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Biochar from agroforestry biomass residues is an alternative source of fertilizers for improving the soil fertility. In Costa Rica, Cedrela odorata is planted in pure plantations and agroforestry systems and different types of substrates are used in the nursery to enhance the growth and performance of the young saplings. The main objective of the present study was to evaluate the growth (in height, diameter, biomass) and distribution of carbon (C), hydrogen (H), and nitrogen (N) for C. odorata plants in a nursery with different application rates of biochar produced from Tectona grandis wood residues. The results showed that the above-measured variables were statistically affected by different application rates of the biochar. The stem diameter, total height, number of leaves, and height increment were statistically significantly higher in the substrate with an application rate of 25–50 tons/ha, in contrast to the 0 and 75 tons/ha application rates, which were statistically the lowest. As for the levels of C, H, and N, there were differences, with the highest values of N and C being in the leaves and stem with the 50 tons/ha application rate and the highest values of H for the 75 tons/ha application rate. The above results showed that applying biochar obtained from T. grandis residues improved soil conditions, resulting in better growth of C. odorata saplings with an application rate of 25 and 50 tons/ha.

This paper presents the effect of thermal modification of 14-15 year-old plantation grown Acacia auriculiformis wood in the 150-240ºC temperature range under vacuum condition. Important techno-mechanical parameters of thermally modified wood such as density, dimensional stability, colour, surface roughness, decay resistance against brown and white rot fungi and flexural properties were evaluated and compared with control. Depending on severity of heat treatment, colour of modified sapwood was turned from light to dark brownish. Moreover, the change in colour was found to be uniform throughout the thickness of wood blocks. Amount of shrinkage of Acacia auriculiformis wood was observed to be decreased with increasing treatment temperatures. Maximum dimensional stability of wood thermally modified at 240ºC was in the range of 60-65%. The surface roughness parameters (Ra and Rz) were reduced significantly after the treatment. The flexural strength (modulus of rupture-MOR) was observed to be reduced with increasing treatment temperatures. However, flexural stiffness (modulus of elasticity-MOE) was not found to be affected significantly up to 210ºC temperature. The lower amount of weight loss of thermally modified wood compared to untreated control showed improved decay resistance against white and brown rot fungi. With desirable improvements in various esthetic and technologically important quality parameters such as enhanced dimensional stability, biological durability against fungi and certain other properties, thermally modified wood from short-rotation Acacia auriculiformis may be considered as viable alternative to scarcely available timber resource for different value-added applications.

This paper presents the effect of thermal modification of 14-15 year-old plantation grown Acacia auriculiformis wood in the 150-240°C temperature range under vacuum condition. Important techno-mechanical parameters of thermally modified wood such as density, dimensional stability, colour, surface roughness, decay resistance against brown and white rot fungi and flexural properties were evaluated and compared with control. Depending on severity of heat treatment, colour of modified sapwood was turned from light to dark brownish. Moreover, the change in colour was found to be uniform throughout the thickness of wood blocks. Amount of shrinkage of Acacia auriculiformis wood was observed to be decreased with increasing treatment temperatures. Maximum dimensional stability of wood thermally modified at 240°C was in the range of 60-65%. The surface roughness parameters (Ra and Rz) were reduced significantly after the treatment. The flexural strength (modulus of rupture-MOR) was observed to be reduced with increasing treatment temperatures. However, flexural stiffness (modulus of elasticity-MOE) was not found to be affected significantly up to 210°C temperature. The lower amount of weight loss of thermally modified wood compared to untreated control showed improved decay resistance against white and brown rot fungi. With desirable improvements in various esthetic and technologically important quality parameters such as enhanced dimensional stability, biological durability against fungi and certain other properties, thermally modified wood from short-rotation Acacia auriculiformis may be considered as viable alternative to scarcely available timber resource for different value-added applications. [ABSTRACT FROM AUTHOR]

• Indicators may play important roles in biodiversity conservation in plantations. • The amount of native trees is a simple biodiversity indicator in plantations. • We developed an empirical model of the indicator using national forest inventory data. • Rate of increase in native trees was greatly influenced by plantation tree species. • Density of planted trees, snow depth and temperature also affected native trees. Plantations are expanding globally and dominate landscapes in many parts of the world. Biodiversity conservation within plantations is becoming an important issue and developing indicators of conservation values is valuable. Although plantations support less biodiversity than natural forests, older plantations can provide habitat for some native trees and associated biota. The amount (basal area) of native trees can be a simple indicator of conservation value of plantations. Various factors are likely to affect rates of increase in native trees in plantations with stand age. We developed an empirical model to predict the amount of broad-leaved trees as an indicator of conservation value of conifer plantations. We quantified relationships between rates of increase in the amount of broad-leaved trees and plantation tree species, density of planted trees, climate, topography and landscape cover. We used a hierarchical modeling framework based on extensive snapshot plot data (n = 3265 plots) from the national forest inventory in Japan. Our results showed that plantation tree species had the largest effect on the rate of increase in broad-leaved trees. Japanese cedar Cryptomeria japonica and hinoki cypress Chamaecyparis obtuse , which are two primary plantation species in Japan (both from the cypress family), had low rates of increase. In plantations of other species (red pine, larch, fir and spruce from the pine family), broad-leaved trees started to increase in amount after 20 years. We found that 50-year-old plantations of the pine family supported 10–20% of the amount of broad-leaved trees typically found in old-growth natural forests. Planted tree density also had important, but nonlinear relationships with the rate of increase in broad-leaved trees. Stands with fewer planted trees had higher rates of increase in broad-leaved trees. Rates of increase also were associated with snow depth, temperature, slope angle and the amount of natural forest in the surroundings. Our results suggest that management practices related to stand age, selection of plantation species and the density of planted trees can contribute to the conservation value of plantations. As our model is based on broadly available covariates and accommodates stand age, it may be applicable to other regions under different management regimes. [ABSTRACT FROM AUTHOR]

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Two new tree variants, namely Acacia hybrid and second-generation Acacia mangium, have been introduced in plantation forests in Sarawak, Malaysia, and their wood qualities were examined. The mean basic density of Acacia hybrid was comparable with Acacia mangium. However basic density and strength properties of second-generation A. mangium were significantly lower compared to Acacia hybrid. The mean fibre length and fibre wall thickness in the hybrid were found to be greater than that of second-generation A. mangium. Fibre diameter and fibre lumen diameter of Acacia hybrid were smaller compared to second-generation A. mangium. Runkel and slenderness ratios of Acacia hybrid and second-generation A. mangium fibres showed that they were suitable for pulp and paper production. Acacia hybrid was more resistant to Coptotermes curvignathus attack than second-generation A. mangium. A laboratory soil block test showed that Acacia hybrid and second-generation A. mangium were moderately durable timbers. In summary, marked differences in wood properties and qualities were observed between Acacia hybrid and second-generation A. mangium.

Accurate quantification of tree biomass is critical and essential for calculating carbon storage, as well as for studying climate change, forest health, forest productivity, nutrient cycling, etc. Tree biomass is typically estimated using statistical models. In this study, a total of 289 trees were harvested and measured for stem, root, branch, and foliage biomass from three coniferous plantation species in northeastern P.R. China. We developed two additive systems of biomass equations based on tree diameter (D) only and both tree diameter (D) and height (H). For each system, likelihood analysis was used to verify the error structures of power functions in order to determine if logarithmic transformation should be applied on both sides of biomass equations. The model coefficients were simultaneously estimated using seemingly unrelated regression (SUR). The results indicated that stem biomass had the largest relative contribution to total biomass, while foliage biomass had the smallest relative proportion for the three species. The root to shoot ratio averaged 0.27 for Korean pine, 0.25 for larch, and 0.23 for Mongolian pine. The two additive biomass systems obtained good model fitting and prediction performance, of which the model Ra2 > 0.80, and the percent mean absolute bias (MAB%), was <17%. The second additive system (D and H) had a relatively greater Ra2 and smaller root mean square error (RMSE). The model coefficient for the predictor H was statistically significant in eight of the twelve models, depending on tree species and biomass component. Adding tree height into the system of biomass equations can marginally improve model fitting and performance, especially for total, aboveground, and stem biomass. The two additive systems developed in this study can be applied to estimate individual tree biomass of three coniferous plantation species in the Chinese National Forest Inventory. [ABSTRACT FROM AUTHOR]

Plantation grown Hevea brasiliensis (rubberwood) was thermally processed in a vacuum-pressure oven in the temperature range of 150-240 °C under two inert environments (vacuum and nitrogen gas) and normal atmospheric pressure (air). Effect of heat treatments on various physical properties of rubberwood such as equilibrium moisture content (EMC), specific gravity, water uptake, shrinkage, colour and surface roughness profiles was evaluated and compared with untreated wood. The EMC of rubberwood was found to be reduced by almost half while specific gravity was reduced slightly after heat treatment. The intensity of darker brown colour was increased with increasing heat treatment temperatures and colour change was observed to be uniform throughout the wood blocks. Dimensional stability, water resistance, colour and surface quality were observed to be improved after thermal processing of rubberwood at moderately high temperatures under inert environments without affecting other properties deleteriously. Based on improved properties, heat treated rubberwood was found to be suitable for nonstructural applications such as flooring, siding, paneling etc. [ABSTRACT FROM AUTHOR]

Two new tree variants, namely Acacia hybrid and second-generation Acacia mangium, have been introduced in plantation forests in Sarawak, Malaysia, and their wood qualities were examined. The mean basic density of Acacia hybrid was comparable with Acacia mangium. However basic density and strength properties of secondgeneration A. mangium were significantly lower compared to Acacia hybrid. The mean fibre length and fibre wall thickness in the hybrid were found to be greater than that of second-generation A. mangium. Fibre diameter and fibre lumen diameter of Acacia hybrid were smaller compared to second-generation A. mangium. Runkel and slenderness ratios of Acacia hybrid and second-generation A. mangium fibres showed that they were suitable for pulp and paper production. Acacia hybrid was more resistant to Coptotermes curvignathus attack than second-generation A. mangium. A laboratory soil block test showed that Acacia hybrid and second-generation A. mangium were moderately durable timbers. In summary, marked differences in wood properties and qualities were observed between Acacia hybrid and second-generation A. mangium. [ABSTRACT FROM AUTHOR]

Plantation establishment using exotic species on disturbed cultivated and undisturbed primary forest soils is common in Gambo district, southern Ethiopia, but their effects on soil properties are not fully known. This study investigated the effects of plantation species on major soil physical and chemical properties and further evaluated the soil quality under different land uses. Soil samples in triplicates, collected under different plantations, were analysed for their physical and chemical properties. Based on these soil properties, an integrated soil quality index was determined. The soil bulk density (BD) varied from 0.72 to 0.80 cm−3 in plantations established on primary forest land and natural forest and from 0.86 to 1.14 g cm−3 in those plantations established on cultivated soils. Also significantly lower pore volume and infiltration rate were observed under plantations established on cultivated lands than those on primary forest soils. Higher water volume (% at −1500 kPa matric potential) was obtained in soils under Juniperus procera and natural forest compared with that under the rest of the plantations investigated. The concentration of soil organic carbon (SOC) varied from 3.4 to 10.2%, N from 0.3 to 1.0% and Av.P from 1.5 to 7.0% in soils under plantations and natural forest. Exchangeable cations generally showed a decreasing trend with depth in all land use types with minor exceptions. The concentrations of exchangeable Ca+2 varied from 6.5 to 22.7 cmol kg−1 and were significantly higher under Juniperus procera than under Eucalyptus species. The soil under plantations on previously cultivated lands showed soil quality index below 0.5 (the baseline value), while those established on undisturbed forest soil were generally above that value. The study results suggest that selecting species such as Juniperus procera and prolonging the harvesting period would improve and maintain the quality of soil properties. [ABSTRACT FROM PUBLISHER]

The plywood industries had been utilizing plantation timbers and other lesser known timbers for making plywood because of non-availability of conventional timbers. Melia dubia (malabar neem wood) has been identified as one of the fast growing species that would be suitable for plywood making and a study was carried out for determining its suitability for plywood manufacture. Investigations have shown that type-B surface veneers could be produced by peeling and the veneers could be dried without major degrades. Gluing and bonding properties have been studied and found that the panels made using urea formaldehyde and phenol formaldehyde adhesives meets the requirement of MR and BWR grade plywood as per relevant specification. [ABSTRACT FROM AUTHOR]

Biochar from agroforestry biomass residues is an alternative source of fertilizers for improving the soil fertility. In Costa Rica, Cedrela odorata is planted in pure plantations and agroforestry systems and different types of substrates are used in the nursery to enhance the growth and performance of the young saplings. The main objective of the present study was to evaluate the growth (in height, diameter, biomass) and distribution of carbon (C), hydrogen (H), and nitrogen (N) for C. odorata plants in a nursery with different application rates of biochar produced from Tectona grandis wood residues. The results showed that the above-measured variables were statistically affected by different application rates of the biochar. The stem diameter, total height, number of leaves, and height increment were statistically significantly higher in the substrate with an application rate of 25–50 tons/ha, in contrast to the 0 and 75 tons/ha application rates, which were statistically the lowest. As for the levels of C, H, and N, there were differences, with the highest values of N and C being in the leaves and stem with the 50 tons/ha application rate and the highest values of H for the 75 tons/ha application rate. The above results showed that applying biochar obtained from T. grandis residues improved soil conditions, resulting in better growth of C. odorata saplings with an application rate of 25 and 50 tons/ha. [ABSTRACT FROM AUTHOR]