Woodland restoration on mineral extraction waste tips: a comparison of tree performance over eight years

Woodland restoration on hard-rock waste tips is often unsuccessful because of inappropriate species selection for planting and poor growth of planted trees after initial establishment. In this study we monitored the growth of three native (Betula pendula, Sorbus aucuparia and Quercus petrea) and one exotic (Alnus cordata) tree species planted in a restoration scheme on slate-waste tips in North Wales. The objectives of this study were to: (i) investigate the relationship between the relative performance of planted species, and the species’ relative success in natural regeneration at the same site; and (ii) investigate how well early performance is correlated with the subsequent success of the species. The growth of the native species did reflect the extent of their natural regeneration at the site (B. pendula > S. aucuparia = Q. petraea). However, while not present as a natural coloniser, A. cordata was the best performing species. Species’ relative growth performance after eight years was predicted by that during the first few months after planting, suggesting that short-term monitoring has value in predicting longer-term establishment success. Of the species studied A. cordata is recommended for planting on slate waste. However, B. pendula is the best of the native species studied

The effects of disease on optimal forest rotation : a generalisable analytical framework

This work is from the project titled Modelling economic impact and strategies to increase resilience against tree disease outbreaks. This is one of seven projects in the Tree Health and Plant Biosecurity Initiative (phase 2) funded by BBSRC, Defra, ESRC, Forestry Commission, NERC and Scottish Government.The arrival of novel pathogens and pests can have a devastating effect on the market values of forests. Calibrating management strategies/decisions to consider the effect of disease may help to reduce disease impacts on forests. Here, we use a novel generalisable, bioeconomic model framework, which combines an epidemiological compartmental model with a Faustmann optimal rotation length model, to explore the management decision of when to harvest a single rotation, even-aged, plantation forest under varying disease conditions. Sensitivity analysis of the rate of spread of infection and the effect of disease on the timber value reveals a key trade-off between waiting for the timber to grow and the infection spreading further. We show that the optimal rotation length, which maximises the net present value of the forest, is reduced when timber from infected trees has no value; but when the infection spreads quickly, and the value of timber from infected trees is non-zero, it can be optimal to wait until the disease-free optimal rotation length to harvest. Our original approach provides an exemplar framework showing how a bioeconomic model can be used to examine the effect of tree diseases on management strategies/decisions.Publisher PDFPeer reviewe

Circular wood use can accelerate global decarbonisation but requires cross-sectoral coordination

Predominantly linear use of wood curtails the potential climate-change mitigation contribution of forestry value-chains. Using lifecycle assessment, we show that more cascading and especially circular uses of wood can provide immediate and sustained mitigation by reducing demand for virgin wood, which increases forest carbon sequestration and storage, and benefits from substitution for fossil-fuel derived products, reducing net greenhouse gas emissions. By United Kingdom example, the circular approach of recycling medium-density fibreboard delivers 75% more cumulative climate-change mitigation by 2050, compared with business-as-usual. Early mitigation achieved by circular and cascading wood use complements lagged mitigation achieved by afforestation; and in combination these measures could cumulatively mitigate 258.8 million tonnes CO 2e by 2050. Despite the clear benefits of implementing circular economy principles, we identify many functional barriers impeding the structural reorganisation needed for such complex system change, and propose enablers to transform the forestry value-chain into an effective societal change system and lead to coherent action. </p

Dissipative and Dispersive Optomechanics in a Nanocavity Torque Sensor

Dissipative and dispersive optomechanical couplings are experimentally observed in a photonic crystal split-beam nanocavity optimized for detecting nanoscale sources of torque. Dissipative coupling of up to approximately $500$ MHz/nm and dispersive coupling of $2$ GHz/nm enable measurements of sub-pg torsional and cantilever-like mechanical resonances with a thermally-limited torque detection sensitivity of 1.2$\times 10^{-20} \text{N} \, \text{m}/\sqrt{\text{Hz}}$ in ambient conditions and 1.3$\times 10^{-21} \text{N} \, \text{m}/\sqrt{\text{Hz}}$ in low vacuum. Interference between optomechanical coupling mechanisms is observed to enhance detection sensitivity and generate a mechanical-mode-dependent optomechanical wavelength response.Comment: 11 pages, 6 figure