Effect of thinning on production and mortality of fine roots in a Pinusradiata plantation on a fertile site in New Zealand

1987 ◽  
Vol 17 (8) ◽  
pp. 919-928 ◽  
Author(s):  
D. Santantonio ◽  
E. Santantonio
Keyword(s):  
Fine Roots ◽  
Standing Crop ◽  
Fine Root ◽  
General Pattern ◽  
Minor Component ◽  
Root Decomposition ◽  
Root Production ◽  
Soil Core ◽  
Stem Wood ◽  
Small Roots

The effects of heavy thinning (60% reduction in basal area) on fine (< 1 mm diam.) and small roots (1–5 mm diam.) were evaluated during the 2nd year following treatment by periodic soil core sampling in a 12-year-old plantation of Pinusradiata D. Don. Data from these samples enabled us to estimate monthly standing crops of live and dead fine roots and seasonal rates of fine-root decomposition. We used a compartment-flow model to estimate production and mortality of fine roots with monthly resolution from these data. The general pattern of production and mortality was modal and out of phase with soil temperature. On an area basis, thinning reduced the overall standing crop of live fine roots from 1.38 to 0.55 Mg/ha; the standing crop of dead fine roots remained unchanged at 4.37 Mg/ha. The standing crop of live small roots declined from 1.03 to 0.54 Mg/ha. Annual production of fine roots was estimated at 2.2 and 1.9 Mg•ha−1•year−1 in the control and thinned treatment, respectively, and mortality was estimated at 2.1 and 2.0 Mg•ha−1•ear−1 in the control and thinned treatment, respectively. Thinning shortened mean fine-root longevity from 6.2 to 2.5 months. With respect to total dry matter production, fine-root production remained a minor component following a heavy thinning. It accounted for only 4.6 and 6.1% of the stand total in the control and thinned treatments, respectively. These results indicate that on a fertile site with a mild climate the opportunity to shift production from fine roots to another component, such as stem wood, is likely to be small.

Estimating fine-root production and turnover from biomass and decomposition data: a compartment–flow model

1987 ◽  
Vol 17 (8) ◽  
pp. 900-908 ◽  
Author(s):  
D. Santantonio ◽  
J. C. Grace
Keyword(s):  
Soil Temperature ◽  
Fine Roots ◽  
Flow Model ◽  
Fine Root ◽  
Net Primary Production ◽  
Independent Set ◽  
Early Summer ◽  
Root Decomposition ◽  
Root Production ◽  
Fine Root Production

Production and replacement of fine roots (diam. < 1 mm) takes 8–67% of net primary production in forests. Most of this production is lost through mortality; little appears as an increment. Traditional biomass methods underestimate fine-root production because estimating production or mortality from changes in standing crop alone does not adequately account for simultaneous and compensating processes of growth, death, and replacement which occur continuously. We propose a compartment–flow model to solve this problem and estimate fine-root production and mortality at a monthly resolution for a pine plantation in New Zealand. The main component of the model is fine-root decomposition, an exponential decay function driven by soil temperature. The model "produces" and "turns over" enough fine roots to maintain observed standing crops of live and dead fine roots given losses through decomposition each month. We have formulated the model as differential and difference equations. Monthly estimates from the model indicated smooth modal patterns. Production and mortality peaked in early spring (September) at about 600 kg•ha−1•month−1 and fell to near zero in summer (January–February). The periodicity of these two processes was out of phase with soil temperature at 10 cm. Decomposition occurred continuously; it peaked in early summer (December) and declined to low levels during winter and was in phase with soil temperature. In a validation of the decomposition portion of the model with an independent set of decomposition data, measured standing crops of dead fine root were not statistically different from predicted values.

Influence of Pruning and Irrigation on Root Longevity of `Concord' Vines

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 511a-511
Author(s):  
L.H. Comas ◽  
D.M. Eissenstat ◽  
A.N. Lakso ◽  
R. Dunst
Keyword(s):  
Fine Roots ◽  
Fine Root ◽  
Cultural Practices ◽  
Growing Season ◽  
Root Production ◽  
Root Dynamics ◽  
Supplemental Irrigation ◽  
Root Longevity ◽  
Root Lifespan ◽  
Median Lifespan

Improved cultural practices in grape require a better understanding of root growth and physiology. Seasonal root dynamics were examined in mature `Concord' vines with balanced or minimal-pruning, and with or without supplemental irrigation in Fredonia, N.Y. Fine roots were continuously produced during the growing season starting in mid-June around time of bloom. Roots began to die in September at verasion. Minimal-pruned vines produced more roots than balanced-pruned vines, with the minimal-pruned/unirrigated vines producing the most roots. Irrigation and pruning delayed fine root production at the beginning of the growing season. Peak fine root flush was 16 June to 21 July 1997 for the minimal-pruned/unirrigated treatment, while peak flush was 7 July to 2 Sept. 1997 for balanced-pruned/irrigated treatment. In minimal-pruned vines, many roots were observed down to depths of 120 cm. In contrast, balanced-pruned vines had very few fine roots deeper than 40 cm. From initial observations, median lifespan of fine roots was 5 to 9.5 weeks, depending on treatment and depth in soil. Fine roots lived longer in the top 15-cm than in the 16- to 30-cm layer of soil in all treatments. Both minimal pruning and irrigation increased root lifespan. Fine roots had the shortest lifespan in the balanced-pruned/unirrigated treatment and the longest lifespan in the minimal-pruned/irrigated treatment.

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 growth and mortality in different-aged ponderosa pine stands

2008 ◽  
Vol 38 (7) ◽  
pp. 1797-1806 ◽  
Author(s):  
Chris P. Andersen ◽  
Donald L. Phillips ◽  
Paul T. Rygiewicz ◽  
Marjorie J. Storm
Keyword(s):  
Root Growth ◽  
Pinus Ponderosa ◽  
Ponderosa Pine ◽  
Standing Crop ◽  
Fine Root ◽  
Tree Age ◽  
Root Production ◽  
Age Classes ◽  
Old Growth ◽  
Pine Stands

Root minirhizotron tubes were installed at two sites around three different age classes of ponderosa pine ( Pinus ponderosa Dougl. ex Laws.) to follow patterns of fine root (≤2 mm diameter) dynamics during a 4 year study. Both sites were old-growth forests until 1978, when one site was clear-cut and allowed to regenerate naturally. The other site had both intermediate-aged trees (50–60 years) and old-growth trees (>250 years old). Estimates of fine root standing crop were greatest around young trees and least around intermediate-aged trees. Root production was highly synchronized in all age classes, showing a single peak in late May – early June each year. Root production and mortality were proportional to standing root crop (biomass), suggesting that allocation to new root growth was proportional to root density regardless of tree age. The turnover index (mortality/maximum standing crop) varied from 0.62 to 0.89·year–1, indicating root life spans in excess of 1 year. It appears that young ponderosa pine stands have greater rates of fine root production than older stands but lose more fine roots each year through mortality. The results indicate that soil carbon may accumulate faster in younger than in older stands.

scholarly journals Effect of Root and Mycelia on Fine Root Decomposition and Release of Carbon and Nitrogen Under Artemisia halodendron in a Semi-arid Sandy Grassland in China

2021 ◽  
Vol 12 ◽  
Author(s):  
Xinping Liu ◽  
Yongqing Luo ◽  
Li Cheng ◽  
Hongjiao Hu ◽  
Youhan Wang ◽  
...  
Keyword(s):  
Fine Roots ◽  
Fine Root ◽  
Organic N ◽  
Root Turnover ◽  
Root Decomposition ◽  
Soil System ◽  
Nitrate N ◽  
Artemisia Halodendron ◽  
Fine Root Decomposition ◽  
Semi Arid

Plant fine root turnover is a continuous process both spatially and temporally, and fine root decomposition is affected by many biotic and abiotic factors. However, the effect of the living roots and the associated mycorrhizal fungal mycelia on fine root decomposition remains unclear. The objective of this study is to explore the influence of these biotic factors on fine root decomposition in a semi-arid ecosystem. In this study, we investigated the effect of fine roots and mycelia on fine root decomposition of a pioneer shrub (Artemisia halodendron) in Horqin sandy land, northeast China, by the ingrowth core method combined with the litterbag method. Litterbags were installed in cores. Results showed that core a allowed the growth of both fine roots and mycelia (treatment R + M), core b only allowed the growth of mycelia (treatment M), and in core c the fine root and mycelia growth were restricted and only bulk soil was present (treatment S). These findings suggest that the process of root decomposition was significantly affected by the living roots and mycelia, and carbon (C) and nitrogen (N) concentration dynamics during root decomposition differed among treatments. Mycelia significantly stimulated the mass loss and C and N release during root decomposition. Treatment R + M significantly stimulated the accumulation of soil total C, total N, and organic N under litterbags. The mycelia significantly stimulated the accumulation of the inorganic N (ammonium-N and nitrate-N) but the presence of fine roots weakened nitrate-N accumulation. The presence of living roots and associated mycelia strongly affected the process of root decomposition and matter release in the litter-soil system. The results of this study should strengthen the understanding of root-soil interactions.

Dynamics of fine-root production and mortality of Scots pine in waterlogged peat soil during the growing season

2020 ◽  
Vol 50 (5) ◽  
pp. 510-518
Author(s):  
Tapani Repo ◽  
Timo Domisch ◽  
Jouni Kilpeläinen ◽  
Sirpa Piirainen ◽  
Raimo Silvennoinen ◽  
...  
Keyword(s):  
Scots Pine ◽  
Tree Growth ◽  
Root Length ◽  
Fine Roots ◽  
Time Course ◽  
Fine Root ◽  
Peat Soil ◽  
Growing Season ◽  
Root Production ◽  
Fine Root Length

Excess water in the rooting zone critically reduces tree growth and may even kill trees; however, the relative importance of damage to roots versus aboveground parts and the time course of damage are not well understood. We studied the dynamics of fine-root growth and mortality of 7-year-old Scots pine (Pinus sylvestris L.) saplings affected by a 5-week period of waterlogging (WL) during the growing season. Two out of six WL-exposed saplings survived the treatment. After 1–2 weeks of WL, the mortality of the first-order short roots (usually mycorrhizas) started to increase and the production of these roots started to decrease. WL decreased the longevity of short and long roots. Total root length (especially of fine roots with a diameter < 0.5 mm), specific fine-root length, total root dry mass (including stump), and reverse-flow root hydraulic conductance were lower in WL saplings than in control saplings at the end of the experiment; however, several root traits were similar in control and surviving WL saplings. Because of the high importance of fine roots for tree growth and carbon sequestration, their responses to elevated water tables should be considered in sustainable use and management of boreal peatland forests, for example, by continuous cover forestry and (or) ditch network maintenance.

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.

CARBON AND NUTRIENT CYCLING THROUGH FINE ROOTS IN RUBBER (HEVEA BRASILIENSIS) PLANTATIONS IN INDIA

2013 ◽  
Vol 49 (4) ◽  
pp. 556-573 ◽  
Author(s):  
M. D. JESSY ◽  
P. PRASANNAKUMARI ◽  
JOSHUA ABRAHAM
Keyword(s):  
Soil Moisture ◽  
Nutrient Cycling ◽  
Fine Roots ◽  
Fine Root ◽  
Nutrient Status ◽  
Root Turnover ◽  
Root Production ◽  
Fine Root Production ◽  
Fine Root Turnover ◽  
Rubber Plantations

SUMMARYUnderstanding the growth dynamics of fine roots and their contribution to soil organic carbon and nutrient pools is crucial for estimating ecosystem carbon and nutrient cycling and how these are influenced by climate change. Rubber is cultivated in more than 10 million hectare globally and the area under rubber cultivation is fast expanding due to socio-economic reasons, apart from the importance given to this species for eco-restoration of degraded lands. An experiment was conducted to quantify fine root production, fine root turnover and carbon and nutrient cycling through fine roots in rubber plantations with different soil nutrient status and rainfall pattern. Fine root production was estimated by sequential coring and ingrowth core methods. Fine root decomposition was determined by the litter bag technique. Carbon and nutrient contents in fine roots were determined and their turnover was computed. Fine root biomass in the top 0–7.5-cm soil layer showed significant seasonal fluctuation and the fluctuations were particularly wide during the transition period from the dry season to the rainy season. Fine root production estimated by the different methods was significantly higher at the lower fertility site and during the higher soil moisture stress year. Fine root turnover ranged from 1.04 to 2.29 year−1. Root carbon and nutrient status showed seasonal variation and lower status was observed during the rainy season. The annual recycling of C, N, P, K, Ca and Mg through fine roots ranged from 590 to 1758, 30 to 85, 3 to 12, 13 to 31, 11 to 35 and 6 to 13 kg ha−1, respectively. Substantial quantities of carbon and nutrients were recycled annually in rubber plantations through fine roots. When soil moisture and nutrient stress were more severe, fine root production, turnover and carbon and nutrient recycling through fine roots were higher.

A comparison of the fine root component of a pure and a mixed coniferous stand

1988 ◽  
Vol 18 (11) ◽  
pp. 1416-1426 ◽  
Author(s):  
H. M. McKay ◽  
D. C. Malcolm
Keyword(s):  
Fine Roots ◽  
Standing Crop ◽  
Fine Root ◽  
Sitka Spruce ◽  
Nitrogen And Phosphorus ◽  
Mixed Stands ◽  
Method Of Calculation ◽  
The Mean ◽  
Phosphorus And Potassium ◽  
Nitrogen Phosphorus

Fine roots were sampled at monthly intervals during 1984–1985 in pure plots of Sitka spruce (Piceasitchensis (Bong.) Carr.) and mixed plots of Scots pine (Pinussylvestris L.) and Sitka spruce established on an upland heath in 1969. Both types of planting had received phosphorus and potassium fertiliser but no nitrogen. The mean standing crop of live roots (<2 mm diameter) in the top 5 cm of pure spruce plots was 112 g • m−2, almost double that of mixed stands (37 g • m−2 of spruce plus 20 g • m−2 of pine). Necromass was 80% of total mass in both stand types. Concentrations of nitrogen and phosphorus were greater in pure plots than in mixed plots, but fine root capital of nitrogen, phosphorus, and potassium was greater in pure spruce than in mixed plots (biomass and necromass contained 11, 2, and 5 and 45, 4, and 7 kg • ha−1 of nitrogen, phosphorus, and potassium, in pure plots, and 7, 1, and 3 and 30, 3, and 3 kg • ha−1 of nitrogen, phosphorus, and potassium in mixed plots, respectively). Production of fine roots in pure and mixed stands was estimated at 181 and 97 g • m−2•year−1 or 715 and 367 g • m−2•year−1, respectively, depending on the method of calculation. Fine roots of pure plots were highly concentrated in the top 3 cm. In mixture, spruce roots had a less extreme vertical distribution and pine roots were more evenly distributed down to 9 cm.

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