Fine root dynamics in lodgepole pine and white spruce stands along productivity gradients in reclaimed oil sands sites

Abstract

Open‐pit mining activities in the oil sands region of Alberta, Canada, create disturbed lands that, by law, must be reclaimed to a land capability equivalent to that existed before the disturbance. Re‐establishment of forest cover will be affected by the production and turnover rate of fine roots. However, the relationship between fine root dynamics and tree growth has not been studied in reclaimed oil sands sites. Fine root properties (root length density, mean surface area, total root biomass, and rates of root production, turnover, and decomposition) were assessed from May to October 2011 and 2012 using sequential coring and ingrowth core methods in lodgepole pine (Pinus contorta Dougl.) and white spruce (Picea glauca (Moench.) Voss) stands. The pine and spruce stands were planted on peat mineral soil mix placed over tailings sand and overburden substrates, respectively, in reclaimed oil sands sites in Alberta. We selected stands that form a productivity gradient (low, medium, and high productivities) of each tree species based on differences in tree height and diameter at breast height (DBH) increments. In lodgepole pine stands, fine root length density and fine root production, and turnover rates were in the order of high > medium > low productivity sites and were positively correlated with tree height and DBH and negatively correlated with soil salinity (P < 0.05). In white spruce stands, fine root surface area was the only parameter that increased along the productivity gradient and was negatively correlated with soil compaction. In conclusion, fine root dynamics along the stand productivity gradients were closely linked to stand productivity and were affected by limiting soil properties related to the specific substrate used for reconstructing the reclaimed soil. Understanding the impact of soil properties on fine root dynamics and overall stand productivity will help improve land reclamation outcomes.

Fine‐root exploitation strategies differ in tropical old growth and logged‐over forests in Ghana

“…), reduced root surface area (Jamro et al . ), and reduced root length in plants (Kormanek et al . ).…”

“…Soil organic matter and nutrient concentration decreased, while bulk density increased with soil depth in both forests (Addo-Danso SD, unpublished data). Indeed, increased soil bulk density may lead to roots with high SRA (Lõhmus et al 1989), reduced root surface area (Jamro et al 2015), and reduced root length in plants (Kormanek et al 2015). The high root length and surface area in the upper 0-10 cm would allow plants to capture the nutrients that are concentrated in that layer, which is particularly important in the tropics where leaching is high.…”

Phosphorus availability and fractionation vary among forest site types in reconstructed oil sands soils

“…Phosphorus concentrations decreased in above-and belowground tissues in trees under low water availability in the soil D r a f t (Peuke and Rennenberg 2004). Therefore, low water availability in pine sites (Duan et al 2015) may be the reason for low foliar P concentration when the concentration of soil available P was high (Fig. 3b).…”

“…Pine and spruce were planted on TS and OB sites, respectively. Details on site characteristics and understory plant communities are given elsewhere (Jung et al 2014;Duan et al 2015). Pine in different stands was planted in during 1991-1996, while spruce was planted during 1982-1992.…”

Fine Root Dynamics in Three Forest Types with Different Origins in a Subalpine Region of the Eastern Qinghai-Tibetan Plateau

“…Although fine roots only comprise a small proportion of total root biomass, their production accounts to 33%-67% of annual net primary production in forest ecosystems [12], and they make a considerable contribution to annual carbon (C) fluxes due to their short lifespan and high decomposability [13][14][15]. Hence, fine root dynamics, such as fine root production and turnover, are key processes that drive biogeochemical nutrient cycling and stand productivity [16,17]. Consequently, the fine root related indices are used to analyze terrestrial ecosystem C sequestration.…”