Center for Sustainable Forestry and Climate Change

Roslin, United Kingdom

Center for Sustainable Forestry and Climate Change

Roslin, United Kingdom
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Pinnington E.M.,University of Reading | Casella E.,Center for Sustainable Forestry and Climate Change | Dance S.L.,University of Reading | Lawless A.S.,University of Reading | And 4 more authors.
Journal of Geophysical Research: Biogeosciences | Year: 2017

The response of forests and terrestrial ecosystems to disturbance is an important process in the global carbon cycle in the context of a changing climate. This study focuses on the effect of selective felling (thinning) at a managed forest site. Previous statistical analyses of eddy covariance data at the study site had found that disturbance from thinning resulted in no significant change to net ecosystem carbon uptake. In order to better understand the effect of thinning on carbon fluxes, we use the mathematical technique of four-dimensional variational data assimilation. Data assimilation provides a compelling alternative to more common statistical analyses of flux data as it allows for the combination of many different sources of data, with the physical constraints of a dynamical model, to find an improved estimate of the state of a system. We develop new observation operators to assimilate daytime and nighttime net ecosystem exchange observations with a daily time step model, increasing observations available by a factor of 4.25. Our results support previous analyses, with a predicted net ecosystem carbon uptake for the year 2015 of 426 ± 116 g C m−2 for the unthinned forest and 420 ± 78 g C m−2 for the thinned forest despite a model-predicted reduction in gross primary productivity of 337 g C m−2. We show that this is likely due to reduced ecosystem respiration postdisturbance compensating for a reduction in gross primary productivity. This supports the theory of an upper limit of forest net carbon uptake due to the magnitude of ecosystem respiration scaling with gross primary productivity. ©2017. The Authors.

Ray D.,Center for Ecosystems | Bathgate S.,Center for Sustainable Forestry and Climate Change | Moseley D.,Center for Ecosystems | Taylor P.,Center for Ecosystems | And 3 more authors.
Regional Environmental Change | Year: 2015

To compare the provision of ecosystem services in plantation forests under alternative climate change adaptation management trajectories, we interpolated climatic variables from the UK 11-member regional climate models to use at high resolution in forest management situations. We used expert opinion to derive the links between coarse-scaled UK National Ecosystem Assessment scenarios and forest management alternatives (FMA) in a simulation of forest planning and management under climate change uncertainty. Nine indicators were used to compare the provision of forest ecosystem services from four alternative management trajectories based on FMA types under a changing climate. These show that by 2080 a ‘business as usual’ form of forest management at both Clocaenog and Gwydyr forests will become unsuitable under the two warmest and driest climate variants, marginal under four variants, and borderline suitable under the remaining five variants. This implies that if future forest policy requires the continued delivery of a wide range of ecosystem services, including, home grown timber, biodiversity, and the carbon mitigation benefit from woodlands, then there is 20–50 % chance of failing to deliver on some of these services, unless some adaptation measures to climatic impacts occurs, such as transformation to more diverse species forests managed using low-impact silviculture systems. We show that the benefits of achieving this will be to minimise most of the impacts that climate change would otherwise have on the delivery of ecosystem services from forests. © 2014, The Author(s).

Keith A.M.,UK Center for Ecology and Hydrology | Rowe R.L.,UK Center for Ecology and Hydrology | Parmar K.,UK Center for Ecology and Hydrology | Perks M.P.,Center for Sustainable Forestry and Climate Change | And 3 more authors.
GCB Bioenergy | Year: 2015

Land-use change can have significant impacts on soil and aboveground carbon (C) stocks and there is a clear need to identify sustainable land uses which maximize C mitigation potential. Land-use transitions from agricultural to bioenergy crops are increasingly common in Europe with one option being Short Rotation Forestry (SRF). Research on the impact on C stocks of the establishment of SRF is limited, but given the potential for this bioenergy crop in temperate climates, there is an evident knowledge gap. Here, we examine changes in soil C stock following the establishment of SRF using combined short (30 cm depth) and deep (1 m depth) soil cores at 11 sites representing 29 transitions from agriculture to SRF. We compare the effects of tree species including 9 coniferous, 16 broadleaved and 4 Eucalyptus transitions. SRF aboveground and root biomass were also estimated in 15 of the transitions using tree mensuration data allowing assessments of changes in total ecosystem C stock. Planting coniferous SRF, compared to broadleaved and Eucalyptus SRF, resulted in greater accumulation of litter and overall increased soil C stock relative to agricultural controls. Though broadleaved SRF had no overall effect on soil C stock, it showed the most variable response suggesting species-specific effects and interactions with soil types. While Eucalyptus transitions induced a reduction in soil C stocks, this was not significant unless considered on a soil mass basis. Given the relatively young age and limited number of Eucalyptus plantations, it is not possible to say whether this reduction will persist in older stands. Combining estimates of C stocks from different ecosystem components (e.g., soil, aboveground biomass) reinforced the accumulation of C under coniferous SRF, and indicates generally positive effects of SRF on whole-ecosystem C. These results fill an important knowledge gap and provide data for modelling of future scenarios of LUC. © 2014 NERC Centre for Ecology and Hydrology.

Hetroy-Wheeler F.,French Institute for Research in Computer Science and Automation | Casella E.,Center for Sustainable Forestry and Climate Change | Boltcheva D.,University of Lorraine
International Journal of Remote Sensing | Year: 2016

This article describes a new semi-automatic method to cluster terrestrial laser scanning (TLS) data into meaningful sets of points to extract plant components. The approach is designed for small plants with distinguishable branches and leaves, such as tree seedlings. It first creates a graph by connecting each point to its most relevant neighbours, then embeds the graph into a spectral space, and finally segments the embedding into clusters of points. The process can then be iterated on each cluster separately. The main idea underlying the approach is that the spectral embedding of the graph aligns the points along the shape’s principal directions. A quantitative evaluation of the segmentation accuracy, as well as of leaf area (LA) estimates, is provided on a poplar seedling mock-up. It shows that the segmentation is robust with false-positive and false-negative rates of around 1%. Qualitative results on four contrasting plant species with three different scan resolution levels each are also shown. © 2016 Informa UK Limited, trading as Taylor & Francis Group.

Wang S.,University of Aberdeen | Hastings A.,University of Aberdeen | Wang S.,University of Swansea | Sunnenberg G.,University of East Anglia | And 12 more authors.
GCB Bioenergy | Year: 2014

The paper presents a model system, which consists of a partial equilibrium model and process-based terrestrial biogeochemistry models, to determine the optimal distributions of both Miscanthus (Miscanthus × giganteus) and short rotation coppice willow (SRC) (Salix. viminalis L. x S. viminalis var Joruun) in Great Britain (GB), as well as their potential contribution to meet heat and electricity demand in GB. Results show that the potential contribution of Miscanthus and SRC to heat and electricity demand is significant. Without considering farm-scale economic constraints, Miscanthus and SRC could generate, in an economically competitive way compared with other energy generation costs, 224 800 GWh yr-1 heat and 112 500 GWh yr-1 electricity, with 8 Mha of available land under Miscanthus and SRC, accounting for 66% of total heat demand and 62% of total electricity demand respectively. Given the pattern of heat and electricity demand, and the relative yields of Miscanthus and SRC in different parts of GB, Miscanthus is mainly favoured in the Midlands and areas in the South of GB, whereas SRC is favoured in Scotland, the Midlands and areas in the South of GB. © 2013 John Wiley & Sons Ltd.

Alexander P.,Scotland’s Rural College | Moran D.,Scotland’s Rural College | Smith P.,University of Aberdeen | Hastings A.,University of Aberdeen | And 9 more authors.
GCB Bioenergy | Year: 2014

To achieve the UK Government's aim of expansion in the growth of perennial energy crops requires farmers to select these crops in preference to conventional rotations. Existing studies estimating the total potential resource have either only simplistically considered the farmer decision-making and opportunity costs, for example using an estimate of annual land rental charge; or have not considered spatial variability, for example using representative farm types. This paper attempts to apply a farm-scale modelling approach with spatially specific data to improve understanding of potential perennial energy crop supply. The model main inputs are yield maps for the perennial energy crops, Miscanthus and willow grown as short-rotation coppice (SRC), and regional yields for conventional crops. These are used to configure location specific farm-scale models, which optimize for profit maximization with risk aversion. Areas that are unsuitable or unavailable for energy crops, due to environmental or social factors, are constrained from selection. The results are maps of economic supply, assuming a homogenous farm-gate price, allowing supply cost curves for the UK market to be derived. The results show a high degree of regional variation in supply, with different patterns for each energy crop. Using estimates of yields under climate change scenarios suggests that Miscanthus supply may increase under future climates while the opposite effect is suggested for SRC willow. The results suggest that SRC willow is only likely to able to supply a small proportion of the anticipated perennial energy crop target, without increases in market prices. Miscanthus appears to have greater scope for supply, and its dominance may be amplified over time by the effects of climate change. Finally, the relationship to the demand side of the market is discussed, and work is proposed to investigate the factors impacting how the market as a whole may develop. © 2013 John Wiley & Sons Ltd.

Hastings A.,University of Aberdeen | Tallis M.J.,University of Southampton | Tallis M.J.,University of Portsmouth | Casella E.,Center for Sustainable Forestry and Climate Change | And 5 more authors.
GCB Bioenergy | Year: 2014

Process and empirical-based models that describe lignocellulosic biomass yield of the perennial energy grass Miscanthus (MiscanFor©), short rotation coppice (SRC) trees and shrubs, poplar and willow (ForestGrowth-SRC) and a number of short rotation forest trees (ESC-CARBINE), were used to estimate the yield potential for current and future climates across Great Britain (GB). In current climates, modelled yields for all feedstock crops varied between 8.1 and 10.6 Mg dry weight (DW) ha-1 yr-1 with willow SRC and poplar SRF producing the lowest and highest yields respectively. For the medium emissions scenario (UKCP09) in 2050, mean yield for all feedstock crops varied between 7.6 and 12.7 Mg DW ha-1 yr-1 with willow SRC and poplar SRF once again the lowest and the highest recorded yields. There were clear geographical trends within GB. Miscanthus yield was higher than all others in the south-west (13.1 Mg DW ha-1 yr-1), SRC willow and SRC poplar in the north-west (12.1-15.8 Mg DW ha-1 yr-1) and in the midlands and south-east, SRF poplar was the highest yielding (10.5-11.6 Mg DW ha-1 yr-1). These geographical trends changed little with climate out to 2050, with mean yield of each 'best feedstock' increasing from 12.7 to 14.2 Mg DW ha-1 yr-1. Out to 2050, SRC declined slightly and Miscanthus and SRF poplar increased as the 'best feedstock' option. Except for a few localized examples, only SRF poplar had a higher yield than SRC or Miscanthus. These data suggest that in current and future climates, lignocellulosic biomass plantation species can be selected and optimized for best yield performance in different regions of GB. This modelling framework provides a valuable starting-point for which to test the performance of new genetic material, as this becomes available and parameterized for the models and socio-economic scenarios that may impact on the bioenergy industry. © 2013 John Wiley & Sons Ltd.

Akerblom M.,Tampere University of Technology | Raumonen P.,Tampere University of Technology | Kaasalainen M.,Tampere University of Technology | Casella E.,Center for Sustainable Forestry and Climate Change
Remote Sensing | Year: 2015

One way to model a tree is to use a collection of geometric primitives to represent the surface and topology of the stem and branches of a tree. The circular cylinder is often used as the geometric primitive, but it is not the only possible choice. We investigate various geometric primitives and modelling schemes, discuss their properties and give practical estimates for expected modelling errors associated with the primitives. We find that the circular cylinder is the most robust primitive in the sense of a well-bounded volumetric modelling error, even with noise and gaps in the data. Its use does not cause errors significantly larger than those with more complex primitives, while the latter are much more sensitive to data quality. However, in some cases, a hybrid approach with more complex primitives for the stem is useful. © 2015 by the authors licensee MDPI, Basel, Switzerland.

McCartan S.A.,Center for Sustainable Forestry and Climate Change | McCartan S.A.,Japan Forestry and Forest Products Research Institute | Jinks R.L.,Center for Sustainable Forestry and Climate Change | Barsoum N.,Center for Ecosystems
Annals of Forest Science | Year: 2015

• Key message: Climate change will affect regeneration. Assisted migration is a climate change adaptation strategy that is associated with risks regarding transfer distance. Thermal time models can provide information about the synchronization of regeneration with seasons and the implications for assisted migration.• Context: Climate change may prevent trees from adapting or migrating fast enough to track their climatic envelopes. Assisted migration facilitates gene flow by sourcing pre-adapted provenances usually from southerly regions representative of future climates.• Aim: The aims were to develop thermal time models for the germination and shoot emergence of two provenances of Quercus robur and to predict the impact of assisted migration on the synchronization of regeneration with seasons.• Methods: Using cumulative germination (radicle emergence) and shoot emergence data from a laboratory experiment, thermal time models were developed for the seedling emergence of Q. robur. Thermal time parameters were then used with climatic data to predict the timing of germination and shoot emergence for English and Italian provenances in southern England.• Results: The thermal time parameters were lower for germination than shoot emergence, resulting in their temporal separation. For Italian acorns, base temperature was lower, but thermal time required was higher for germination and shoot emergence compared to English acorns indicating local adaptation. Predictions suggest little difference in the timing of germination and shoot emergence for the two provenances in the future climate of southern England (2080s).• Conclusions: Q. robur has a robust regeneration mechanism where the thermal time parameters constrain germination and shoot emergence to safe windows and thereby ensure synchronization with seasons. © 2015, INRA and Springer-Verlag France.

PubMed | University of Colorado at Boulder, McMaster University, French Climate and Environment Sciences Laboratory, ETH Zurich and 31 more.
Type: Journal Article | Journal: Proceedings of the National Academy of Sciences of the United States of America | Year: 2015

Terrestrial gross primary productivity (GPP) varies greatly over time and space. A better understanding of this variability is necessary for more accurate predictions of the future climate-carbon cycle feedback. Recent studies have suggested that variability in GPP is driven by a broad range of biotic and abiotic factors operating mainly through changes in vegetation phenology and physiological processes. However, it is still unclear how plant phenology and physiology can be integrated to explain the spatiotemporal variability of terrestrial GPP. Based on analyses of eddy-covariance and satellite-derived data, we decomposed annual terrestrial GPP into the length of the CO2 uptake period (CUP) and the seasonal maximal capacity of CO2 uptake (GPPmax). The product of CUP and GPPmax explained >90% of the temporal GPP variability in most areas of North America during 2000-2010 and the spatial GPP variation among globally distributed eddy flux tower sites. It also explained GPP response to the European heatwave in 2003 (r(2) = 0.90) and GPP recovery after a fire disturbance in South Dakota (r(2) = 0.88). Additional analysis of the eddy-covariance flux data shows that the interbiome variation in annual GPP is better explained by that in GPPmax than CUP. These findings indicate that terrestrial GPP is jointly controlled by ecosystem-level plant phenology and photosynthetic capacity, and greater understanding of GPPmax and CUP responses to environmental and biological variations will, thus, improve predictions of GPP over time and space.

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