scholarly journals Dynamic Responses of Multidiameter-class Fine Roots at Different Soil Depths to Thinning Measures in a Secondary Forest in China

2021 ◽  
Author(s):  
Yue Pang ◽  
Jing Tian ◽  
Dexiang Wang
Keyword(s):  
Biomass Production ◽  
Dynamic Characteristics ◽  
Fine Roots ◽  
Root Biomass ◽  
Turnover Rate ◽  
Fine Root ◽  
Secondary Forest ◽  
Fine Root Biomass ◽  
Dynamic Responses ◽  
Qinling Mountains

Abstract Background: Fine roots make critical contributions to carbon stocks and terrestrial productivity, and multidiameter-class fine roots exhibit functional heterogeneity. However, the dynamic characteristics of multidiameter-class fine roots at different soil depths following thinning disturbances are poorly understood. We investigated the biomass, production, mortality and turnover rate of < 0.5 mm, 0.5–1 mm and 1–2 mm fine roots at 0-20 cm, 20-40 cm and 40-60 cm soil depths under five thinning intensities (0%, 15%, 30%, 45%, and 60%) in a secondary forest in the Qinling Mountains. Results: The biomass, production and turnover rate of < 0.5 mm fine roots fluctuated with increasing thinning intensity, while 0.5-1 mm and 1-2 mm fine root biomass significantly decreased. Thinning measures had no effects on fine root necromass (except for T4) or mortality. The fine root dynamic characteristics in deeper soils were more sensitive to thinning measures. Principal component analysis results show that increased < 0.5 mm fine root biomass and production resulted from increased shrub and herb diversity and biomass and decreased soil nutrient availability, stand volume and litter biomass, whereas 0.5-1 mm and 1-2 mm fine root biomass showed the opposite trends and change mechanisms. Conclusions: Our results provide evidence of the positive effect of thinning on very fine root (< 0.5 mm) biomass and production and the negative effect on thicker fine roots (0.5-1, 1-2 mm) or all fine root (< 2 mm) biomass. From the perspective of fine root biomass and productivity, T2 (30%) is recommended for use in secondary forests of the Qinling Mountains. Moreover, our results suggest that thinning practices have varied effects on the dynamic characteristics of multidiameter-class fine roots.

scholarly journals An improved method for quantifying total fine root decomposition in plantation forests combining measurements of soil coring and minirhizotrons with a mass balance model

2020 ◽  
Vol 40 (10) ◽  
pp. 1466-1473
Author(s):  
Xuefeng Li ◽  
Kevan J Minick ◽  
Tonghua Li ◽  
James C Williamson ◽  
Michael Gavazzi ◽  
...  
Keyword(s):  
Fine Roots ◽  
Root Biomass ◽  
Turnover Rate ◽  
Fine Root ◽  
Fine Root Biomass ◽  
Balance Model ◽  
Root Decomposition ◽  
Mass Balance Model ◽  
Monthly Total ◽  
Fine Root Decomposition

Abstract Accurate measurement of total fine root decomposition (the amount of dead fine roots decomposed per unit soil volume) is essential for constructing a soil carbon budget. However, the ingrowth/soil core-based models are dependent on the assumptions that fine roots in litterbags/intact cores have the same relative decomposition rate as those in intact soils and that fine root growth and death rates remain constant over time, while minirhizotrons cannot quantify the total fine root decomposition. To improve the accuracy of estimates for total fine root decomposition, we propose a new method (balanced hybrid) with two models that integrate measurements of soil coring and minirhizotrons into a mass balance model. Model input parameters were fine root biomass, necromass and turnover rate for Model 1, and fine root biomass, necromass and death rate for Model 2. We tested the balanced hybrid method in a loblolly pine plantation forest in coastal North Carolina, USA. The total decomposition rate of absorptive fine roots (ARs) (a combination of first- and second-order fine roots) using Models 1 and 2 was 107 ± 13 g m−2 year−1 and 129 ± 12 g m−2 year−1, respectively. Monthly total AR decomposition was highest from August to November, which corresponded with the highest monthly total ARs mortality. The ARs imaged by minirhizotrons well represent those growing in intact soils, evident by a significant and positive relationship between the standing biomass and the standing length. The total decomposition estimate in both models was sensitive to changes in fine root biomass, turnover rate and death rate but not to change in necromass. Compared with Model 2, Model 1 can avoid the technical difficulty of deciding dead time of individual fine roots but requires greater time and effort to accurately measure fine root biomass dynamics. The balanced hybrid method is an improved technique for measuring total fine root decomposition in plantation forests in which the estimates are based on empirical data from soil coring and minirhizotrons, moving beyond assumptions of traditional approaches.

Fine root biomass and nutrient content in a black spruce peat soil with and without alder

1998 ◽  
Vol 78 (1) ◽  
pp. 163-169 ◽  
Author(s):  
J. S. Bhatti ◽  
N. W. Foster ◽  
P. W. Hazlett
Keyword(s):  
Fine Roots ◽  
Root Biomass ◽  
Fine Root ◽  
Black Spruce ◽  
Peat Soil ◽  
Chemical Properties ◽  
Nutrient Content ◽  
Fine Root Biomass ◽  
Boreal Peatlands ◽  
Strong Positive Relationship

Vertical distribution of fine root biomass and nutrient content was examined within a black spruce (Picea mariana) stand growing on a boreal peat soil in northeastern Ontario. The influence of site physical and chemical properties on fine root biomass production was assessed. More then 80% of the fine roots were present in moss plus the top 10 cm of peat where nutrients and aeration are most favourable. The fine root biomass (W/V) was significantly higher with alder (5.9 kg m−3) (Alnus rugosa) as understory vegetation compared to non-alder locations (2.9 kg m−3). Total nutrient content in fine roots was 54, 3.2, 5.4, 63 and 5.7 kg ha−1 on the alder site and 20, 1.4, 2.3, 28 and 4.2 kg ha−1 of N, P, K, Ca, and Mg on the non-alder site, respectively. The mass (W/V) of nutrients in fine roots was strongly dependent upon the availability of nutrients in the peat. Fine root content had a strong positive relationship with peat available P and exchangeable K contents suggesting that P and K may be limiting nutrients for black spruce in this peat soil. Key words: Nitrogen, phosphorus, potassium, boreal peatlands, aeration, water table

scholarly journals Effect of Altitude on Nutrient Concentration, Nutrient Stock and Uptake in Fine Root of Sal (Shorea Robusta Gaertn.) Forest in Terai and Hill Areas of Eastern Nepal

2020 ◽  
Vol 25 (1) ◽  
pp. 24-29
Author(s):  
Krishna Prasad Bhattarai ◽  
Tej Narayan Mandal ◽  
Tilak Prasad Gautam
Keyword(s):  
Fine Roots ◽  
Root Biomass ◽  
Nutrient Concentration ◽  
Nutrient Dynamics ◽  
Fine Root ◽  
Soil Depth ◽  
Fine Root Biomass ◽  
Root Production ◽  
Nutrient Stock ◽  
Sal Forest

The present study was conducted to understand the effect of altitude on the nutrient concentration, nutrient stock, and uptake in the fine root of the Terai Sal forest (TSF) and Hill Sal forest (HSF) in eastern Nepal. Annual mean fine root biomass in 0-30 cm soil depth was found higher in HSF (6.27 Mg ha-1) than TSF (5.05 Mg ha-1). Conversely, fine root production was higher in TSF (4.8 Mg ha-1 y-1) than HSF (4.12 Mg ha-1 y-1). Nitrogen, phosphorus, and potassium content in fine roots were slightly higher in TSF than HSF. Nutrient concentration in fine roots of smaller size (<2 mm diameter) was nearly 1.2 times greater than that of larger size (2–5 mm diameter) in both forests. In HSF total stock of different nutrients (kg ha-1) in fine root was 55.62 N, 4.99 P, and 20.15 K whereas, these values were 49.49 N, 4.14 P, and 19.27 K only in TSF. However, total nutrient uptake (kg ha-1y-1) by fine root (both size classes) was greater in TSF (48.5 N, 4.3 P, and 18.6 K) than HSF (36.9 N, 3.3 P, and 13.5 K). The variability in fine root nutrient dynamics between these two forests was explained by the differences in fine root biomass and production which were influenced by the combined effect of varied altitude and season. The fine root, as being a greater source of organic matter, the information on its nutrient dynamics is inevitable for the management of soil nutrients in the forest ecosystem.

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

2021 ◽  
Author(s):  
Rachita Pandey ◽  
Surendra Singh Bargali ◽  
Kiran Bargali
Keyword(s):  
Fine Roots ◽  
Root Biomass ◽  
Fine Root ◽  
Soil Depth ◽  
Winter Season ◽  
Fine Root Biomass ◽  
Spatial And Temporal Variation ◽  
Root Dynamics ◽  
Bottom Line ◽  
The Impact

Abstract Fine roots (≤ 2 mm of diameter) contribute diminutive fractions of the overall tree biomass but are highly zestful and functionally remarkable component for assessing forest carbon and nutrient budgets. This study assessed how tree girth influenced fine root biomass (FRB), production (FRP) and turnover rate (FRT) in sub tropical sal forest.Four sites (S1, S2, S3, S4) were established in the bhabhar region of Nainital district, Uttarakhand, India within an elevational range of 405m and 580m. On the basis of girth size, sal trees were categorized in five girth size classes. Fine roots were sampled seasonally to a depth of 60 cm and divided into 3 layers (0-20, 20-40 and 40-60 cm).FRB was significantly affected by tree girth size (p< 0.05) while FRP and FRT showed insignificant effect. FRB was higher in lower girth classes (A-C) as compared to higher girth classes (D-E).Seasonal variation of FRB in all girth sizes showed a keen resemblance as the standing FRB reached pinnacle during rainy season and reached bottom-line in the winter season. Maximum FRB was reported for uppermost organo-mineralic soil depth (0-20 cm) at 1 m distance from tree bole and decreased with increasing soil depth and distance from tree bole while FRT showed a reverse trend. The present study will provide a holistic outlook on variations in FRB, FRP and FRT and the impact of edaphic characteristics and tree girth on fine root dynamics with respect to the studied forest stands.

scholarly journals RAINFALL REGIME ON FINE ROOT GROWTH IN A SEASONALLY DRY TROPICAL FOREST

2020 ◽  
Vol 33 (2) ◽  
pp. 458-469
Author(s):  
EUNICE MAIA DE ANDRADE ◽  
GILBERTO QUEVEDO ROSA ◽  
ALDENIA MENDES MASCENA DE ALMEIDA ◽  
ANTONIO GIVANILSON RODRIGUES DA SILVA ◽  
MARIA GINA TORRES SENA
Keyword(s):  
Root Growth ◽  
Root Length ◽  
Fine Roots ◽  
Root Biomass ◽  
Fine Root ◽  
Fine Root Biomass ◽  
Rainfall Regime ◽  
Seasonally Dry ◽  
Fine Root Length ◽  
Fine Root Growth

ABSTRACT Seasonally dry tropical forests (SDTF) usually present dry seasons of eight or more months. Considering the concerns about the resilience of SDTF to climate changes, the objective of this study was to evaluate the effect of the rainfall regime on fine root growth in a SDTF. The experiment started at the end of the wet season (July 2015), when fine roots were evaluated and ingrowth cores were implemented. The temporal growth of fine roots in the 0-30 cm soil layer was monitored, considering the 0-10, 10-20, and 20-30 cm sublayers, through six samplings from November 2015 to July 2017. The characteristics evaluated were fine root biomass, fine root length, fine root specific length, and fine root mean diameter. The significances of the root growths over time and space were tested by the Kruskal-Wallis test (p<0.05). Fine roots (Ø<2 mm) were separated and dried in an oven (65 °C) until constant weight. The root length was determined using the Giaroots software. The fine root biomass in July 2015 was 7.7±5.0 Mg ha-1 and the length was 5.0±3.2 km m-2. Fine root growth in SDTF is strongly limited by dry periods, occurring decreases in biomass and length of fine roots in all layers evaluated. Fine root growth occurs predominantly in rainy seasons, with fast response of the root system to rainfall events, mainly in root length.

scholarly journals Fine Root and Soil Nitrogen Dynamics during Stand Development Following Shifting Agriculture in Northeast India

Forests ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1236
Author(s):  
Dipendra Singha ◽  
Francis Q. Brearley ◽  
Shri Kant Tripathi
Keyword(s):  
N Mineralization ◽  
Fine Roots ◽  
Root Biomass ◽  
Fine Root ◽  
Fine Root Biomass ◽  
Northeast India ◽  
Stand Age ◽  
N Dynamics ◽  
Available N ◽  
Shifting Agriculture

Nitrogen (N) dynamics during changes in land use patterns in tropical forests may profoundly affect fine root dynamics and nutrient cycling processes. Variations in fine root biomass and soil N dynamics were assessed in developing stands of increasing ages following shifting agriculture in Mizoram, Northeast India, and comparisons were made with a natural forest stand. Concentrations of soil available N (NH4-N and NO3-N) and the proportion of NH4-N in total available N increased with stand age. The N-mineralization rate also increased with stand age whilst the proportion of nitrification relative to ammonification declined during succession. Fine root biomass and N-mineralization increased, and available N decreased during the monsoon season while this pattern was reversed during the winter season. A greater proportion of fine roots were <0.5 mm diameter in the younger sites, and turnover of fine roots was more rapid in the developing stands compared to the natural forest. Fine root biomass was correlated positively with N-mineralization rate and soil water content. Thus, it can be concluded that the fine root growth was aided by rapid N-mineralization, and both fine root growth and N-mineralization increase as stands redevelop following shifting cultivation disturbance.

Biomass and production of two vascular plants in a boreal mesotrophic fen

1996 ◽  
Vol 74 (6) ◽  
pp. 934-938 ◽  
Author(s):  
Timo Saarinen
Keyword(s):  
Fine Roots ◽  
Vascular Plants ◽  
Turnover Rate ◽  
Fine Root ◽  
Belowground Biomass ◽  
Fine Root Biomass ◽  
Total Production ◽  
Carex Rostrata ◽  
Direct Input ◽  
The Vertical Distribution

The vertical distribution of biomass and production was measured using indirect 14C isotope techniques in a boreal mesotrophic fen dominated by Carex rostrata and Potentilla palustris. The biomass of C. rostrata was high (2290 g∙m−2), 78% of which was fine-root biomass. Even with a low turnover rate (0.59 yr−1), fine roots also accounted for 74% of the total production of 1424 g∙m−2∙yr−1. The majority of the belowground biomass was found in the uppermost 30 cm. However, living roots of C. rostrata were found down to a depth of 230 cm. In fen ecosystems, the direct input of carbon through deep-penetrating roots to slowly decomposing layers may considerably affect the accumulation of peat. Keywords: biomass, Carex rostrata, fen, peat, production, roots.

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