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

Abstract

Fine roots play a crucial role in plant survival potential and biogeochemical cycles of forest ecosystems. Subalpine areas of the Eastern Qinghai-Tibetan Plateau have experienced different forest re-establishment methods after clear-cutting primary forest. However, little is known about fine root dynamics of these forests originating from artificial, natural and their combined processes. Here, we determined fine root traits (biomass, production and turnover rate) of three subalpine forest types, i.e., Picea asperata Mast. plantation forest (artificial planting, PF), natural secondary forest (natural without assisted regeneration, NF) and P. asperata broadleaved mixed forest (natural regeneration after artificial planting, MF) composed of planted P. asperata and naturally regenerated native broadleaved species. At the soil depth of 0–30 cm, fine root biomass was the highest in PF and fine root production was the highest in NF, and both were the lowest in MF. Fine root dynamics of the three forest types tended to decrease with soil depth, with larger variations in PF. Fine root biomass and production were the highest in PF in 0–10 cm soil layer but were not significantly different among forest types in the lower soil layers. There were positive correlations between these parameters and aboveground biomass across forest types in soil layer of 0–10 cm, but not in the lower soil layers. Fine root turnover rate was generally higher in mixed forests than in monocultures at all soil depths. In conclusion, the natural regeneration procedure after clear-cutting in the subalpine region of western Sichuan seems to be superior from the perspective of fine root dynamics.

Short-term effects of organic amendments on soil fertility and root growth of rubber trees on Hainan Island, China

“…Tree root systems are vitally important for the proper functioning of forest ecosystems because of their pivotal roles in the absorption of soil nutrients and water, soil organic matter stock, and for maintaining plant growth, tree stability and stem straightness (Lindström and Rune 1999;Collins and Bras 2007;Xi et al 2011;Pransiska et al 2016;Bo et al 2018;Wang and Xie 2018). Fine roots (diameter < 2 mm) are the most active segments of root systems and respond rapidly to variations in the soil environment (Hendrick and Pregitzer 1992;Lukac and Godbold 2010;Montagnoli et al 2012;Jha 2018;Liu et al 2018). For instance, fine root biomass rapidly increased when soil moisture increased after drought.…”

Responses of Soil Microbial Community Composition and Enzyme Activities to Land-Use Change in the Eastern Tibetan Plateau, China

“…Therefore, studies on belowground communities in response to land-use change can provide a good opportunity to improve the understanding of C patterns and nutrient cycling in the subalpine forests. To date, studies on land-use change in this region have focused mainly on aboveground components, with less focus on soils and belowground community processes [18][19][20][21]. The size, structure, and function of microbial communities in soils may rapidly response to any changes in plant and soil characteristics because of different nutrient availability, substrate's quality and quantity, root exudates, and rhizodeposits [22][23][24].…”

Fine root dynamics and partitioning of root respiration into growth and maintenance components in cool temperate deciduous and evergreen forests

“…Fine root phenology strongly influences belowground carbon dynamics and allocation, whereas seasonality and variability in the production and respiration of fine roots are not well understood among forest types (Abramoff and Finzi 2015;McCormack et al 2014;Radville et al 2016). Moreover, the underlying mechanisms controlling fine root dynamics remain limited because of the lack of experimental evidence (Liu et al 2018;Radville et al 2016). In particular, the dynamic functions of fine roots, such as respiration, are not quantitatively understood, which has restrained the improvement of terrestrial biosphere models to predict the responses of forest ecosystems to environmental changes (McCormack et al 2015;Warren et al 2015).…”