Analysis of some sources of error in methods used to determine fine root production in forest ecosystems: a simulation approach

1987 ◽  
Vol 17 (8) ◽  
pp. 909-912 ◽  
Author(s):  
W. A. Kurz ◽  
J. P. Kimmins

Fine root production rates are most commonly calculated from periodic measurements of live and dead fine root biomass. The accuracy of production estimates based on this method is very sensitive to violations of the inherent assumptions, particularly the assumption that the processes of fine root production and mortality are temporally separate. A simple model was used to simulate data for a variety of seasonal patterns of live and dead fine root biomass. Fine root production and mortality rates were calculated from these simulated data using two different computational methods. Comparison of the calculated rates with the known rates (the rates used to generate the seasonal patterns) revealed that violations of the above assumptions can result in inaccurate rate estimates. When fine root production and mortality occur simultaneously within a sampling interval, the calculated production rate will greatly underestimate the true value. Additional error in the rate estimates may result from sampling error associated with the fine root biomass data. The model suggested that sampling error can cause either overestimation or underestimation of fine root production.

1993 ◽  
Vol 23 (6) ◽  
pp. 1179-1186 ◽  
Author(s):  
David A. Publicover ◽  
Kristiina A. Vogt

A simulation model approach was used to assess the performance of several methods for calculating fine root production under various conditions that could lead to errors in production estimates. The models included two methods that utilize periodic data on live only or live and dead fine root biomass, plus one method (the compartment-flow model) that also incorporates root decomposition rates. Potential sources of error included long sampling intervals, random sampling error, use of an incorrect decay constant, and sample processing errors (undermeasurement of fine root biomass and inaccuracy in identifying live and dead roots). The compartment-flow method was the most accurate and overcomes the problems of underestimation of production to which the biomass-only methods are subject. The sensitivity of the method to processing errors varies according to the method used to determine decay rates. The measurement of true decay rates is the biggest obstacle to accurate estimation of fine root production when using the compartment-flow method.


Author(s):  
Meimei Sun ◽  
Bo-Chao Zhai ◽  
Qiu-Wen Chen ◽  
Guoqing Li ◽  
Sheng Du

AbstractFine roots are the most active and functional component of root systems and play a significant role in the acquisition of soil resources. Density is an important structural factor in forest plantations but information on changes in fine roots along a density gradient is limited. In this study, plantations of black locust (Robinia pseudoacacia L.) and Chinese pine (Pinus tabuliformis Carr.) with four density classes were analyzed for the influence of soil and leaf traits on fine root growth. Fine root biomass increased with stand density. High fine root biomass was achieved through increases in the fine root production and turnover rate in the high-density black locust plantations and through an increase in fine root production in the pine plantations. In the high-density Chinese pine stand, there was a high fine root turnover which, coupled with high fine root production, contributed to a high fine root biomass. Overall, fine root production and turnover rate were closely related to soil volumetric water content in both kinds of plantations, while fine root biomass, especially the component of necromass, was related to soil nutrient status, which refers to phosphorous content in black locust plantations and nitrogen content in Chinese pine plantations. There was a close linkage between leaf area index and fine root dynamics in the black locust plantations but not in the pine plantations.


2020 ◽  
Vol 25 (1) ◽  
pp. 24-29
Author(s):  
Krishna Prasad Bhattarai ◽  
Tej Narayan Mandal ◽  
Tilak Prasad Gautam

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.


1984 ◽  
Vol 62 (4) ◽  
pp. 823-829 ◽  
Author(s):  
Kathryn A. Saterson ◽  
Peter M. Vitousek

Seasonal changes in total fine-root biomass and the allocations of nitrogen and phosphorus to roots, root crowns, and leaves of Aristida stricta were measured on a North Carolina coastal plain savanna. Total fine-root biomass was determined from sequential root cores taken over 12 months. Total root biomass decreased from spring to late fall and then increased in winter. Root production and turnover estimates indicate that this low-fertility savanna has a relatively large root biomass and slow turnover. The pattern of allocation of biomass, nitrogen, and phosphorus to different tissues of Aristida stricta indicates that throughout the year the greatest percentage of biomass and nutrients is in roots.


Trees ◽  
2020 ◽  
Author(s):  
Ji Young An ◽  
Akira Osawa

Abstract Key message Fine root and litterfall are major contributor of NPP and fine root production may reflect forest productivity in a warm-temperate forest in Japan. Abstract Forest ecosystems play an important role as the major carbon sink on land, with fine root dynamics and litterfall representing major carbon fluxes. The objectives of this research were to estimate NPP including annual fine root production values, to investigate fine root dynamics and the relationships between above– and belowground organs in konara oak (Quercus serrata) and hinoki cypress (Chamaecyparis obtusa) forests. Litterfall was collected seasonally for 1 year from June 2013. The ingrowth core method and the sequential soil core method were applied with a root litterbag experiment to estimate fine root (< 2 mm) production (FRP), mortality (FRM), and decomposition (FRD) for 1 year (from 2013 to 2014), using the continuous inflow estimate method and the simplified decision matrix. The total NPP ranged from 8.2 to 13.9 (t ha− 1 yr− 1), and the sum of aboveground litterfall and FRP accounted for 60% of the total NPP on average, confirming the significance of above- and belowground litter for the forest NPP as a source of detritus for the decomposer system. In hinoki cypress stand, fine root biomass peaked in the end of winter while fine root necromass showed the highest peak in late summer. In konara oak stand, only very fine root (< 0.05 mm) biomass and necromass demonstrated significant seasonal patterns. The seasonal patterns of fine root production did not differ between forest types and root diameter classes. We found a possible relationship between above- and belowground production and fine root production tended to be high in productive forests. This study improves our understanding of different patterns of carbon dynamics between temperate broadleaved and coniferous forest ecosystems.


2001 ◽  
Vol 31 (4) ◽  
pp. 644-653 ◽  
Author(s):  
William J Dress ◽  
Ralph EJ Boerner

This study compares standing root biomass from sequential root cores and new root production in ingrowth cores in three watersheds: an unburned control watershed, a watershed burned once in 1996, and a watershed burned for three consecutive years (1996–1998). Based on root cores collected on six sampling dates from April through November 1998, maximum standing live root biomass occurred approximately 1 month earlier in the growing season in the site burned three times, presumably because of increased soil temperature after the fires. Standing live fine root biomass was significantly lower in the site burned three times in three of the six sampling dates (April, June, and November) and when averaged over the whole growing season. Most of this effect was due to lesser root biomass in the most mesic landscape position. New root production was measured during three ingrowth core intervals: April to August 1998, August to November 1998, and August 1998 to November 1999. Net production was significantly greater in sample plots in xeric landscape positions during each sampling interval. Overall, differences in standing root biomass were inversely correlated with fire-induced changes in N mineralization and increased soil temperature after burning shifted the phenology of root biomass accumulation earlier in the growing season.


2005 ◽  
Vol 83 (10) ◽  
pp. 1317-1321 ◽  
Author(s):  
Numa P. Pavón

The contribution of cacti and shrubs to root biomass and fine-root production was described in a semiarid Mexican scrub. Both life forms were evaluated for fine-root production variation in relation to changes of nitrogen in the soil, with a fertilization experiment. Cacti represented 78% of the total mean root biomass (660 ± 70 g·m–2 (mean ± SE)) in the complete soil profile (50 cm in depth). In both life forms, root biomass was higher near the surface of the soil. Roots <3 mm in diameter represented 92.5% for cactus root biomass and 69.4% for shrubs. Monthly root biomass varied significantly between months, and significant differences were obtained between plant life forms. Fine and very fine root production was estimated as 3.76 Mg·ha–1·year–1, and cactus contribution to total root production was 81.2%. Significant differences were obtained between life forms. It was clear that a low concentration in the soil nitrogen diminishes fine-root production, supporting the hypothesis that in arid ecosystems nitrogen is a limiting factor for primary production.


2019 ◽  
Vol 7 (9) ◽  
pp. 230-245
Author(s):  
Abebe Worku ◽  
Masresha Fetene ◽  
Solomomn Zewdie ◽  
Yoseph Assefa

Fine roots biomass of Erica trimera was investigated at three altitudinal levels, i.e. 3000, 3300, and 3500 masl across  three depth classes (0-10, 10-20, and 20-40 cm) for each of the four seasons of Bale Mountains by using sequential soil coring. Soil chemical characteristics and moisture were analyzed for all of the three altitudinal levels and depth classes. The annual fine root production of the species was calculated based on min-max method. Fine root production increased markedly from 3270 kg. ha-1. yr-1 at 3000 masl and 2850 kg. ha-1. yr-1 at 3300 masl to 9987 kg. ha-1. yr-1 at 3500 masl. Total nitrogen, available phosphorous, organic carbon, moisture content and PH of the soil increased significantly as altitude increased. In the two lower altitudinal levels, 3000 and 3300masl, fine root mass and biomass decreased as depth increased, but at the higher altitude (3500 masl) fine root tended to more concentrated at the deeper depths while  the availability of soil nutrient and soil acidity showed a tendency to decreased as depth increased at all of the three sites. The highest fine root mass and biomass was recorded at the major rainy season followed by the transition period, the small rainy and dry period, in that order. The highest fine root mass during the major rainy season and lowest fine root mass in the dry season indicated that soil moisture was critical factor in governing the pattern of root growth in this ecosystem.


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