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Preservation of δ13C signatures in oak charred wood: Application to the "forest" of Notre-Dame de Paris
Full text linkThe fire of the Notre-Dame de Paris’s cathedral (NDP) in 2019 brought a unique opportunity to study the past environmental conditions in the region during the High Middle Ages through the charred oak beams of the “Forest” (name given to its framework). However, as a preamble, there is a need to evaluate the preservation of the stable carbon isotope signatures (δ13C) in response to changes in molecular composition, occurring with carbonisation. To this end, experimental studies were conducted on modern and NDP oak wood at both inter- and intra-annual levels. Laser ablation was used for the first time on burnt wood. Results show that regardless of the charring duration, at temperatures above 500 °C, carbonisation‑induced 13C fractionation shows a consistent decrease (Δ13C) of approximately 1 ‰ relative to uncharred values. Despite a slight decrease in variance, a strong and significant correlation (rmean = 0.9, p < 0.01) was observed between the uncharred time series and the carbonised counterpart, showing that the C isotopic variability is preserved. This study paves the way to use the charcoal remains from the Notre-Dame de Paris framework as a unique paleoenvironmental archive
Effects of logging residue on the growth and properties of the humus layer in Scots pine and Norway spruce stands
Full text linkThe utilisation of forest-based primary biomass as a source of renewable energy is becoming increasingly prevalent as a means of reducing the reliance on fossil fuels. However, there has been a growing concern about the potential impact of increased organic matter and nutrient removal on long-term forest productivity. The objective of this study was to investigate the impact of logging residue removal on stand productivity and soil C and N levels in Finland. The material was collected from young Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.) stands 20–21 years following the final felling, as well as from a pine experiment that was established in conjunction with an intermediate thinning 20 years ago. In the young stands after final felling, the treatments were whole-tree harvesting, stem-only harvesting, and stem-only harvesting with a double amount of logging residues left on the plots. In the middle-aged stand after thinning, the residue levels were 0, 10, 20, and 30 Mg ha−1. In the young spruce stands, the removal of logging residue following the final felling resulted in a negative growth response, but the doubling of logging residue did not result in a further growth increase. In contrast, no treatment effects were observed in the growth of the Scots pine stands, both in the young stands after final felling and in the middle-aged stand after thinning. In the young stands after final felling, the logging residues had no significant impact on the amounts of humus layer C or N. In contrast, the logging residues increased the levels of both C and N in the humus layer of the middle-aged pine stand after thinning. It can be concluded that the removal of nutrients following the harvest of logging residue in final felling and thinning does not indicate significant issues with regard to the availability of nutrients, based on the data on tree growth
Forest damage
Full text linkHeterobasidion root and butt rot pose a greater risk in continuous cover forestry (CCF) than in rotation forestry (RF) in conifer-dominated forests, regardless of whether selective, gap or shelterwood cutting is used.
Damage from wind, snow, spruce bark beetle, and large pine weevil are likely to be less severe in CCF than in RF. However, the conversion of RF to CCF may briefly expose stands to windthrow.
Browsing by large herbivores on saplings may limit regeneration of tree species other than spruce in continuous cover forestry and reduce tree species diversity, but alternative silvicultural practices may also increase forage availability in the field and shrub layer. Browsing damage outcomes for saplings in CCF are difficult to predict.
For many types of damage in CCF, substantial knowledge gaps complicate the assessment of damage risk
Effects of wood ash, nitrogen, and biosolids fertilisation on the growth and soil properties of Scots pine and Norway spruce stands
Full text linkThe recycling of wood ash back to forests has the potential to restore nutrients that are removed during the harvesting of wood chips for bioenergy. Biosolids are nutrient-rich organic residual materials derived from biowaste and sewage sludge with potential use as fertiliser. The objective of this study was to assess the impact of wood ash fertilisation, with and without nitrogen (N) addition, as well as biosolids addition, on forest growth, and soil properties and processes. The material was collected from fertilisation experiments in southern Finland, two in Scots pine (Pinus sylvestris L.) stands and four in Norway spruce (Picea abies (L.) Karst.) stands on mineral soil, approximately 10 years after the treatments were applied. The treatments were as follows: a control with no fertilisation, two doses of wood ash (3000 kg ha−1, and 9000 kg ha−1), a nitrogen addition (180 kg ha−1), and treatments with N and ash additions. In addition, biosolids (4400 kg ha−1) were applied. The treatments had only a slight impact on growth in both pine and spruce stands. The most notable impact on the chemical properties of the humus layer was a reduction in acidity and an increase in base cation concentrations on the plots fertilised with ash. Conversely, the addition of N and/or wood ash did not result in a consistent impact on the C-to-N ratio, rates of carbon and net N mineralisation, or carbon and N amounts. The limited growth response to the N addition in any form is attributable to the minor alteration in N availability. Furthermore, the application of wood ash and biosolids did not result in any discernible adverse effects on soil properties
Integration soil contact model : A flexible pressure-sinkage method for simulating low speed vehicles with wheels and tracks
Full text linkAn integration soil contact model and a modular terramechanics simulator VieteriSim for vehicles running on wheels and tracks were developed. The presented computational method extends the soil contact model by introducing a user defined pressure-sinkage relationship according to a theoretical function or an experimental data set, a numerical integration of pressure over a contact area with a desired resolution and vector based rolling resistance coefficient calculation. The convergence of the model and the capability of the computational method are demonstrated by simulating a cut-to-length timber forwarder running on a soft terrain with and without bogie tracks
Progressive degradation of acetylated wood by the brown rot fungi Coniophora puteana and Rhodonia placenta
Full text linkAcetylation is a wood modification method that reduces the hygroscopicity of wood and increases its resistance to degradation by wood decaying fungi. Even though acetylated wood can have very high decay resistance, the wood material can be degraded and sometimes deacetylated by fungi. This study investigated the degradation and deacetylation of acetylated wood by Coniophora puteana and Rhodonia placenta to better understand the relationship between degradation and deacetylation in two different brown rot fungi. Wood samples were exposed to the fungi in a stacked-sample decay test, followed by acetyl content measurements and FTIR spectroscopy to investigate chemical changes in the samples. The results showed that both fungi could degrade acetylated wood to high mass loss despite a strong reduction in moisture content, but only R. placenta was found to cause preferential deacetylation. The deacetylation was slight and only observed in the early stages of decay in highly acetylated wood. Otherwise, acetyl groups were lost from the samples at the rate of mass loss. FTIR spectroscopy confirmed the loss of acetyl groups and revealed some chemical differences between unacetylated and acetylated wood. The spectral data indicated the loss of acetyl groups from lignin, which suggests that the loss of acetyl groups is not only due to the degradation of acetylated carbohydrates. The degradation of acetylated wood required further investigation, but it is clear that extensive deacetylation is not a requirement for brown rot degradation
Can a 12 Km GFS model simulate the observed relationship between cloud optical properties and extreme rainfall of Indian Summer monsoon?
No full textReduced Numbers of Returning Atlantic Salmon (Salmo salar) and Thiamine Deficiency Are both Associated with the Consumption of High-Lipid Prey Fish
Full text linkIn 2023, exceptionally few salmon (Salmo salar) ascended from the Baltic Sea to
spawn in the Rivers Tornionjoki and Simojoki, regardless of the proper number of smolts
descending to the sea in preceding years. We investigated how the numbers of age-0
and young herring (Clupea harengus) and sprat (Sprattus sprattus), which are the principal
prey species of salmon in the Baltic Proper, the main feeding area of these salmon, as
well as the amount of lipid obtained from them and their protein-to-lipid ratio, correlated
with the number of returning salmon and the thiamine (vitamin B1) status of spawning
salmon. The fewer the 0-year-old herring were and the more abundant were the youngish
sprat in the Baltic Proper when the post-smolts arrived there, and the greater the lipid
content and lower the protein-to-lipid ratio of the prey fish, the fewer salmon returned to
the Rivers Tornionjoki and Simojoki to spawn two years later. The number of returning
salmon was lowest with a high ratio of youngish sprat, 1–3 years old, regarding the River
Tornionjoki and 1–2 years old regarding the River Simojoki post-smolts, to 0-year-old
herring, which were of a suitable size to be the prey for the post-smolts upon their arrival
in the Baltic Proper. In 2021, the ratios were lowest due to the record-low number of
0-year-old herring. The poor thiamine status of spawning salmon was also associated with
the high lipid content of available prey fish and with the abundance of youngish sprat,
which have twice the lipid content of age-0 herring. Our findings parallel the observations
in the early 1990s when post-smolt survival declined concurrently with the outbreak of
thiamine deficiency, M74. We conclude that consuming high-lipid marine fish reduces the
survival of post-smolts and, thus, the number of returning salmon, in addition to causing
thiamine deficiency