The 24-chain core-shell nanostructure of wood cellulose microfibrils in seed plants

Wood cellulose microfibrils (CMFs) are the most abundant organic substance on earth, but their nanostructures are poorly understood. There are controversies regarding the glucan chain number (N) of CMFs during initial synthesis and whether they become fused afterwards. Here, we combined small-angle X-ray scattering (SAXS), solid-state nuclear magnetic resonance (ssNMR) and X-ray diffraction (XRD) analyses to resolve these controversies. We successfully developed SAXS measurement methods for the cross-section aspect ratio and area of the crystalline-ordered CMF core, which showed higher density than the semi-disordered shell. The 1:1 aspect ratio suggested that CMFs remain mostly segregated, not fused. The area measurement revealed the chain number in the core zone (Ncore). The ratio of ordered cellulose over total cellulose, termed Roc, was determined by ssNMR. Using the formula N = Ncore / Roc, we found that the majority of wood CMFs contain 24 chains, conserved between gymnosperm and angiosperm trees. The average wood CMF has a crystalline-ordered core of ~2.2 nm diameter and a semi-disordered shell of ~0.5 nm thickness. In naturally and artificially aged wood, we only observed CMF aggregation (contact without crystalline continuity) but not fusion (forming conjoined crystalline unit). This further argued against the existence of partially fused CMFs in new wood, overturning the recently proposed 18-chain fusion hypothesis. Our findings are important for advancing wood structural knowledge and more efficient utilization of wood resources in sustainable bio-economies.

Megaherbivores modify forest structure and increase carbon stocks through multiple pathways

Megaherbivores have pervasive ecological effects. In African rainforests, elephants can increase aboveground carbon, though the mechanisms are unclear. Here we combine a large unpublished dataset of forest elephant feeding with published browsing preferences totaling > 120,000 records covering 700 plant species, including nutritional data for 102 species. Elephants increase carbon stocks by: 1) promoting high wood density tree species via preferential browsing on leaves from low wood density species, which are more digestible; 2) dispersing seeds of trees that are relatively large and have the highest average wood density among tree guilds based on dispersal mode. Loss of forest elephants could cause a 5-12% decline in carbon stocks due to regeneration failure of elephant-dispersed trees and an increase in abundance of low wood density trees. These results show the major importance of megaherbivores in maintaining diverse, high-carbon tropical forests. Successful elephant conservation will contribute to climate mitigation at a scale of global relevance.

CHARACTERIZATION OF PAULOWNIA TOMENTOSA STEUD TREES GROWN IN A 5-YEAR-OLD PLANTATION IN COSTA RICA

Paulownia tomentosa is utilized in Costa Rica and other countries for wood production and as feedstock for biomass, though the variation of wood properties for this species is scarcely known. In this work, the specific wood properties of a 5-year-old plantation in Costa Rica were studied. The results showed that bark and pith percentage and wood specific gravity (SG) increased with tree trunk height, while the proportion of heartwood, green wood density and green wood moisture content decreased. The average wood SG was 0.26 and tended to increase from pith to bark. Low wood SG values are related to low mechanical properties, with the advantage that wood shrinkage is low as well, which gives this wood species the potential to be utilized for reforestation purposes in Costa Rica. The gross calorific value of this species was 17809 kJ/kg, which, together with its cellulose and extractives contents, recommend P. tomentosa as a biomass source for energy production.

Modeling of technical, economic, environmental and ergonomic parameters of forestry machines in function of the quantity of days of the working scale

Forest machine operators work on a long scale of work, which causes physical and psychological wear and consequently reduced productivity and increased fuel consumption. The objective of this research was to verify the influence of the number of days of the work schedule of harvester and forwarder operators in low-volume forest on technical, economic, environmental and ergonomic parameters. The research was performed in forest stands with an average wood volume of 0.10 m³ tree-1. In the first, second, third and fourth day of the work schedule, productivity, energy demand, production cost, carbon dioxide emission and the occurrence of fatigue in the operators were determined. The productivity values ??of harvester operators on the third and fourth days of the work schedule decreased by 2.62 and 7.74%, respectively, in relation to the average value of the first and second days. The productivity of forwarder operators was similar in the first three days of the work schedule, with a more marked reduction in the fourth day. The reduction in the number of days in the forest machine operators’ work schedule makes the operation more sustainable from a technical, economic, environmental and ergonomic point of view.

Tree Communities and Aboveground Biomass in the Submontane Zone of Ketambe Resort, Mount Leuser National Park, Aceh

Mount Leuser National Park is one of the largest conservation areas and plays important ecological and economic functions. To support forest management, it is important to gain current vegetation data. The sampling method of a 0.1 hectare plot was carried out on two sampling sites in the submontane zone of Ketambe Resort, Mount Leuser National Park, Aceh. The diversity of trees was not significantly different, while species composition was different. Site one was dominated by Syzygium spp. and Shorea platyclados, while site two was dominated by Altingia excelsa and Bridelia glauca. Lauraceae, Myrtaceae, and Dipterocarpace families dominated in both sites. Tree structures formed three strata and showed a good capacity for forest regeneration. The aboveground biomass of site one was higher than site two due to the presence of more large trees. Pioneer species, cultivated plants, a low average wood density, and low aboveground biomass indicated secondary forest characteristics in both sites. Abstrak: Taman Nasional Gunung Leuser merupakan salah satu kawasan konservasi yang terluas dan memiliki fungsi ekologi dan ekonomi yang penting. Data vegetasi terkini penting didapatkan untuk mendukung pengelolaan hutan. Metode sampling dengan plot 0.1 hektar dilakukan di dua lokasi pada zona submontana Resort Ketambe, Taman Nasional Gunung Leuser, Aceh. Keanekaragaman jenis pohon tidak berbeda secara nyata sementara komposisi jenis berbeda. Lokasi satu didominasi oleh Syzygium spp. dan Shorea platyclados, sementara lokasi dua didominasi oleh Altingia excelsa dan Bridelia glauca. Suku Lauraceae, Myrtaceae dan Dipterocarpace mendominasi pada kedua lokasi. Struktur pohon membentuk tiga strata dan menunjukkan kemampuan regenerasi hutan yang baik. Biomassa pohon di atas permukaan pada lokasi satu lebih tinggi dibandingkan lokasi dua karena lebih banyaknya pohon berukuran besar. Jenis pionir, tanaman budidaya, rata-rata berat jenis kayu dan biomassa di atas permukaan yang rendah mengindikasikan karakteristik hutan sekunder pada kedua lokasi.

Evaluation of novel drum chipper technology: pilot-scale production of short wood chips

Impregnation of wood chips with acidic pulping liquors is improved when using short chip lengths. If the average wood chip length is too short, conventional chipping technology will generate excess small material, such as pin chips and fines. The possibility of using newly developed drum chipping technology to produce shortlength wood chips was evaluated with a pilot drum chipper operating at different drum velocities and in-feed angles. With a drum velocity of 30 m/s, the average wood chip lengths and the combined fractions of pin chips and fines were 24 mm and 3.3%, 22 mm and 4.2%, and 17 mm and 8.5%. The highest fractions of total accept chips (large and small accepts), 89% to 90% without screening, were observed for drum velocities of 30–34 m/s and average wood chips lengths of 21–22 mm. The results indicate the potential of drum chipping technology for producing short wood chips with relatively high fractions of accept chips and tolerable fractions of pin chips and fines.

PENGARUH PENGASAPAN TERHADAP KEAWETAN KAYU BINTANGUR (Chalophyllum sp.) DAN KAYU MEDANG (Chinnamomum sp) DARI SERANGAN RAYAP TANAH Coptotermes curvignathus Holmgren

Medang wood (Chinnamumum sp) and Bintangur wood (Calophyllum sp) was used for timber construction even they have low quality on the durability. The efforts need to improve their durability, especially against subterranean termites, the most destructive wood organism. One methods of preservation which can improve the durability was fumigation. Fumigation can be processed with traditional methods and modern methods. The aim of the study was to improve the durability of Medang wood (Chinnamumum sp) and Bintangur wood (Calophyllum sp)with modern fumigation methods and evaluation the durability against subterranean termites Coptotermes curvignathus Holmgren. Wood sample was measured 2 cm x 2 cm x 1 cm. The fumigation treatment was conducted with oven. The oven size was 1 m x 1 m x 50 cm. Treatments of fumigation consits of 12 hours and 24 hours. The treatment of evaluation the durability agaisnt termites was conducted for 21 days. The wood sample was put on the bottle and 50 termites consist of 45 workers and 5 soldiers were put in the wood sample. The parameter of indicator was termite’s mortality and wood weight loss. Result of the research showed that average termites mortality was reach 100% at wood sample with fumigation method for 24 hours, and 89.2% for wood sample with fumigation method for 12 hours. Meanwhile in control wood the termite’s mortality only 8.6%. The level of termites mortality with fumigation methods for 24 hours was classified very strong and for fumigation methods for 12 hours was classified as strong. The average wood weight loss was 1.21% - 1.30%. This wood weight loss was classified as very low. From the research it is concluded that fumigation method can increased the durability of wood, both on Medang wood and Bintangur wood against the subterranean termites Coptotermes curvignathus Holmgren. The optimal fumigation methods was on 12 hours, both on Medang wood and Bintangur wood.Keywords: Calophyllum sp, Chinnamumum sp, Coptotermes curvignathus, fumigation, wood preservation

WOOD SUPPLY OPTIMIZATION IN BRAZILIAN PULP INDUSTRY INVOLVING FORESTRY OUTGROWER SCHEME

ABSTRACT The objective of this study was to identify the best regions for allocation of a forestry outgrower scheme, and the most efficient transportation system, using a mathematical programming model to minimize the wood supply costs in three Brazilian states. The forest outgrower scheme is a partnership between producers and forest companies, without land acquisition by the companies. Forest producers are recognized as an important source of growth for forest production. In order to achieve successful partnerships, the company needs to plan its hiring. In this study, the partnerships are made through formal contracts and the model does not allow breach of contract. Six scenarios were modeled and evaluated based on the total cost of the objective function, average wood cost (USD/m3), average transport distance (km) and processing time. The mathematical model showed its efficiency, effectiveness, and flexibility in generating scenarios to support company managers in the decision-making and to avoid breach of contract. Hiring planning benefits both sides as it ensures the company’s production and provides financial security to forest producers. In addition, the model suggests alternatives such as the differential pricing of wood according to the location of the regions and the formation of homogeneous blocks of contracting/renewal of outgrower schemes around the pulp mill.