A global map of root biomass across the world's forests

Abstract. As a key component of the Earth system, roots play a key role in linking Earth's lithosphere, hydrosphere, biosphere and atmosphere. Here we combine 10 307 field measurements of forest root biomass worldwide with global observations of forest structure, climatic conditions, topography, land management and soil characteristics to derive a spatially explicit global high-resolution (∼ 1 km) root biomass dataset, including fine and coarse roots. In total, 142 ± 25 (95 % CI) Pg of live dry-matter biomass is stored belowground, representing a global average root : shoot biomass ratio of 0.25 ± 0.10. Earlier studies (Jackson et al., 1997; Robinson, 2007; Saugier et al., 2001) are 44 %–226 % larger than our estimations of the total root biomass in tropical, temperate and boreal forests. The total global forest root biomass from a recent estimate (Spawn et al., 2020) is 24 % larger than this study. The smaller estimation from this study is attributable to the updated forest area, spatially explicit aboveground biomass density used to predict the patterns of root biomass, new root measurements and the upscaling methodology. We show specifically that the root shoot allometry is one underlying driver that has led to methodological overestimation of root biomass in previous estimations. Raw datasets and global maps generated in this study are deposited at the open-access repository Figshare (https://doi.org/10.6084/m9.figshare.12199637.v1; Huang et al., 2020).

Download Full-text

A global map of root biomass across the world’s forests

10.1101/2020.01.14.906883 ◽

2020 ◽

Author(s):

Yuanyuan Huang ◽

Phillipe Ciais ◽

Maurizio Santoro ◽

David Makowski ◽

Jerome Chave ◽

...

Keyword(s):

Boreal Forests ◽

Root Biomass ◽

Dry Matter ◽

Field Measurements ◽

Climatic Conditions ◽

Spatially Explicit ◽

Biomass Density ◽

Coarse Roots ◽

Below Ground ◽

Shoot Allometry

Abstract (150 words limits)Root plays a key role in plant growth and functioning. Here we combine 10307 field measurements of forest root biomass worldwide with global observations of forest structure, climatic conditions, topography, land management and soil characteristics to derive a spatially-explicit global high-resolution (~ 1km) root biomass dataset, including fine and coarse roots. In total, 142 ± 32 Pg of live dry matter biomass is stored below-ground, that is a global average root:shoot biomass ratio of 0.25 ± 0.10. Our estimations of total root biomass in tropical, temperate and boreal forests are 44-226% smaller than earlier studies1–3. The smaller estimation is attributable to the updated forest area, spatially explicit above-ground biomass density used to predict the patterns of root biomass, new root measurements and upscaling methodology. We show specifically that the root shoot allometry is one underlying driver that leads to methodological overestimation of root biomass in previous estimations.

Download Full-text

A global map of root biomass across the world's forests

10.5194/essd-2021-25 ◽

2021 ◽

Author(s):

Yuanyuan Huang ◽

Phillipe Ciais ◽

Maurizio Santoro ◽

David Makowski ◽

Jerome Chave ◽

...

Keyword(s):

Boreal Forests ◽

Root Biomass ◽

Field Measurements ◽

Climatic Conditions ◽

Spatially Explicit ◽

Biomass Density ◽

Coarse Roots ◽

The Earth ◽

Below Ground ◽

Shoot Allometry

Abstract. As a key component of the Earth system, root plays the key role in linking Earth's lithosphere, hydrosphere, biosphere, and atmosphere. Here we combine 10307 field measurements of forest root biomass worldwide with global observations of forest structure, climatic conditions, topography, land management and soil characteristics to derive a spatially explicit global high-resolution (~1 km) root biomass dataset, including fine and coarse roots. In total, 142 ± 25 (95 % CI) Pg of live dry matter biomass is stored below-ground, representing a global average root:shoot biomass ratio of 0.25 ± 0.10. Our estimations of total root biomass in tropical, temperate and boreal forests are 44–226 % smaller than earlier studies (Jackson et al., 1997; Robinson, 2007; Saugier et al., 2001). The smaller estimation is attributable to the updated forest area, spatially explicit above-ground biomass density used to predict the patterns of root biomass, new root measurements and upscaling methodology. We show specifically that the root shoot allometry is one underlying driver that leads to methodological overestimation of root biomass in previous estimations. Raw datasets and global maps generated in this study are deposited at the open access repository Figshare (https://figshare.com/articles/Supporting_data_and_code_for_A_global_map_of_root_biomass_across_the_world_s_forests/ 12199637).

Download Full-text

The vertical and horizontal distribution of roots in northern hardwood stands of varying age

Canadian Journal of Forest Research ◽

10.1139/x05-254 ◽

2006 ◽

Vol 36 (2) ◽

pp. 450-459 ◽

Cited By ~ 67

Author(s):

Ruth D Yanai ◽

Byung B Park ◽

Steven P Hamburg

Keyword(s):

Root Biomass ◽

Fine Root ◽

Forest Type ◽

Soil Depth ◽

Horizontal Distribution ◽

Biomass Density ◽

Coarse Roots ◽

Northern Hardwood ◽

Clear Cutting ◽

Distribution Of Roots

Coring methods cannot reveal the distribution of roots with depth in rocky soil, and fine roots are typically sampled without regard to the location of trees. We used quantitative soil pits to describe rooting patterns with soil depth and distance to trees in northern hardwood stands. We sited three 0.5 m2 quantitative soil pits in each of three young (1927 years) and three older (5669 years) stands developed after clear-cutting. Live roots were divided into diameter classes delimited at 0.5, 1, 2, 5, 10, 20, and 100 mm; dead roots were not distinguished by size. Mean total live-root biomass was 2900 ± 500 g·m2 in older stands and 1500 ± 400 g·m2 in young stands. The root mass in the 220 mm class was 2.7 times greater in the older stands (p = 0.03); fine-root (<2 mm) biomass was 1.5 times greater (p = 0.12), suggesting that fine-root biomass continues to increase past the age of canopy closure in this forest type. Root biomass density declined with soil depth, with the finest roots (<0.5 mm) declining most steeply; roots were found at low densities well into the C horizon. We analyzed root biomass density as a function of the influence of nearby trees (represented as the sum of basal area divided by the distance from the pit) and found that fine as well as coarse roots reflected this influence. In systems where this is the case, root measurements should be made with attention to patterns of tree distribution.

Download Full-text

Growth Responses of Boreal Scots Pine, Norway Spruce and Silver Birch Seedlings to Simulated Climate Warming over Three Growing Seasons in a Controlled Field Experiment

Forests ◽

10.3390/f11090943 ◽

2020 ◽

Vol 11 (9) ◽

pp. 943

Author(s):

Katri Nissinen ◽

Virpi Virjamo ◽

Antti Kilpeläinen ◽

Veli-Pekka Ikonen ◽

Laura Pikkarainen ◽

...

Keyword(s):

Norway Spruce ◽

Scots Pine ◽

Root Biomass ◽

Growing Season ◽

Silver Birch ◽

Shoot Biomass ◽

Growth Responses ◽

Growing Seasons ◽

Simulated Climate ◽

Shoot And Root Biomass

We studied the growth responses of boreal Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies L. Karst.) and silver birch (Betula pendula Roth) seedlings to simulated climate warming of an average of 1.3 °C over the growing season in a controlled field experiment in central Finland. We had six replicate plots for elevated and ambient temperature for each tree species. The warming treatment lasted for the conifers for three growing seasons and for the birch two growing seasons. We measured the height and diameter growth of all the seedlings weekly during the growing season. The shoot and root biomass and their ratios were measured annually in one-third of seedlings harvested from each plot in autumn. After two growing seasons, the height, diameter and shoot biomass were 45%, 19% and 41% larger in silver birch seedlings under the warming treatment, but the root biomass was clearly less affected. After three growing seasons, the height, diameter, shoot and root biomass were under a warming treatment 39, 47, 189 and 113% greater in Scots pine, but the root:shoot ratio 29% lower, respectively. The corresponding responses of Norway spruce to warming were clearly smaller (e.g., shoot biomass 46% higher under a warming treatment). As a comparison, the relative response of height growth in silver birch was after two growing seasons equal to that measured in Scots pine after three growing seasons. Based on our findings, especially silver birch seedlings, but also Scots pine seedlings benefitted from warming, which should be taken into account in forest regeneration in the future.

Download Full-text

Drone-Based Remote Sensing for Research on Wind Erosion in Drylands: Possible Applications

Remote Sensing ◽

10.3390/rs13020283 ◽

2021 ◽

Vol 13 (2) ◽

pp. 283

Author(s):

Junzhe Zhang ◽

Wei Guo ◽

Bo Zhou ◽

Gregory S. Okin

Keyword(s):

Remote Sensing ◽

Wind Erosion ◽

Field Measurements ◽

Spatially Explicit ◽

Surface Model ◽

High Resolution Imagery ◽

Soil Elevation ◽

3D Photogrammetry ◽

Using Data ◽

Sample Set

With rapid innovations in drone, camera, and 3D photogrammetry, drone-based remote sensing can accurately and efficiently provide ultra-high resolution imagery and digital surface model (DSM) at a landscape scale. Several studies have been conducted using drone-based remote sensing to quantitatively assess the impacts of wind erosion on the vegetation communities and landforms in drylands. In this study, first, five difficulties in conducting wind erosion research through data collection from fieldwork are summarized: insufficient samples, spatial displacement with auxiliary datasets, missing volumetric information, a unidirectional view, and spatially inexplicit input. Then, five possible applications—to provide a reliable and valid sample set, to mitigate the spatial offset, to monitor soil elevation change, to evaluate the directional property of land cover, and to make spatially explicit input for ecological models—of drone-based remote sensing products are suggested. To sum up, drone-based remote sensing has become a useful method to research wind erosion in drylands, and can solve the issues caused by using data collected from fieldwork. For wind erosion research in drylands, we suggest that a drone-based remote sensing product should be used as a complement to field measurements.

Download Full-text

Are Wildfires a Threat to Fungi in European Pinus Forests? A Case Study of Boreal and Mediterranean Forests

Forests ◽

10.3390/f10040309 ◽

2019 ◽

Vol 10 (4) ◽

pp. 309 ◽

Cited By ~ 3

Author(s):

Iván Franco-Manchón ◽

Kauko Salo ◽

Juan Oria-de-Rueda ◽

José Bonet ◽

Pablo Martín-Pinto

Keyword(s):

Boreal Forests ◽

Fungal Diversity ◽

Community Dynamics ◽

Forest Products ◽

Climatic Conditions ◽

Fungal Communities ◽

Mediterranean Forests ◽

Natural Forests ◽

Edible Fungi ◽

Pinus Species

Natural forests and plantations of Pinus are ecologically and economically important worldwide, producing an array of goods and services, including the provision of non-wood forest products. Pinus species play an important role in Mediterranean and boreal forests. Although Pinus species seem to show an ecological adaptation to recurrent wildfires, a new era of mega fires is predicted, owing to climate changes associated with global warming. As a consequence, fungal communities, which are key players in forest ecosystems, could be strongly affected by these wildfires. The aim of this study was to observe the fungal community dynamics, and particularly the edible fungi, in maritime (Pinus pinaster Ait.), austrian pine (Pinus nigra J.F. Arnold), and scots pine (Pinus sylvestris L.) forests growing under wet Mediterranean, dry Mediterranean, and boreal climatic conditions, respectively, by comparing the mushrooms produced in severely burned Pinus forests in each area. Sporocarps were collected during the main sampling campaigns in non-burned plots, and in burned plots one year and five years after fire. A total of 182 taxa, belonging to 81 genera, were collected from the sampled plots, indicating a high level of fungal diversity in these pine forests, independent of the climatic conditions. The composition of the fungal communities was strongly affected by wildfire. Mycorrhizal taxa were impacted more severely by wildfire than the saprotrophic taxa, particularly in boreal forests—no mycorrhizal taxa were observed in the year following fire in boreal forests. Based on our observations, it seems that fungal communities of boreal P. sylvestris forests are not as adapted to high-intensity fires as the Mediterranean fungal communities of P. nigra and P. pinaster forests. This will have an impact on reducing fungal diversity and potential incomes in rural economically depressed areas that depend on income from foraged edible fungi, one of the most important non-wood forest products.

Download Full-text

Early root development of Eucalyptus pellita F. Muell. seedlings from seed and stem cutting at nursery stage

10.21203/rs.3.rs-104802/v1 ◽

2020 ◽

Author(s):

Affendy Hassan ◽

Parveena Balachandran ◽

Khairiyyah Razanah Khamis

Keyword(s):

Root Development ◽

Root Length ◽

Root Biomass ◽

Nitrogen Concentration ◽

Stem Cutting ◽

Shoot Biomass ◽

Forest Plantation ◽

Plant Materials ◽

Eucalyptus Pellita ◽

Root Intensity

Abstract BackgroundEucalyptus is among the important fast-growing species, and is typically managed on short rotation to sustain the production of timber, pulpwood, charcoal, and fire-wood. Macro-propagation using cutting for larger multiplying seedlings is cheaper and efficient instead of clonal seeds for uniform plant material seedling production. However, information on root growth of Eucalyptus pellita at early development from seed and stem cutting of E. pellita seedlings is still lacking. This is probably due to the difficulty in investigation belowground, and also due to methodological problems. With such information, it is useful for forest plantation company management in enhancing the understanding on strategies to optimize yield production with the appropriate agronomic or silvicultural approach in the field planting. Therefore, the objectives of this study were; to compare the root development of two different propagation seedlings of E. pellita; and to study the effect of various nitrogen concentration levels on two types of propagation of E. pellita seedlings. ResultsThe study was conducted using E. pellita seedlings from two types of propagation, namely, seed and stem cuttings, along with three different nitrogen concentrations (0, 50, and 200 kg N ha-1). Shoot biomass, root intensity (RI), total root intensity (TRI), root biomass, root length density (RLD), and specific root length (SRL) were recorded. Dried shoot biomass, RLD and SRL of E. pellita seedlings using stem cutting were significantly higher (P<0.05) compared to seed. Whereas, there were no significant differences (P>0.05) for root biomass, TRI and RI between the propagation types of E. pellita seedlings. Conclusions:E. pellita seedlings from stem cutting was greater in terms of root distribution compared to propagation by seeds at the nursery stage, and 50 kg N ha-1 was the optimal nitrogen concentration level from the considered levels to be applied to the E. pellita seedlings. The present study therefore provides more information and understanding on E. pellita for forest plantation companies in producing plant materials using stem cutting in a cost-effective and efficient manner. This would help the forest plantation companies in planning appropriate agronomic management in the future.

Download Full-text

Herbage biomass and its relationship to soil carbon under long-term grazing in northern temperate grasslands

Canadian Journal of Plant Science ◽

10.1139/cjps-2018-0251 ◽

2019 ◽

Vol 99 (6) ◽

pp. 905-916

Author(s):

E.W. Bork ◽

M.P. Lyseng ◽

D.B. Hewins ◽

C.N. Carlyle ◽

S.X. Chang ◽

...

Keyword(s):

Soil Carbon ◽

Root Biomass ◽

Mineral Soil ◽

Belowground Biomass ◽

Cattle Grazing ◽

Shoot Biomass ◽

Positive Contribution ◽

Temperate Grasslands ◽

Soil C

While northern temperate grasslands are important for supporting beef production, it remains unclear how grassland above- and belowground biomass responds to long-term cattle grazing. Here, we use a comprehensive dataset from 73 grasslands distributed across a broad agro-climatic gradient to quantify grassland shoot, litter, and shallow (top 30 cm) root biomass in areas with and without grazing. Additionally, we relate biomass to soil carbon (C) concentrations. Forb biomass was greater (p < 0.05) in grazed areas, particularly those receiving more rainfall. In contrast, grass and total aboveground herbage biomass did not differ with grazing (total: 2320 kg ha−1 for grazed vs. 2210 kg ha−1 for non-grazed; p > 0.05). Forb crude protein concentrations were lower (p < 0.05) in grazed communities compared with those that were non-grazed. Grasslands subjected to grazing had 56% less litter mass. Root biomass down to 30 cm remained similar between areas with (9090 kg ha−1) and without (7130 kg ha−1) grazing (p > 0.05). Surface mineral soil C concentrations were positively related to peak grassland biomass, particularly total (above + belowground) biomass, and with increasing forb biomass in grazed areas. Finally, total aboveground shoot biomass and soil C concentrations in the top 15 cm of soil were both positively related to the proportion of introduced plant diversity in grazed and non-grazed grasslands. Overall, cattle grazing at moderate stocking rates had minimal impact on peak grassland biomass, including above- and belowground, and a positive contribution exists from introduced plant species to maintaining herbage productivity and soil C.

Download Full-text

Vegetable Crops Grown under High Soil Water Availability in Mediterranean Greenhouses

Water ◽

10.3390/w12041110 ◽

2020 ◽

Vol 12 (4) ◽

pp. 1110 ◽

Cited By ~ 1

Author(s):

Santiago Bonachela ◽

Alicia M. González ◽

María D. Fernández ◽

Francisco J. Cabrera-Corral

Keyword(s):

Soil Water ◽

Water Availability ◽

Root Biomass ◽

Management Practice ◽

Soil Layer ◽

Soil Water Availability ◽

Shoot Biomass ◽

Vegetable Crops ◽

Irrigation Frequency ◽

High Soil

The soil water availability of six vegetable crop cycles, irrigated with water of 0.4 dS m−1 electrical conductivity, was modified by varying the irrigation frequency in typical Mediterranean greenhouses at SE Spain. The soil matric water potential (SMP) in the middle of the loamy soil layer where most roots usually grow was maintained between −10 and −20 kPa (H), −20 and −30 kPa (C), and −30 and −50 kPa (L) for the crops grown under high, conventional and low soil water availability, respectively, while the total irrigation water applied was similar for the three treatments. The high soil water availability (H) did not improve the fresh weight of total, marketable and first class fruits, or the shoot biomass and partitioning. The irrigation frequency did not affect the total root biomass at the end of the autumn–winter cucumber, but the crop under L distributed its root biomass more homogenously throughout the soil profile than the crop under H. Regulating the soil water availability (maintaining the SMP higher than or close to the level at which crop water stress may occur) over the cycle as a function of crop conditions or farmers’ requirements appears to be a useful management practice for controlling soil root distribution or shoot partitioning.

Download Full-text

Barley shoot biomass responds strongly to N:P stoichiometry and intraspecific competition, whereas roots only alter their foraging

Plant and Soil ◽

10.1007/s11104-020-04626-w ◽

2020 ◽

Vol 453 (1-2) ◽

pp. 515-528 ◽

Cited By ~ 1

Author(s):

Amit Kumar ◽

Richard van Duijnen ◽

Benjamin M. Delory ◽

Rüdiger Reichel ◽

Nicolas Brüggemann ◽

...

Keyword(s):

Root System ◽

Intraspecific Competition ◽

Root Length ◽

Root Biomass ◽

Specific Root Length ◽

Plant Performance ◽

Shoot Biomass ◽

P Availability ◽

Soil Layers ◽

N:P Stoichiometry

Abstract Aims Root system responses to the limitation of either nitrogen (N) or phosphorus (P) are well documented, but how the early root system responds to (co-) limitation of one (N or P) or both in a stoichiometric framework is not well-known. In addition, how intraspecific competition alters plant responses to N:P stoichiometry is understudied. Therefore, we aimed to investigate the effects of N:P stoichiometry and competition on root system responses and overall plant performance. Methods Plants (Hordeum vulgare L.) were grown in rhizoboxes for 24 days in the presence or absence of competition (three vs. one plant per rhizobox), and fertilized with different combinations of N:P (low N + low P, low N + high P, high N + low P, and high N + high P). Results Shoot biomass was highest when both N and P were provided in high amounts. In competition, shoot biomass decreased on average by 22%. Total root biomass (per plant) was not affected by N:P stoichiometry and competition but differences were observed in specific root length and root biomass allocation across soil depths. Specific root length depended on the identity of limiting nutrient (N or P) and competition. Plants had higher proportion of root biomass in deeper soil layers under N limitation, while a greater proportion of root biomass was found at the top soil layers under P limitation. Conclusions With low N and P availability during early growth, higher investments in root system development can significantly trade off with aboveground productivity, and strong intraspecific competition can further strengthen such effects.

Download Full-text