ABSTRACT

Using a representative sample of partial cut and clear-cut harvests from Northern California, we estimated the financial and climate benefits of the harvested products. Ton for ton, sawlogs generate far more climate benefits than wood chips initially used for energy. The presence of wood-fired energy plants provided forest managers with the opportunity to economically utilize residues that otherwise would have decomposed in the forest. The energy captured at harvest sites, sawmills, and waste-to-energy plants in urban areas are additional climate benefits not included in the forestry chapter of national greenhouse gas inventories. When current utilization practices throughout the full wood products use cycle are considered, the total estimated climate benefits per unit of harvest volume are two times larger than estimates based on historical wood utilization coefficients. A full accounting of the climate benefits across all sectors is necessary to develop accurate estimates of the climate benefits associated with harvested products under different forest management regimes.

Abstract

A survey of stem sinuosity severity and occurrence was conducted on six sites in North Carolina and South Carolina (USA) in Pinus taeda stands approximately 2 years after establishment. Approximately 1,400 trees on each site were measured for height, diameter, and degree of sinuosity in the stem at the beginning of the growing season and again after the completion of the growing season. Fifty-two percent of the trees increased in sinuosity over the growing season. Using stand records and observations by local foresters, two mature stands of loblolly pine (Pinus taeda) were located in the Atlantic Coastal Plain, where excessive stem sinuosity was reported to be present at ages 1 to 3 years. Seven trees were felled from each site. The 2.4-m butt logs were removed from each tree along with a 0.61-m bolt from the remaining felled tree. Slices were then cut through the log progressing through the pith. A single veneer containing the pith from each log was then selected for calculation of log volume, juvenile wood volume, and the volume of sinuous growth. Seven trees at the two sites were found to have had severe sinuosity earlier in their lives. Of the seven sinuous trees, three trees took only 1 year to correct the sinuous growth and return to a normal growth pattern. Two trees took an additional year to return to cylindrical growth, one tree returned to normal growth after the third year, and a single tree returned to a straight appearance by the end of the fifth year after the initiation of sinuous growth. Therefore, the sinuous portions of all seven trees were entirely contained within the juvenile core of the tree. Clear static bending specimens were machined and tested. Trees that were found to be nonsinuous produced mature wood that was significantly stiffer than the sinuous trees.

Abstract

Gross biomass stocks were estimated during 2010 and 2011 on three areas to be surface mined in central West Virginia. Approximately 835 acres of forest lands had been harvested for merchantable timber on the study sites during 2009 and 2010, leaving wood fiber that was to be disposed of before mining. A total of 133 one-fifth-acre forest inventory plots were established to develop standing resource and logging residue estimates. The sampled plots were dominated by cucumber tree (Magnolia acuminatae), followed by red maple (Acer rubrum), sugar maple (Acer saccharum), and yellow-poplar (Liriodendron tulipifera). The average diameter of all standing trees was 7.9 inches, and the average merchantable height of all trees was 32.5 feet. Biomass availability per acre before grubbing operations was estimated to be 31.3 green tons/acre, including 17.0 green tons/acre standing trees and 14.4 green tons/acre logging residues. When the estimated availability of 31.4 green tons/acre is extrapolated to the entire surface mine permit area, the total amount of gross biomass resources available is 26,160.6 tons and, when expanded statewide, represents 352,619 tons. The results indicate that a significant amount of woody biomass is available during surface mining operations in West Virginia.

Abstract

This exploratory study evaluated the environmental impacts associated with Bleached Eucalyptus Kraft Pulp supplied from a eucalyptus plantation in South China by applying the life-cycle analysis approach. The system boundary was defined by a “cradle-to-gate” perspective including the forest subsystem and the pulp mill subsystem. Key processes were investigated and site-specific data were collected during 2009 and 2010 through field trips to a leading plantation operator and a representative pulp mill in China. Umberto 5.5 software was used to conduct a life-cycle inventory, which compiled all the inputs and outputs of the examined system. Hot-spot processes with high environmental burdens were identified with regard to selected impact categories of global warming, acidification, eutrophication, nonrenewable resources depletion, and human toxicity.

According to the findings of this study, the forest subsystem showed significant contributions to the total environmentaltable4 burdens in almost all impact categories, mainly due to the application of fertilizers in eucalyptus plantation management. The study discovered that while the pulp mill subsystem was the primary contributor to global warming impacts, the upstream processes of raw materials and energy production accounted for more than half of the impacts of acidification, human toxicity, and resources depletion. Therefore, eucalyptus plantation management and the supply of raw materials and energy in pulp mills in China are concluded to be concerns for future development. These findings may help the Chinese forest industry and pulp industry achieve better environmental performance toward sustainable development.

Abstract

In the secondary hardwood industry, rough mills convert hardwood lumber into dimension parts for furniture, cabinets, and other wood products. ROMI 4.0, the US Department of Agriculture Forest Service's ROugh-MIll simulator, is a software package designed to simulate the cut-up of hardwood lumber in rough mills in such a way that a maximum possible component yield is achieved. ROMI 4.0 simulates the cut-up of lumber using two common processing modes: rip first and chop first. Additionally, this latest version of ROMI includes a novel feature that allows users to analyze each board's yield when processed in either rip-first or chop-first mode. This permits yield gains to be achieved, resulting in lower material costs for industry participants. The software also allows a user to model, simulate, and examine the complex relationship among cutting bills; part dimensions, quantities, and qualities; processing options; and lumber grade mix. ROMI 4.0 includes many improvements over the previous version, including the combined rip-and-chop option and various improvements to the user interface. We subjected the software to a complete review to assure functionality and user-friendliness. This article discusses these improvements and demonstrates the usefulness of ROMI 4.0 for hardwood dimension mills for researching yield and process improvement opportunities.

Abstract

The vacuum–steam treatment of pallets and pallet parts for compliance with the International Standards for Phytosanitary Measures No. 15 regulation was evaluated. Vacuum–steam treatment consists of four steps: (1) vacuum, (2) heating, (3) holding at an increased temperature for a period of time, and (4) cooling. The system produces steam and maintains the saturation or superheated state in a flexible container. Hardwood dry and green pallets (122 by 101.6 cm) and notched stringers (122 cm long) were treated. After the vacuum was drawn, steam was injected into the container to heat the pallets through condensation. The steam was turned off when the center of the pallets or stringers reached 56°C. The stringer parts were treated in three stacking patterns: deadpacked piles of 12, 2, and 5 layers in a stack. Vacuum–steam treatment is significantly faster than conventional convective hot air treatment. The pallets were treated in less than 65 minutes, which included a vacuum time of 5 minutes and a holding time of 30 minutes. The average treatment times of dry pallets were 7.1 and 10.4 percent faster than green pallets at 400 and 665 mbar, respectively. Wood species affected the treatment time. The average treatment time of dry yellow-poplar pallets was 15.9 percent faster than that of dry red oak pallets at 400 mbar. Pressure also affected the treatment duration. The stringers could be successfully treated even when they were arranged in various stacking patterns. The moisture content increased after the treatment, but the change was less than 3 percent for both green and dry pallets.

Abstract

Small-diameter Masson pine (Pinus massoniana) logs with a length of 800 mm and a diameter ranging from 108 to 132 mm were dried with a mild schedule in a laboratory dryer. The drying experiments were done using logs with or without bark and with or without a longitudinal cut. The reduction in moisture content over time was monitored by a resistance-type moisture meter. The results indicated that small-diameter Masson pine logs can be dried by the proposed schedule successfully. Debarking reduced drying times; however, more checks on the log surfaces were detected. Making a longitudinal cut in logs helped to increase the drying rate and reduce drying stresses.

Abstract

Traditionally, wood has been widely used for construction in Finland and other Scandinavian countries and has been the dominant floor material in Finland. Solid wood floors that were installed more than 100 years ago are still in service. In Finland, however, the current attitude toward using wood floorings differs from that in the past.

This review evaluates how current wood floor constructions differ from those used in the past. The review covers the period from the early 19th century, when stone-based floor construction became common in Finland, to the present. The review includes only solid wood floors.

The largest change in floor construction occurred when insulation was added below the whole boarded floor. The wood species used for the floor boards have remained unchanged, but the dimensions have decreased and become consistent and uniform over time. The insulation materials have developed from dry clay and moss to the current mineral wool. Availability of coatings has also increased remarkably. Examples of old buildings show that properly built solid wood floors provide a useful service life of more than 100 years.

The processes and properties of sliced bamboo veneer are discussed in this article. The results show that using a dry–wet process in the assembly of wet laminated bamboo lumber is the key technology for improving the yield of sliced bamboo veneer. Use of the dry–wet process increases the moisture absorption of laminated bamboo lumber, which results in the improvement of heat transfer and makes it possible to solve the problems of bamboo damage caused by uneven softening. The yield of sliced bamboo veneer is 66 percent by the dry–wet process, which is significantly higher than the previous dry process (20%). The final moisture content and appearance quality of sliced bamboo veneer in the dry–wet process are improved compared with the previous dry or wet processes.

The present work deals with studying the influence of different steam digestion retention times on properties of finished medium-density fiberboard (MDF). It aims to operate the defibration process with the minimum deterioration of stored bagasse-fiber strength. In this respect the wet-stored bagasse (WSB) samples were studied, parallel to dry-stored bagasse (DSB) samples, at different digestion retention times. Regression equations of quadratic order were used to optimize the independent variables (retention time and storage period).

The results obtained show that a relatively higher digestion time (353 s) reduced the hollocellulose and hemicellulose contents of WSB. In the case of DSB, the changes in chemical constituents as a function of retention time were not very significant because the mechanical properties of MDF (static bending, internal bond, and screw holding) produced from applying a higher digestion time do not fulfill the standard requirements of ANSI A208.2. However, digestion at a shorter retention time (253 s) is recommended for stored bagasse in order to produce a board that complies with the European standards on MDF. DSB fibers at all the examined retention times are recommended for comparison. The advantage of applying a shorter retention time is evident from preserving, to some extent, the chemical constituents of WSB fibers.

Abstract

The purpose of this study was to modify Italian poplar (Populus euramevicana cv. ‘I-214’) wood with urea-formaldehyde prepolymer followed by hot pressing. The timbers were impregnated with urea-formaldehyde prepolymer using a pulsed-dipping machine and cured in a hot press. The results showed that the timbers could be easily compressed and cured at temperatures between 90°C and 120°C. The characteristics and quality of the modified wood were up to A grade according to Chinese Standard GB/T 6491‐1999. The air-dried density of modified wood was improved by 58 percent, and the hardness in the transverse, tangential, and radial directions was increased by 67, 210, and 160 percent, respectively. The bending strength was improved by 78 percent; the bend elastic modulus was improved by 66 percent. The water absorption of treated wood decreased relative to that of the untreated timbers. Fourier transform infrared spectroscopy of the modified wood showed a significant reduction in the C=O absorbance at 1,750 cm⁻¹. The peak at 1,645 cm⁻¹ was found to increase as a result of treatment with the prepolymer.

Abstract

Three particleboard types, including urea-formaldehyde (UF), melamine-formaldehyde (MF), and binderless, were made from three wood species, sengon (Paraserianthes falcataria), gmelina (Gmelina arborea), and mindi (Melia azedarach). Wood particle sizes of 10 to 20 mesh were manufactured for the 30 by 30 by 0.7-cm (length by width by thickness) boards, with 0.75 g/cm³ as the density target. Binderless particleboards were made through particle activation with hydrogen peroxide and ferrous sulfate as the catalyst, and the boards were hot pressed at 180°C for 12 minutes. For the purpose of comparison, conventional particleboards were made with UF and MF, with the resin level at 10 percent and the boards hot pressed at 120°C for 7 minutes. All particleboards were conditioned for 8 months prior to testing against the subterranean termite (Coptotermes curvignathus Holmgren) in laboratory and field tests, and against the dry wood termite (Cryptotermes cynocephalus Light) in laboratory tests. Results showed that wood species affected particleboard resistance in both of the subterranean termite tests and that the type of particleboard affected board resistance in field tests. Particleboard from sengon wood had the lowest resistance in both tests, followed by from gmelina and mindi woods, and particleboards with UF and MF resins had better resistance than binderless particleboard in field tests. Particleboard type and wood species did not affect board resistance to dry wood termite attack.