Healthy peatlands provide vital ecosystem services to society including nature conservation, water regulation and carbon sequestration . Degradation from past management, such as drainage and afforestation (including 21 000 km2 in the UK, predominantly in Scotland) , has resulted in peatland restoration being undertaken to reinstate these key services. Poor tree growth, degradation of surface peat and loss of associated services is leading to increased “forest-to-bog” restoration (by tree removal and drain blocking), aiming to recreate functioning open bog habitat .
Forest-to-bog restoration can initiate successful recovery towards near natural conditions . However, in initial years following restoration, the physical and biogeochemical disturbance of tree removal and drain blocking can have significant effects on water quality, enhancing nutrient concentrations [4,5]. One of the principal factors affecting water quality following forest-to-bog restoration is the presence of brash (treetops and branches), which can be left on site post-restoration, following harvesting of main tree stems - as extra costs are incurred for brash removal. Decomposing brash is a significant source of nutrients to surface waters , and its removal can significantly reduce nutrient loads . However, the precise mechanisms involved are not clear. Thus, there is a need to understand how brash affects the medium to longer-term recovery of water quality at restoration sites, which can inform future peatland restoration and forestry practice.
As a lignocellulose biomass, brash can be converted to biochar through pyrolysis. Biochar derived from lignocellulose materials has been effectively used for many purposes including water treatment . Therefore, through conversion to biochar there is the potential to create a useful added-value product from waste brash, in creating a marketable water treatment product, or, using biochar on-site, to help mitigate nutrient pollution in surface waters following peatland restoration/ forestry operations.
Thus, this PhD project aims to develop innovative brash management techniques which can have applications within forestry management and potentially enhance restoration of drained afforested peatlands. This will be done through 1) investigation of the mechanistic and longer-term role of brash in terms of impacts on water quality (i.e., in peatland restoration areas), and 2) considering the development of brash biochar based materials for use in water treatment/water quality improvement or enhancing peatland restoration/forestry practices.
The student will address the following research objectives:
1. Field and laboratory assessment of the mechanisms underlying brash effects on water quality - in forest felling and forest-to-bog restoration areas, relative to other sources which impact water quality, including medium-long term effects
2. Production of biochar(s) from varying conifer brash material (from forestry/restoration sites) and investigation of its physico-chemical properties
3. Laboratory experiments to investigate potential use of brash biochar in various water treatment scenarios (i.e., nutrient removal)
4. Field trials utilizing brash biochar(s) for water treatment in forestry/peatland restoration sites
5. Evaluation of the cost effectiveness of utilizing biochar from waste brash as a potential water treatment tool – assessment of the economic potential for scaling-up
The student will be based at the Environmental Research Institute, North Highland College, University of the Highlands and Islands in Thurso, Northern Scotland. This location allows access to numerous peatland restoration and forestry field sites managed by the partner organisations in this project. The student will gain a valuable skill set ranging from peatland ecology to analytical chemistry and materials science and will benefit from access to a wide range of instrumental facilities available at the Environmental Research Institute.
Applicants are strongly advised to make an informal enquiry about the PhD to the primary supervisor well before the final submission deadline. Applicants must send a completed application form (available here https://www.hydronationscholars.scot/apply
), their Curriculum Vitae and a covering letter to the primary supervisor by the final submission deadline of 8th January.