Influences of Root Diameter, Tree Age, Soil Depth and Season on Fine Root Survivorship in Prunus avium

Abstract

The rapid turnover of the fine root system is a major pathway of carbon and nutrient flow from plant to soil in forest ecosystems. In order to quantify these fluxes there is a need to understand how fine root demography is influenced by edaphic, environmental and plant ontogenetic factors. We studied the influence of four major factors (season, depth, root diameter and tree age) on the survivorship and longevity of fine roots of Prunus avium L. (wild cherry) over two years in North East Scotland. Survival analysis of data derived from minirhizotron observations showed that, for the range of root diameters studied, an increase in root diameter of 0.1 mm was associated with a 16% decrease in the risk of death. Depth was also an important factor; roots present at a depth of 10 cm had significantly lower survivorship than did roots at all lower depths studied. The effects of tree age and season on root production were more complex. Roots of old trees were more likely to die in the spring and roots of young trees were more likely to die in the autumn. Our data illustrate the complex factors that must be taken into account when scaling up information from individual observations of root longevity to model the contribution of fine roots to C and nutrient fluxes in forest ecosystems.

Response of the fine root production, phenology, and turnover rate of six shrub species from a subtropical forest to a soil moisture gradient and shading

“…However, the variation in the total production and turnover rates from year to year has generally been recorded within a single tree species and/or stand (Burke and Raynal 1994;Rytter 2013;Leppälammi-Kujansuu et al 2014), and the interannual variability in the fine root turnover rate was equal to or greater than the difference among species obtained for some temperate tree species (McCormack et al 2014). In addition, soil depth could also have a major influence on the fine root dynamics of shrubs (Aerts et al 1989;Baddeley and Watson 2005). Therefore, the long-term trend requires further study to identify the average variation in the annual production and turnover rates along the soil profile among the studied shrub species.…”

“…Three of the investigated species are evergreen, whereas the other three species are deciduous. Although soil depth could have a major influence on fine root dynamics due to the variations in soil microenvironment (Aerts et al 1989;Baddeley and Watson 2005), shallow roots were responsible for the majority of total annual fine root production and mortality (Hendrick and Pregitzer 1996). Therefore, we focused on the fine roots in top soil layer in this study.…”

Fine root dynamics along a 2,000-m elevation transect in South Ecuadorian mountain rainforests

“…Similarly, other authors also found this strong dependence of root survivorship on root diameter (Gill and Jackson 2000;Wells and Eissenstat 2001;King 1,050, 1,540, 1,890 m a.s.l. 1,890, 2,380, 3, et al 2002;Baddeley and Watson 2005). This may be explained by higher nutrient concentrations and respiration rates of small diameter roots, i.e.…”

Considerations in the study of tree fine-root turnover with minirhizotrons

“…It is also known that the season (or time) of emergence can alter fine-root life span (e.g. Tingey et al, 2000;Ponti et al, 2004; Table 1), as can tree age (Copeland, 1952;Baddeley and Watson, 2005). The categorization according to micro-size root diameter revealed that thinner fine roots tended to have shorter life spans than thicker fine roots (Wells and Eissenstat, 2001;Baddeley and Watson, 2005).…”

“…Tingey et al, 2000;Ponti et al, 2004; Table 1), as can tree age (Copeland, 1952;Baddeley and Watson, 2005). The categorization according to micro-size root diameter revealed that thinner fine roots tended to have shorter life spans than thicker fine roots (Wells and Eissenstat, 2001;Baddeley and Watson, 2005). The diameter of 'fine roots' can also differ along root branching orders: roots with an apex (root tip) are thinner than the axis roots to which they are attached (Pregitzer et al, 2002;Guo et al, 2004), suggesting shorter life spans in thinner apical roots.…”