Forestry measurement is aimed at volumetric production of wood; however, for the pulp processing industry, the main interest is productivity in wood biomass and, to know this variable, it is ...necessary to determine the basic wood density (BWD) beforehand. Artificial neural networks (ANN) have been used in the forestry sector quite successfully to describe the dynamics of forest characteristics, such as estimating wood volume. In this context, the objective of this study was to assess the accuracy of the basic wood density estimates by means of ANN’s with Continuous Forest Inventory (CFI) and edaphoclimatic input variables. The database consisted of 3,797 data, from permanent plots of the CFI conducted in Eucalyptus sp stands and edaphoclimatic data from the planting sites. The five best ANNs were selected and the analysis of the estimates was carried out through the correlation between the estimated and BWD, the relative root mean square error (RMSE%) and graphical information. It was observed that both the CFI, edaphoclimatic information and the combination of both are potential and present similar results for the basic wood density estimate, and the errors associated with the estimates are between 3.9% to 3.5%. The ANNs based only on the CFI information presented higher RMSE. The use of ANN’s is feasible for estimating BWD and allows for excellent accuracy statistics.
•Mean annual increment (MAI) changes in greater proportion than basic density (BD).•Precipitation and temperature have more influence over the wood BD and MAI variations.•The SWS had no significant ...influence on changes in the BD and MAI.•Clones E5 and G7 are more sensitive to climatic variations than clone P7.•Groups were formed based on a 80% score, representing the original BD and MAI variables.
Eucalyptus plantations are some of the most productive, and adaptable to different environmental conditions. However, harsh environmental conditions can limit the quality of the wood, and its potential use. The TECHS project investigates the sensitivity of 18 eucalyptus clones to environmental stresses, and their productivity responses in different edaphoclimatic scenarios. The aim of this paper is to evaluate the influence of edaphoclimatic variables on the basic density (BD), and mean annual increment (MAI) of eucalyptus wood. Three different clones, planted at 10 growth sites in Brazil, 4 years of age, were analyzed. During the years 2012 to 2015. Variables such as precipitation, temperature, vapor pressure deficit, and the water storage capacity of the soil were considered. Canonical correlation techniques, principal components, and cluster analyses were performed in order to verify if there were influences of any of the edaphoclimatic variables on the set of production variables (BD and MAI). The variables were also used to organize the sites into groups based on their similarities. There was a significant influence of the edaphoclimatic variables at the different sites regarding the BD and MAI variables (rU1V1 = 0.77). Precipitation was positively correlated with the production variable (0.64), while the temperature (−0.59) and the vapor pressure deficit (−0.52) correlated negatively. The water storage capacity of the soil did not contribute to the set of edaphoclimatic variables that affected the production variable (0.16). Among the clones studied, E5 and G7 were more sensitive to climatic variations in different sites than the clone P7. The responses of the wood to the BD and MAI are clone-specific, and the mean annual increment of the wood changes in a greater proportion than the basic density faced with environmental variations. Understanding the responses of eucalyptus clones to environmental variations, mainly temperature and precipitation, facilitates forest planning, regarding the supply, and the quality of the wood.
Display omitted
•Despite the growth, the climate also influences heartwood formation.•Moist sites produced more heartwood in E. urophylla clones.•The climate influences more heartwood percentage than ...density.•Response variability for wood properties is also influenced by genetic.•Huber value was not related to climatic conditions.
One of the forms used to differentiate wood is heartwood and sapwood classifications, as variations in the proportions influence wood use. The aim of this study was to compare the heartwood percentage (H%) and wood density (WD) of eucalyptus in plantations along a climatic gradient, and to estimate these characteristics using meteorological variables and tree growth rate. E. urophyla clones at 6 years old were analyzed in 12 sites distributed across a wide geographic variation in Brazil. Seven trees from each site were sampled, and a disc was taken from the DBH position. H% was determined by image analysis, while heartwood density (HD), sapwood density (SD) and wood density (WD) by X-ray densitometry. H%, HD, SD and WD data were submitted to analysis of individual variance and the sites means were compared. WD and H% were correlated with the following variables: temperature (T), precipitation (P), soil water deficit (SWD), water use index (W), water use efficiency (WUE) and mean annual increment (MAI); these variables were also used in the multiple regression analysis in the adjustment of equations. The differentiation between heartwood and sapwood by color was possible in all sites. The sites located in higher and more humid latitudes presented the highest H% values (between 61 and 67%). In general, HD was lower than SD, with the sites with the lowest MAI values showing the lowest SD values, and wet sites with higher MAI and the highest densities. H% showed strong and significant correlations with T, P, SWD, W and MAI, whereas HD only showed moderate and significant correlations with T, MAI and WUE. The best equation for estimating H% used the P and MAI variables, which managed to explain 79% of the variation. In the WD estimation, the best equation only used the WUE variable and obtained an explanation power of 53%. In addition to the strong relationship between heartwood percentage and growth, it was found that the climate also influences heartwood formation. Use the equation obtained for clone A1 in other clones confirmed that the response variability for wood properties is also influenced by genetic. No relationship was observed between the Huber value and climatic conditions, however, the factors influencing SA:LA ratio behavior are complex and requires considering other components. H% was shown to be more correlated with climate than density, and the observed variability between sites suggests the inclusion of heartwood content assessments in this species in management and breeding programs.
As in other countries, In Brazil, new genetic materials of Eucalyptus spp. and their hybrids are multiplied through cloning. These materials, currently in experimental trials, must undergo several ...stages to select the best ones for pulp and paper production. Therefore, new studies on wood quality are essential. Therefore, this study aimed to group 11 clones of Eucalyptus spp. wood, from a clonal plantation in the municipality of Palmital, São Paulo State, for the production of paper and cellulose. For this purpose, four trees of each clone of 4-year-old Eucalyptus spp. were collected. From each tree, a log of 1 m in length was taken from the base of the tree, for the study of the characterization of the basic density and cellular dimensions of the wood. The results showed that there were significant differences between clones for basic density, fiber length, vessel element length and fiber wall thickness. The Runkel ratio, wall fraction and stiffness coefficient did not show significant differences between the different genotypes. From the results obtained, we can conclude that clones can be differentiated only by basic density, fiber length, vessel element length and fiber wall thickness. The Runkel index, flexibility coefficient and wall fraction of Eucalyptus spp. were more efficient to group the clones into two groups.
Rahmawati RB, Widiyatno, Hardiwinoto S, Budiadi, Nugroho WD, Wibowo A, Rodiana D. 2022. Effect of spacing on growth, carbon sequestration, and wood quality of 8-year-old clonal teak plantation for ...sustainable forest teak management in Java Monsoon Forest. Biodiversitas 23: 4180-4188. Lowland monsoon forest dominated by teak was one of the tropical forest types that can contribute to producing wood production, carbon storage, reduction of emissions, and other ecosystem services. Increasing teak forest productivity could be obtained through teak breeding to get superior teak clones with high diameter growth. Thus, spacing is an important consideration for optimizing the growth, carbon sequestration, and wood properties of teak. However, the study of the growth, carbon sequestration, and wood quality of teak was conducted separately. This research used a selected teak clone aged 8 years with RCBD design with 4 blocks as replications. There were four different spacing as treatments, namely 10 m x 2 m, 8 m x 2 m, 6 m x 2 m, and 3 m x 3 m. The results showed that spacing was a significant effect on DBH, tree height, bole height, carbon sequestration, and volume of teak clones aged 8 years. On the other hand, spacing didn’t significantly affect the physical and mechanical properties of wood. The wood quality test showed that the 6 m x 2 m spacing had high values of bending strength and compressive strength parallel. The highest percentage of heartwood was at a narrow spacing of 6 m x 2 m and did not differ significantly with wide spacing. This indicated that wide spacing was beneficial in terms of teak growth, but wide spacing didn’t significantly affect on wood quality of the teak.
Charcoal productivity in brick kilns is controlled by factors such as, the pyrolysis process and kind of raw material, which impose a challenge for the selection of the best clones. This study ...investigates the tree growth characteristics as a parameter for the improvement of selection and classification of Eucalyptus clones, with the quality and availability required by the steel industry, in addition to the properties of wood and charcoal. Parameters as the diameter at breast height (DBH), total height, and wood basic density (WBD) of fourteen clones were measured. Wood specimens were converted to charcoal in laboratory conditions and the carbonization yields, charcoal properties, and the volume of wood required to produce 1 t of charcoal (specific consumption) were evaluated. Eucalyptus clones with DBH ≥15.1 cm, WBD ≥560 kg/m3, and gravimetric yield ≥35% provided low specific consumption (<5.1 m³/t), increased brick kilns productivity, and resulted in denser charcoals (380 kg/m3). Clones with WBD ≤500 kg/m3 are not recommended for steel charcoal production. The E. urophylla x E. camaldulensis hybrid (clone 1004), E. urophylla (clone 1009), and E. grandis hybrid (clone 1039) highlighted due to the productivity, bioreducer quality, and specific consumption (<5.2 m³/t).
Display omitted
•Eucalyptus with wood density ≤500 kg/m3 is not recommended for energy purposes.•The diameter at breast height is criterion for classification of Eucalyptus clones.•Wood density is a key criterion for selecting charcoal for steel production.•Wood density, tree growth, and pyrolysis yields indicates best clones.•The carbonization of wood with WBD ≥560 kg/m3 results in denser charcoals.
•The effect of late thinning on unmanaged chestnut plantation performance was tested.•The thinning effect on tree growth decreased considerably after 5 years.•The proportion of bifurcated trees was ...50 % lower in one plantation 19 years later.•Progressive and frequent thinning improves growth and timber quality.
Chestnut (Castanea sativa Mill.) is an interesting species for high-quality timber production. It is well known that the species responds to early thinning, but there is no information on the impact of late interventions. The objective of this study was to assess the effect of a late thinning on the performance of unmanaged adult chestnut plantations in Chile. Future-tree selective thinning and control were compared in adult plantations using a randomized complete block design with three replicates at three sites, Minas, Pillo-Pillo and Pumillahue. Tree growth was evaluated periodically during the first 7 years after thinning in all plantations. Additionally, almost 20 years after the intervention, the Pumillahue plantation was measured for growth and tree shape variables. In this case study, the effect of thinning on tree growth decreased considerably after 5 years, with a maximum DBH increment in the third year after the intervention (45.8 %, 68.6 %, and 42.2 % in Minas, Pillo-Pillo and Pumillahue, respectively). In all plantations, basal area was smaller in the thinned plots in the first years after the intervention, but in Pumillahue, 19 years after thinning, no differences were found among treatments. Height was statistically greater under thinning seven years after the intervention; this effect was also found in Pumillahue plantation 19 years after thinning. Most trees showed high vigor, and were straight and healthy, even in control plots. Late effect of thinning was observed 19 years after thinning on tree shape, with a reduction in the proportion of bifurcated trees from 16 % to 8 %. The results suggest that late thinning is an effective silvicultural intervention to produce high-quality chestnut timber in unmanaged adult plantations. Progressive and frequent thinning should be used to increase growth and improve timber production in chestnut.
•Density and stiffness of planted E. nitens depend more on tree than on site factors.•E. nitens density is influenced by tree size, temperature, and precipitation extremes.•E. nitens stiffness ...depends on tree slenderness, height, density and site variables.•Predictive models of the two properties are developed at the tree and site level.•The models can be used for plantations management and harvesting for timber products.
Wood density and stiffness are among the most important wood quality traits for timber products and the prediction of these traits in trees planted across large geographic areas is of increasing interest for the forest industry. This study was conducted across 65 stands of E. nitens fibre-grown plantations, the most widely planted hardwood species in Tasmania, Australia, and aimed to (i) identify the main sources of variability in density (basic density, ρb) and stiffness (dynamic modulus of elasticity, Ed) of E. nitens fibre-grown trees, (ii) identify site, climatic, environmental and geomorphological factors across the E. nitens estate and tree characteristics at the site level that influence ρb and Ed of the trees, and based on this information (iii) develop models to predict the two wood properties at the tree and site level. An extensive dataset (n = 1880) of tree ρb and Ed measures was obtained through direct tree wood sampling for basic density and non-destructive acoustic assessments for stiffness. Large variation in tree density and stiffness was found across the study sites and among trees, with basic density ranging from 0.36 g cm−3 to 0.65 g cm−3 and stiffness from 9.2 GPa to 24.7 GPa. Candidate models to predict the two properties were developed on a training dataset and validated on a separate part of the dataset. The best tree-level models describing the variation of ρb and Ed included both tree and site factors. The best model describing ρb variation on trees included tree diameter, maximum temperature of the warmest period and precipitation of the wettest period as explanatory variables, while the best Ed model for trees included tree slenderness, height and basic density and the climatic variables, elevation and site index. The predictive models explained 31% of the total variability of ρb and 59% of the total variability of Ed across the validation sites. At the site level, the best models for density and stiffness included forest structure, climatic, and geomorphological variables, as well as plot location. The model for site density explained 73% of the variability of average density, while the model for site stiffness explained 35% of the variability of average stiffness.
These findings demonstrate that different site and tree factors influence the two commercially important wood quality traits, and these can be used in combination to satisfactorily predict tree basic density and stiffness across different environments both at the tree and site level. This knowledge can be employed to support the forest and wood processing industry to expand the possible uses of E. nitens fibre-grown trees, to better manage the harvest for specific products, and to develop models for planning next generation plantings.
PDF