Environment and Rural Affairs Monitoring & Modelling Programme ERAMMP - Report-32: National Forest in Wales - Evidence Review

This review was commissioned by Welsh Government (WG) from the Environment and Rural Affairs Monitoring and Modelling Programme (ERAMMP) to provide key evidence of potential benefits and disbenefits of woodland creation, woodland expansion and managing undermanaged woodland, to provide an evidence base to inform the development of a National Forest for Wales. During the commissioning process, WG emphasised that the evidence provided must reflect the collective views of the community by reviewing the literature in an objective way highlighting where evidence is contradictory or weak. Within the time available, evidence of causality of impacts, the likely timescales and magnitude of these impacts should be also be presented, for both positive and negative impacts of woodland expansion and management of undermanaged woodlands. This Evidence Pack should also build on the evidence put forward in the ERAMMP Sustainable Farm Scheme (SFS) (https://erammp.wales/en/resources) which included a range of assessments of the value of intervention measures which promoted trees within a landscape setting for a range of environmental, economic and social outcomes. The required rapid production of the review in four months meant an expert approach of key evidence was expected rather than a systematic review. Key topics to cover were selected, in partnership with WG, focussing on issues that could fundamentally change decision-making going forward. The final agreed list was arranged under a series of high-level subject headings, and the individual reviews published as ERAMMP Reports 33 to 38 and include; Biodiversity; Managing Undermanaged Woodland; Future-proofing our Woodland; Climate Change Mitigation; Ecosystem Services, and Economics and Natural Capital Accounting. An Integrated Assessment was also commissioned to provide a synthesis of cross-cutting themes and dependencies between topics. These ERAMMP reports are all provided as Annexes to this report

Difference in soil methane (CH4) and nitrous oxide (N2O) fluxes from bioenergy crops SRC willow and SRF Scots pine compared with adjacent arable and fallow in a temperate climate

Soil greenhouse gas (GHG) fluxes of methane (CH4) and nitrous oxide (N2O) were measured over a two year period from several land-use systems on adjacent sites under the same soil and climatic conditions to assess the influence of the transition from arable agricultural (barley) and fallow to perennial bioenergy crops short rotation coppice (SRC) willow (Salix spp.) and short rotation forest (SRF) Scots pine (Pinus silvestris). There were no significant differences between CH4 and N2O fluxes measured from the SRC, SRF and fallow but the arable agricultural site showed an order of magnitude larger N2O emissions compared with the others. Fertiliser application to the arable crop was the major factor influencing N2O emissions and both air and soil temperature showed no significant effects on fluxes between the different land-use systems. Soil moisture was significantly different from the arable crop, showing a greater range than from SRF and SRC. Hence these bioenergy crops might be viable options for water stressed areas

Estimates and relationships between aboveground and belowground resource exchange surface areas in a Sitka spruce managed forest

Our knowledge of the nature of belowground competition for moisture and nutrients is limited. In this study, we used an earth impedance method to determine the root absorbing area of Sitka spruce (Picea sitchensis (Bong.) Carr.) trees, making measurements in stands of differing density (2-, 4- and 6-m inter-tree spacing). We compared absorbing root area index (RAIabsorbing; based on the impedance measure) with fine root area index (RAIfine; based on estimates of total surface area of fine roots) and related these results to investment in conductive roots. Root absorbing area was a near-linear function of tree stem diameter at 1.3 m height. At the stand level, RAIabsorbing, which is analogous to and scaled with transpiring leaf area index (maximum stomatal pore area per unit ground area; LAItranspiring), increased proportionally with basal area across the three stands. In contrast, RAIfine was inversely propotional to basal area. The ratio of RAIabsorbing to LAItranspiring ranged from 7.7 to 17.1, giving an estimate of the relative aboveground versus belowground resource exchange areas. RAIabsorbing provides a way of characterizing ecosystem functioning as a physiologically meaningful index of belowground absorbing area. © The Author 2010. Published by Oxford University Press. All rights reserved.SCOPUS: ar.jinfo:eu-repo/semantics/publishe