scholarly journals Forage value of vegetative leaf and stem biomass fractions of selected grasses indigenous to African rangelands

2021 ◽  
Author(s):  
Kevin Z. Mganga ◽  
Aphaxard J. N. Ndathi ◽  
Stephen M. Wambua ◽  
Luwieke Bosma ◽  
Eric M. Kaindi ◽  
...  
Keyword(s):  
Stem Biomass ◽  
Forage Value ◽  
Vegetative Leaf

Influence of cellular metabolites on RNA and protein syntheses by Xanthium nuclei of different developmental phases

1986 ◽  
Vol 64 (12) ◽  
pp. 2922-2927
Author(s):  
A. Jana ◽  
S. P. Sen
Keyword(s):  
Rna Synthesis ◽  
Supernatant Fraction ◽  
Xanthium Strumarium ◽  
Low Molecular Weight ◽  
Transcriptional Level ◽  
Protein Patterns ◽  
Rna Molecules ◽  
Reproductive Tissues ◽  
Developmental Phases ◽  
Vegetative Leaf

Leaf nuclei of vegetative and reproductive plants of Xanthium strumarium L. were incubated with the postribosomal supernatant of either phase and changes at the transcriptional level were studied in homologous and heterologous combinations. In the presence of the supernatant of reproductive plants, RNA synthesis by vegetative nuclei was decreased by 25%. Reproductive nuclei were less active in RNA synthesis. Gel electrophoretic studies revealed four RNA bands in vegetative nuclei incubated with reproductive supernatant, including a fast-moving low molecular weight band that could not be detected when the "vegetative" supernatant was used. The adenine/uracil ratios of the newly synthesized RNA of vegetative nuclei treated with vegetative and reproductive supernatants were 1.46 and 1.54, respectively, compared with 1.15 and 1.04 in the reproductive nuclei. Competitive DNA–RNA hybridization experiments indicated that about 2% of the [3H]RNA synthesized by nuclei of vegetative plants in the presence of the supernatant of reproductive plants could not be beaten out by the RNA of vegetative plants. Small quantitative differences, thus, may be expected in the RNA molecules synthesized by nuclei in the presence of the supernatant fraction of vegetative and reproductive plants. The supernatant fraction of the reproductive tissues decreased the incorporation of [3H]alanine and [3H]leucine in both the buffer-soluble and acid-soluble proteins and the nuclei of vegetative plants were more active in protein synthesis. Protein patterns as studied by acrylamide gel electrophoresis revealed alterations when vegetative leaf nuclei were incubated with the supernatant of reproductive tissues.

scholarly journals Generic Additive Allometric Models and Biomass Allocation for Two Natural Oak Species in Northeastern China

Forests ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 715
Author(s):  
Shengwang Meng ◽  
Fan Yang ◽  
Sheng Hu ◽  
Haibin Wang ◽  
Huimin Wang
Keyword(s):  
Biomass Allocation ◽  
Tree Height ◽  
Northeastern China ◽  
Seemingly Unrelated Regression ◽  
Biomass Estimation ◽  
Model Parameters ◽  
Stem Biomass ◽  
Crown Width ◽  
Biomass Models ◽  
Mongolian Oak

Current models for oak species could not accurately estimate biomass in northeastern China, since they are usually restricted to Mongolian oak (Quercus mongolica Fisch. ex Ledeb.) on local sites, and specifically, no biomass models are available for Liaodong oak (Quercuswutaishanica Mayr). The goal of this study was, therefore, to develop generic biomass models for both oak species on a large scale and evaluate the biomass allocation patterns within tree components. A total of 159 sample trees consisting of 120 Mongolian oak and 39 Liaodong oak were harvested and measured for wood (inside bark), bark, branch and foliage biomass. To account for the belowground biomass, 53 root systems were excavated following the aboveground harvest. The share of biomass allocated to different components was assessed by calculating the ratios. An aboveground additive system of biomass models and belowground equations were fitted based on predictors considering diameter (D), tree height (H), crown width (CW) and crown length (CL). Model parameters were estimated by jointly fitting the total and the components’ equations using the weighted nonlinear seemingly unrelated regression method. A leave-one-out cross-validation procedure was used to evaluate the predictive ability. The results revealed that stem biomass accounts for about two-thirds of the aboveground biomass. The ratio of wood biomass holds constant and that of branches increases with increasing D, H, CW and CL, while a reverse trend was found for bark and foliage. The root-to-shoot ratio nonlinearly decreased with D, ranging from 1.06 to 0.11. Tree diameter proved to be a good predictor, especially for root biomass. Tree height is more prominent than crown size for improving stem biomass models, yet it puts negative effects on crown biomass models with non-significant coefficients. Crown width could help improve the fitting results of the branch and foliage biomass models. We conclude that the selected generic biomass models for Mongolian oak and Liaodong oak will vigorously promote the accuracy of biomass estimation.

scholarly journals Allometric equations for estimating stem biomass of Artocarpus chaplasha Roxb. in Sylhet hill forest of Bangladesh

2021 ◽  
pp. 100084
Author(s):  
Md. Rafikul Islam ◽  
Md. Salim Azad ◽  
Abdus Subhan Mollick ◽  
Md. Kamruzzaman ◽  
Md. Nabiul Islam Khan
Keyword(s):  
Allometric Equations ◽  
Stem Biomass

scholarly journals Aboveground Biomass Allocation of Boreal Shrubs and Short-Stature Trees in Northwestern Canada

Forests ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 234
Author(s):  
Linda Flade ◽  
Christopher Hopkinson ◽  
Laura Chasmer
Keyword(s):  
Short Stature ◽  
Biomass Allocation ◽  
Aboveground Biomass ◽  
Leaf Biomass ◽  
Sectional Area ◽  
Plant Component ◽  
Cross Sectional ◽  
Allometric Models ◽  
Stem Biomass ◽  
Model Fits

In this follow-on study on aboveground biomass of shrubs and short-stature trees, we provide plant component aboveground biomass (herein ‘AGB’) as well as plant component AGB allometric models for five common boreal shrub and four common boreal short-stature tree genera/species. The analyzed plant components consist of stem, branch, and leaf organs. We found similar ratios of component biomass to total AGB for stems, branches, and leaves amongst shrubs and deciduous tree genera/species across the southern Northwest Territories, while the evergreen Picea genus differed in the biomass allocation to aboveground plant organs compared to the deciduous genera/species. Shrub component AGB allometric models were derived using the three-dimensional variable volume as predictor, determined as the sum of line-intercept cover, upper foliage width, and maximum height above ground. Tree component AGB was modeled using the cross-sectional area of the stem diameter as predictor variable, measured at 0.30 m along the stem length. For shrub component AGB, we achieved better model fits for stem biomass (60.33 g ≤ RMSE ≤ 163.59 g; 0.651 ≤ R2 ≤ 0.885) compared to leaf biomass (12.62 g ≤ RMSE ≤ 35.04 g; 0.380 ≤ R2 ≤ 0.735), as has been reported by others. For short-stature trees, leaf biomass predictions resulted in similar model fits (18.21 g ≤ RMSE ≤ 70.0 g; 0.702 ≤ R2 ≤ 0.882) compared to branch biomass (6.88 g ≤ RMSE ≤ 45.08 g; 0.736 ≤ R2 ≤ 0.923) and only slightly better model fits for stem biomass (30.87 g ≤ RMSE ≤ 11.72 g; 0.887 ≤ R2 ≤ 0.960), which suggests that leaf AGB of short-stature trees (<4.5 m) can be more accurately predicted using cross-sectional area as opposed to diameter at breast height for tall-stature trees. Our multi-species shrub and short-stature tree allometric models showed promising results for predicting plant component AGB, which can be utilized for remote sensing applications where plant functional types cannot always be distinguished. This study provides critical information on plant AGB allocation as well as component AGB modeling, required for understanding boreal AGB and aboveground carbon pools within the dynamic and rapidly changing Taiga Plains and Taiga Shield ecozones. In addition, the structural information and component AGB equations are important for integrating shrubs and short-stature tree AGB into carbon accounting strategies in order to improve our understanding of the rapidly changing boreal ecosystem function.

Assessment of biomass functions for calculating bark proportions and ash contents of refined biomass fuels derived from major boreal tree species

2012 ◽  
Vol 42 (1) ◽  
pp. 59-66 ◽  
Author(s):  
Torbjörn A. Lestander ◽  
Anders Lundström ◽  
Michael Finell
Keyword(s):  
Betula Pendula ◽  
Quality Parameter ◽  
Sample Population ◽  
Tree Biomass ◽  
Stem Biomass ◽  
Fuel Pellets ◽  
Current Limit ◽  
Forest Survey ◽  
Betula Pubescens Ehrh ◽  
Biomass Functions

Knowledge of the components of above-ground biomass of low-quality stems harvested to produce biofuel pellets is important, since bark has higher ash contents (a key quality parameter for the pellets) than wood. Therefore, single-tree biomass functions by Marklund (1988. Rep. 45. Department of Forest Survey, Swedish University of Agricultural Sciences, Umea, Sweden.) were evaluated using a sample population of 1612 Scots pine ( Pinus sylvestris L.), Norway spruce ( Pices abies (L.) Karst.), and birch ( Betula pendula Roth and Betula pubescens Ehrh.) trees and three methods to model bark proportions. Bark percentages calculated subtractively using functions for stem biomass over and under bark showed anomalous patterns, especially for pine and birch. However, additive use of biomass functions for bark biomass and stem biomass under bark resulted in similar patterns to bark percentages traditionally calculated from bark biomass and stem biomass over bark. Published ash contents of bark and stemwood indicate that pine, birch, and spruce stems with breast height (1.3 m) diameters of 4–40, 4–30, and >19 cm, respectively, have <0.7% ash contents (the current limit for the highest quality fuel pellets). However, if the highest recorded ash contents are used, only pine stems meet this criterion. Thus, material of different species and stem dimensions may need to be carefully mixed when whole-stem biomass is used as feedstock for pelletizing.

scholarly journals Effect of Climatic Factors on Stem Biomass and Carbon Stock of Larix gmelinii and Betula platyphylla in Daxing’anling Mountain of Inner Mongolia, China

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Dilawar Khan ◽  
Muhammad Atif Muneer ◽  
Zaib-Un- Nisa ◽  
Sher Shah ◽  
Muhammad Amir ◽  
...  
Keyword(s):  
Inner Mongolia ◽  
Negative Impact ◽  
Climatic Factors ◽  
High Temperature Stress ◽  
Climatic Conditions ◽  
Larix Gmelinii ◽  
Maximum Temperature ◽  
Betula Platyphylla ◽  
Stem Biomass ◽  
Annual Minimum Temperature

Climate change has become a global concern for scientists as it is affecting almost every ecosystem. Larix gmelinii and Betula platyphylla are native and dominant forest species in the Daxing’anling Mountains of Inner Mongolia, playing a major role in carbon sequestration of this region. This study was carried out to assess the effect of climate variables including precipitation and temperature on the biomass of Larix gmelinii and Betula platyphylla forests. For this purpose, we used the climate-sensitive stem biomass allometric model for both species separately to find out accurate stem biomass along with climatic factors from 1950 to 2016. A total of 66 random plots were taken to attain the data from this study area. Larix gmelinii and Betula platyphylla stem biomass have a strong correlation with annual precipitation (R2 = 0.86, R2 = 0.71, R2 = 0.79, and R2 = 0.59) and maximum temperature (R2 = 0.76, R2 = 0.64, R2 = 0.67, and R2 = 0.52). However, annual minimum temperature (R2 = 0.58, R2 = 0.43, R2 = 0.55, and R2 = 0.46) and annual mean temperature (R2 = 0.40, R2 = 0.22, R2 = 0.36, and R2 = 0.19) have a relatively negative impact on tree biomass. Therefore, we suggest that both species have a very strong adaptive nature with climatic variation and hence can survive under drought and high-temperature stress climatic conditions.

scholarly journals Evaluation and improvement of the Community Land Model (CLM 4.0) in Oregon forests

2012 ◽  
Vol 9 (9) ◽  
pp. 12757-12802
Author(s):  
T. W. Hudiburg ◽  
B. E. Law ◽  
P. E. Thornton
Keyword(s):  
Primary Production ◽  
Forest Inventory ◽  
Net Primary Production ◽  
Forest Carbon ◽  
Physiological Parameters ◽  
Process Models ◽  
Study Region ◽  
Stem Biomass ◽  
Community Land Model ◽  
Semi Arid

Abstract. Ecosystem process models are important tools for determining the interactive effects of global change and disturbance on forest carbon dynamics. Here we evaluated and improved terrestrial carbon cycling simulated by the Community Land Model (CLM4), the land model portion of the Community Earth System Model (CESM1.0.4). Our analysis was conducted primarily in Oregon forests using FLUXNET and forest inventory data for the period 2001–2006. We go beyond prior modeling studies in the region by incorporating regional variation in physiological parameters from >100 independent field sites in the region. We also compare spatial patterns of simulated forest carbon stocks and net primary production (NPP) at 15 km resolution using data collected from federal forest inventory plots (FIA) from >3000 plots in the study region. Finally, we evaluate simulated gross primary production (GPP) with FLUXNET eddy-covariance tower data at wet and dry sites in the region. We improved model estimates by making modifications to CLM4 to allow physiological parameters (e.g. foliage carbon to nitrogen ratios and specific leaf area), mortality rate, biological nitrogen fixation, and wood allocation to vary spatially by plant functional type (PFT) within an ecoregion based on field plot data in the region. Prior to modifications, default parameters resulted in underestimation of stem biomass in all forested ecoregions except the Blue Mountains and annual NPP was both over and underestimated. After modifications, model estimates of mean NPP fell within the observed range of uncertainty in all ecoregions (two-sided p-value = 0.8) and the underestimation of stem biomass was reduced. This was an improvement from the default configuration by 50% for stem biomass and 30% for NPP. At the tower sites, modeled monthly GPP fell within the observed range of uncertainty at both sites for the majority of the year, however summer GPP was underestimated at the Metolius semi-arid pine site and spring GPP was overestimated at the Campbell River mesic Douglas-fir site, indicating GPP may be an area for further improvement. The low bias in summer maximum GPP at the semi-arid site could be due to seasonal response of Vcmax to temperature and precipitation while overestimated spring values at the mesic site could be due to response of Vcmax to temperature and daylength.

scholarly journals Multivariate clustering of reindeer herding districts in Sweden according to range prerequisites for reindeer husbandry

Rangifer ◽  
2009 ◽  
Vol 27 (2) ◽  
pp. 107-119
Author(s):  
Henrik Lundqvist ◽  
Öje Danell
Keyword(s):  
Geographical Information Systems ◽  
Large Scale ◽  
Global Climate ◽  
Meteorological Data ◽  
Principal Component ◽  
Geographical Information ◽  
Reindeer Herding ◽  
Factors Affecting ◽  
Decision Tools ◽  
Forage Value

The 51 reindeer herding districts in Sweden vary in productivity and prerequisites for reindeer herding. In this study we characterize and group reindeer herding districts based on relevant factors affecting reindeer productivity, i.e. topography, vegetation, forage value, habitat fragmentation and reachability, as well as season lengths, snow fall, ice-crust probability, and insect harassment, totally quantified in 15 variables. The herding districts were grouped into seven main groups and three single outliers through cluster analyses. The largest group, consisting of 14 herding districts, was further divided into four subgroups. The range properties of herding districts and groups of districts were characterized through principal component analyses. By comparisons of the suggested grouping of herding districts with existing administrative divisions, these appeared not to coincide. A new division of herding districts into six administrative sets of districts was suggested in order to improve administrative planning and management of the reindeer herding industry. The results also give possibilities for projections of alterations caused by an upcoming global climate change. Large scale investigations using geographical information systems (GIS) and meteorological data would be helpful for administrative purposes, both nationally and internationally, as science-based decision tools in legislative, economical, ecological and structural assessments. Abstract in Swedish / Sammanfattning: Multivariat gruppering av svenska samebyar baserat på renbetesmarkernas grundförutsettningar Svenska renskötselområdet består av 51 samebyar som varierar i produktivitet och förutsättningar för renskötsel. Vi analyserade variationen mellan samebyar med avseende på 15 variabler som beskriver topografi, vegetation, betesvärde, fragmentering av betesmarker, klimat, skareförekomst och aktivitet av parasiterande insekter och vi föreslår en indelning av samebyar i tio grupper. Den största gruppen, som bestod av 14 samebyar, delades vidare in i 4 undergrupper. Klusteranalyser med 4 olika linkage-varianter användes till att gruppera samebyarna. Principalkomponentsanalys användes för att kartlägga undersökta variabler och de resulterande samebygruppernas karaktär. Samebygrupperna följde inte länsgränser och tre samebyar föll ut som enskilda grupper. Denna undersökning ger underlag för jämförelser mellan samebyar med beaktande av likheter och olikheter i fråga om produktivitet och funktionella särdrag istället för länsgränser och historik. Vi föreslår en ny administrativ indelning i sex områden som skulle kunna fungera som ett alternativt underlag för planering och beslut som rör produktionsaspekter i rennäringen. Resultaten ger också underlag för förutsägelser av förändringar i samebyars produktionsförutsättningar till följd av klimatförändringar.

scholarly journals Production potential of the Kabardino-Balkarian Republic pasture ecosystems

2021 ◽  
Vol 262 ◽  
pp. 03023
Author(s):  
Aida Tamahina ◽  
Urfa Turan Ogly Turabov
Keyword(s):  
Perennial Grasses ◽  
Production Potential ◽  
Short Term ◽  
Alpha And Beta Diversity ◽  
Pasture Digression ◽  
Erosion Processes ◽  
Grass Stand ◽  
Degraded Pasture ◽  
Forage Value ◽  
Soil Deflation

The pasture digression of meadows followed by soil deflation is one of the pressing environmental problems. This problem is typical for mountain pastures that are constantly in economic circulation. The article presents the results of a geobotanical survey of the Zolsky pastures on the territory of the Kabardino-Balkarian Republic in 2018-2020. The results of a geobotanical survey show that the pasture phytocenoses are characterized by high floristic diversity due to the heterogeneity of edaphic and orographic factors. The flora of the pastures is represented by postwood moist sedgy-and-tussock-grass, mesophilic woodreed-and-agrostidinic grass, cereal forb, forbs cereal mesophilic and subalpine meadows, low sedgy meadow steppes. The average yield for the pasture period varies from 7.2 to 16.6 centners/ha of dry eaten mass. The consequence of prolonged pasturage and excessive pasture load was a decrease in alpha and beta diversity, the formation of low-productive secondary plant communities of non-food, poisonous and weed grasses, the destruction of sod and soil outcropping. Restoration of degraded pasture ecosystems is possible on the basis of ecological intensification, which provides for the regulation of pasture loads, adherence to grazing terms, phytomelioration using perennial grasses, and short-term isolation of pastures from grazing. This will prevent erosion processes, increase biodiversity, productivity, forage value of grass stand and stability of pasture ecosystems.

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