Individual tree and stand-level carbon and nutrient contents across one rotation of loblolly pine plantations on a reclaimed surface mine

While reclaimed loblolly pine (Pinus taeda L.) plantations in east Texas, USA have demonstrated similar aboveground productivity levels relative to unmined forests, there is interest in assessing carbon (C) and nutrients in aboveground components of reclaimed trees. Numerous studies have previously documented aboveground biomass, C, and nutrient contents in loblolly pine plantations; however, similar data have not been collected on mined lands. We investigated C, N, P, K, Ca, and Mg aboveground contents for first-rotation loblolly pine growing on reclaimed mined lands in the Gulf Coastal Plain over a 32-year chronosequence and correlated elemental rates to stand age, stem growth, and similar data for unmined lands. At the individual tree level, we evaluated elemental contents in aboveground biomass components using tree size, age, and site index as predictor variables. At the stand-level, we then scaled individual tree C and nutrients and fit a model to determine the sensitivity of aboveground elemental contents to stand age and site index. Our data suggest that aboveground C and nutrients in loblolly pine on mined lands exceed or follow similar trends to data for unmined pine plantations derived from the literature. Diameter and height were the best predictors of individual tree stem C and nutrient contents (R ≥ 0.9473 and 0.9280, respectively) followed by stand age (R ≥ 0.8660). Foliage produced weaker relationships across all predictor variables compared to stem, though still significant (P ≤ 0.05). The model for estimating stand-level C and nutrients using stand age provided a good fit, indicating that contents aggrade over time predictably. Results of this study show successful modelling of reclaimed loblolly pine aboveground C and nutrients, and suggest elemental cycling is comparable to unmined lands, thus providing applicability of our model to related systems

Torrefied biomass in biofuel production system

Ukraine produces large amounts of crop residues every year, much which could be utilized to produce biofuel. However, efficient supply chains and system configurations are needed to make such systems efficient and cost effective. One option is to integrate torrefaction, power production and biofuel production into a single, coordinated system. This approach allows for high value product (i.e. biofuel), greater utilization of the energy content of the feedstock, and supply chain efficiency. Initial analyses indicate that revenues can be enhanced through this approach, and further analyses and optimization efforts could identify a sustainable approach to renewable fuel and power production for Ukraine. The question of scale and layout remains of interest as well, and a thorough logistical study is needed to identify the most suitable configuration. Agricultural operations often benefit from smaller scales of operation, whereas fuel production processes tend to operate profitably only at very large scale. Thus, a balance must be struck between the needs of both ends of the supply chain. The processing center concept helps to balance those needs. A system such as this also has potential to synergize with other agricultural production systems, such as the production of animal feed, fertilizer, and other bio-based products. The complexities of the Ukrainian agricultural market will need to be reflected carefully in any model that seeks to assess the system's potential. Presents a concept for coupling thermal pretreatment (torrefaction with biofuel and power production for the transformation of wheat straw into a value added product for Ukraine. Torrefaction provides supply chain savings, while conversion provides added value to the product. This paradigm has potential to utilize a widely produced waste material into a valuable source of energy and possibly other products for the country.</jats:p