C allocation among fine roots, above-, and belowground wood in a deciduous forest and its implication to ecosystem C cycling: a modelling analysis

Abstract. Knowledge about allocation of carbohydrates among tree organs with different life times and decomposition rates is crucial in determining the residence time of carbon (C) in forests and the overall ecosystem C cycling rate. A new model (named CAF) able to simulate C allocation among fine roots, above-, and belowground wood in deciduous forests was developed and integrated into the net ecosystem exchange model FORUG. CAF draws on growth rules and source-sink relationships. Maintenance and growth of the modelled sinks i.e. fine roots, coarse roots, stems, and branches, are controlled by phenology, environment, and by the reserve of non-structural carbohydrates. CAF was parameterized for 2-y and tested against 6-y observations from a beech (Fagus sylvatica L.) stand in North-East France, experiencing summer droughts of different intensities. The model reproduced well (i) the C fluxes allocated annually to assimilation, respiration and biomass production, and (ii) the interannual pattern of wood biomass accumulation. Seasonality of C reserve and wood growth was captured, but some discrepancies were detected at the onset of the growing season. The allocation pattern differed among years, although the overall net primary production decreased only in case of severe drought. During a year with severe drought, the fraction of C allocated to production of fast-decomposing C pools (e.g. fine roots, C reserve) increased by +13% than years without drought, whereas the same fraction increased on average by +18% in case of low to moderate drought. Carbon invested in biomass during a year with summer drought has therefore a shorter residence time in the ecosystem than the C stored during a year without summer drought.

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Carbon allocation of mature spruce upon drought release – results from a whole-tree 13C-labeling study

10.5194/egusphere-egu21-11173 ◽

2021 ◽

Author(s):

Kyohsuke Hikino ◽

Jasmin Danzberger ◽

Vincent Riedel ◽

Benjamin D. Hafner ◽

Benjamin D. Hesse ◽

...

Keyword(s):

Carbon Allocation ◽

Belowground Biomass ◽

Early Summer ◽

Summer Drought ◽

Root Tips ◽

Coarse Roots ◽

Allocation Pattern ◽

Recovery Processes ◽

Source Sink ◽

Whole Tree

This contribution presents the result of a free-air 13C labeling experiment on mature Norway spruce (P. abies [L.] KARST.) upon watering after five years of recurrent summer drought in southern Germany, focusing on whole tree allocation processes. Mature spruce trees had been exposed to recurrent summer drought from 2014 to 2018 through complete exclusion of precipitation throughfall from spring to late fall (i.e., March to November).&#160; In early summer 2019, the drought stressed spruce trees were watered to investigate their recovery processes. In parallel with the watering, we conducted a whole-tree 13C labeling in canopies and traced the signal in various C sinks, i.e. stem phloem and CO2 efflux, tree rings at different heights, coarse roots, fine root tips, mycorrhiza, root exudates, and soil CO2 efflux.We hypothesize that drought stressed spruce preferentially allocates newly assimilated C to belowground sinks upon drought release. Conversely to our expectations, allocation to belowground C sinks was not stimulated in drought stressed compared to control spruce. Likewise, the relative amount of recently fixed C allocated to aboveground sinks did not differ between treatments. Our findings suggest that the belowground C sinks are not of higher priority for the allocation of newly assimilated C upon watering after long-term drought. The observed allocation pattern is discussed taking total above- and belowground biomass as well as C source/sink relations into account.

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Dynamics in maturing Scots pine monoculture in north-east Belgium

Silva Gandavensis ◽

10.21825/sg.v55i0.901 ◽

1990 ◽

Vol 55 ◽

Cited By ~ 1

Author(s):

D. Maddelein ◽

N. Lust ◽

S. Meyen ◽

B. Muys

Keyword(s):

Scots Pine ◽

Deciduous Forest ◽

Forest Type ◽

Deciduous Tree ◽

Red Oak ◽

Black Cherry ◽

Deschampsia Flexuosa ◽

North East ◽

Stand Conversion ◽

Pine Stands

The State Forest Pijnven, created early this century by afforestation with Scots pine (Pinus sylvestris L.) of heathland areas is now characterised in most stands by an important ingrowth of deciduous tree species. Ingrowth is dominated by red oak (Quercus rubra L.) and black cherry (Prunus serotina Ehrh.), both species originating from North America. Deciduous ingrowth in the pine stands profoundly influences herbal composition of the stand. Deschampsia flexuosa (L.) Trin., abundant in all older pine stands, disappears when deciduous trees settle and species diversity, already low in the pine stands, further diminishes. Important oak and cherry regeneration is depending on the presence of seed trees in the vicinity; when lacking, a new pine generation manages to settle. A good red oak regeneration can be useful as a basis for stand conversion towards a mixed, uneven-aged deciduous forest type, but in many cases this possibility is hampered by massive invasion of black cherry, preventing all other species to regenerate.

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Caucasian clover performance in a year of severe drought

Proceedings of the New Zealand Grassland Association ◽

10.33584/jnzg.1998.60.2321 ◽

1998 ◽

pp. 119-125

Author(s):

R.N. Watson ◽

F.J. Neville ◽

N.L. Bell

Keyword(s):

White Clover ◽

Growth Rates ◽

Volcanic Ash ◽

Severe Drought ◽

Summer Drought ◽

Volcanic Ash Soil ◽

Summer Growth

In a year of spring-summer drought on a sandy volcanic ash soil, ryegrass/caucasian clover (RG/ CC) and RG/white clover (RG/WC) pastures had similar rapid increases in pasture growth rates during September. Growth rates peaked around 25 October (65-70 kg DM/ha/day) for RG/CC and around 14 October (50-60 kg DM/ha/day) for RG/ WC. As drought intensified the declines in pasture growth rates were similar, but delayed by up to 3 weeks for RG/CC. Both pastures reached minimum summer growth rates of

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Análisis de crecimiento de tres especies de Caesalpinia (Leguminosae) de la selva baja caducifolia de Chamela, Jalisco

Botanical Sciences ◽

10.17129/botsci.1606 ◽

2017 ◽

pp. 5

Author(s):

Emmanuel Rincón ◽

Pilar Huante ◽

Mariana Álvarez-Añorve

Keyword(s):

Leaf Area ◽

Biomass Allocation ◽

Deciduous Forest ◽

Growth Period ◽

Growth Patterns ◽

Tropical Deciduous Forest ◽

Total Biomass ◽

Allocation Pattern ◽

Location Patterns ◽

Net Assimilation

The objective of this study is to assess the biomass allocation pattern s and growth characteristics of three species of Caesalpinia (Leguminosae) from the highly diverse and seasonal Chamela tropical deciduous forest , where the plant growth period is restricted to the rainy season. The studied species, although they are phylogenetically related, presented different biomass al location patterns and RGR during growth, in order to carry out a differential exploitation of resources and to promote their coexistence. There were differences in relative growth rate (RGR), root to shoot ratio (R/ S), net assimilation rate (E), biomass allocation patterns and total biomass and leaf area attained among the studied species. Caesalpinia eriostachys and C. platyloba showed similar growth patterns between them but contrasting with those of C. sclerocarpa. This suggests a temporal uncuopling of their maximum resource demand. RGR was determined to a greater extent by parameters related with E than by parameters related with the specific leaf area (SLA).

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Summer drought stress: differential effects on cane anatomy and non-structural carbohydrate content in overwintering Cabernet Sauvignon and Syrah vines

BIO Web of Conferences ◽

10.1051/bioconf/20191303007 ◽

2019 ◽

Vol 13 ◽

pp. 03007 ◽

Cited By ~ 2

Author(s):

Rachele Falchi ◽

Elisa Petrussa ◽

Marco Zancani ◽

Valentino Casolo ◽

Paola Beraldo ◽

...

Keyword(s):

Water Stress ◽

Drought Stress ◽

Biochemical Characterization ◽

Carbon Allocation ◽

Starch Accumulation ◽

Cabernet Sauvignon ◽

Severe Drought ◽

Summer Drought ◽

Long Term Effects ◽

Experimental Conditions

Grapevines store non-structural carbohydrates (NSC) during late summer to sustain plant development at the onset of the following spring’s growth. Starch is the main stored carbohydrate, found in the wood-ray parenchyma of roots and canes. Although the relationship between hydraulic and plant photosynthetic performance is well-recognized, little research has been done on the long-term effects of drought in grapevines adopting different strategies to cope with water stress (i.e. isohydric and anisohydric). We performed our study by exposing two different grape cultivars (Syrah and Cabernet Sauvignon) to a short but severe drought stress, at two stages of the growing season (July and September). No marked differences in the physiological and hydraulic responses of the two varieties were found, probably due to our experimental conditions. However, anatomical and biochemical characterization of overwintering canes pointed out several interesting outcomes. We found a significant and parallel increase of starch and medullar ray number in both cultivars exposed to early water stress. We hypothesize that stressed vines limited their carbon allocation to growth, while shifting it to starch accumulation, with a most evident effect in the period of intense photosynthetic activity. We also speculate that a different aptitude to osmotic adjustment may underlay variation in starch increase and the specific involvement of bark NSC in the two cultivars.

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Decomposing uncertainties in the future terrestrial carbon budget associated with emission scenarios, climate projections, and ecosystem simulations using the ISI-MIP results

Earth System Dynamics ◽

10.5194/esd-6-435-2015 ◽

2015 ◽

Vol 6 (2) ◽

pp. 435-445 ◽

Cited By ~ 24

Author(s):

K. Nishina ◽

A. Ito ◽

P. Falloon ◽

A. D. Friend ◽

D. J. Beerling ◽

...

Keyword(s):

Net Primary Production ◽

Global Climate Models ◽

Climate Projections ◽

Emission Scenarios ◽

Climate Division ◽

C Dynamics ◽

C Cycling ◽

Vegetation Models ◽

Global Vegetation ◽

Uncertainty Source

Abstract. We examined the changes to global net primary production (NPP), vegetation biomass carbon (VegC), and soil organic carbon (SOC) estimated by six global vegetation models (GVMs) obtained from the Inter-Sectoral Impact Model Intercomparison Project. Simulation results were obtained using five global climate models (GCMs) forced with four representative concentration pathway (RCP) scenarios. To clarify which component (i.e., emission scenarios, climate projections, or global vegetation models) contributes the most to uncertainties in projected global terrestrial C cycling by 2100, analysis of variance (ANOVA) and wavelet clustering were applied to 70 projected simulation sets. At the end of the simulation period, changes from the year 2000 in all three variables varied considerably from net negative to positive values. ANOVA revealed that the main sources of uncertainty are different among variables and depend on the projection period. We determined that in the global VegC and SOC projections, GVMs are the main influence on uncertainties (60 % and 90 %, respectively) rather than climate-driving scenarios (RCPs and GCMs). Moreover, the divergence of changes in vegetation carbon residence times is dominated by GVM uncertainty, particularly in the latter half of the 21st century. In addition, we found that the contribution of each uncertainty source is spatiotemporally heterogeneous and it differs among the GVM variables. The dominant uncertainty source for changes in NPP and VegC varies along the climatic gradient. The contribution of GVM to the uncertainty decreases as the climate division becomes cooler (from ca. 80 % in the equatorial division to 40 % in the snow division). Our results suggest that to assess climate change impacts on global ecosystem C cycling among each RCP scenario, the long-term C dynamics within the ecosystems (i.e., vegetation turnover and soil decomposition) are more critical factors than photosynthetic processes. The different trends in the contribution of uncertainty sources in each variable among climate divisions indicate that improvement of GVMs based on climate division or biome type will be effective. On the other hand, in dry regions, GCMs are the dominant uncertainty source in climate impact assessments of vegetation and soil C dynamics.

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The impact of drought on total ozone flux in a mountain Norway spruce forest

Journal of Forest Science ◽

10.17221/129/2019-jfs ◽

2020 ◽

Vol 66 (No. 7) ◽

pp. 280-278 ◽

Cited By ~ 1

Author(s):

Thomas Agyei ◽

Stanislav Juráň ◽

Kojo Kwakye Ofori-Amanfo ◽

Ladislav Šigut ◽

Otmar Urban ◽

...

Keyword(s):

Norway Spruce ◽

Stomatal Closure ◽

Severe Drought ◽

Summer Drought ◽

Spruce Forest ◽

Soil Humidity ◽

Drought Period ◽

The Impact ◽

Mild Drought ◽

Norway Spruce Forest

In order to understand the impact of summer drought on dry deposition of tropospheric ozone (O3), we compared severe and mild drought periods of summer 2018 in a mountain Norway spruce forest at Bílý Kříž, Beskydy Mts. An eddy covariance technique was applied to measure diurnal courses of the ecosystem O3 and CO2 fluxes. Low O3 deposition was recorded in the morning and evening, while the highest CO2 and O3 fluxes were recorded during the central hours of the day. Total O3 deposition during severe drought (soil humidity 13%) was significantly higher than the deposition during the mild drought period (soil humidity 19%). Our data indicate that high vapour pressure deficit and low soil humidity during severe drought led to the stomatal closure, while non-stomatal O3 deposition, associated with chemical reactions of O3 with NO and volatile organic compounds, are responsible for higher total O3 deposition during the severe drought period. Therefore, we assume that under severe drought stomatal O3 uptake decreases but non-stomatal depositions to forest ecosystems substantially increase.

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Carbohydrate dynamics in mature Pinuselliottii var. elliottii trees

Canadian Journal of Forest Research ◽

10.1139/x91-240 ◽

1991 ◽

Vol 21 (12) ◽

pp. 1742-1747 ◽

Cited By ~ 38

Author(s):

Henry L. Gholz ◽

Wendell P. Cropper Jr.

Keyword(s):

Fine Roots ◽

Soluble Sugars ◽

Late Winter ◽

Seasonal Patterns ◽

Coarse Roots ◽

Carbohydrate Storage ◽

Carbohydrate Dynamics

Starch is the main carbohydrate storage form in conifers and is derived from the translocation of photosynthate (soluble sugars) in the phloem. We examined seasonal patterns in concentrations of both carbohydrate forms in the needles, twigs and branches, stems, and coarse and fine roots of mature Pinuselliottii Engelm. var. elliottii trees in a north Florida plantation. Starch showed marked and similar seasonality in all the tissues, with maxima in the late winter near the time of the inception of new growth in the spring. Sugars showed little seasonality, except in the fine roots. Repeated fertilization had little effect on either sugar or starch concentrations in all tissues. Using published biomass data from these same stands, we estimated that coarse roots store more than half of the starch in these stands over the year, with foliage and fine roots storing less than 5%.

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Above- and below-ground biomass and fine roots of 4-year-old hybrids of Populustrichocarpa × Populusdeltoides and parental species in short-rotation culture

Canadian Journal of Forest Research ◽

10.1139/x94-156 ◽

1994 ◽

Vol 24 (6) ◽

pp. 1186-1192 ◽

Cited By ~ 76

Author(s):

P.E. Heilman ◽

G. Ekuan ◽

D. Fogle

Keyword(s):

Aboveground Biomass ◽

Fine Roots ◽

Soil Depth ◽

Alluvial Soil ◽

Specific Root Length ◽

Soil Surface ◽

Sand Content ◽

Coarse Roots ◽

Short Rotation ◽

Root Shoot Ratio

Mean annual aboveground leafless biomass production averaged 14.8, 11.4, and 24.3 Mg•ha−1•year−1 at harvest at 4 years of age for Populustrichocarpa Torr. & Gray, Populusdeltoides Marsh., and P. trichocarpa × P. deltoides hybrids, respectively. These trees were planted at 1 × 1 m spacing on a medium- to coarse-textured alluvial soil in western Washington. Branches accounted for 13.2–20.3% of the aboveground weight. Total weight of stumps and coarse roots at harvest varied from 12.3 to 29.6 Mg•ha−1, or 22–33% of the weight of aboveground leafless biomass. Small and fine roots sampled to a depth of 3.17 m using soil cores amounted to an additional 6.6–11 Mg•ha−1 of roots. Stumps and all roots as a ratio of aboveground biomass (root/shoot ratio) ranged from 0.34 to 0.42, with hybrids accounting for the entire range of values present. Mass of the fine roots (less than 0.5 mm diameter) ranged from 4.0 to 6.5 Mg•ha−1, or an average of 6.8% of the aboveground biomass. The smallest of the fine roots measured 0.06 mm in diameter. Specific root length of fine roots averaged 50.7 m•g−1 for P. deltoides, 42 m•g−1 for P. trichocarpa, and 30–47 m•g−1 for hybrids. Total length of fine roots to a depth of 3.17 m ranged from 179 000 to 284 000 km•ha−1. Density of fine roots by length per unit soil volume was greatest at the surface with the range of means for clones in the top 0.18 m being 2.4–6.3 cm•cm−3; at 1.0–3.17 m soil depth, density was 0.02–0.6 cm•cm−3. For two of the hybrid clones, the density of fine roots at the soil surface was half that of the other clones. The distribution of fine roots in the stratified soil profile was correlated with soil depth, Kjeldahl N, and organic matter, with the latter two parameters showing the highest coefficients of determination (0.73 and 0.71, respectively). In the more sandy but layered subsoil (0.36–3.17 m depth), soil depth, Kjeldahl N, and sand content were most strongly correlated with fine root density, with depth and sand content giving the highest coefficients of determination (0.32 and 0.31, respectively). Roots in sandy subsoil were coarser and much less branched than in adjacent finer textured layers.

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Respiration and C dynamics in Poplar roots

10.5194/egusphere-egu2020-13469 ◽

2020 ◽

Author(s):

Boaz Hilman ◽

Jan Muhr ◽

Juliane Helm ◽

Iris Kuhlmann ◽

Susan Trumbore

Keyword(s):

Fine Roots ◽

Soluble Sugars ◽

Turnover Rates ◽

Tree Roots ◽

Coarse Roots ◽

Before And After ◽

The Mean ◽

The 1960S ◽

June July ◽

Stem Girdling

Large amounts of C are allocated to tree roots, but little is known about the age and dynamics of their non-structural C (NSC). We measured bomb-radiocarbon (14C) in respired CO2, non-structural (mainly sugars), and structural (cellulose) C in roots. The steady decline of &#916;14C in atmospheric CO2 since the 1960s indicates the mean time elapsed since the C in these pools was fixed. We measured coarse (>2 mm, mean 2.91 mm) and fine (<2 mm) roots from 12 German poplar trees sampled before and after girdling of 6 of the trees. All samples were taken in 2018, an exceptionally dry summer in Europe. The mean &#916;14C &#177;SD of root-respired CO2 (4.1 &#177; 3.6 &#8240;) in June-July was equal to current atmospheric &#916;14CO2 (1.2 &#8240;), irrespective of the mean age of root cellulose. During extended incubations, the &#916;14C of root-respired CO2 increased to ~10 &#8240; 8 days after harvesting and up to 42 &#8240; 17 days after harvesting. The mean &#916;14C of soluble sugars in the roots was ~21&#160;&#8240;. In September-October, almost three months after girdling, roots from girdled trees respired CO2 with &#916;14C of 7.9 &#177;&#160;6.6&#160;&#8240; vs. 2.3 &#177;&#160;6.1&#160;&#8240; in the ungirdled control trees. However, in both groups the respired CO2&#173;-&#916;14C correlated with cellulose-&#916;14C (R2 = 0.37, 0.26 for girdled and control trees, respectively), suggesting that roots respired more stored C in the later growing season in this drought year, independent of treatment. The &#916;14C values of soluble sugars were correlated with the &#916;14C values of the cellulose (R2=0.83). On average, C in sugars was fixed more recently than cellulose, suggesting mixing of young C from other parts of the tree into the roots. Stem girdling did not affect the &#916;14C of soluble sugars. Average total sugar concentrations (sucrose+ glucose+ fructose) were ~42 mg g-1 and did not vary with sampling date, root class or treatment. Starch, measured only in September-October, was higher in coarse than in fine roots (12 vs. 3.8 mg g-1). Respiratory loss of C was higher in the fine roots (~4 mgC g-1 day-1) than coarse roots (~2.4 mgC g-1 day-1), with no effect of girdling or sampling month. When normalize (expressed per gram dry root material), the NSC reservoirs and C loss rates suggest C turnover rates are 2-fold higher in fine roots than in coarse roots. The extended incubations indicate that detached roots are able to quickly utilize stored NSC, as indicated by the sharp &#916;14CO2 increase. In comparison, stem girdling had no measurable effect on respired CO2-&#916;14C, suggesting internal re-allocation of C from the lower stem base or large roots to smaller roots, and/or lower than expected metabolic consumption of C in reaction to girdling or because of the exceptional drought.

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