Spatial and temporal patterns of root distribution in developing stands of four woody crop species grown with drip irrigation and fertilization

Abstract

In forest trees, roots mediate such significant carbon fluxes as primary production and soil C 0 2 efflux. Despite the central role of roots in these critical processes, information on root distribution during stand establishment is limited, yet must be described to accurately predict how various forest types, which are growing with a range of resource limitations, might respond to environmental change. This study reports root length density and biomass development in young stands of eastern cottonwood (Populus deltoidies Bartr.) and American sycamore (Platanus occidentalis L.) that have narrow, high resource site requirements, and compares them with sweetgum (Liquidambar styraczj7ua L.) and loblolly pine (Pinus taeda L.), which have more robust site requirements. Fine roots (<1 mm), medium roots (1 to 5 mm) and coarse roots (>5 mm) were sampled to determine spatial distribu-

Soil carbon and nitrogen content and stabilization in mid-rotation, intensively managed sweetgum and loblolly pine stands

“…Samuelson et al (2004aSamuelson et al ( , 2008 demonstrated that increasing management intensity on loblolly pine (Pinus taeda L.) stands in Georgia increased above-and belowground (coarse root) biomass and foliar biomass in loblolly pine. Similar results were detected by Coleman (2007) in a study examining the effects of irrigation and fertilization on four woody crop species (sweetgum (Liquidambar styraciflua L.), loblolly pine, American sycamore (Platanus occidentalis L.) and eastern cottonwood (Populus deltoidies Bartr.). Thus, any land management that increases NPP, also potentially increases the organic matter input into the soil.…”

“…Fertilization has been shown to decrease loblolly pine fine root biomass (Maier and Kress, 2000) but increase turnover (King et al, 2002) on a nutrient deficient site. Coleman (2007) reported increases in fine root biomass with increasing resource availability for loblolly and sweetgum. Samuelson et al (2004aSamuelson et al ( , 2008 demonstrated that increasing management intensity on loblolly pine (Pinus taeda L.) stands in Georgia increased above-and belowground (coarse root) biomass and foliar biomass in loblolly pine.…”

Above- and below-ground biomass accumulation, production, and distribution of sweetgum and loblolly pine grown with irrigation and fertilization

“…The site, plant materials, sampling methods, and experimental design were described previously (Coleman et al 2004b;Coyle and Coleman 2005;Coleman 2007); a brief description follows.…”

“…A detailed description of fine-root biomass sampling methods is provided by Coleman (2007). Briefly, we removed 4.9 cm diameter cores from 0-15, 15-45, and 45-105 cm depths.…”

“…Whole stumps were dried and weighed in 2001, whereas fresh stump masses were measured in the field with subsamples removed to determine water mass in 2003. We estimated peripheral coarse root biomass by digging three random 0.19 m2 holes that were 30 cm deep within the sampled tree's growing space yet outside of the 1 m2 stump sampling area (Coleman 2007). All coarse roots (>5 mm) were collected from the samples and soil was rinsed prior to drying and weighing.…”