Allometric Models for Estimating Aboveground Biomass in Short Rotation Crops of Acacia Species in Two Different Sites in Chile

We evaluated the ability of different allometric models to estimate the biomass production of short-rotation woody crops of Acacia dealbata, A. mearnsii and A. melanoxylon. Models considered the adjustment and validation of biomass functions and biological restrictions, such as the use of additive components of the biomass (stem, branches, and leaves). Adjustments of linear and nonlinear models of the three acacia species—established in two locations and of three densities in southern Chile—were utilized. Systems of equations were adjusted to guarantee the addition of the biomass components and the trees’ total biomass. The selection of models was performed based on their goodness of fit and predictive quality. Methods that accounted for the correlation between biomass components granted an additively consistent equations system with efficient estimates and reliable prediction intervals.

Effects of Mechanical Site Preparation, Planting Stock, and Planting Aids on the Survival and Growth of American Sycamore in a Marginal Old Field Riparian Restoration

Survival and growth of planted tree species are common indices used to evaluate success of wetland restoration efforts used to compensate for wetland losses. Restoration efforts on marginal agricultural lands have typically resulted in less than satisfactory survival and growth of desired tree species. In an attempt to determine the effects of bottomland hardwood silvicultural methods on the survival and growth of pioneer tree species, this study evaluated combinations of five mechanical site-preparation techniques (mound, bed, rip, disk, pit), four levels of planting stock (gallon, tubeling, bare root, and direct seed), and three planting aids (mat, tube, none) on the four-year survival and growth of American sycamore planted in an old field riparian area in the Piedmont of Virginia. After four growing seasons, results indicated that mounding mechanical site preparation combined with gallon (3.8 L) planting stock provided the most positive influences on mean survival (100%), height (4.72 m), and groundline diameter (9.52 cm), and resulted in the greatest aboveground dry biomass accumulation (5.44 Mg/ha/year). These treatments may be economically viable for restoration and mitigations efforts, and could offer other economic alternatives such as short-rotation woody crops, which might make restoration efforts in marginal old field areas more attractive to private landowners.

Economic impacts of short rotation woody crops in Canada

Canada is seeking cost-effective means to mitigate greenhouse gas emissions, particularly CO2. One of the promising means is the short rotation woody crops (SRWC) plantation, a silvicultural approach to establishing and managing fast growing plantations on previously cleared lands. This paper utilizes the data set provided by recent harvesting operations at the Ellerslie SRWC Technical Development Site in Edmonton (Alberta) to assess the ability of SRWC using High Yield Afforestation to mitigate GHG emissions and generate more wood fibre and the investment attractiveness to establish future plantations. Results illustrate that at current trading prices for carbon credits and market prices of woodchips, expected rates of return on investment for SRWC were relatively low, despite a positive net present value ($400/ha for 20 year planting cycle without carbon credits). However, estimates from the Ellerslie site indicate that 330 tons of CO2-eq per hectare are captured above and below ground over the 20 year plantation cycle. However, higher future carbon prices, a well-developed market for buying and selling carbon credits, as well as adapted policy including additional government sponsored programs for carbon credits, could make SRWC more attractive and dramatically change the economics of afforestation in the future.

Wood Volume of Eucalyptus Clones Established Under Different Spacings in the Brazilian Cerrado

Eucalyptus plantations are expanding in Brazil to meet growing demands for wood-based products, such as pulp, paper, and bioenergy. New clones and silvicultural adjustments are needed with the advance of eucalypts to new regions within Brazil. This study’s objective was to evaluate the effect of variable spacing on the development of six Eucalyptus clones cultivated in the Cerrado region of Brazil. These clones were evaluated in a systematic design, with 23 spacing treatments and five biological replicates. Spacing per tree ranged from 1.20 m2 to 21 m2. At two, four, and six years after planting, diameter at breast height (DBH) and height of all trees were measured to estimate wood volume. Regression models were fitted for each trait (DBH, height, and wood volume) and showed that DBH growth was positively affected by spacing, especially at four and six years after planting (R2 > 0.58). Consequently, estimates of individual volume per tree also had a positive relationship with spacing. Total stand volume, on the other hand, was higher under densest spacings. The GG100 clone outperformed all other clones, with higher stand wood volume, especially under the densest spacings. The CCL55 clone is a promising genotype, especially under dense plantations. Study Implications Short-rotation woody crops can help meet future feedstock demands. Eucalyptus species have been introduced around the world to meet global demands for fiber and energy. One of the main factors that affects the growth and management of forests is the spacing among trees. Spacing has silvicultural, technological, and economic implications, as it can interfere with growth rates, forestry practices, wood quality, and production costs. This study showed that Eucalyptus plantations with higher density of trees per hectare could lead to higher wood productivity, even in a region with 4–5 months of drought.

Productivity and Biomass Properties of Poplar Clones Managed in Short-Rotation Culture as a Potential Fuelwood Source in Georgia

Georgian forests are very valuable natural resources, but due to the lack of affordable alternatives to firewood, people are forced to use forest resources illegally and unsustainably. The aim of this study was to determine the productivity and biomass properties of four poplar clones from Aigeiros and Tacamahaca and one control clone, considering their wood and bark characteristics and their proportion in the stems. Short-rotation woody crops with these clones represent a potential source of commercial fuelwood production in Georgia as an alternative to natural forests. These tree characteristics were evaluated after three years of growth. The survival of the clones was generally high. No significant differences in biomass production (dry matter, DM) were found among the four clones tested (DM of approximately 4 Mg ha−1 yr−1), while the control clone achieved significantly lower values for DM. The biomass specific density was exceptionally high, at 481–588 kg m−3, which was a result of the high proportion of bark mass in the stem (23.3–37.7%), with a density almost twice that of wood. On the other hand, the tested clones had a very high ash content in the biomass (2.6–4.5%), which negatively affected their energy potential expressed as a lower heating value (17,642–17,849 J g−1). Our preliminary results indicated that both the quantity and quality of biomass are important factors to justify the investment in an intensive poplar culture. The four clones should be further considered for commercial biomass production and tested at different sites in Georgia to evaluate the genotype-by-environment interactions and identify the site conditions required to justify such an investment.

Avian Breeding Season Diversity and Community Composition in Camden White Gum and Slash Pine Plantations

In the southern United States, some landowners have established plantations of eucalyptus (Eucalyptus spp.) and are managing them on short rotations (<15 years) to provide wood for fiber and other potential uses. Establishment of short-rotation woody crops dominated by nonnative species has implications for resident fauna in the United States that are largely unknown. We compared avifauna abundance, diversity, and community composition in newly established Camden white gum (Eucalyptus benthamii) plantations with slash pine (Pinus elliottii) plantations of the same age and height (one to two and six to seven years old, respectively) in southwestern Louisiana, USA. Species richness, diversity, and community composition in newly established eucalyptus plantations and six- to seven-year-old pines were similar. More birds were observed, and bird detections varied less in eucalyptus plantations. Indigo buntings (Passerina cyanea) and other shrub-associated species were detected more often in eucalyptus stands. In contrast, species that inhabit herbaceous-dominated communities, such as eastern meadowlarks (Sturnella magna), or that were associated with a dense graminoid community (e.g., Bachman’s sparrow [Peucaea aestivalis]) were detected less often in eucalyptus. Overall, breeding bird communities in eucalyptus plantations one to two years postestablishment differed little from plantations dominated by slash pine. Study Implications Compared with slash pine (Pinus elliottii Englem) plantations of similar age and height (one to two years and six to seven years old, respectively) we found one- to two-year-old eucalyptus (Eucalyptus benthamii Maiden & Cambage) plantations supported similar avian species richness and diversity to six- to seven-year-old pine stands. Furthermore, we found these eucalyptus plantations (E13) supported an avian community that was intermediate to similar aged pine (S13) and pine of similar height (S08). However, avian communities will likely change as eucalyptus plantations age (Christian et al. 1997). Continued monitoring and assessment of community composition, richness, and abundance is important for determining the magnitude of this change. Future investigations focused on nest success, fecundity, postfledging monitoring, and survivorship compared with other types of planted forests and native cover types would help us better understand eucalyptus plantation effects on avifauna demographics (Van Horne 1983, Martin 1998, Jones 2001, Wood et al. 2004, Sage et al. 2006, Riffell et al. 2011).

Reflections on the contributions of Populus research at Rhinelander, Wisconsin, USA

The United States Department of Agriculture Forest Service established three regional Institutes of Forest Genetics in the United States in the 1950s to improve trees for reforestation and improve the management of forests. The institute in Rhinelander, Wisconsin, started in 1956 as part of the Lake States Forest Experiment Station. Since that time, the “Rhinelander Lab” has undergone changes in research priorities, organizational changes, and name changes while becoming an international center of forest scientific excellence. Many of the researchers’ key findings over the years were published in the Canadian Journal of Forest Research. In this paper, for the 50th anniversary edition of the Journal, we reflect upon one part of those accomplishments: the history of the contributions of Populus L. research at Rhinelander. We discuss major research programs and the scientists conducting this work, including (i) physiology of wood formation, (ii) short rotation intensive culture and short rotation woody crops, (iii) intensively cultured plantations, (iv) physiology and utilization of short rotation poplar yields, (v) breeding and selection, (vi) biotechnology and molecular genetics, (vii) atmospheric pollution and climate change, (viii) phytotechnologies, and (ix) ecosystem services. Also, we describe four major international conferences held in Rhinelander and (or) hosted by Rhinelander researchers.

Hot Water Extraction: Short Rotation Willow, Mixed Hardwoods, and Process Considerations

Short rotation woody crops (SRWC) like shrub willow are highly productive biomass resources of interest for energy and fuel applications. Hot water extraction (HWE) as an upgrading tool to enable the use of willow biomass in pellet applications has been proposed, and is of increasing interest. This study treats willow and mixes of willow and conventional mixed hardwood feedstock with HWE in a tumbling laboratory reactor to elucidate the effects of time, temperature, feedstock mixes, and other process considerations (water:biomass ratio, presteaming, counter-current processing) on mass removals and other extraction outcomes (e.g., sugar, acetate, and furan yields). Results demonstrated alignment of extraction outcomes with P-factor from 155 °C to 175 °C, with a good compromise of removed mass and co-product potential in the range from 575–800 P-factor. The preferred condition was chosen as 575 P-factor. HWE of mixes of willow and hardwood feedstocks showed a linear response of extraction outcomes to willow:hardwood ratios. Testing of water:biomass ratios demonstrated that this is a significant consideration, with each outcome being affected somewhat differently, and indicating that HWE is more diffusion dependent than expected. Presteaming shows little to no effect on extraction outcomes, while multi-stage cooks simulating counter-current operation indicate a significant potential value in counter-current extraction.

Plant Parasitic Nematodes on Paulownia tomentosa in Poland

Fast growing woody crops are currently a very important source for the generation of energy biomass. As short-rotation woody crops, the genus Paulownia has already attracted growing attention. These trees are used to produce biomass and reduce the carbon dioxide concentration in the atmosphere. Most projects for biomass production, however, may affect soil properties and status. For this reason, it is important to know the effects of Paulownia plantations on the microbiological properties of the soils on agricultural areas in Poland. This article provides information on plant parasitic nematodes inhabiting the root zone of Paulownia tomentosa L. in Poland. The only report of Meloidogyne hapla Chitwood, 1949 shows the potential pathogenicity of the root-knot nematodes. Furthermore, nothing is known about plant parasitic nematodes inhabiting the root zone of Paulownia tomentosa L.in Poland. Determining the trophic group of plant parasitic nematodes was undertaken by a process of centrifugation. Measurements showed a decrease in the population reproduction factor (Pf/Pi) which reached a value of 0.1. Paulownia tomentosa L. taken from seven different locations in Poland revealed the presence of M. hapla.