Can Urban Tree Roots Improve Infiltration through Compacted Subsoils for Stormwater Management?

Abstract

Global land use patterns and increasing pressures on water resources demand creative urban stormwater management. Strategies encouraging infiltration can enhance groundwater recharge and water quality. Urban subsoils are often relatively impermeable, and the construction of many stormwater detention best management practices (D-BMPs) exacerbates this condition. Root paths can act as conduits for water, but this function has not been demonstrated for stormwater BMPs where standing water and dense subsoils create a unique environment. We examined whether tree roots can penetrate compacted subsoils and increase infiltration rates in the context of a novel infiltration BMP (I-BMP). Black oak (Quercus velutina Lam.) and red maple (Acer rubrum L.) trees, and an unplanted control, were installed in cylindrical planting sleeves surrounded by clay loam soil at two compaction levels (bulk density = 1.3 or 1.6 g cm(-3)) in irrigated containers. Roots of both species penetrated the more compacted soil, increasing infiltration rates by an average of 153%. Similarly, green ash (Fraxinus pennsylvanica Marsh.) trees were grown in CUSoil (Amereq Corp., New York) separated from compacted clay loam subsoil (1.6 g cm(-3)) by a geotextile. A drain hole at mid depth in the CUSoil layer mimicked the overflow drain in a stormwater I-BMP thus allowing water to pool above the subsoil. Roots penetrated the geotextile and subsoil and increased average infiltration rate 27-fold compared to unplanted controls. Although high water tables may limit tree rooting depth, some species may be effective tools for increasing water infiltration and enhancing groundwater recharge in this and other I-BMPs (e.g., raingardens and bioswales).

Management of crop water under drought: a review

“…In case of intermediate compaction levels, tap-rooted crops with strong root mechanical resistance against buckling (Clark and Barraclough 1999) and perennial forage legumes (Lesturgez et al 2004) can be sufficiently effective. In case of strong compaction or naturally hardset horizons, woody species (Yunusa et al 2002;Bartens et al 2008) would be required to effectively improve penetrability of these layer for subsequent crops.…”

Analysis of vegetation from satellite images correlated to the bird species presence and the state of health of the ecosystems of Bucharest during the period from 1991 to 2006

“…Green areas deliver a series of natural functions, often named ecosystemic services, including the air and water purification, healthier soils, improvement of the urban climate and microclimate (Millennium Ecosystem Assessment, 2003;Wolch, et al, 2014;Nita, 2016), playing an important role in water infiltration in the ground and in the restoration of aquifers (Xiao, et al 2006;Bartens, et al, 2008), water interception at the tree canopy level (Xiao, et al, 2006), as well as the flooding control (Lull, Sopper 1969;Craul, 1992;Chen, et al, 2006 quoted by Wolch, et al, 2014), diminishing the environment pollution by capturing the dust particles (Nowak, et al, 2006;Mitchell, et al, 2010;Dogon-Yaro, et al, 2016), increase of biodiversity and habitats (Lima, et al, 2013;Petrisor, 2015;Hüse, et al, 2016), low noise (Fang, Ling, 2003;Van Renterghem, et al, 2012;Wolch, et al, 2014).…”

Evaluation of Soil Disturbance Using Fuzzy Indicator Approach

“…With this tool, equations can be used to predict the areal extent of detrimental soil disturbance from timber harvest, resulting in a geospatial map. On the other hand, tree roots can penetrate highly compacted soil (1.6 g cm-3 clay loam) and increase infiltration rates under experimental conditions (Bartens et al, 2008).…”

“…This commonly leads to loss of surface organic matter and a reduction in soil quality. There has been a lot of research published related to soil disturbance (Bartens et al, 2008;Gabriels et al, 1997;Gregory et al, 2006;Reeves, 2011; Soil quality criteria relative to disturbance and reclamation, 2004; Hazard assessment keys for evaluating site sensitivity to soil degrading processes guidebook, 1999; Torbert & Gebhart, 2012). For example, soil tillage has been shown to induce loss of soil strength, with soil loosening inevitably bringing a greater risk of subsequent soil compaction (Gabriels et al, 1997).…”