Buildings are one of the major consumers of energy and make up a considerable portion in the generation of greenhouse gases. Green roofs are regarded as an appropriate strategy to reduce the heating and cooling loads in buildings. However, their energy performance is influenced by different design parameters which should be optimized based on the corresponding climate zone. Previous investigations mainly analyzed various design parameters in a single climate zone. However, the interaction of parameters in different climate zones was not considered. Also, the studies have been conducted mostly for commercial or residential buildings. Among different building types, schools with large roof surface are one of the major consumers of energy in North America. However, the literature review shows the lack of study on the effect of green roof on the thermal and energy performance of this type of building. This study performs a comprehensive parametric analysis to evaluate the influence of the green roof design parameters on the thermal or energy performance of a secondary school building in four climate zones in North America (i.e. Toronto, ON; Vancouver, BC; Las Vegas, NV and Miami, FL). Soil moisture content, soil thermal properties, leaf area index, plant height, leaf albedo, thermal insulation thickness and soil thickness were used as variables. Optimal parameters of green roofs were found to be closely related to meteorological conditions in each city. In terms of energy savings, the results show that the light substrate has better thermal performance for the uninsulated green roof. Also, the recommended soil thickness and leaf area index in the four cities are 0.15 m and 5, respectively. The optimal plant height for the cooling dominated climates is 0.3 m and for the heating dominated cities are 0.1 m. The plant albedo had the least impact on the energy consumption while it is effective in mitigation effect of heat island effect. Finally, unlike the cooling load which is largely influenced by the substrate and vegetation, the heating load is considerably affected by the thermal insulation instead of green roof design parameters. / Graduate

This study examined leaf area index (LAI) and relationships with corresponding tree growth, climate and soil characteristics across New Zealand forest plantations. The aim of this study was to determine if quick measures of projected leaf area across environmental gradients of New Zealand were an accurate indicator of site quality. Projected leaf areas of Pinus radiata D Don and Cupressus lusitanica Mills seedlings were measured using a Li-Cor LAI-2000 plant canopy analyser at 22 locations representing the soil and climatic diversity across New Zealand plantation forests. Seedlings planted at 40 000 stems per hectare were used to test treatment effects of fertiliser, site disturbance and species over a 4 year period. It was hypothesised that collected climate and soil information would explain differences in LAI development patterns across sites as the canopies approached site and seasonal maxima. Averaged across sites Cupressus lusitanica 7.28 (± 2.59 Std.) m2 m-2 had significantly (p = 0.0094) greater projected LAIs than Pinus radiata 6.47 (± 2.29) m2m-2. Maximum site LAI (LAImax) varied from 2.9 to 11.8 m2 m-2 for Pinus radiata and from 3.1 to 12.6 m2 m-2 for Cupressus lusitanica. LAImax of both species was significantly and positively correlated with vapour pressure deficit, soil carbon, nitrogen, phosphorous and CEC, but negatively with solar radiation, temperature and soil bulk density. A seasonal model of LAI across sites illustrated an 8.5% fluctuation in LAI of established canopies over the course of a year. Despite considerable variation in climate and soil characteristics across sites the combined effects of LAI at harvest and temperature were significantly correlated with site productivity (r2 = 0.84 and 0.76 for Pinus radiata and Cupressus lusitanica respectively). A national model of LAImax (r2 = 0.96) was proposed for Pinus radiata across climate and soil environments and the significance of LAImax as a component of site quality monitoring tools is discussed.

Field experiments were conducted in Kentucky and Louisiana in 2008 and 2009 (split-plot in a randomized complete block design with four replications) to investigate it is possible to simulate with manual defoliation the effect of soybean rust (SBR) (Phakopsora pachyrhizi Syd. and P. Syd) injury on a healthy soybean [Glycine max, (L.) Merr.] canopy, understand how defoliation affects the growth dynamics and canopy light interception, and if defoliation affectsleaf senescence and nitrogen remobilization during the seed-filling period. Two manual defoliation treatments based on changes in effective leaf area index (ELAI) (calculated as the reduction in leaf area equivalent to SBR-induced premature leaf abscission, loss in green leaf area, and reduction in photosynthetic capacity of diseased leaves) in infected canopies in Brazil were used to simulate SBR infection at growth stage R2 (full flowering) and R5 (beginning of seed-fill). Both defoliation treatments reduced yield in all experiments and the reduction was larger for the treatments at growth stage R2. The yield losses were equivalent to that observed in infected soybean canopies in Brazil. This suggests that a system of manual defoliation to simulate changes in effective leaf area duration shows promise as a tool to simulate the impact of SBR on soybean yield. The radiation use efficiency and crop growth rate from growth stage R2 to R5 were not influenced by defoliation. Defoliation started at growth stage R2 reduced seed number per unit area, while defoliation started at growth stage R5 reduced seed size due to shortening the seed-fill duration and a lower seed growth rate. There is no evidence that manual defoliation affected leaf senescence or nitrogen redistribution to the seed. This study found that the reduction of light interception by SBR was the main reason for the reductions in soybean growth and yield.

The number one highest growth-limiting factor in Swedish forests is nitrogen, because of that fertilization often gives a significant growth increase, wherever you are in Sweden. Specific leaf area (SLA) can be used as a standard measurement of how much resources a tre has to use to build up light absorbing leaf area of needles/leaves. Since there is a strong linear relationship between tree growth and leaf area, there should also be a clear correlation between each leaf area of single trees and its diameter, basal area and volume growth (Xiao, 2005).The datamaterial for the study was collected at the forest estate, Toftaholm, near Ljungby in Kronoberg County (57 ° 0´N; 14 ° 3`E). Data were collected from birches growing in both in fertilized and unfertilized young stands of Birch during the growing season of 2018. The biomass sampling occured in May, July and August. At each occasion, samples were taken from 40 birches (a total of 120 samples were collected).The average value of SLA for all samples on the fertilized treatment was 17.33 m² / kg and 16.41 m² / kg for the non-fertilized treatment (Figure 4). The significance analysis obtained a p-value of 0.019 (Table 2), which confirms that there is a significant difference between the fertilized and the unfertilized treatment.In the significance analysis, it could be concluded that with a 95% probability, there is a significant difference between the comparison of all samples from the fertilized (G) and non-fertilized (OG) treatment.

Leaf Area Index (LAI) is an important input variable for forest ecosystem modeling as it is a factor in predicting productivity and biomass, two key aspects of forest health. Current in situ methods of determining LAI are sometimes destructive and generally very time consuming. Other LAI derivation methods, mainly satellite-based in nature, do not provide sufficient spatial resolution or the precision required by forest managers. This thesis focused on estimating LAI from: i) height and density metrics derived from Light Detection and Ranging (LiDAR); ii) spectral vegetation indices (SVIs), in particular the Normalized Difference Vegetation Index (NDVI); and iii) a combination of these two remote sensing technologies. In situ measurements of LAI were calculated from digital hemispherical photographs (DHPs) and remotely sensed variables were derived from low density LiDAR and high resolution WorldView-2 data. Multiple Linear Regression (MLR) models were created using these variables, allowing forest-wide prediction surfaces to be created. Results from these analyses demonstrated: i) moderate explanatory power (i.e., R2 = 0.54) for LiDAR models incorporating metrics that have proven to be related to canopy structure; ii) no relationship when using SVIs; and iii) no significant improvement of LiDAR models when combining them with SVI variables. The results suggest that LiDAR models in boreal forest environments provide satisfactory estimations of LAI, even with low ranges of LAI for model calibration. On the other hand, it was anticipated that traditional SVI relationships to LAI would be present with WorldView-2 data, a result that is not easily explained. Models derived from low point density LiDAR in a mixedwood boreal environment seem to offer a reliable method of estimating LAI at a high spatial resolution for decision makers in the forestry community. / Thesis (Master, Geography) -- Queen's University, 2012-09-24 16:18:09.96

No description available.

Thesis (Ph. D.)--Oregon State University, 2010. / Printout. Includes bibliographical references (leaves 160-172). Also available on the World Wide Web.

The increasing interest of modeling global carbon cycling during the past two decades has driven this research to map leaf area index (LAI) at multiple spatial resolutions by combining LAI field observations with various sensor images at local, regional, and global scale. This is due to its important role in process based models that are used to predict carbon sequestration of terrestrial ecosystems. Although a substantial research has been conducted, there are still many challenges in this area. One of the challenges is that various images with spatial resolutions varying from few meters to several hundred meters and even to 1 km have been used. However, a method that can be used to collect LAI field measurements and further conduct multiple spatial resolution mapping and accuracy assessment of LAI is not available. In this study, a pilot study in a complex landscape located in the Southern Illinois was carried out to map LAI by combining field observations and remotely sensed images. Multi-scale mapping and accuracy assessment of LAI using aerial photo, Landsat TM and MODIS images were explored by developing a multi-scale sampling design. The results showed that the sampling design could be used to collect LAI observations to create LAI products at various spatial resolutions and further conduct accuracy assessment. It was also found that the TM derived LAI maps at the original and aggregated spatial resolutions successfully characterized the heterogeneous landscape and captured the spatial variability of LAI and were more accurate than those from the aerial photo and MODIS. The aerial photo derived models led to not only over- and under-estimation, but also pixilated maps of LAI. The MODIS derived LAI maps had an acceptable accuracy at various spatial resolutions and are applicable to mapping LAI at regional and global scale. Thus, this study overcame some of the significant gaps in this field.

Submitted by SAULO STRAZEIO CARDOSO null (strazeio@yahoo.com.br) on 2016-05-30T13:30:04Z No. of bitstreams: 1 Tese_Saulo_Strazeio_Cardoso_2016.pdf: 1108227 bytes, checksum: 7a20eb4027477bb234b8c00a9a50f02f (MD5) / Approved for entry into archive by Ana Paula Grisoto (grisotoana@reitoria.unesp.br) on 2016-05-31T14:06:10Z (GMT) No. of bitstreams: 1 cardoso_ss_dr_jabo.pdf: 1108227 bytes, checksum: 7a20eb4027477bb234b8c00a9a50f02f (MD5) / Made available in DSpace on 2016-05-31T14:06:10Z (GMT). No. of bitstreams: 1 cardoso_ss_dr_jabo.pdf: 1108227 bytes, checksum: 7a20eb4027477bb234b8c00a9a50f02f (MD5) Previous issue date: 2016-04-29 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Apesar de sua importância, ainda há uma escassez com relação a estudos relacionados à nutrição mineral de forrageiras, especialmente trabalhos sobre a adubação potássica. Assim, o objetivo desse trabalho foi avaliar os efeitos da adubação potássica em diferentes solos, nas concentrações de K na parte aérea, área foliar e produção de massa seca do capim-marandu. O delineamento experimental empregado foi inteiramente casualizado em esquema fatorial 5 x 5, constituído por cinco solos (Nitossolo Vermelho eutroférrico latossólico, Latossolo Vermelho distrófico típico, Chernossolo Argilúvico Órtico abrúptico saprolítico, Argissolo Vermelho-Amarelo eutrófico típico e Neossolo Quartzarênico Órtico típico) e cinco doses de K (0; 30; 60; 120 e 180 mg kg-1) aplicadas antes do plantio das forrageiras. Em intervalos de aproximadamente 30 dias (crescimento), a parte aérea das plantas eram colhidas, totalizando sete crescimentos sucessivos. Em cada crescimento foi avaliado a concentração de K na parte aérea, área foliar e produção de massa seca. Os solos estudados apresentaram capacidade diferenciada no fornecimento de K para as plantas, sendo maior nos MTor e menor no RQo. A adubação potássica promoveu incrementos significativos na concentração de K na parte aérea, na área foliar e na produção de massa seca do capim-marandu sendo mais evidente até o terceiro crescimento sucessivo das plantas. / Despite its importance, there is still a shortage of studies related to mineral nutrition of forage plants, especially on potassium fertilization. The aim of this study was to evaluate the effects of potassium fertilizer in different types of soils, the K concentrations in aerial part, leaf area and dry matter production of Marandu grass. The experimental design was completely randomized in a factorial 5 x 5 consisting of five soil types (Oxisol–Rhodic Eutrodox, Oxisol–Rhodic Hapludox, Argiluvic Chernosol Orthic Saprolite, Ultisol–Typic Hapladult and Typical Orthic Quartzarenic Neosol) and five K doses (0, 30, 60, 120 and 180 mg kg-1) applied before planting the forage plants. At intervals of approximately 30 days (growth), the shoots were harvested, making a total of seven consecutive growths. In each growth was evaluated the concentration of K in shoots, leaf area and dry matter production. The soils showed different ability in providing K for plants, being higher in mTOR and lower in RQo. Potassium fertilization promoted significant increases in the concentration of K in shoots, leaf area and dry matter production of Marandu grass, being more evident until the third successive plant growth.

Continental scale analysis of the savanna biome indicated that fire did not spread at tree canopy cover above 40%. This study investigates this relationship in a field study. It is possible that the type of tree (forest vs. savanna) may influence the amount of shade experienced by the understory and therefore this study also explores differences in LAI between congeneric pairs of forest and savanna tree species. Data were collected in two major South African savanna parks. Plots were set out to measure grass biomass in reference to canopy cover in both Kruger National Park (n=60) and the Hluhluwe-iMfolozi Game Reserve (n=82). Seven congeneric pairs were selected to compare leaf area and LAI between forest and savanna tree species using a destructive method. Against expectations, it was only when canopy cover reached 80% that grass fuel load was too low to support fire spread in all Kruger National Park plots (Pr=O) and 89% of the Hluhluwe-iMfolozi Game Reserve plots (Pr=0.11). No consistent, general relationships were evident with leaf area or LAI in comparisons between forest-savanna congeneric pairs. The significance of these findings and future direction is discussed.