Can tree shelterbelts on agricultural land reduce flood risk?

Abstract

Abstract. Agricultural practices in the UK have come under increased scrutiny since the heavy and widespread flooding of 2000 and 2001. Although the impact of land use on runoff and flood risk is of growing concern, there are few quantitative data available. A preliminary study was undertaken in the Nant Pontbren catchment, mid‐Wales. Experimental tree shelterbelts were established in selected pastures of land used for sheep grazing. Water infiltration rates were up to 60 times higher in areas planted with young trees than in adjacent grazed pastures. This demonstrates that farm trees could represent a key landscape feature, reducing run‐off even when only present as a small proportion of the land cover. This is likely to be just one of the environmental and economic benefits of planting trees to re‐create a more diverse agricultural landscape.

Case study results from southeast Houston, Texas: identifying the impacts of residential location on flood risk and loss

“…Soil compaction from plows and heavy machinery, loss of vegetative cover, and rapid drainage off properties are all linked to increased surface run‐off and potential flood losses (O'Connell et al ., ; Wheater and Evans, ). In particular, reduction in soil infiltration rates and water storage capacity can significantly increase overland flow into adjacent areas (Carroll et al ., ). However, not all agricultural operations are the same.…”

The impact of rural land management changes on soil hydraulic properties and runoff processes: results from experimental plots in upland UK

“…To address this research gap, an experimental programme was undertaken between 2004 and 2012 at Pontbren in Wales (Figure ) as part of a UK flood risk management research programme (Pender, ; Marshall et al ., ). Building upon preliminary studies that showed how destocking and tree planting can significantly improve infiltration rates (Carroll et al , ), a component of the Pontbren experiment has been to establish small‐scale manipulation plots to investigate the hydrological effects of destocking and native broadleaf tree planting under controlled conditions, and the variability of effects over space and time. In this paper, the results from the plot scale experiments are discussed in the context of previous research aiming to provide new insights into the effects of upland land management change on runoff processes, particularly in relation to climatic variability.…”

“…Conversely, the removal of livestock is generally observed to lead to a reduction in surface flow volumes that is attributed to an improvement in the structure of the upper layers of the soil, enhanced infiltration, and evaporation (e.g. Gifford and Hawkins, ; Greenwood et al ., ; Nguyen et al ., ; Greenwood and McKenzie, ; Carroll et al ., ; Carroll et al ., ).…”

“…Carroll et al . () measured soil infiltration rates that were up to 60 times greater in areas planted with young trees compared with those measured in adjacent pastures. In their review of available literature, Chandler and Chappell () listed both positive and negative effects of trees on soil hydraulic conductivity.…”

The impact of upland land management on flooding: insights from a multiscale experimental and modelling programme

“…They have also noted that ‘shelter belts’– small strips of land planted with trees for the purpose of providing shelter to livestock – have mitigated the increase in runoff rates. A preliminary study, examining the impacts of tree plantations on soil at the Pontbren farms, indicated that strategically placed, small‐scale planting of trees for shelter can be used to improve the infiltration capacity of grazed permanent pasture (Carroll et al , 2004). Following this, an intensive experimental programme was initiated under the FRMRC to further examine how changes in land use might impact at different spatial scales – plot scale, field scale and catchment scales.…”