The Role of Fine Roots in the Functioning of Alaskan Boreal Forests

2006 ◽  
Author(s):  
Roger W. Ruess ◽  
Ronald L. Hendrick
Keyword(s):  
Fine Roots ◽  
Root Biomass ◽  
Fine Root ◽  
Root Systems ◽  
Simple Fact ◽  
Coarse Root ◽  
Spruce Stands ◽  
Boreal Ecosystem ◽  
N Incorporation

The patterns of production described in Chapter 11 tell only half of the story about boreal forest production because a large proportion of the carbon (C) acquired by plants is allocated belowground in ways that have traditionally been extremely difficult to quantify. Work in the Bonanza Creek LTER provides considerable insight into the patterns, causes, and consequences of this belowground C allocation. Belowground allocation has a number of important ecosystem consequences beyond the simple fact that C allocated belowground comes at the expense of aboveground growth. Belowground and aboveground tissues differ substantially in the rates of C and nitrogen (N) incorporation into new tissue, the ratio of growth to respiration, and the rate of tissue decay. For example, despite the small biomass of fine roots relative to aboveground tissues in forest ecosystems, disproportionate amounts of C and N cycle annually through fine roots, which grow, die, and decompose very rapidly and have high N concentrations (Hendrick and Pregitzer 1992, Ruess et al. 1996, 2003). The objectives of this chapter are to (1) summarize our understanding of the structure and function of fine-root systems in forest types within the Bonanza Creek Experimental Forest, (2) compare our findings with the results of studies of other boreal and temperate ecosystems in order to develop a broader understanding of fine-root function, and (3) identify critical research gaps in our understanding of the role of fine-root systems in boreal ecosystem function. Fine roots grow more rapidly than the rest of the root system in a forest and are responsible for the bulk of nutrient and water acquisition. Until recently, fine roots were defined rather arbitrarily as roots less than 1–2 mm in diameter, while roots larger than this were considered coarse roots. Only one data set for fine and coarse root biomass has been published for interior Alaskan forests (Ruess et al. 1996), which shows (1) live fine-root biomass ranging from 221 g m-2 in floodplain white spruce stands to 832 g m-2 in upland birch-aspen stands, (2) a positive correlation between fine-root and coarse-root biomass, with coarse-root biomass averaging 50% greater than fine roots, and (3) no relationship between aboveground biomass and fine or coarse root biomass.

scholarly journals Theory predicts plants grow roots to compete with only their closest neighbours

2019 ◽  
Vol 286 (1912) ◽  
pp. 20191129 ◽  
Author(s):  
Caroline E. Farrior
Keyword(s):  
Fine Roots ◽  
Root Biomass ◽  
Fine Root ◽  
Tree Height ◽  
Fine Root Biomass ◽  
Plant Roots ◽  
Spatial Extent ◽  
Individual Strategies ◽  
Made In

The combination of individual-based selection with shared access to resources drives individuals to invest more than necessary in taking up their share of resources due to the threat of other individuals doing the same (competitive overinvestments). This evolutionary escalation of investment is common, from deer antlers and peacock feathers to tree height and plant roots. Because plant roots seem to be well intermingled belowground, the simplifying assumption that belowground resources are perfectly well mixed is often made in models—a condition that favours maximal fine-root overinvestments. Here, I develop simple models to investigate the role of space in determining the overlap among individuals belowground and resulting fine-root biomass. Without costs of growing roots through space, evolutionary optimization leads individuals to intermingle their fine roots perfectly and to invest just as much in these roots, whether there are two individuals competing or many. However, if there are any costs of sending roots through soil, investment in fine roots is constrained in amount and spatial extent. Dominant individuals are those that keep their roots in the soil closest to their own stem and the stems of their closest neighbours. These results highlight the importance of space in determining individual strategies as well as competitive networks.

Fine and coarse root parameters from mature black spruce displaying genetic × soil moisture interaction in growth

2012 ◽  
Vol 42 (11) ◽  
pp. 1926-1938 ◽  
Author(s):  
John E. Major ◽  
Kurt H. Johnsen ◽  
Debby C. Barsi ◽  
Moira Campbell
Keyword(s):  
Fine Roots ◽  
Root Biomass ◽  
Fine Root ◽  
Black Spruce ◽  
Soil Depth ◽  
Moisture Stress ◽  
Root Mass ◽  
Coarse Root ◽  
N Concentration ◽  
Root Size

Fine and coarse root biomass, C, and N mass parameters were assessed by root size and soil depths from soil cores in plots of 32-year-old black spruce ( Picea mariana (Mill.) Britton, Sterns & Poggenb.) from four full-sib families studied previously for drought tolerance and differential productivity on a dry and wet site. All fine and coarse root size categories had greater root biomass on the dry than on the wet site. Most of the site differences resided in 0–20 cm soil depth. The wet site had greater root N concentration than the dry site, despite the same soil N; thus, virtually no differences were observed in total fine and coarse root N mass between sites. Root N concentration declined with increases in both soil depth and root size. Fine roots (<2 mm) accounted for 73% and 38% of the total fine and coarse N and C mass, respectively. The dry site had lower needle mass and more fine root mass than the wet site, demonstrating an adaptation to moisture stress change through the rebalancing of resource-obtaining organs. Drought-tolerant families had the same quantity of fine roots as drought-intolerant families but were able to support more foliage and aboveground mass per unit fine root mass than intolerant families.

scholarly journals Thinning effects on biomass and element concentrations of roots in adjacent hornbeam and oak stands in Istanbul, Turkey

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Serdar Akburak ◽  
Ender Makineci
Keyword(s):  
Fine Roots ◽  
Root Biomass ◽  
Fine Root ◽  
Basal Area ◽  
Fine Root Biomass ◽  
Root Diameter ◽  
Coarse Roots ◽  
Coarse Root ◽  
Element Concentrations ◽  
Diameter Classes

Abstract Background Thinning is a commonly used treatment in forest management which affects the tree root systems. The effects of thinning on element concentrations and seasonal change of roots were evaluated in adjacent oak (Quercus frainetto Ten.) and hornbeam (Carpinus betulus L.) stands according to the different root diameter classes. Method Two replicated control and thinning plots (50 m × 50 m) were set for each species (hornbeam and oak). Thinning treatments (November 2010) reduced 50% of the basal area in both oak and hornbeam stands. Roots were assessed by seasonal collection over 2 years (from October 2010 to October 2012). The roots were then sorted into diameter classes of 0–2 mm (fine roots), 2–5 mm (small roots) and > 5 mm (coarse roots). C, N, P, K, Ca, Na, Mg, S, Mn, Fe, Al, Zn, Pb, Ni, Cu and Cd were analyzed. Results Except coarse roots, the highest root biomasses were determined in April-2011 in all plots. Fine-root biomass in oak was found significantly higher in control plots. In contrast to the oak, the fine-root biomass in the thinned hornbeam plots was higher than in the controls. The small-root biomass did not significantly differ between the thinned and the control plots in both oak and hornbeam stands. However, the coarse-root biomass showed significant differences between the control (1989 g∙m− 2) and thinned plots (1060 g∙m− 2) in oak, while no difference was detected in hornbeam. The concentrations of C, Al, Pb, Cd, Ni, Zn, Mn, Na, K, Mg and P in the fine roots of oak were significantly higher in the thinned plots. However, the concentration of Pb, Cd and Fe in the fine roots was significantly higher in the thinned plots of hornbeam. Significant differences were observed between the species for all elements in the fine roots except for C, N and P. In particular, elements in the fine roots tended to increase in July in the oak. In the hornbeam, all element concentrations in the fine roots (except C, N, and S) in the thinned plots showed a tendency to increase in April. The concentrations of Pb, Ni, Al, Fe, Cu, Ca, Na, K, Mg and P in the hornbeam control plots increased during the April 2011 period. Conclusion The results indicated that thinning effects on temporal changes and concentrations of elements in the roots could be attributed to species-specific characteristics.

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.

Fine root biomass in two black spruce stands in interior Alaska: effects of different permafrost conditions

Trees ◽  
2015 ◽  
Vol 30 (2) ◽  
pp. 441-449 ◽  
Author(s):  
Kyotaro Noguchi ◽  
Yojiro Matsuura ◽  
Stephen D. Sparrow ◽  
Larry D. Hinzman
Keyword(s):  
Root Biomass ◽  
Fine Root ◽  
Black Spruce ◽  
Fine Root Biomass ◽  
Interior Alaska ◽  
Spruce Stands

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 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.

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.

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