Implications of land‐use change to Short Rotation Forestry in Great Britain for soil and biomass carbon

Abstract

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.

Planted forests and invasive alien trees in Europe: A Code for managing existing and future plantings to mitigate the risk of negative impacts from invasions

“…Many other alien species, including clones, hybrids and genetically modified trees, are used or are being tested for SRF/SRC, e.g., Robinia pseudoacacia in Albania, Italy, Germany, Hungary and Spain (Grünewald et al 2009, González-García et al 2011, Rédei et al 2011a, Kellezi et al 2012, Ciccarese et al 2014, Acacia saligna in Israel (Eggleton et al 2007), and Eucalyptus spp. in Portugal (Knapic et al 2014) and in the UK (Evans 1980, Leslie et al 2012, Keith et al 2015.…”

A synthesis of the ecosystem services impact of second generation bioenergy crop production

“…Land use transitions can exert a marked influence on levels of SOC [102] with studies of transition to 2G feedstock production [35,77,[103][104][105][106][107][108][109] demonstrating changes that can be considered as neutral to broadly positive depending on original land use, with most benefits accruing from conversion of arable land. The need to fully account for GHG emissions from 2G feedstock production to inform policy has led to an increasing literature that examines the implications of such transitions on soil carbon.…”

“…[105,106]) and the UK (e.g. [104]) together with the review of Ref. [103] report changes in soil carbon in detail and we refer the reader to these for a detailed discussion.…”

“…Contextual information was also important in developing the impact matrix as factors such as geographic location [105,120,122], previous land use [105,123], and temporal dynamics [59,114] could all influence reported effects of transitions. Taking soil quality as an example, although studies that focus on changes in soil organic carbon return a mixture of positive and neutral impacts for transitions to 2G feedstock production [77,[103][104][105][106] reports of enhanced microbial activity [110,124], increased porosity and litter input [79] and reduction in wind erodability [77] under 2G feedstocks strengthen the case for a net positive effect of this transition.…”

Plastic Allometry in Coarse Root Biomass of Mature Hybrid Poplar Plantations

“…Therefore, increasing our knowledge about C cycling and storage in poplar plantations is important to assess the C balance of this expanding type of land use. There is growing evidence that the establishment of short rotation coppices and fast-growing plantations of broadleaved species on agricultural land may not increase soil C stocks on a general basis [9][10][11], with considerable uncertainties regarding the sustainability of soil organic C enrichment in bioenergy woody crops [12]. However, many of these systems may increase, on the shortterm, belowground C storage through root biomass growth [13].…”