in broad agreement with independent regional scale hydroclimatic reconstructions from tree-ring (East Anglia), historical, speleothem and peat water level proxy archives in the United Kingdom and appear coupled with reconstructed sea surface temperature changes in the North Atlantic which in turn influence the Atlantic meridional overturning circulation and westerly airflow across the UK.

The relative influence of climate and Indigenous cultural burning on past forest composition in southern New England, US, remains debated. Employing varied analyses, this study compared data on Indigenous settlements from over 5000 years before present (YBP) with relative tree abundances estimated from pollen and land survey records. Results suggested that fire-tolerant vegetation, mainly oak (Quercus spp.), was more abundant near Indigenous settlements from 4955 to 205 YBP (i.e., 86–91% fire-tolerant trees), and significantly (p < 0.05) higher from 3205 to 205 YBP; fire-tolerant vegetation was less abundant away from settlements, where it also experienced greater fluctuations. Correlative models showed that warmer temperatures and distance to Indigenous settlement, which are both indicators of fire, were important predictors in the 17th–18th centuries of fire-tolerant tree abundance; soil variables were less important and their relationships with vegetation were unclear. A marked increase in oak abundance occurred above 8 °C mean annual temperature and within 16 km of major Indigenous settlements. Pyrophilic vegetation was most correlated with distance to Indigenous villages in areas with 7–9 °C mean annual temperature, typical of higher latitudes and elevations that usually supported northern hardwoods. Widespread burning in warmer areas potentially weakened relationships between distance and pyrophilic abundance. Indigenous land use imprinted upon warmer areas conducive to burning created patterns in fire-tolerant vegetation in southern New England, plausibly affecting most low-elevation areas. Results imply that restoration of fire-dependent species and of barrens, savannas, and woodlands of oak in southern New England benefit from cultural burning.