Ground Vegetation Biomass Research Articles

Influence of clear-cutting on ground vegetation biomass and dwarf shrubs increment in the Scots pine forests of the European North-East

Influence of clear-cutting on ground vegetation biomass and dwarf shrubs increment in the Scots pine forests of the European North-East

Carbon Budget of Undrained and Drained Nutrient-Rich Organic Forest Soil

The impact of the moisture regime on the carbon budget of organic soils with different nutrient statuses has not been fully studied in hemiboreal forests thus far. This study evaluated soil carbon (C) stock changes in forests with drained and undrained nutrient-rich organic soils by estimating C loss through respiration and C input through the litter. The study sites included forest stands dominated by Norway spruce (Picea abies), silver birch (Betula pendula), black alder (Alnus glutinosa), and clear-cuts. Soil respiration was measured using the chamber method, and to estimate the soil C input by litter—the biomass and the C content of the foliar litter, ground vegetation, and fine-root production were measured. The soil in forest stands acted as a C sink. The carbon dioxide (CO2) removal rates of 0.4 ± 0.4 t C ha−1 year−1 and 0.1 ± 0.4 t C ha−1 year−1 were estimated for undrained and drained soil in forest stands, respectively. The soil in the clear-cuts acted as a CO2 source, and the annual emissions ranged from 0.4 ± 0.4 t C ha−1 year−1 in undrained to 0.9 ± 0.7 t C ha−1 year−1 in drained conditions. The reason for the soil in clear-cuts being a C source was increased C loss by respiration and reduced soil C input by litter. Furthermore, the mean soil C input by ground vegetation biomass in the clear-cuts was considerably higher than in the forest stands, which did not compensate for the increase in soil respiration and the absence of C input by foliar litter and the fine roots of trees. The results of the study on annual soil C stock changes can be used as an emission factor in national greenhouse gas inventories of forest land in the hemiboreal zone.

Effects of long-term N fertilization on nitrate leaching and vegetation responses in a spruce stand after severe wind damage

Wind damage in a forest stand can result in varying soil effects depending on the pre-history of the site, but areas with storm-felled trees can generally be expected to show more nitrate leaching than undamaged stands. Previous fertilization in such areas, especially with nitrogen (N) fertilizer, may further increase nitrate leaching. This study examined the effect of partial felling of a 42-year-old Norway spruce stand in the Skogaby experimental forest in Sweden during Storm Gudrun in 2005. Nitrate leaching was measured one year before and six years after the storm, in three experimental treatments: fertilization-irrigation with complete nutrient admixture (IF), fertilization with N-free nutrient admixture (V), and an untreated control (0). The 0 and IF treatments had some undamaged replicate plots, but V plots had no trees left after the storm. Compared with undamaged plots and the pre-disturbance level, nitrate leaching was significantly higher in all storm-felled plots, and in the soil solution nitrate dominated strongly over ammonium. Leaching peaked during the second and third post-storm years (2006–2007) and decreased to near pre-storm levels during the fifth and sixth years (2009–2010). Total nitrate leaching 2005–2010 was estimated to be 414, 233, and 218 kg N ha−1 in the damaged IF, 0, and V plots, respectively. Total nitrate leaching in undisturbed plots in the IF and 0 treatments was 37 and 0.3 kg N ha−1, respectively. Ground vegetation coverage, biomass, and biomass N increased with time and were negatively correlated with nitrate discharge. However, plant uptake of N only partly explained the significant decline in nitrate leaching between 2006 and 2010. This decrease could also be explained by N immobilization in fungi decomposing woody roots with low N concentrations.

Airborne Heavy Metal Pollution and its Effects on Biomass of Ground Vegetation, Foliar Elemental Composition and Metabolic Profiling of Forest Plants in the Kola Peninsula (Russia)

Airborne Heavy Metal Pollution and its Effects on Biomass of Ground Vegetation, Foliar Elemental Composition and Metabolic Profiling of Forest Plants in the Kola Peninsula (Russia)

Soil and Nutrient Cycling Responses in Riparian Forests to the Loss of Ash (Fraxinus spp. L) from Emerald Ash Borer (Agrilus planipennis, Fairmaire)

Emerald ash borer (EAB) is an alien invasive species that is spreading across Canada and the United States killing ash trees. In riparian forests where ash may be abundant; loss of ash can induce significant structural changes; including the creation of canopy gaps; changes in light penetration; expansion of ground vegetation; and alteration of soil nitrogen and carbon cycling. In 2014 and 2015, we examined the effects of EAB-caused gaps in riparian forests on soil nutrient dynamics. Two sites with different infestation timelines, a “new” site (mortality in past 2–3 years) and an “old” site (infested 10 years previous) were selected to determine temporal differences in effects of canopy gaps created by ash loss on litterfall, herbaceous ground vegetation, and soil nutrient cycling. Within both sites, plots with clustered dead ash (canopy gap plots—CG) were paired with nearby plots of full canopy and no ash (canopy closed plots—CC), and differences between paired plots determined. Total litterfall was observed at all sites but was only significant at the new infestation site. Reductions in leaf litter deposition in CG plots resulted in reduced N and C flux to the forest floor but soil C and N concentrations, and nitrogen mineralization rates, were not significantly different between CG and CC plots. Nitrate concentration in soil solution was significantly greater in CG plots compared to CC plots at the new infestation sites but showed the opposite trend at the old infestation sites. Herbaceous ground vegetation biomass was significantly greater (up to 10×) in CG plots than in CC plots. Overall, despite changes to riparian forest canopy structure and litterfall, there was no significant difference in soil nutrient cycling between EAB-induced canopy gaps and closed canopy plots after 10 years, suggesting a high resilience of riparian forest soils to EAB infestation

Effects of reindeer grazing and recovery after cessation of grazing on the ground-dwelling spider assemblage in Finnish Lapland.

The effect of reindeer Rangifer tarandus L. grazing on the ground-dwelling spider assemblage in Northern Finland was studied. Changes in species richness, abundance and evenness of spider assemblages were analyzed in relation to changes in vegetation and environmental factors in long term grazed and ungrazed sites as well as sites that had recently switched from grazed to ungrazed and vice versa. Grazing was found to have a significant impact on height and biomass of lichens and other ground vegetation. However, it seemed not to have an impact on the total abundance of spiders. This is likely caused by opposing family and species level responses of spiders to the grazing regime. Lycosid numbers were highest in grazed and linyphiid numbers in ungrazed areas. Lycosidae species richness was highest in ungrazed areas whereas Linyphiidae richness showed no response to grazing. Four Linyphiidae, one Thomisidae and one Lycosidae species showed strong preference for specific treatments. Sites that had recovered from grazing for nine years and the sites that were grazed for the last nine years but were previously ungrazed resembled the long term grazed sites. The results emphasize the importance of reindeer as a modifier of boreal forest ecosystems but the impact of reindeer grazing on spiders seems to be family and species specific. The sites with reversed grazing treatment demonstrate that recovery from strong grazing pressure at these high latitudes is a slow process whereas reindeer can rapidly change the conditions in previously ungrazed sites similar to long term heavily grazed conditions.

No Detectable Broad-Scale Effect of Livestock Grazing on Soil Blue-Carbon Stock in Salt Marshes

Grassland capturing and storage (CCS) is thought to benefit from regulation of grazing. The impact is likely to depend on livestock density. Yet, few studies have tested this principle or evaluated the consistency of grazer-carbon relationships across multiple sites. We sampled four intertidal zones across 22 salt marshes along a 650 km stretch of coast in the UK to examine the impact of livestock density on globally important saltmarsh blue carbon stocks. Although there were marked impacts of grazing pressure on above ground vegetation composition, structure and biomass, there was no detectable relationship between grazing intensity and soil organic carbon, irrespective of tidal zone in the marsh or soil depth-layer analyzed. A substantial spatial variation in soil was instead explained by contextual environmental variables. There was evidence that compensatory responses by vegetation, such as increased root growth, countered loss from grazing impacts. Our work suggests that grazing effects on stocks are minimal on broader scales in comparison with the influence of environmental context. The benefits of grazing management to stores are likely to be highly context dependent.

Contrasting effects of reindeer grazing on CO2, CH4, and N2O fluxes originating from the northern boreal forest floor

AbstractReindeer (Rangifer tarandus L.) is considered to be an important mammalian herbivore, strongly influencing Arctic lichen‐dominated ecosystems. There is no wide knowledge about the effect of reindeer on greenhouse gas (GHG) fluxes in northern boreal forests. Ground vegetation plays an important role in absorbing nitrogen (N) and carbon dioxide (CO2) from the atmosphere. Lately, it has also been found to be a significant source of nitrous oxide (N2O) and a small source of methane (CH4). We investigated the influence of reindeer grazing on field layer GHG (CO2, CH4, and N2O) fluxes, ground vegetation coverage and biomass, and soil physical properties (temperature and moisture) in a northern boreal forest. At our study site, the reindeer‐induced replacement of lichen by mosses had contrasting effects on the GHG fluxes originating from the field layer. Field layer CO2 efflux was significantly higher in grazed areas. The field layer was a CH4 sink in all areas, but grazed areas absorbed more CH4 compared to non‐grazed areas. Although total N2O fluxes remained around 0 in grazed areas, a small N2O sink occurred in non‐grazed areas with lower moss biomass. Our results indicated that grazing by reindeer in northern boreal forests affects GHG fluxes from the forest field layer both positively and negatively, and these emissions largely depend on grazing‐induced changes in vegetation composition.

Conifer proportion explains fine root biomass more than tree species diversity and site factors in major European forest types

Abstract Fine roots (diameter ≤ 2 mm) contribute significantly to the forest carbon cycle and are essential for resource acquisition from the soil. We conducted a study to assess the relationships between tree and ground vegetation fine root biomass and tree species diversity (monocultures compared to 2–5 species mixtures), conifer proportion and other site factors (stand basal area, soil carbon stocks and C:N ratio) in the six major European forest types, boreal forest in Finland, temperate forests in Poland, Germany and Romania, thermophilous deciduous forests in Italy, and Mediterranean forests in Spain. We sampled the fine roots of trees and ground vegetation to the depth of 20 cm in the mineral soil and allocated the fine root biomass to individual tree species using near-infrared reflectance spectroscopy (NIRS). We did not find any general positive effects of tree species diversity on the fine root biomass of trees or ground vegetation across the forest types and tree species combinations. However, our results suggest that tree fine root biomass increases with tree species diversity in pure broadleaf forests, but not in pure conifer forests. Species diversity explained 7% of the variation in tree fine root biomass in the broadleaf stands. The narrow tree species diversity gradient (1–2 species) in the conifer forests compared to the broadleaf forests (1−4) may have decreased the probability of conifer species combinations with below-ground functional traits conducive to over-yielding. Some evidence of diversity-mediated changes in the vertical rooting patterns of broadleaf trees and ground vegetation were found within the entire organic and 0–20 cm mineral soil layer although the weighted mean depth of fine root biomass was not affected. Negative diversity effects were found in the organic layer and positive diversity effects in the 0–10 cm mineral soil layer for broadleaf tree fine root biomass. Diversity effects were negative for ground vegetation fine root biomass in the 0–10 cm mineral soil layer. There was a general positive effect of conifer proportion on total fine root biomass in the organic layer, but not in the mineral soil layers. In general conifer proportion and site factors explained more of the variation in tree fine root biomass than tree species diversity. More research covering the annual variation in fine root biomass and deeper soil layers is needed before recommending managing species-rich forest for increasing below-ground biomass and carbon pools.

Intensive ground vegetation growth mitigates the carbon loss after forest disturbance

AimsSlow or failed tree regeneration after forest disturbance is increasingly observed in the central European Alps, potentially amplifying the carbon (C) loss from disturbance. We aimed at quantifying C dynamics of a poorly regenerating disturbance site with a special focus on the role of non-woody ground vegetation.MethodsSoil CO2 efflux, fine root biomass, ground vegetation biomass, tree increment and litter input were assessed in (i) an undisturbed section of a ~ 110 years old Norway spruce stand, (ii) in a disturbed section which was clear-cut six years ago (no tree regeneration), and (iii) in a disturbed section which was clear-cut three years ago (no tree regeneration).ResultsTotal soil CO2 efflux was similar across all stand sections (8.5 ± 0.2 to 8.9 ± 0.3 t C ha−1 yr.−1). The undisturbed forest served as atmospheric C sink (2.1 t C ha−1 yr.−1), whereas both clearings were C sources to the atmosphere. The source strength three years after disturbance (−5.5 t C ha−1 yr.−1) was almost twice as high as six years after disturbance (−2.9 t C ha−1 yr.−1), with declining heterotrophic soil respiration and the high productivity of dense graminoid ground vegetation mitigating C loss.ConclusionsC loss after disturbance decreases with time and ground vegetation growth. Dense non-woody ground vegetation cover can hamper tree regeneration but simultaneously decrease the ecosystem C loss. The role of ground vegetation should be more explicitly taken into account in forest C budgets assessing disturbance effects.

Carbon stock in aboveground biomass of vegetation at the High Tatra Mts. twelve years after disturbance

AbstractThe paper focused on the estimation of aboveground biomass and its carbon stock in the vegetation cover on the territory of the High Tatras twelve years after a large-scale wind disturbance. Besides biomass quantification of main plant groups (i.e. trees and ground vegetation) we considered plant components with special regard to carbon rotation rate. The measurements were performed on two transects each containing 25 plots sized 4 × 4 m. Height and stem diameter of all trees on the plots were measured and used for biomass estimation. To quantify the biomass of ground vegetation, six subplots sized 20 × 20 cm were systematically placed on each plot and the aboveground biomass was harvested. The plant material was subjected to chemical analyses to quantify its carbon concentration. The study showed that while the wind disturbance caused dramatic decrease of carbon stock, young post-disturbance stands with abundant ground vegetation, represented large carbon flux via litter fall. Twelve years after the wind disturbance, the trees contributed to carbon stock more than the ground vegetation. However, the opposite situation was recorded for the carbon flux to litter that was related to the dominance of annual plants in the above-ground biomass of ground vegetation. The carbon stock in the biomass of young trees and ground vegetation represented about 8,000 kg per ha. The young stands manifested a dynamic growth, specifically the aboveground biomass increased annually by one third. The results confirmed different carbon regimes in the former old (pre-disturbance) and sparse young (post-disturbance) stands.

Quantifying vegetation biomass impacts on vehicle mobility

Soil impacts on vehicle mobility are well known; however, most data are for bare soil or the type and amount of vegetation is not documented. This study summarizes results from experiments to quantify the effect of above ground and below ground vegetation biomass on vehicle performance. Soil–vegetation combinations of three soils and three grasses were used. The vegetation was tested at various growth stages and was also subjected to stressors such as trafficking, burning, and cutting. Vegetation measurements included above ground (leaves and shoots) and below ground (root) biomass weights, lengths, diameters and surface area parameters. The soils were characterized for size distribution, moisture, density and terrain strength for each test condition. Vehicle traction and motion resistance were measured for each soil–grass combination using the CRREL Instrumented Vehicle. Results showed an increase in net traction biomass in sandy soils. For clay soils above ground biomass generally increased resistance while increased root diameter clearly decreased resistance. This study represents the first measurements quantifying the impacts of specific biomass parameters on vehicle mobility. The results will serve to guide new experimental methods, improve datasets, and develop physics-based models for years to come.

Modelling fine root biomass of boreal tree stands using site and stand variables

Quantification of fine root biomass is needed for estimating the role of roots as carbon (C) stores and sources of C input into the soil, as well as for modelling of forest nutrient cycling. Due to the laborious nature of root biomass determinations, there is a need to develop indirect methods that would allow fine root biomass to be estimated using data on easily measurable stand and site variables. We developed models for estimating tree fine root (diameter⩽2mm) biomass of boreal forests by compiling data from 95 Finnish forest stands (55 on upland soils and 40 on drained peatlands). Stand basal area predicted fine root biomass (R2-adj.=0.35, p<0.001) better than any other stand variable alone. A model that included stand basal area, dominant tree species group [birch/other], soil type [upland soil/drained peatland], temperature sum and the interaction of soil type and temperature sum accounted for 46% of the variation in fine root biomass. Stand basal area, the C:N ratio of the organic layer or upper 0–20cm peat layer and the dominant tree species group together explained 45% of the variation in fine root biomass. Temperature sum correlated with fine root biomass in opposite ways in upland soils and in drained peatlands: fine root biomass increased with decreasing temperature sum in upland soil sites, whereas in peatlands fine root biomass decreased as the temperature sum decreased. Although the models were based on a large dataset representing well the variation in stand age, basal area, site fertility and climatic conditions in northern European boreal forests, half of the variation in fine root biomass remained unexplained. More comprehensive fine root biomass sampling in relation to spatial and temporal variation in the forthcoming studies, for example in connection with monitoring campaigns, and additional predictors such as soil texture, successional stage and the fine root biomass of ground vegetation might improve the predictive power of fine root biomass models.

Dirvos paruošimo įtaka žolinių augalų vystymuisi miško želdiniuose žemės ūkiui naudotuose plotuose ir kirtavietėse

The influence of soil preparation on the development of ground vegetation during the establishment of forest plantations was studied. It was found that in the first-year plantations on former farmland the least biomass of ground vegetation develops on furrows. Complete soil tillage to the depth of 22-27 cm, ploughed in berms or elimination of weeds with Roundup Bio may reduce the biomass of ground vegetation by up to two times. Soil ploughing in berms or piles always reduced the mass of weeds. In the second year of plantations' growth, differences in the biomass of weeds among different soil preparation treatments decreased. On fresh clear-cut areas of fertile mineral soils any mechanical method of soil preparation reduced the biomass of ground vegetation. With increasing soil preparation depth (down to 40 cm) and the width of the strip (up to 100 cm), the biomass of ground vegetation decreased. The least (4-9 times less compared with unprepared soil) ground vegetation biomass was observed when the soil had been prepared in furrows, berms or piles. Soil preparation method affected also the height of ground vegetation. It depended on soil fertility and moisture content, weed species, spring and summer weather conditions. The shading class of seedlings and the volume of plantation tending depended on soil preparation method too. Seedlings planted on wide (100 cm) furrows and on 30 cm high piles were the least shaded, while those growing on unprepared, completely ploughed soil or on inverted humus mounds experienced the greatest suppression.

Does species richness affect fine root biomass and production in young forest plantations?

Tree species diversity has been reported to increase forest ecosystem above-ground biomass and productivity, but little is known about below-ground biomass and production in diverse mixed forests compared to single-species forests. For testing whether species richness increases below-ground biomass and production and thus complementarity between forest tree species in young stands, we determined fine root biomass and production of trees and ground vegetation in two experimental plantations representing gradients in tree species richness. Additionally, we measured tree fine root length and determined species composition from fine root biomass samples with the near-infrared reflectance spectroscopy method. We did not observe higher biomass or production in mixed stands compared to monocultures. Neither did we observe any differences in tree root length or fine root turnover. One reason for this could be that these stands were still young, and canopy closure had not always taken place, i.e. a situation where above- or below-ground competition did not yet exist. Another reason could be that the rooting traits of the tree species did not differ sufficiently to support niche differentiation. Our results suggested that functional group identity (i.e. conifers vs. broadleaved species) can be more important for below-ground biomass and production than the species richness itself, as conifers seemed to be more competitive in colonising the soil volume, compared to broadleaved species.

Normalized difference vegetation index (NDVI) as a predictor of forage availability for ungulates in forest and field habitats

Quantifying available plant biomass is a crucial step towards improving our understanding of herbivore ecology and trophic interactions. Thanks to the development of satellite-derived vegetation indices such as the normalized difference vegetation index (NDVI), ecologists have been provided with indirect estimates of primary production at various temporal and spatial scales. When it comes to forested ecosystems, most mammalian herbivores predominantly rely on the ground vegetation, yet little is known regarding the suitability of NDVI to predict this component of forest vegetation cover. This study compares the relationship between NDVI and ground vegetation biomass in two contrasting habitats (field and forest) in Eastern Poland over the spring and summer seasons (2007–2008). Results indicate that seasonality shapes the relationship between NDVI and ground vegetation biomass for each habitat type. In the field habitat, NDVI and ground vegetation biomass were positively related, with a stronger correlation between the two variables occurring in summer. In the forest habitat, a switch in the direction of the correlation between biomass and NDVI (from positive in spring to negative in summer) was detected. The timing of the switch was related to the timing of full development of tree and shrub leaves (late May–early June). This suggests that the usefulness of NDVI as a predictor of ground vegetation biomass is dependent upon the habitat considered and the targeted season.

Effects of pre-harvest fertilization and subsequent soil scarification on the growth of planted Pinus sylvestris seedlings and ground vegetation after clear-felling

Fertilization and scarification are both performed to increase tree production at different stages of forest rotation periods. In this study, the effects of previous nitrogen fertilizations and scarification after clear felling on planted Pinus sylvestris L. seedlings and ground vegetation were investigated. Two fertilization experiments established around 1980 were harvested in 2006, after which the plots were scarified by disc trenching and re-planted. The plots had been repeatedly fertilized over a 20-year period before harvesting, with total N doses of 0, 450, 900 or 1800 kg N ha -1. After five growing seasons, the growth, survival and nutrient contents of the seedlings were measured, and ground vegetation was collected to estimate its biomass and nutrient content. Pre-harvest fertilization alone had only minor effects on the results, but scarification increased both the survival and growth of the planted seedlings. However, without scarification, seedling mortality increased with increasing fertilization intensity. The ground vegetation biomass was higher in plots without scarification, but the total biomass of seedlings and ground vegetation was similar in all treatments. Scarification thus favored seedling growth at the expense of ground vegetation. Only a few effects on nutrient content were found, but there were no signs of nutrient imbalance in any of the treatments. At higher levels of fertilization, the K:N ratio in the seedlings decreased while the K content in the ground vegetation increased. Overall, scarification had a greater impact than pre-harvest fertilization on the planted seedlings and the ground vegetation.

Notes on the biomass expansion factors of Quercus mongolica and Quercus variabilis forests in Korea

Biomass expansion factors, which convert timber volume (or dry weight) to biomass, are used for estimating the forest biomass and accounting for the carbon budget at a regional or national scale. We estimated the biomass conversion and expansion factors (BCEF), biomass expansion factors (BEF), root to shoot ratio (R), and ecosystem biomass expansion factor (EBEF) for Quercus mongolica Fisch. and Quercus variabilis Bl. forests based on publications in Korea. The mean BCEF, BEF, and R for Q. mongolica was 1.0383 Mg/m 3 (N = 27; standard deviation [SD], 0.5515), 1.3572 (N = 27; SD, 0.1355), and 0.2017 (N = 32; SD, 0.0447), respectively. The mean BCEF, BEF, and R for Q. variabilis was 0.7164 Mg/m 3 (N = 17; SD, 0.3232), 1.2464 (N = 17; SD, 0.0823), and 0.1660 (N = 8; SD, 0.0632), respectively. The mean EBEF, as a simple method for estimating the ground vegetation biomass, was 1.0216 (N = 7; SD, 0.0232) for Q. mongolica forest ecosystems, and 1.0496 (N = 8; SD, 0.0725) for Q. variabilis forest ecosystems. The biomass expansion factor values in this study may be better estimates of forest biomass in Q. mongolica or Q. variabilis forests of Korea compared with the default values given by the Intergovernmental Panel on Climate Change (IPCC).

Relationship between Aboveground Biomass and Percent Cover of Ground Vegetation in Canadian Boreal Plain Riparian Forests

Vegetation biomass is the ideal variable to estimate vegetation abundance and productivity and is necessary for studies of community structure. However, biomass data are difficult and destructive to collect, unlike areal cover data. To date, equations to predict biomass from percent cover have been developed for upland ground flora; however, these equations are lacking for riparian forests. We quantified relationships between aboveground biomass and percent cover of eight ground floristic growth forms (short forbs, tall forbs, ferns, clubmosses, horsetails, graminoids, dwarf shrubs, and bryoids) in riparian forests of the Canadian Boreal Plain and tested whether relationships differ for ground plants growing in two different successful stages (early and late). Without exception, linear relationships were identified with percent cover (P 0.001) that explained 61-93% of the variation in biomass. Slopes of these lines depended on growth form but not on successional stage. When direct biomass measurements are not appropriate or possible, the relationships presented can be used to rapidly and nondestructively estimate biomass in the Boreal Plain riparian forests. FOR .S CI. 58(1):47-53.

Preliminary studies on the influence of dune-slope exposure on a pine forest ecosystem in the Toruń Basin

Ekspozycja stoków wydm w Kotlinie Toruńskiej a wybrane elementy ekosystemu boru sosnowego - wstępne wyniki badań