Effect of Stand Age on Fine Root Biomass, Production and Morphology in Chinese Fir Plantations in Subtropical China

Abstract

Abstract:Despite the great importance of fine roots, which are referred to as roots smaller than 2 mm in diameter, in terms of carbon and nutrient cycling in terrestrial ecosystems, how fine root biomass, production, and turnover rate change with stand development remains poorly understood. Here we assessed the variations of fine root biomass, production, and morphology of trees and understory vegetation in Chinese fir (Cunninghamia lanceolata (Lamb.) Hook) plantations at the ages of 7 years old, 17 years old and 25 years old in southern China, representing the sapling, pole and mature stage, respectively. Fine roots of trees and understory vegetation were sampled with sequential coring method to a depth of 60 cm and sliced into 4 layers (0-15, 15-30, 30-45 and 45-60 cm). Fine root biomass and necromass were highest in the pole stages among these three different aged Chinese fir plantations, although the significant differences were only detected for fine root necromass between 25-year-old and 7-year-old plantations. Fine root biomass of Chinese fir was heterogeneous in both temporal and spatial dimensions. Seasonal variation of fine root biomass in three age groups showed a similar pattern that the standing fine root biomass reached a peak in January and fell to the lowest in July. Vertically, the fine root biomass decreased with the increase of soil depth, but this extinction rate decreased with stand development. The effects of stand age on either total fine root length and surface area, or specific root length were not significant. However, the root tissue density increased significantly with Chinese fir stand ages, which suggested that the fine roots on Chinese fir may resort more to the mycorrhizal associations for the nutrient and water acquisition in the later stage of Chinese fir plantations. In addition to the stand age effect, the fine roots exhibited highly spatial and temporal variations in Chinese plantations, indicating different root foraging strategies for soil nutrient and water acquisition. Therefore, the fine root research not only helps to understand its role in carbon sequestration in terrestrial ecosystem under global climate change, but can also improve our understanding of nutrient management in forest ecosystem. At the same time, the research on the productivity of the Chinese fir growth stage provides guiding significance for the construction and management of Chinese fir.

Fine root vertical-seasonal distribution of Robinia pseudoacacia in relation to abiotic factors in a chronosequence in coastal saline alkali land of the Yellow River Delta, China

“…The underlying mechanisms are supposed to be related to both physiological and ecological effects, though the exact mechanisms for the age-related patterns of these trees have not been published yet. In our study, FRB increased with stand age, which was consistent with the results reported (Pei et al, 2018).…”

Spatial and Temporal Variation in Fine Root Biomass, Productivity and Turnover in Shorea Robusta Along the Gradient of Tree Girth Size

“…The age of the stand has a huge impact on FRB and generally, the younger stands possess more FRB in comparison to older stands (Claus and George (2005). Similar ndings were reported by Pei et al (2018), while negative interaction among stand age and FRB was observed by Leuschner and Hertel 2003. Several studies conducted on FRB dynamics (Finer et al 2011;Di Lorio et al 2013) also reported that FRB was tremendously affected by tree age.…”

Seasonal Changes and Vertical Distribution of Fine Root Biomass During Vegetation Restoration in a Karst Area, Southwest China

“…In most ecosystems, roots tend to be most abundant in the topsoil layer, decreasing exponentially with increasing soil depth (Zhou et al, 2016). Some studies indicated that biomass and productivity are strongly dependent on stand age or developmental stage (Yuan and Chen, 2012; Sun et al, 2015; Pei et al, 2018). Studies have shown that fine roots can show considerable fluctuations in biomass and production throughout the season or among years (Zhiyanski, 2014; Wang P. et al, 2016).…”

“…Information on the temporal variation in fine root biomass is essential for estimating fine root turnover and production (Fukuzawa et al, 2013). Previous studies have also recorded that fine root biomass is dependent upon soil properties (texture, moisture, chemistry, nutrients) and climate conditions (geographical location, elevation, precipitation, and temperature) (Pei et al, 2018). For example, necromass was higher at both low and high latitudes, whereas less at mid latitudes on a large scale.…”