While the southeastern United States, including the state of Mississippi, has a strong natural resource base, woody biomass is not fully utilized to produce bioenergy in this region. This study intended to explore opportunities, issues, and the economic potential of wood-based bioenergy in the state of Mississippi. Realizing the importance of private forest landowner decisions in sustaining a bioenergy feedstock supply, one aim of this study was to understand their choices for preferred harvesting methods of supplying woody biomass for wood-based bioenergy industries. Study results indicated that landowners were interested in optimizing revenue from woody biomass utilization while minimizing damage to the surrounding environment and facilitating less site preparation. Similarly, by administering a survey instrument, total and unused volumes of residues in primary and secondary mill operations were also estimated. Availability of woody residue was higher in the primary wood processing industry. Similarly, the likelihood of getting feedstock would be higher if a wood-based bioenergy generating facility could be located near a larger, year round operational forest product industry. This study further accounted for the potential direct, indirect, and induced economic impacts of a state wood-based bioenergy industry. Three potential wood-based bioenergy industries namely wood-pellet, bio-oil and methanol-based gasoline facilities were considered for an economic analysis. Study results revealed that operation of a wood-pellet industry would contribute 82 full- and part-time jobs to the economy with $12 million worth of economic output to the Mississippi economy. Likewise, the operation of a bio-oil industry would generate 165 new full- and part-time jobs and provide an economic output of $17 million. Also, $96 million in economic output and 795 full- and part-time more jobs would be added by establishing a methanol-based gasoline industry. Clearly, these impacts are substantial and are likely to draw the attention of policy makers and investors towards wood-based bioenergy in Mississippi.

Cranberry (Vaccinium macrocarpon Ait.) is a woody perennial crop that can remain productive for decades. Competition for resources between cranberries and weeds can depress cranberry farm yields, resulting in large annual crop losses. Renewed interest in reducing chemical inputs into cranberry systems has provided the motivation to evaluate methods, such as flame cultivation (FC), as potential nonchemical options for weed control. Also known as thermal weeding, FC exposes plants to brief periods of high temperature that causes the water in the plant tissue to expand rapidly, rupturing plant cells and leading to necrosis. Various FC methods have been used successfully in annual crops as both a preemergence and postemergence weed control, but few scientific reports have been published on the use of FC on perennial weeds in a woody perennial crop system. Dewberry (Rubus spp.), sawbrier (Smilax glauca), and common rush (Juncus effusus) are cranberry weeds that are difficult to control, spread quickly and can cause significant crop loss. Flame cultivation may be an effective non-chemical means for controlling these weeds in cranberry systems. FC would ideally be used as a spot treatment for weeds growing in the cranberry canopy, as well as on larger non-production areas where cranberry vines are not as abundant, such as bog edges, ditches, and dikes. Using FC to treat weeds within the cranberry canopy will likely cause localized damage to cranberry plants immediately surrounding the weeds, thus cranberry response to FC is also of interest. The following experiments were designed to examine the response of weeds and cranberry plants to FC. Perennial plants rely on reserves of nonstructural carbohydrates (NSC) for growth and survival, thus the efficacy of FC treatments to weeds will likely be impacted by the timing and frequency of treatments as they relate to the specific carbohydrate cycles of targeted weeds, such as dewberry. An additional experiment studied the seasonal fluctuations of NSC in dewberry roots. Cranberry growers were also surveyed on their past experiences with FC, as well as their willingness to adopt FC if proven an effective method for controlling weeds.

京都大学 / 新制・課程博士 / 博士(農学) / 甲第24656号 / 農博第2539号 / 新制||農||1097(附属図書館) / 学位論文||R5||N5437(農学部図書室) / 京都大学大学院農学研究科森林科学専攻 / (主査)教授 北山 兼弘, 教授 田中 千尋, 教授 松浦 健二 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DGAM

<p dir="ltr">Woody debris (WD) is an important element in forest ecosystems. It provides critical habitat for plants, animals, and insects; but it is also a source of fuel contributing to fire propagation and sometimes leads to catastrophic wildfire. Usually, WD inventory is conducted through field surveys using transects and sample plots. Light Detection and Ranging (LiDAR) point clouds are emerging as a valuable source for the development of comprehensive WD detection strategies. Although results from previous LiDAR-based WD detection approaches have been promising, there is still a lack of a general strategy for handling acquired point clouds by different platforms with varying characteristics (e.g., point density) in a complex environment, especially in natural forests. Here, we propose a general morphological WD detection strategy which requires a few intuitive thresholds, making it applicable to multi-platform LiDAR datasets in both plantation and natural forests. The conceptual basis of the strategy is that WD LiDAR points exhibit non-planar characteristics, distinct intensity, and comprise clusters that exceed a minimum size. The developed strategy is tested using leaf-off point clouds acquired by Geiger-mode, uncrewed aerial vehicle (UAV), and backpack LiDAR systems. The developed approach achieved an average recall of 0.83 indicating a low rate of omission errors. Datasets with higher point density (i.e., from UAV and backpack LiDAR) showed better performance. As for the precision evaluation metric, it ranges from 0.40 to 0.85, indicating a higher level of commission errors at the lower range. The commission errors depend on the presence of bushes and undergrowth, with a lower percentage in forest plantations.</p>

This study aimed at developing allometric equations for the estimation of aboveground biomass of black willow and eastern cottonwood and determine biomass production by these species under several planting spacing and harvest frequency combinations. Logarithmic model with dbh and tree height was the best fitting model for individual tree aboveground biomass estimation of both species. At area level, logarithmic models with stand age, dominant height, and planting density produced the best results. Mixed-effects modeling showed statistically significant effects of harvest frequency for eastern cottonwood but not for black willow. Overall, we conclude that, biomass production of black willow and eastern cottonwood would play a critical role in the fulfillment of the wood energy demands and biomass yields can be enhanced by considering management factors during plantation. These findings will be useful to forest owners in Lower Mississippi Alluvial Valley for estimating biomass without destructive sampling and have optimal biomass production.

Woody breast (WB) is a meat quality problem that has caused significant economic losses for the poultry industry. Ross × Ross 708 chicks were randomly assigned to a 3 (diet) × 2 (cocci challenge) × 2 (sex) factorial arrangement of treatments. The three diets included the control diet (corn-soybean meal basal diet), antibiotic diet (basal diet + 6.075 mg bacitracin /kg feed), and probiotic diet (basal diet + 2.2 × 108 CFU Bacillus subtilis PB6 /kg feed). Birds in the cocci challenge treatment group received 20 × the live cocci vaccine as an inoculum on d 14. Growth performance and WB score were measured to understand the effects of management factors (diet and coccidiosis) on broiler growth and WB development. Results indicated that dietary bacitracin and Eimeria spp. increased WB incidence, body weight, and growth rate. Bacillus subtilis increased WB incidence in male broilers without affecting body weight and growth rate. The association of the development of the internal organs and skeletal muscle with WB myopathy incidence in broilers were evaluated. The digestion organs (proventriculus and gizzard) and the skeletal muscles (drumsticks, thighs, and wings) developed at lower rates in birds with WB. In addition, the effects of the dietary and challenge interventions on the gut microbiota diversity and composition associated with WB in broilers were investigated. Results showed that cocci challenge altered gut microbiota composition and various biosynthetic pathways. Maintaining a healthy gut ecosystem is critical for the reduction of WB incidence in broilers. Gene expression related to oxidative stress, gut barrier function, and inflammation in jejunal mucus was investigated. Results showed that WB is related to decreased mucin expression (MUC6) in mucus, indicating a correlation between WB incidence and a lessening of the secretion of gel-forming mucin. In conclusion, dietary antibiotic and probiotic and challenge intervention strategies increased WB incidence, and microbiota composition and gut health gene expression differed in broilers exhibiting WB myopathy.

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This dissertation describes research investigating the potential for using Landsat data to identify and characterize woody canopy cover on reclaimed coal-mined lands through three separate studies. The objective of the first study was to assess whether surface coal mines in the forested central Appalachian regions of the US can be separated from the other prevalent forest-replacing disturbances through analysis of an interannual chronosequence of Landsat images. Disturbances were classified using descriptors of the disturbance/recovery trajectories: disturbance minimum, recovery slope and recovery maximum. Three vegetation indices (VIs) (normalized difference vegetation index, NDVI; tasseled cap greenness/brightness ratio, TC G/B; and inverse of Landsat band 3, B3I) were used to analyze multitemporal trajectories generated using both pixels and objects. Classification accuracies using objects were better than those obtained using pixels for all VIs. The highest object-based classification accuracy was achieved using TC G/B (89%), followed by NDVI (88%) and B3I (80%). The objective of the second study was to evaluate performance of a woody canopy cover (including both native and invasive species) estimation method based on the 2011 National Land Cover Database (NLCD) protocol for both mined and non-mined areas of the central Appalachians. Potential explanatory variables included raw and derived bands from leaf-on and leaf-off Landsat scenes plus terrain descriptors. Results show that the model developed to estimate canopy cover for mines (R2 = 0.78, Adj. R2 = 0.77, RMSE = 16%) is more robust than the models developed for non-mines, mixed, and all areas combined. The objective of the third study was to determine whether four disturbance/recovery parameters (recovery time, disturbance minimum, recovery slope, and recovery maximum), alone or in combination with variables identified in the second study, enable robust estimation of woody canopy cover on reclaimed surface coal mines. Of the disturbance/recovery parameters, only recovery time made a significant contribution to the model (R2 0.45, Adj. R2 0.44, RMSE 14%). Addition of leaf-on and leaf-off NDVI improved the R2 to 0.54 (Adj. R2 0.53, RMSE 13%). Analysis of Landsat data has strong potential for identifying reclaimed mines and characterizing the extent to which woody canopy has recovered post-reclamation. / Ph. D.