To see the other types of publications on this topic, follow the link: Stand Biomass.
Dissertations / Theses on the topic 'Stand Biomass'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 42 dissertations / theses for your research on the topic 'Stand Biomass.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Heng, Sovanchandara. "Thinning Effects on Forest Stands and Possible Improvement in a Stand Reconstruction Technique." Kyoto University, 2019. http://hdl.handle.net/2433/242684.
Full text
2
Nordh, Nils-Erik. "Long term changes in stand structure and biomass production in short rotation willow coppice /." Uppsala : Dept. of Crop Production Ecology, Swedish University of Agricultural Sciences, 2005. http://epsilon.slu.se/2005120.pdf.
Full text
3
Zhang, Gong. "Integrating Remote Sensing and Ecosystem Models for Terrestrial Vegetation Analysis: Phenology, Biomass, and Stand Age." DigitalCommons@USU, 2012. https://digitalcommons.usu.edu/etd/1316.
Full textAbstract:
Terrestrial vegetation plays an important role in global carbon cycling and climate change by assimilating carbon into biomass during the growing season and releasing it due to natural or anthropogenic disturbances. Remote sensing and ecosystem models can help us extend our studies of vegetation phenology, aboveground biomass, and disturbances from field sites to regional or global scales. Nonetheless, remote sensing-derived variables may differ in fundamental and important ways from ground measurements. With the growth of remote sensing as a key tool in geoscience research, comparisons to ground data and intercomparisons among satellite products are needed. Here I conduct three separate but related analyses and show promising comparisons of key ecosystem states and processes derived from remote sensing and theoretical modeling to those observed on the ground. First, I show that the Moderate Resolution Imaging Spectroradiometer (MODIS) greenup product is significantly correlated with the earliest ground phenology event for North America. Spring greenup indices from different satellites demonstrate similar variability along latitudes, but the number of ground phenology observations in summer, fall, and winter is too limited to interpret the remote sensing-derived phenology products. Second, I estimate aboveground biomass (AGB) for California and show that it agrees with inventory-based regional biomass assessments. In this approach, I present a new remote sensing-based approach for mapping live forest AGB based on a simple parametric model that combines high-resolution estimates of Leaf Area Index derived from Landsat and canopy maximum height from the space-borne Geoscience Laser Altimeter System (GLAS) sensor. Third, I built a theoretical model to estimate stand age in primary forests by coupling a carbon accumulation function to the probability density of disturbance occurrences, and then ran the model with satellite-derived AGB and net primary production. The validated remote sensing data, integrated with ecosystem models, are particularly useful for large-region vegetation research in areas with sparse field measurements, and will help us to explore the long-term vegetation dynamics.
4
Loeser, Mathias. "Microscale biomass generation for continuous power supply to remote customers." Thesis, University of Bath, 2010. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.528152.
Full textAbstract:
Remotely located and sparsely populated areas often do not have access to an efficient grid connection for electricity supply. However, plenty of biomass is normally available in such areas. Instead of employing island solutions such as small diesel generators or large battery stacks for power provision, a flexibly operating microscale biomass power plant using locally available and renewable feedstock is not only an efficient way of providing those areas with competitive and reliable electricity, but also a step towards energy self sufficiency for a large share of areas worldwide, and towards mitigating the looming high costs of grid infrastructure upgrading and extension. A novel power plant design combining thermo chemical and biochemical biomass treatment was developed in this research. This system consists of a small scale gasifier and an anaerobic digester unit, both coupled to a gas storage system and a micro turbine as the generation unit. This design is suitable to continuously provide reliable electricity and accommodate fluctuating residential power demand, and it can be scaled to a level of around 100kWe, which is a fitting size for a group of residential customers, such as in a remote village. The project covers a review of available technology; the choice of suitable technology for such a plant and the design of the system; the set up of a detailed plant model in chemical engineering software; extensive simulation studies on the basis of load profiles to evaluate and optimise operation; and feedstock sourcing, efficiency and economic analyses. It will be shown that such a system is a feasible and economic solution for remote power supply, and that it can overcome many of the current obstacles of electrifying rural regions.
5
Hoffmann, Madonna Bridget, and Madonna hoffman@dpi qld gov au. "Application of tree and stand allometrics to the determination of biomass and its flux in some north-east Australian woodlands." Central Queensland University. Biological and Environmental Sciences, 2007. http://library-resources.cqu.edu.au./thesis/adt-QCQU/public/adt-QCQU20070525.144254.
Full textAbstract:
This thesis examines the effects of species, rainfall and soil type on tree biomass
regressions, as well as the effects of stand dominance and structure on stand biomass
regressions in north-east Australian woodlands. This was achieved by examining tree
characteristics and biomass relationships for a series of woodland monitoring sites
throughout the study area. This study utilised a modified data set from this permanent
monitoring site network to provide structural attributes for trees and communities of
varying composition in the grazed woodlands. These data were supplemented with
environmental data and tree harvest data sets.
Initially, the research reported in this thesis developed allometric and stand biomass
regressions for Callitris glaucophylla communities. This research also demonstrated
that changes in tree-form were not reflected in changes in the environment, nor did
such changes reflect changes in tree biomass regressions for three eucalypt species.
As a result, a common regression provides a robust estimate of total aboveground
biomass of eucalypt trees in the study area. Thus expensive destructive harvesting
can generally be avoided for minor eucalypt species. Finally, this study demonstrated
a successful methodology that described the stand structure of all the grazed
woodland sites based on tree heights. This methodology was developed to allow the
expansion of a single stand regression to estimate stand biomass across the entire
north-east Australian woodlands.
The findings demonstrated in this study, combined with the long-term data from the
permanent monitoring network sites, should enhance the estimation of carbon flux
within eucalypt communities of north-east Australias grazed woodlands.
6
Løtveit, Marte Wiig. "System Design and Configuration of a Stand-Alone PV-Biomass Micro Grid : An Application for Wawashang, Nicaragua." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for elkraftteknikk, 2014. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-27157.
Full textAbstract:
In this thesis, an evaluation of a stand-alone hybrid micro grid for the Wawashang Complex is presented. A solution for a new electricity supply and distribution system for the complex is proposed with a focus on optimal configuration of the system. A field trip to Wawashang was conducted in April 2014 in order to collect data regarding biomass potential for electricity production and information for a possible distribution system design. The demand to be covered is divided into two systems; the micro grid, which denotes all buildings excluding the carpentry workshop and is the system for which the distribution system is designed, and the carpentry workshop. A single-phase/three-wire (split-phase) solution is suggested for the distribution system configuration, presenting the advantage of considerably smaller conductor size requirements than single-phase/two-wire systems for the same voltage drop and power loss. The total power loss of the distribution system is 896 kWh/year or 2.4 % of the demand. The production system for the micro grid consists of a PV array and a battery bank, and for the carpentry workshop a diesel generator. Additionally, a biomass based generator is available for both systems according to a defined schedule. The simulation software HOMER is used to run simulations for the two systems simultaneously, with the intention of obtaining optimal operation of the biomass generator. Two cases are evaluated on both technical and economical aspects. In Case I, the high frequency AC power output from the biomass generator is rectified to DC power and then connected to the single-phase AC bus of the micro grid through a DC-AC converter and similarly to the three-phase AC loads of the carpentry workshop. In Case II, the output from the biomass generator is connected to the DC bus of the micro grid after rectification. The simulation results shows that the optimal solution in both cases is to operate the biomass generator as much as possible in the carpentry workshop with the diesel generator available to cover peak loads. In Case I, the biomass generator is operated with a load following strategy, while in Case II a cycle charging strategy is applied, resulting in a higher exploitation of the available biomass resource in the latter. Both cases present advantages and disadvantages and are similar in reliability and cost. Case II is evaluated as the optimal solution for the Wawashang Complex, as it is the overall least expensive, most reliable and least unbalanced system when it comes to seasonal variations. The system consists of a 9 kW converter, a PV array with a global power of 30 kWp, producing a total of 37 254 kWh/year and a battery bank with a nominal capacity of 294 kWh (for the micro grid), a 15 kW biomass generator producing a total of 38 477 kWh/year divided between the micro grid (19.4 %) and the carpentry workshop (80.6 %) and a 15 kW diesel generator producing 5 400 kWh/year for the carpentry workshop. Total excess electricity is 6.3 % and unmet load is 0.21 %. Total NPC is US$ 311 224 and levelized COE is US$ 0.285/kWh.
7
Ali, Wael. "Modelling of Biomass Production Potential of Poplar in Short Rotation Plantations on Agricultural Lands of Saxony, Germany." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2009. http://nbn-resolving.de/urn:nbn:de:bsz:14-ds-1237199867841-24821.
Full textAbstract:
The interest in renewables for energy has increased in the last 2-3 decades because of the negative environmental impact caused by the burning of fossil fuels, the raising prices of traditional fuels, the dependence on foreign oil, and the decrease in fossil fuels resources. Biomass energy represents one of the most promising alternatives. Many studies worldwide were devoted to investigate growth and yield of short rotation forestry plantations for energetic use and several empirical and process-based models were developed to predict the potential production of biomass. The current work was concentrated on modelling site productivity (potential of biomass production) of specific poplar clones planted on arable Saxon land under different stocking densities. Empirical data collected from several experimental areas were used. Site productivity has been predicted depending on stand age and site variables using a two-step model. In step one age and site variables were used to model stand dominant height and in step two the constructed dominant height was involved with stocking density to predict stand oven dried biomass. Depending on data availability the model was parameterized for four different groups of poplar clones: Androscoggin (clone Androscoggin), Matrix (Matrix and hybrid 275), Max (Max 1 …Max 5) and Münden (clone Münden). Both stand dominant height and stand dry biomass were modelled for ages 2 – 9 years for clone groups: Matrix and Max and for ages 2 – 7 years for clone groups: Androscoggin and Münden. The model has been tested and validated using several statistical and graphical methods. The relative bias (ē %) in the dominant height estimates ranged between 0.5 % > ē % > - 0.5 % in all clone groups and had a maximum bias of 10.41 % in stand biomass estimates. Model accuracy (mx %) in the dominant height estimates ranged between 12.25 and 17.56 % and between 8.05 and 27.32 % in stand biomass estimates. Two different scenarios were presented to show the potential of biomass that can be produced from poplar plantations on arable and former fallow Saxon lands at different stocking densities. ArcGIS has been used to visualize model application results. In order to produce a mean annual increment ≥ 8 [dry t/ha/a] from poplar plantations (Max group) for more than 50 % of arable or former fallow lands in the first rotation at least 9 years are required under stocking density of 4000 stems/ha and 7 years for both stocking densities 8333 and 10,000 stems/haDie Nachfrage nach Holz für energetische Zwecke nimmt in Deutschland und ganz Europa zu. Um diesen Bedarf künftig besser befriedigen zu können, müssen verstärkt Ressourcen aus verschiedenen Quellen wie z. B. Holz aus Niederwäldern oder Durchforstungsreserven im Hochwald mobilisiert und ergänzend Holz in Kurzumtriebsflächen produziert werden (Guericke, M. 2006). Ziel dieser Arbeit war es, das Ertragspotential von Pappelklonen in Kurzumtriebsplantagen unterschiedlicher Baumdichte auf sächsischen Ackerflächen zu untersuchen. Hierzu wurden die potentiellen Erträge anhand empirischer, auf verschiedenen Versuchsflächen erhobener Daten modelliert. Zur Schätzung des Ertragspotentials wurde ein zweistufiges Modell entwickelt: Im ersten Schritt erfolgte die Modellierung der Oberhöhe eines Bestandes (ho, m) in Abhängigkeit von Bestandesalter und Standortfaktoren unter Verwendung einer multiplen linearen Regressionsanalyse, dabei wurden Bestimmtheitsmaße (R²) von 0,975 bis 0,989 erreicht. In einem zweiten Schritt lässt sich dann der Biomassevorrat [tatro/ha/a] mittels nichtlinearer Regressionsanalyse durch die Bestandesoberhöhe schätzen. Das Bestimmtheitsmaß von R² ≥ 0,933 weist auch hier auf eine hohe Anpassungsgüte hin. Die Modellparametrisierung erfolgte für folgende vier Gruppen von Pappelklonen: • Max-Gruppe: Klone Max 1, Max 2, Max 3, Max 4 und Max 5, Altersbereich 2 – 9 Jahre, Baumdichten von 1150 – 13000 Stämmen/ha; • Matrix-Gruppe: Klon Matrix und Hybride 275, Altersbereich 2 – 9 Jahre, Baumdichte 1550 Stämme/ha; • Androscoggin-Gruppe: Klon Androscoggin, Altersbereich 2 – 7 Jahre, Baumdichte 1550 Stämme/ha; und • Münden-Gruppe: Klon Münden, Altersbereich 2 – 7 Jahre, Baumdichte 1550 Stämme/ha. Die Güte des Modells wurde mit Hilfe verschiedener statistischer Verfahren überprüft. Bei der Validierung anhand des Datensatzes, welcher für die Modellkonstruktion Verwendung fand, zeigte das Modell eine Verzerrung bzw. einen Bias von 0,5 % > ē % > - 0,5 % bei der Bestandesoberhöhenschätzung und einen maximalen Bias von 10,41 % bei der Schätzung der Bestandesbiomasse. Die Treffgenauigkeit (mx %) des Modells hingegen variierte zwischen 12,25 % und 17,56 % bzw. 8,05 und 27,32 % (bei Schätzung der Bestandesoberhöhe bzw. der Bestandesbiomasse). Zudem wies das Modell keinen systematischen Fehler zwischen den geschätzten und den realen Werten auf. Bei der Validierung mit einem unabhängigen Datensatz betrug die Treffgenauigkeit (mx %) für die Schätzung der Bestandsoberhöhe und des Biomassevorrates 15,72 bzw. 26,68 %. Um das Ertragspotenzial von Pappelplantagen für die gesamte sächsische Ackerfläche bzw. die gesamte ehemalige Stilllegungsfläche zu bestimmen, wurden die zu Schätzung erforderlichen Standortvariablen auf Gemeindebasis kalkuliert, mittels ArcGIS dargestellt sowie Simulationsrechungen für verschiedene Bestandsdichten vorgenommen und ebenfalls visualisiert. Den Ergebnissen der Simulationsrechnungen zufolge wäre bei einer Stammzahl von 4000 N/ha eine Rotationslänge von 9 Jahren, bei 8333 bis 10.000 N/ha von 7 Jahren erforderlich, um einen durchschnittlichen Gesamtzuwachs (dGz) von ≥ 8 [tatro/ha/a] auf mehr als 50 % der sächsischen Ackerflächen bzw. ehemaligen Stilllegungsflächen in erster Rotation zu erreichen. Würde die gesamte ehemalige sächsische Stilllegungsfläche mit einer Baumdichte von 10.000 Stämmen/ha bepflanzt werden, könnten Pappelplantagen im Alter 9 einen dGz von 520.000 [tatro/a] (entsprechend 250.000 Kubikmeter Diesel) erreichen. Bei Bestockung aller sächsischen Ackerflächen würde sich der Ertrag auf bis zu 9.087.000 [tatro/a] (entsprechend 4.367.000 Kubikmeter Diesel) erhöhen
8
Ali, Wael. "Modelling of Biomass Production Potential of Poplar in Short Rotation Plantations on Agricultural Lands of Saxony, Germany." Doctoral thesis, Technische Universität Dresden, 2008. https://tud.qucosa.de/id/qucosa%3A23743.
Full textAbstract:
The interest in renewables for energy has increased in the last 2-3 decades because of the negative environmental impact caused by the burning of fossil fuels, the raising prices of traditional fuels, the dependence on foreign oil, and the decrease in fossil fuels resources. Biomass energy represents one of the most promising alternatives. Many studies worldwide were devoted to investigate growth and yield of short rotation forestry plantations for energetic use and several empirical and process-based models were developed to predict the potential production of biomass. The current work was concentrated on modelling site productivity (potential of biomass production) of specific poplar clones planted on arable Saxon land under different stocking densities. Empirical data collected from several experimental areas were used. Site productivity has been predicted depending on stand age and site variables using a two-step model. In step one age and site variables were used to model stand dominant height and in step two the constructed dominant height was involved with stocking density to predict stand oven dried biomass. Depending on data availability the model was parameterized for four different groups of poplar clones: Androscoggin (clone Androscoggin), Matrix (Matrix and hybrid 275), Max (Max 1 …Max 5) and Münden (clone Münden). Both stand dominant height and stand dry biomass were modelled for ages 2 – 9 years for clone groups: Matrix and Max and for ages 2 – 7 years for clone groups: Androscoggin and Münden. The model has been tested and validated using several statistical and graphical methods. The relative bias (ē %) in the dominant height estimates ranged between 0.5 % > ē % > - 0.5 % in all clone groups and had a maximum bias of 10.41 % in stand biomass estimates. Model accuracy (mx %) in the dominant height estimates ranged between 12.25 and 17.56 % and between 8.05 and 27.32 % in stand biomass estimates. Two different scenarios were presented to show the potential of biomass that can be produced from poplar plantations on arable and former fallow Saxon lands at different stocking densities. ArcGIS has been used to visualize model application results. In order to produce a mean annual increment ≥ 8 [dry t/ha/a] from poplar plantations (Max group) for more than 50 % of arable or former fallow lands in the first rotation at least 9 years are required under stocking density of 4000 stems/ha and 7 years for both stocking densities 8333 and 10,000 stems/ha.Die Nachfrage nach Holz für energetische Zwecke nimmt in Deutschland und ganz Europa zu. Um diesen Bedarf künftig besser befriedigen zu können, müssen verstärkt Ressourcen aus verschiedenen Quellen wie z. B. Holz aus Niederwäldern oder Durchforstungsreserven im Hochwald mobilisiert und ergänzend Holz in Kurzumtriebsflächen produziert werden (Guericke, M. 2006). Ziel dieser Arbeit war es, das Ertragspotential von Pappelklonen in Kurzumtriebsplantagen unterschiedlicher Baumdichte auf sächsischen Ackerflächen zu untersuchen. Hierzu wurden die potentiellen Erträge anhand empirischer, auf verschiedenen Versuchsflächen erhobener Daten modelliert. Zur Schätzung des Ertragspotentials wurde ein zweistufiges Modell entwickelt: Im ersten Schritt erfolgte die Modellierung der Oberhöhe eines Bestandes (ho, m) in Abhängigkeit von Bestandesalter und Standortfaktoren unter Verwendung einer multiplen linearen Regressionsanalyse, dabei wurden Bestimmtheitsmaße (R²) von 0,975 bis 0,989 erreicht. In einem zweiten Schritt lässt sich dann der Biomassevorrat [tatro/ha/a] mittels nichtlinearer Regressionsanalyse durch die Bestandesoberhöhe schätzen. Das Bestimmtheitsmaß von R² ≥ 0,933 weist auch hier auf eine hohe Anpassungsgüte hin. Die Modellparametrisierung erfolgte für folgende vier Gruppen von Pappelklonen: • Max-Gruppe: Klone Max 1, Max 2, Max 3, Max 4 und Max 5, Altersbereich 2 – 9 Jahre, Baumdichten von 1150 – 13000 Stämmen/ha; • Matrix-Gruppe: Klon Matrix und Hybride 275, Altersbereich 2 – 9 Jahre, Baumdichte 1550 Stämme/ha; • Androscoggin-Gruppe: Klon Androscoggin, Altersbereich 2 – 7 Jahre, Baumdichte 1550 Stämme/ha; und • Münden-Gruppe: Klon Münden, Altersbereich 2 – 7 Jahre, Baumdichte 1550 Stämme/ha. Die Güte des Modells wurde mit Hilfe verschiedener statistischer Verfahren überprüft. Bei der Validierung anhand des Datensatzes, welcher für die Modellkonstruktion Verwendung fand, zeigte das Modell eine Verzerrung bzw. einen Bias von 0,5 % > ē % > - 0,5 % bei der Bestandesoberhöhenschätzung und einen maximalen Bias von 10,41 % bei der Schätzung der Bestandesbiomasse. Die Treffgenauigkeit (mx %) des Modells hingegen variierte zwischen 12,25 % und 17,56 % bzw. 8,05 und 27,32 % (bei Schätzung der Bestandesoberhöhe bzw. der Bestandesbiomasse). Zudem wies das Modell keinen systematischen Fehler zwischen den geschätzten und den realen Werten auf. Bei der Validierung mit einem unabhängigen Datensatz betrug die Treffgenauigkeit (mx %) für die Schätzung der Bestandsoberhöhe und des Biomassevorrates 15,72 bzw. 26,68 %. Um das Ertragspotenzial von Pappelplantagen für die gesamte sächsische Ackerfläche bzw. die gesamte ehemalige Stilllegungsfläche zu bestimmen, wurden die zu Schätzung erforderlichen Standortvariablen auf Gemeindebasis kalkuliert, mittels ArcGIS dargestellt sowie Simulationsrechungen für verschiedene Bestandsdichten vorgenommen und ebenfalls visualisiert. Den Ergebnissen der Simulationsrechnungen zufolge wäre bei einer Stammzahl von 4000 N/ha eine Rotationslänge von 9 Jahren, bei 8333 bis 10.000 N/ha von 7 Jahren erforderlich, um einen durchschnittlichen Gesamtzuwachs (dGz) von ≥ 8 [tatro/ha/a] auf mehr als 50 % der sächsischen Ackerflächen bzw. ehemaligen Stilllegungsflächen in erster Rotation zu erreichen. Würde die gesamte ehemalige sächsische Stilllegungsfläche mit einer Baumdichte von 10.000 Stämmen/ha bepflanzt werden, könnten Pappelplantagen im Alter 9 einen dGz von 520.000 [tatro/a] (entsprechend 250.000 Kubikmeter Diesel) erreichen. Bei Bestockung aller sächsischen Ackerflächen würde sich der Ertrag auf bis zu 9.087.000 [tatro/a] (entsprechend 4.367.000 Kubikmeter Diesel) erhöhen.
9
Keane, Michael Gerard. "Aspects of needle morphology, biomass allocation and foliar nutrient composition in a young fertilized stand of repressed lodgepole pine." Thesis, University of British Columbia, 1985. http://hdl.handle.net/2429/25811.
Full textAbstract:
The dramatic decline in stand productivity associated with very high stand densities in naturally regenerated post-fire interior lodgepole pine (Pinus contorta var. latifolia) stands is called "repression". The reasons for it are unknown. Biomass allocation, needle morphology and foliar nutrition associated with repression were studied in a 20-year-old stand on plots at five densities ranging from 3,500 to 109,000 sph and fertilized at 0, 100 and 200 kg N ha⁻¹ with ammonium nitrate.
At higher stand densities, specific leaf area increased while leaf area index declined and light intensities increased below the canopy. As stand density increased from 5000 sph to 90,000 sph, the above-ground biomass decreased from 61 t ha⁻¹ to 16 t ha⁻¹, the proportion allocated to the stem increased from 58% to 78% and the leaf area/sapwood area decreased from 0.3 to 0.13 m² cm⁻². Mean earlywood percentage decreased from 62% to 8% in codominants at 6,500 and 109,000 sph respectively.
Although nitrogen deficiency was evident in all stand densities, there were no significant differences between vigorous and repressed stands for the various macro- (N, P, K, S) or micro-nutrients (Cu, Fe, 'active' Fe) examined.
It is hypothesized that the decreased proportion of earlywood in repressed trees causes a reduction in stem conductivity leading to the reported drop in the leaf area/sapwood area ratio. The resulting decrease in the photosynthetic/respiratory surface area ratio in repressed stands may lead to their reduced productivity.Forestry, Faculty of
Graduate
10
Win, Maung Aye. "Ecological Studies on Locally-managed Mangrove Forests in Taninthayi Region, Myanmar." Kyoto University, 2020. http://hdl.handle.net/2433/253396.
Full text
11
Bortolot, Zachary Jared. "An Adaptive Computer Vision Technique for Estimating the Biomass and Density of Loblolly Pine Plantations using Digital Orthophotography and LiDAR Imagery." Diss., Virginia Tech, 2004. http://hdl.handle.net/10919/27454.
Full textAbstract:
Forests have been proposed as a means of reducing atmospheric carbon dioxide levels due to their ability to store carbon as biomass. To quantify the amount of atmospheric carbon sequestered by forests, biomass and density estimates are often needed. This study develops, implements, and tests an individual tree-based algorithm for obtaining forest density and biomass using orthophotographs and small footprint LiDAR imagery. It was designed to work with a range of forests and image types without modification, which is accomplished by using generic properties of trees found in many types of images. Multiple parameters are employed to determine how these generic properties are used. To set these parameters, training data is used in conjunction with an optimization algorithm (a modified Nelder-Mead simplex algorithm or a genetic algorithm). The training data consist of small images in which density and biomass are known. A first test of this technique was performed using 25 circular plots (radius = 15 m) placed in young pine plantations in central Virginia, together with false color othophotograph (spatial resolution = 0.5 m) or small footprint LiDAR (interpolated to 0.5 m) imagery. The highest density prediction accuracies (r2 up to 0.88, RMSE as low as 83 trees / ha) were found for runs where photointerpreted densities were used for training and testing. For tests run using density measurements made on the ground, accuracies were consistency higher for orthophotograph-based results than for LiDAR-based results, and were higher for trees with DBH ≥10cm than for trees with DBH ≥7 cm. Biomass estimates obtained by the algorithm using LiDAR imagery had a lower RMSE (as low as 15.6 t / ha) than most comparable studies. The correlations between the actual and predicted values (r2 up to 0.64) were lower than comparable studies, but were generally highly significant (p ≤ 0.05 or 0.01). In all runs there was no obvious relationship between accuracy and the amount of training data used, but the algorithm was sensitive to which training and testing data were selected. Methods were evaluated for combining predictions made using different parameter sets obtained after training using identical data. It was found that averaging the predictions produced improved results. After training using density estimates from the human photointerpreter, 89% of the trees located by the algorithm corresponded to trees found by the human photointerpreter. A comparison of the two optimization techniques found them to be comparable in speed and effectiveness.Ph. D.
12
De, Clerck Fabrice Alain Jacqueline. "The effect of conifer richness on stand biomass, stability and resource use efficiency in upper montane conifer forests of the northern Sierra Nevada /." For electronic version search Digital dissertations database. Restricted to UC campuses. Access is free to UC campus dissertations, 2004. http://uclibs.org/PID/11984.
Full text
13
Huotari, N. (Noora). "Recycling of wood- and peat-ash – a successful way to establish full plant cover and dense birch stand on a cut-away peatland." Doctoral thesis, Oulun yliopisto, 2011. http://urn.fi/urn:isbn:9789514295324.
Full textAbstract:
Abstract Mechanical harvesting of peat changes the original mire ecosystem completely, and without active measures these areas may remain non-vegetated even for decades. Afforestation is one of the most popular after-use options for cut-away peatlands in Finland since it has both economic and aesthetic values. Recycling of wood-ash as a fertilizer has been studied extensively in peatlands drained for forestry. Wood-ash is reported to promote tree growth in these areas without any significant negative impact to the environment and could, therefore, be a suitable option also on cut-away peatlands. However, the environmental effects of ash-fertilization on cut-away areas and on ground vegetation are not fully understood. The impact of wood- and peat-ash application on the early establishment of ground vegetation and downy birch (Betula pubescens) seedlings and on post-fertilization element concentrations in plants and peat substrate were studied in a cut-away peatland. Six treatments of wood-ash, peat-ash, biotite or Forest PK-fertilizer were replicated in three blocks in different mixtures and quantities corresponding to 50 kg ha-1 of phosphorus. All the fertilizers accelerated the revegetation of the bare peat surface significantly, whereas the establishment of plants in the unfertilized area was non-existent even several years after the peat harvesting had ceased. The most striking difference between the wood- and peat-ash-fertilizers and the commercial Forest PK-fertilizer was the extensive coverage of fire-loving moss species in all the areas where ash was spread. Wood- and peat-ash application also accelerated the germination and early establishment of downy birch seedlings more efficiently than the PK-fertilizer. Ground vegetation proved to be highly important in increasing the early biomass production and carbon sequestration on ash-fertilized cut-away peatland. In addition, the below-ground biomass was equal to the above-ground biomass, or even greater. Both wood- and peat-ash fertilization ensured an adequate level of nutrients for the early establishment of ground vegetation and birch seedlings in a cut-away peatland. The mosses and herbaceous plants proved to have a major role in retaining the nutrients and heavy metals that otherwise might have leached away from the ash-fertilized cut-away site during the early stages of the afforestation. Although both wood- and peat-ash proved to be suitable for the initial fertilization of afforested cut-away peatlands, a later application of nutrients may be needed to guarantee the growth in a energy-wood stand of downy birch over its entire rotationTiivistelmä Turvetuotannon päätyttyä jäljelle jäävä suopohja on aluksi täysin paljas ja vailla maaperän siemenpankkia. Kasvipeitteen luontainen uudistuminen voi viedä jopa vuosikymmeniä. Ympäristönhoidollisesti onkin tärkeää, että suopohjat otetaan uuteen käyttöön mahdollisimman nopeasti tuotannon päätyttyä. Metsitys on tällä hetkellä suosituin suopohjien jälkikäyttömuoto Suomessa. Suopohjan turpeessa on tyypillisesti runsaasti typpeä, mutta niukasti muita kasvuun tarvittavia ravinteita. Puutuhka on osoittautunut pitkäaikaisissa metsäojitettujen turvemaiden tutkimuksissa kilpailukykyiseksi vaihtoehdoksi kaupallisille lannoitteille. Energiantuotannon sivutuotteena syntyvä puu- ja turvetuhka voisi soveltua hyvin myös suopohjien lannoitteeksi. Tuhkan käytöstä lannoitteena turvetuotannosta vapautuneilla suopohjilla ei kuitenkaan ole riittävästi tutkimustietoa. Tässä työssä tutkittiin puu- ja turvetuhkan vaikutuksia turvetuotannosta vapautuneen suopohjan kasvittumiseen ja puun taimien alkukehitykseen viiden ensimmäisen kasvukauden ajan. Lisäksi tutkittiin kasvillisuuden ravinne- ja raskasmetallipitoisuuksien muutoksia sekä turpeen ravinteisuutta lannoituksen jälkeen. Kaikki lannoitteet nopeuttivat merkittävästi kasvillisuuden muodostumista paljaalle suopohjalle, kun taas lannoittamaton alue pysyi kasvittomana. Tuhkalannoitetuille alueille syntyi nopeasti laajoja palopaikoilla viihtyvien pioneerisammalten kasvustoja, jotka peittivät ja samalla sitoivat paljaan ja irtonaisen turvemaan pinnan. Tuhkalannoitus edisti myös koivun taimien alkukehitystä tehokkaammin kuin kaupallinen Metsän PK-lannoite. Sammalista ja ruohovartisista kasveista muodostuva aluskasvillisuus ylitti puuntaimet selvästi biomassan määrässä ja toimi metsityksen alkuvaiheessa puuntaimia merkittävämpänä hiilensitojana. Lisäksi kasvien maanalainen biomassa oli maanpäällistä biomassaa suurempi. Sekä puu- että turvetuhka takasivat riittävän määrän ravinteita energiapuumetsikön alkukehitykselle. Aluskasvillisuus osoittautui tärkeäksi tuhkasta liukenevien ravinteiden ja raskasmetallien sitojaksi metsityksen alkuvaiheessa. Vaikka sammalten kadmiumpitoisuudet nousivat tuhkalannoituksen seurauksena, ne olivat kuitenkin alhaisia Suomessa aiemmin mitattuihin sammalten yleisiin pitoisuuksiin suhteutettuna. Tuhkalannoitus ei lisännyt haitallisten raskasmetallien pitoisuuksia koivun taimien ja ruohovartisten kasvien lehdissä ja varsissa. Tutkimuksen tulokset tukevat puu- ja turvetuhkan käyttöä energiapuumetsiköiden alkuvaiheen lannoitteena turvetuotannosta vapautuneilla suopohjilla
14
Knust, Christine, and Karl-Heinz Feger. "Estimation of Nutrient Exports Resulting from Thinning and Intensive Biomass Extraction in Medium-Aged Spruce and Pine Stands in Saxony, Northeast Germany." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-220531.
Full textAbstract:
A growing interest in using forest biomass for bioenergy generation may stimulate intensive harvesting scenarios in Germany. We calculated and compared nutrient exports of conventional stem only (SO), whole tree without needles (WT excl. needles), and whole tree (WT) harvesting in two medium aged Norway spruce (Picea abies L. Karst.) and Scots pine (Pinus sylvestris L.) stands differing in productivity, and related them to soil nutrient pools and fluxes at the study sites. We established allometric biomass functions for each aboveground tree compartment and analyzed their nutrient contents. We analyzed soil nutrient stocks, estimated weathering rates, and obtained deposition and seepage data from nearby Level II stations. WT (excl. needles) and WT treatments cause nutrient losses 1.5 to 3.6 times higher than SO, while the biomass gain is only 1.18 to 1.25 in case of WT (excl. needles) and 1.28 to 1.30 in case of WT in the pine and spruce stand, respectively. Within the investigated 25-year period, WT harvesting would cause exports of N, K+, Ca2+, and Mg2+ of 6.6, 8.8, 5.4, and 0.8 kg·ha−1 in the pine stand and 13.9, 7.0, 10.6, and 1.8 kg·ha−1 in the spruce stand annually. The relative impact of WT and WT (excl. needles) on the nutrient balance is similar in the pine and spruce stands, despite differences in stand productivities, and thus the absolute amount of nutrients removed. In addition to the impact of intensive harvesting, both sites are characterized by high seepage losses of base cations, further impairing the nutrient budget. While intensive biomass extraction causes detrimental effects on many key soil ecological properties, our calculations may serve to implement measures to improve the nutrient balance in forested ecosystems.
15
Knust, Christine, and Karl-Heinz Feger. "Estimation of Nutrient Exports Resulting from Thinning and Intensive Biomass Extraction in Medium-Aged Spruce and Pine Stands in Saxony, Northeast Germany." Molecular Diversity Preservation International (MDPI), 2016. https://tud.qucosa.de/id/qucosa%3A30201.
Full textAbstract:
A growing interest in using forest biomass for bioenergy generation may stimulate intensive harvesting scenarios in Germany. We calculated and compared nutrient exports of conventional stem only (SO), whole tree without needles (WT excl. needles), and whole tree (WT) harvesting in two medium aged Norway spruce (Picea abies L. Karst.) and Scots pine (Pinus sylvestris L.) stands differing in productivity, and related them to soil nutrient pools and fluxes at the study sites. We established allometric biomass functions for each aboveground tree compartment and analyzed their nutrient contents. We analyzed soil nutrient stocks, estimated weathering rates, and obtained deposition and seepage data from nearby Level II stations. WT (excl. needles) and WT treatments cause nutrient losses 1.5 to 3.6 times higher than SO, while the biomass gain is only 1.18 to 1.25 in case of WT (excl. needles) and 1.28 to 1.30 in case of WT in the pine and spruce stand, respectively. Within the investigated 25-year period, WT harvesting would cause exports of N, K+, Ca2+, and Mg2+ of 6.6, 8.8, 5.4, and 0.8 kg·ha−1 in the pine stand and 13.9, 7.0, 10.6, and 1.8 kg·ha−1 in the spruce stand annually. The relative impact of WT and WT (excl. needles) on the nutrient balance is similar in the pine and spruce stands, despite differences in stand productivities, and thus the absolute amount of nutrients removed. In addition to the impact of intensive harvesting, both sites are characterized by high seepage losses of base cations, further impairing the nutrient budget. While intensive biomass extraction causes detrimental effects on many key soil ecological properties, our calculations may serve to implement measures to improve the nutrient balance in forested ecosystems.
16
Urbano, Andrea Rose. "Long-term forest carbon storage and structural development as influenced by land-use history and reforestation approach." ScholarWorks @ UVM, 2016. http://scholarworks.uvm.edu/graddis/448.
Full textAbstract:
Temperate forests are an important carbon sink, yet there is uncertainty regarding land-use history effects on biomass accumulation and carbon storage potential in secondary forests. Understanding long-term biomass dynamics is important for managing forests as carbon sinks and for co-benefits such as watershed protection and biodiversity. However there are many unanswered questions regarding these dynamics in northeastern U.S. forests: How have secondary forests of the U.S. Northeast recovered post nineteenth century agricultural abandonment? How has the region's extensive land-use history influenced long-term structural development and aboveground carbon storage? To answer these questions, we employed a longitudinal study based on twelve years of empirical data (2001-2013) from the Marsh-Billings-Rockefeller (MBR) National Historical Park in Woodstock, VT. MBR Park was the first parcel of land to actively be reforested in the eastern U.S., and as such, its diverse forest mosaic reflects a history of alternate reforestation approaches and varied successional trajectories indicative of secondary forest recovery occurring across the broader northeastern forest landscape. We also used 150 years of documentary data from park management records. This research evaluates the effects of reforestation approaches (planting vs. natural regeneration), management regimes (long-term low-to-intermediate harvest intensities at varied harvest frequencies), and stand development pathways on biomass outcomes. We generated biometrics representative of stand structural complexity, including the H' structural diversity index, and aboveground biomass (live trees, snags, and downed coarse woody debris pools) estimates. Multivariate analyses evaluated the predictive strength of reforestation approach, management history, and site characteristics relative to aboveground carbon pools and stand structural complexity.
Classification and Regression Tree (CART) analysis ranked reforestation approach (plantation or natural regeneration) as the strongest predictor of long-term mean total aboveground carbon storage, while harvest frequency, and stand age were selected as secondary variables. CART ranked forest percent conifer (a metric closely associated with reforestation approach) as the strongest predictor of H' index, while harvest intensity, and harvest frequency were selected as secondary variables. Increases in harvest intensity can significantly reduce aboveground carbon storage. Our results suggest that a variety of long-term recovery pathways converge on high levels of aboveground carbon storage, including both conifer plantations and naturally regenerated hardwood stands, but choice of silvicultural management approach can dramatically alter those trajectories. Importantly, total aboveground biomass (i.e., carbon) co-varied with H' (r2 = 0.25), and thus, our dataset showed a positive relationship between forest carbon storage and structural complexity, supporting the concept of multifunctional forestry emphasizing late-successional habitats.
17
Butcher, Jerrod Anthony. "Minimum patch size thresholds of reproductive success of songbirds." Thesis, [College Station, Tex. : Texas A&M University, 2008. http://hdl.handle.net/1969.1/ETD-TAMU-2842.
Full text
18
Redaud, Louis. "Les forêts montagnardes de chênes dans le fonctionnement des systèmes agraires du Centre Népal : évolutions régressives et équilibres, essai de typologie." Grenoble 1, 1987. http://www.theses.fr/1987GRE10078.
Full textAbstract:
Les regions des hautes collines du centre nepal presentent encore, a partir de 2500 m, de vastes zones boisees; mais sous l'effet des prelevements (bois de feu et de construction, fourrage. . . ) la foret climacique a quercus semecarpifolia de l'etage montagnard fait place a des formations degradees. Dix-huit stations forestieres, situees au sud du dhaulagiri, entre 2300 et 2900 m, ont ete analysees par la methode du transpect lineaire. Les caracteristiques des peuplements (structures specifiques et spatiales, regeneration) permettent de distinguer deux types
19
Schwer, Laura Mary Jane. "SMALL MAMMAL POPULATIONS IN SWITCHGRASS STANDS MANAGED FOR BIOMASS PRODUCTION COMPARED TO HAY AND CORN FIELDS IN KENTUCKY." UKnowledge, 2011. http://uknowledge.uky.edu/gradschool_theses/138.
Full textAbstract:
Switchgrass (Panicum virgatum), a native warm-season grass, has been investigated as a renewable energy crop that may provide viable wildlife habitat. This study investigated small mammal populations in switchgrass, hay, and corn to assess the relative habitat quality. Four, three-night trapping sessions were conducted at four locations in Kentucky using Sherman livetraps. Trapping occurred in spring (before first hay harvest), summer, fall (before switchgrass and corn harvest), and winter (post-harvest). Relative abundance of small mammals, calculated using a capture per unit effort index (per 100 trapnights), and mean taxonomic richness were used to compare habitats. Switchgrass had a significantly greater mean taxonomic richness than hay but not corn; however, four genera were captured in switchgrass and only two in corn. Switchgrass had a greater relative abundance of small mammals than hay during the summer, and corn and hay during the fall. Vegetative cover was positively correlated with relative abundance of small mammals. No-till corn and three year old switchgrass had a greater relative abundance of small mammals than conventionally tilled corn and two year old switchgrass, respectively. In conclusion, switchgrass stands managed as a renewable energy crop has the potential to be viable wildlife habitat for some small mammal species.
20
Coopersmith, David J. "Root and fungal biomass production on low, medium and high productivity second-growth douglas-fir stands on Vancouver Island." Thesis, University of British Columbia, 1986. http://hdl.handle.net/2429/25864.
Full textAbstract:
This study compared and contrasted fine root and fungal biomass production estimates using sand-filled in-growth bags, native-soil-filled in-growth bags, and sequential soil cores in xeric, mesic, and hygric stands of 50-year-old Douglas-fir on Vancouver Island. Although no significant differences in overstorey fine-plus-small (≤5 mm) root production could be found between the three sites, proportional allocations of net primary production to the belowground ecosystem decreased with increasing site productivity. The total annual overstorey biomass production on the low-productivity xeric site was 15.7 t ha⁻¹ yr⁻¹. Of this total, 26.5 percent was allocated to belowground components. On the mid-slope mesic site, total overstorey biomass production increased to 22.9 t ha⁻¹ yr⁻¹, while allocation to the belowground decreased to 24.5 percent. On the high-productivity hygric site, total overstorey production increased to 25.0 t ha⁻¹ yr⁻¹, of which the belowground component represented 20.0 percent.
Large differences were found in the estimates of standing crop of roots between in-growth bags and sequential soil cores. Estimates of annual fine root production, however, were much more similar for native-soil-filled in-growth bags and sequential soil cores.
The quality of growth medium within the in-growth bags was also found to have a significant effect on estimates of standing crop and annual production of roots. Greater amounts of root biomass were found in the in-growth bags which contained nutrient-rich growth media.Forestry, Faculty of
Graduate
21
Klinka, Karel, D. Bradley Collins, and Christine Chourmouzis. "Investigation into the productivity of single- and mixed-species, second-growth stands of western hemlock and western redcedar." Forest Sciences Department, University of British Columbia, 2001. http://hdl.handle.net/2429/698.
Full textAbstract:
In BC, it is required that harvested areas be regenerated with a mixture of tree species whenever appropriate to the site. This policy is based upon the assumption that increases in stand productivity, reliability, and/or biodiversity can be achieved in mixed-species stands. However, the knowledge justifying this policy is at best incomplete.
Differences in forest productivity of mixed-species stands have been attributed mostly to competition. However, an increasing number of studies are providing evidence to support alternate theories, in which positive plant interactions play a major role. Positive plant interactions are divided into two components: (i) competitive reduction through structural and physiological differences in above and below ground structures, and (ii) facilitation through any positive effect on the growing environment of one plant species by another. These theories have yet to be tested in forest ecosystems. The objectives of this study, with respect to naturally established, unmanaged, second-growth stands of western hemlock (Hw) (Tsuga heterophylla (Raf.) Sarg.), western redcedar (Cw) (Thuja plicata Donn ex D. Don in Lamb.), and their mixtures, were: (1) to review the mechanisms of positive plant interactions and their potential to occur in these mixtures, and (2) to compare the productivity of these three stand types, using relative and absolute yield.
22
Jacob, Andreas Verfasser], Christoph [Akademischer Betreuer] Leuschner, and Dirk [Akademischer Betreuer] [Hölscher. "Effects of tree species composition on fine root biomass and dynamics in the rhizosphere of deciduous tree stands in the Hainich National Park (Thuringia) / Andreas Jacob. Gutachter: Christoph Leuschner ; Dirk Hölscher. Betreuer: Christoph Leuschner." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2013. http://d-nb.info/1044871601/34.
Full text
23
Paschlau, Helmut F. [Verfasser], Dietmar Akademischer Betreuer] Matthies, Frank-Martin [Akademischer Betreuer] Belz, and Martin [Akademischer Betreuer] [Moog. "Kurzumtriebsplantagen : Stand der Umsetzbarkeit, Organisation und ein Modell zur ökonomischen Bewertung von Produktion und Bereitstellung schnell wachsenden Holzes aus Kurzumtriebsplantagen als biogener Festbrennstoff für Biomasse(heiz)kraftwerke in Bayern / Helmut Paschlau. Gutachter: Dietmar Matthies ; Frank-Martin Belz ; Martin Moog. Betreuer: Martin Moog." München : Universitätsbibliothek der TU München, 2011. http://d-nb.info/1014861772/34.
Full text
24
Wong, Ann Yone. "Relationships between coastal Douglas-fir stand biomass and stand characteristics." Thesis, 2002. http://hdl.handle.net/2429/13042.
Full textAbstract:
The purpose of the study was to investigate how the above-ground tree biomass components
(stem, branches, and foliage) and the ratios between these biomass components change with age,
site quality, initial spacing, and total stand volume. The species studied was coastal Douglas-fir
(Pseudotsuga menziesii (Mirb.) Franco). To examine stands of various stand characteristics,
virtual stands were generated from the Tree and Stand Simulator (TASS), a provincial growth
and yield model. The stands ranged in site index (height at 50 years breast-height age) from 20
to 40 m at 5 m site index intervals, initial plant spacing of 1.0 to 5.0 m at 0.5 m spacing intervals,
and from 10 to 200 years at 10-year intervals, for a total combination of 900 stands. Published
tree biomass equations from the Pacific Northwest were applied to these generated stands to
produce a stand-level biomass estimate for each stand. Stand-level biomass regressions were
also developed from the modelled stands. Over the modelled 200-year horizon, stand-level stem
and branch biomass is expected to increase, whereas foliage biomass is predicted to increase then
plateau or peak then decline. At a given age, predicted biomass was higher for denser stands and
richer sites. However, for a given total stand volume and initial spacing, predicted biomass was
slightly higher for poor sites. At a given volume, more dense stands also had lower predicted
stem and branch biomass, and higher predicted foliage biomass. In terms of the proportion ratios
among components of biomass, the proportion of foliage and branch biomass in total
aboveground tree biomass over time was predicted to decrease then plateau, whereas the
proportion of stem biomass was predicted to increase then plateau. For a given stand volume,
denser stands had proportionally less predicted above-ground tree biomass in stem biomass and
proportionally more in foliage and branch biomass. From the stand-level biomass regression
analysis, it was found that in addition to total stand volume, other stand variables, especially
basal area, improved the predictive abilities of the stand-level biomass equations.
25
Chen, Yu-Kang, and 陳羽康. "Biomass and Stand Structure of Taiwania cryptomerioides." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/45003082957408741039.
Full textAbstract:
碩士國立屏東科技大學
森林系所
98
The greenhouse has been aggravating the Earth, and therefore it is very important to reduce carbon dioxide emissions. Trees have excellent organism of carbon sequestration. Taiwania cryptomerioides Hayata is common plantation species in Taiwan. The purpose of this study was to analyze the basic data of T. cryptomerioides biomass and realize the forest structure and stock of biomass. Based on DBH distribution of stand, the data of this research was gathered from 62 sample trees from Forestry Bureau permanent plots around the island, and the estimation of aboveground biomass was learned by the results of stem analysis. From the date of 43 permanent sample plots from 1997 to 2007, this study was built to fit models of site index and stand structure. Regarding regression models of aboveground biomass, the best model was with the use of DBH and tree height as independent variables and the second-best one was with the use of DBH as a single independent variable. Both showed that R2 is at least 0.9. The result of stand structure said that in stand at an regular growth rate of above 50%, distribution of central tendency decreased and tended towards normality because the smallest DBH increased. In Weibull function, the three parameters all increased in good stand. On the contrary, they rarely changed in stand at negative growth rate. As the result, it is meaningful to survey plantation, build database, and estimate the biomass of stand.
26
Yu, Li-Yu, and 游麗玉. "Biomass and Nutrient Accumulation of Makino Bamboo stand in ental Forest Station." Thesis, 1995. http://ndltd.ncl.edu.tw/handle/96831439754673047663.
Full textAbstract:
碩士國立中興大學
森林學系
83
The purpose of this study is to investigate the aboveground biomass and nutrient accumulation of unmanaged careful makino bamboo (Phyllostachys makinoi) stands in Hui-Sun Experimental forest station. Sample trees were selected from different DBH classes, using the stratified clip method, to obtain the growth parameters, dissected structure, and volume. And then use the allometric method to estimate the stand biomass. The results show that the stand density is 17,445 culms/ha. The new culms of 1-year-old is about 5.1% and the old culms of over 5-year- old (inculding 5-year-old) is about 36.3% respectively of the culms in the whole stand. The new culms produced after 9 months of clear cutting are exceeding. The biomass of underground rhizome distribute mainly in of 0- 20 cm depth, and lesser in 20-40cm layer. The distribution of rhizome beneath 40cm depth is very few. The volume of this bamboo stand is about 41.26 m3/ ha estimated by allometry method. The aboveground biomass is about 44.26 ton/ha, and underground biomass is 40.12 ton/ha. The ratio of biomass for clums : branches : leaves is 75:19:6. The nutrient accumulation of aboveground component is mostly in culms. The nutrent content in branches and leaves is changed by age. The amount of underground nutrient accumulation is largest for Nitrogen. The next is Postassium, and followed by P, Na, and Mg.
27
Shun-Fan, Yang, and 楊順帆. "Comparisons of Above-ground Biomass and Carbon Storage between A Seven-year-old Reforestation Stand and Nearby Leucaena leucocephala Stand in Kenting Area." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/88524664863460905026.
Full textAbstract:
碩士國立屏東科技大學
森林系所
101
Forests are capable of absorbing carbon dioxide. Thus, establishing new forest stands can achieve the benefits of carbon reduction. This research investigated above-ground biomass and carbon storage of a 7-year-old reforestation stand, a plantation after the removal of Leucaena leucocephala, in Kenting, Pingtung. Comparisons were made with a nearby L. leucocephala stand to understand the benefits of carbon reduction. The density of five planted tree species, namely Terminalia catappa, Acacia confusa, Millettia pinnata, Casuarina equisetifolia, and Cerbera manghas, were 1,056, 512, 440, 356, and 260 stem ha-1, respectively. These summed to a total of 2,624 stem ha-1. The nearby L. leucocephala stand had a high density of 11,160 stem ha-1, which is more than tripled than the reforestation stand. Above-ground biomass was 8.73, 7.39, 12.44, 0.79, and 1.46 Mg ha-1, and carbon storage was 3.78, 3.60, 5.75, 0.37, and 0.59 Mg ha-1 for T. catappa, A. confusa, M. pinnata, Cas. equisetifolia and Cer. manghas, respectively. In total, this reforestation stand had above-ground biomass of 30.81 Mg ha-1 and carbon storage of 14.1 Mg ha-1, while the control L. leucocephala stand had above-ground biomass of 28.3 Mg ha-1 and carbon storage of 11.03 Mg ha-1. After 7 years’ growth, the reforestation stand showed 9% and 28% more in above-ground biomass and carbon storage, respectively, than the L. leucocephala stand. In conclusion, carbon storage in the 7-year-old reforestation stand could increase 3.1 Mg than that in the L. leucocephala stand. This is the benefits of carbon reduction of this reforestation stand.
28
Chen, Kai-Shin, and 陳凱欣. "Estimation of biomass and canopystructure in a yellow cypress stand ofYung-Yang Lake forest ecosystem." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/43565328149290563460.
Full textAbstract:
碩士國立東華大學
自然資源管理研究所
93
The objective of this study was to estimate the aboveground biomass and to analyze the canopy structure of a naturally regenerated yellow cypress (Chamaecyparis obtusa var. formosana) forest in Yuanyang Lake (YYL) site. Eight trees of difference size classes were selected and destructive methods were applied. The results showed high correlations among DBH, tree height, number of branch, and crown profile of these trees, but not for living clear height. The biomass of leaf, branch and stem increased as DBH increased. The leaf, branch and stem components and total biomass of this stand were 12.3(13.9％), 13.5(15.4％), 62.2(70.7％), and 88.0 ton ha-1 , respectively. The biomass fraction of stem was much higher than that of leaf and branch. The biomass of leaf and branch were concentrate of in the upper or middle parts of the crown. The branch density decreased vertically. The horizontal and vertical dimensions of the primary branches increased from the apex downwards, and reached a maximum around the crown base for the horizontal component and around the middle of the crown for the vertical component. The inclination of the branch relative to the horizontal plane showed a poor correlation with tree height. Cumulative leaf mass increased with distance from the crown apex in the upper part of the crown, but the increase was less in the lower part of the crown. The leaf weight can be used to discriminate upper and lower crown by maximum leaf density distribution. The branches were not evenly distributed in every direction. The direction of the branches varied with sample trees. Uaing hemispherical photography, the average leaf area index of the study site in 2004 was 5.93. There was little seasonal in mean leaf area index of the stand, but varied a lot for some plots at the study site.
29
Gries, James F. "Biomass and net primary production for a northern hardwood stand developmental sequence in the Upper Peninsula, Michigan." 1995. http://catalog.hathitrust.org/api/volumes/oclc/35105724.html.
Full textAbstract:
Thesis (M.S.)--University of Wisconsin--Madison, 1995.Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 22-28).
30
Grenkow, Laryssa. "Effect of seed-placed phosphorus and sulphur fertilizers on canola plant stand, early season biomass and seed yield." 2013. http://hdl.handle.net/1993/22150.
Full textAbstract:
Seed-placed phosphorus (P) and sulphur (S) fertilizers can reduce canola plant stands. Field studies were conducted to determine the effect of various sources and rates of seed-placed P and S fertilizers on canola plant stand, early season biomass accumulation and seed yield. Conventional granular P and S blends increased the risk of seedling damage, but increased the frequency of yield response. Liquid fertilizers were similar in seedling damage but generally less effective in increasing seed yield compared to granular fertilizers. Novel fertilizers were more seed-safe but less reliable than conventional sources in increasing seed yield. A growth room experiment was conducted to determine the effect of soils from different landscape positions on the toxicity of seed-placed ammonium sulphate (AS) and monoammonium phosphate (MAP). Canola emergence was reduced and delayed by seed-placed MAP and AS. Ammonium sulphate in particular has a high risk of NH3 toxicity on calcareous hilltop soils
31
Cheng, Ching-Peng, and 鄭景鵬. "Study of the impact of Plantation Environment on the Stand Structure, Growing Stock, and Biomass of Pinus taiwanensis." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/30625212224925509346.
Full textAbstract:
碩士國立嘉義大學
森林暨自然資源學系研究所(Graduate Institute of F
98
This research focuses on the influence on stand structure, volume stock, and biomass stock in Yushan working cirde and Chrishan working cirde through the measure of permanent plot, stem analysis, biomass analyze, and dendrochronology. According to the theory of volume rotation, this research estimates the productivity on the 20th, 40th, and 45th of Yushan working cirde and Chrishan working cirde. It indicates that under the influence of integrated habitat environmental factors, the stand structure, volume stock, and the potential capacity of biomass stock are continuing changing with the time pass by. On the other hand, Weibull 3- parameter probability density function could effectively indicates the distribution of the DBH-class between these two working cirde. The DBH-class could also be calculated the volume stock and the biomass stock. The stand structure of Chrishan working cirde is positively-skewed type, and the volume stock and the biomass stock were 379.77 m3 and173.37 ton. And the Yushan working cirde was approximately normal distribution. The volume stock and the biomass stock are 687.23 m3 and318.23 ton. The percent of the leaf biomass of sample extends with the sample’s DBH-class, and the moisture of bark and branches declined with the DBH-class. The total of the stem and branches is 98.85% of the above ground biomass. According to internal growth analysis, the Pinus taiwanensis in Yushan working cirde of age 32 is the highest production rate. The growing average of the volume stock and biomass stock are 15.3 m3 and 7.1 ton. And the highest production rate of standing tree in the Chrishan working cirde is on the age of 22th, and the average of the volume stock and biomass stock are 10.0 m3 and 4.6 ton. By the relation between the growing and climate on tree ring of Pearson correlation coefficient analyze, the results indicates that the precipitation in September and the temperature in May, July, and August affect the standing tree of tree ring of Pinus taiwanensis that in Yushan working cirde most. The precipitation in July and the temperature in February and May affect the standing tree of tree ring of Pinus taiwanensis that in Chrishan working cirde most. The productivity of the plantation changes with the environments day by day. The site index would describe a special species of potential capacity of timeber production. The volume retation of 20th indicates the Chrishan working cirde has better yield. And the volume retation of 40th indicates the Yushan working cirde has better yield.
32
Oliveira, Tânia Sofia Moreira de Paiva de Almeida. "Sistema para a predição de biomassa aérea total e por componentes em povoamentos puros regulares de Eucalyptus globulus Labill." Master's thesis, 2008. http://hdl.handle.net/10400.5/1056.
Full textAbstract:
Mestrado em Engenharia Florestal e dos Recursos Naturais - Instituto Superior de AgronomiaThe growing need for information about carbon stocks and sequestration by forests has made forest biomass estimation a relevant issue, far more important in the case of fast growing and intensively managed species such as Eucalyptus globulus Labill.. Several methods have been used to estimate the existing biomass at stand level, but using data resulting from forest inventories is simpler and easily applicable. This thesis, starting from the work already developed for the Globulus 3.0 model, developed two systems of allometric equations for predicting total aboveground biomass and the different biomass components for Eucalyptus globulus Labill. guarantying the equality of the estimate of total aboveground biomass with the sum of the estimates for the different biomass components. The systems use as regressors just stand variables that are usually a result of forest inventories so that they can be easily applicable .
33
Du, Toit Ben. "Effects of site management on nutrition, sustainability and productivity in a Eucalyptus Grandis stand in South Africa." Thesis, 2008. http://hdl.handle.net/10539/5323.
Full text
34
Veselský, Marek. "Biomass estimation of European beech stands." Master's thesis, 2017. http://www.nusl.cz/ntk/nusl-431226.
Full textAbstract:
Forest ecosystems plays an important role in the global carbon cycle of carbon sinks of terrestrial ecosystem. Carbon sequestered or stored in forest trees is mostly referred to as the biomass of tree, site or forest. This diploma thesis deals with biomass estimation of European beech stands at the Holíkov (the Drahanská vrchovina Highlands) and Štítná nad Vláří (the Bílé Karpaty Mts.) study sites in the Czech Republic. Study was conducted in the period of 2010 to 2015. 65 allometric equations were tested for the purpose of determining the most suitable candidate for the estimation of aboveground and belowground biomass of stands and of all the major tree compartments. It is obvious from the results that the allometric equations performed very differently from each other. It was also found, based on the obtained results, that the most suitable allometric equations for the study sites are by Vejpustková et al. 2013 and Wutzler et al. 2008.
35
Γκόπης, Χρήστος, and Βάιος Βαϊνάς. "Ανάλυση υβριδικού συστήματος ηλεκτροπαραγωγής με ΑΠΕ." Thesis, 2012. http://hdl.handle.net/10889/5240.
Full textAbstract:
Η διπλωματική εργασία που ακολουθεί, παρουσιάζει τη μελέτη και μοντελοποιήση ενός αυτόνομου υβριδικού συστήματος. Το αυτόνομο σύστημα που εξετάζεται είναι ένα υβριδικό σύστημα ηλεκτροπαραγωγής που αποτελείται από ένα φωτοβολταϊκό πάρκο, μία ανεμογεννήτρια, μία μονάδα υδρογόνου και δύο γεννήτριες βιομάζας και φυσικού αερίου. Για την μοντελοποίηση του συστήματος χρησιμοποιείται το πρόγραμμα σχεδιάσης και προσομοίωσης ηλεκτρικών συστημάτων PSCAD.
Στην εργασία αυτή το ενδιαφέρον εστιάζεται στη συμπεριφορά του συστήματος στη μόνιμη κατάσταση λειτουργίας και στη συμπεριφορά σε κάποια μεταβατικά φαινόμενα.
Τα μεταβατικά φαινόμενα που εξετάζονται είναι τα εξής:
- Βραχυκύκλωμα των τριών φάσεων ως προς γη στο ζυγό της σύγχρονης γεννήτριας φυσικού αερίου
- Συμπεριφορά συστήματος σε απότομη αποσύνδεση της ανεμογεννήτριας
- Συμπεριφορά συστήματος σε διακοπή παροχής ρεύματος στην μονάδα υδρογόνου από το Φ/Β πάρκο
Στο Κεφάλαιο 1 γίνεται μία γενικότερη αναφορά στο Φ/Β σύστημα.
Στο Κεφαλαιο 2 γίνεται μία γενικότερη αναφορά στην αιολική ενέργεια.
Στο Κεφάλαιο 3 γίνεται μία γενικότερη αναφορά στο υδρογόνο.
Στο Κεφάλαιο 4 γίνεται μία γενικότερη αναφορά στην βιομάζα.
Στο Κεφάλαιο 5 γίνεται μία γενικότερη αναφορά στο φυσικό αέριο.
Στο Κεφάλαιο 6 γίνεται μία γενικότερη αναφορά στις σύγχρονες μηχανές και στο μαθηματικό τους υπόβαθρο.
Στο Κεφάλαιο 7 περιγράφεται η δομή και τα στοιχεία που αποτελούν το αυτόνομο υβριδικό δίκτυο ηλεκτροπαραγωγής στο περιβάλλον του προγράμμματος μοντελοποιήσης, του PSCAD και παρουσιάζονται τα μοντέλα που απαρτίζουν το συνολικό σύστημα.
Στο Κεφάλαιο 8 εξετάζεται η συμπεριφορά του συστήματος στη μόνιμη κατάσταση λειτουργίας.
Στο Κεφάλαιο 9 εξετάζεται η συμπεριφορά του συστήματος στα τρία μεταβατικά φαινόμενα που έχουν προαναφερθεί, στο βραχυκύκλωμα των τριών φάσεων ως προς γη στο ζυγό της σύγχρονης γεννήτριας φυσικού αερίου, στην απότομη αποσύνδεση της ανεμογεννήτριας και στην διακόπη παροχής ρεύματος στην μονάδα υδρογόνου.The thesis that follows, presents the study and the modelling of an autonomous hybrid system. The autonomous system that is examined is an electricity generating hybrid system that constists of a photovoltaic system, a wind generator, a hydrogen unit, a biomass generator and a natural gas generator. For the modelling of the system a designing and simulation program is used known as PSCAD. The main course of the current subject is the behavior of the system in the permanent situation of operation and the behavior of it in certain transient states. The transient states that are examined are the following: - Short-circuit of the three phases as for the ground on the natural gas generator bus. - Behavior of system in abrupt detachment of wind generator. - Behavior of system in abrupt detachment of the hydrogen unit. In Chapter 1 follows a theoretical analysis of the PV system. In Chapter 2 follows a theoretical analysis of the wind generator. In Chapter 3 follows a theoretical analysis of the hydrogen unit. In Chapter 4 follows a theoretical analysis of the biomass. In Chapter 5 follows a theoretical analysis of the natural gas. In Chapter 6 follows a theoretical and mathematical analysis of the synchronous machines. In Chapter 7 we describe the structure and the elements that constitute the autonomous hybrid system of electric generation in the environment of PSCAD. Also, the models that compose the total system are shown. In Chapter 8 is examined the reaction of system in the permanent situation of operation. In Chapter 9 is examined the reaction of system in the three transient states that have been mentioned before.
36
ŠOBROVÁ, Martina. "Vliv různých způsobů obhospodařování na porostovou skladbu a produkci biomasy travního porostu." Master's thesis, 2014. http://www.nusl.cz/ntk/nusl-174549.
Full textAbstract:
This thesis summarizes the results obtained from a study of long-term field trials with permanent grassland, which based on Faculty of Agriculture, University of South Bohemia in the České Budějovice between years 2010 - 2013. Permanent grasslands are managed in different ways (mowing, mulching, fallow) and the intensity of exploitation (harvested 1 - 3 times a year, fertilization). The work was focused on the evaluation of changes in growth composition, biomass production and dry matter content of hay variants. Also were evaluated biodiversityand grazing value of the crop stand. Before each harvest (mowing or mulching) was evaluated growth composition of experimental grasslands on an area of 20 m2. Plant species coverage of individual agro botanical groups was estimated by the reduced projective dominance (% D). Harvested biomass of grassland was considered and sample mown every variantof the experiment was dried (dry matter content). Species diversity was expressed as the number of species and species diversity was expressed in the form of Simpson's index. It was also calculated value describing the quality and productivity ofthe crop stand.
37
De, los Santos-Posadas Hector Manuel. "From branches to crown development of crown biomass models for intensively treated stands of loblolly pine with mixed effects models /." 2003. http://purl.galileo.usg.edu/uga%5Fetd/de%5Flos%5Fsantos-posadas%5Fhector%5Fm%5F200305%5Fphd.
Full text
38
Gyawali, Nabin. "Aboveground biomass partitioning due to thinning in naturally regenerated even-aged shortleaf pine (Pinus echinata Mill.) stands in southeast Oklahoma." 2008. http://digital.library.okstate.edu/etd/umi-okstate-2846.pdf.
Full text
39
Westbrook, Michael D. "Forest biomass recovery by adding small chippers to tree-length harvesting systems in planted pine stands of the southern USA." 2008. http://purl.galileo.usg.edu/uga%5Fetd/westbrook%5Fmichael%5Fd%5F200805%5Fms.
Full text
40
Ruark, Gregory A. "Biomass, net primary production, and nutrient distribution in successionary Populus tremuloides michx. stands on an entic harlorthod in north-central Wisconsin." 1985. http://catalog.hathitrust.org/api/volumes/oclc/13388174.html.
Full text
41
Jacob, Andreas. "Effects of tree species composition on fine root biomass and dynamics in the rhizosphere of deciduous tree stands in the Hainich National Park (Thuringia)." Doctoral thesis, 2012. http://hdl.handle.net/11858/00-1735-0000-0001-BC6B-D.
Full text
42
Bagherzadeh, Chaharjouee Ali. "Mechanisms of Carbon and Nitrogen transformations in Forest floors of Beech-, Spruce- and Mixed Beech-Spruce Stands." Doctoral thesis, 2004. http://hdl.handle.net/11858/00-1735-0000-0006-B108-0.
Full text