Rolling Shear Properties of Cross-Laminated Timber Made from Australian Plantation Eucalyptus nitens under Planar Shear Test

With the increasing availability of fast-growing Eucalyptus plantation logs in Australia in recent years, the timber manufacturing sector has become interested in discovering the opportunities of producing value-added timber products from this resource. Cross-laminated timber (CLT) could be a potential sustainable product recovered from this resource and supply material for commercial buildings. Shear of the inner cross-laminates, known as rolling shear, is one of the governing factors in serviceability and limit state design for this product under out-of-plane loading. This study evaluated the rolling shear (RS) properties of CLT with heterogonous layup configurations using different structural grade Eucalyptus nitens (E. nitens) timber under the planar shear test. Based on the results, Gr and τr values were shown to be significantly correlated with the density of the CLT panel. There was also a positive correlation between the RS modulus and MOR of the CLT panel. The specimens with high MOE in the top and bottom layers indicated the highest τr and Fmax values. This indicated that using high-grade boards in the top and bottom lamellae plays an important role in increasing the RS strength, whereas using them in the cross-layer has a positive contribution in increasing shear modulus. The maximum observed RS strength and modulus ranged from 2.8–3.4 MPa and 54.3–67.9 MPa, respectively, exceeding the RS characteristic values of the resource. The results obtained in this study were comparable to those recommended in European standards for softwood CLT, demonstrating the potential use for eucalypt timber boards in CLT production. This paper provides an important insight into supporting the potential engineering applications of CLT panel products fabricated with eucalypt plantation.

Land-Use Change Depletes Quantity and Quality of Soil Organic Matter Fractions in Ethiopian Highlands

The depletion of soil organic matter (SOM) reserve after deforestation and subsequent management practices are well documented, but the impacts of land-use change on the persistence and vulnerability of storage C and N remain uncertain. We investigated soil organic C (SOC) and N stocks in a landscape of chrono-sequence natural forest, grazing/crop lands and plantation forest in the highlands of North-West Ethiopia. We hypothesized that in addition to depleting total C and N pools, multiple conversions of natural forest significantly change the relative proportion of labile and recalcitrant C and N fractions in soils, and thus affect SOM quality. To examine this hypothesis, we estimated depletion of SOC and N stocks and labile (1 & 2) and recalcitrant (fraction 3) C and N pools in soil organic matter following the acid hydrolysis technique. Our studies showed the highest loss of C stock was in grazing land (58%) followed by cropland (50%) and eucalyptus plantation (47%), while on average ca. 57% N stock was depleted. Eucalyptus plantation exhibited potential for soil C recovery, although not for N, after 30 years. The fractionation of SOM revealed that depletions of labile 1 C stocks were similar in grazing and crop lands (36%), and loss of recalcitrant C was highest in grazing soil (56%). However, increases in relative concentrations of labile fraction 1 in grazing land and recalcitrant C and N in cropland suggest the quality of these pools might be influenced by management activities. Also, the C:N ratio of C fractions and recalcitrant indices (RIC and RIN) clearly demonstrated that land conversion from natural forest to managed systems changes the inherent quality of the fractions, which was obscured in whole soil analysis. These findings underscore the importance of considering the quality of SOM when evaluating disturbance impacts on SOC and N stocks.

Soil Bacterial and Fungal Community Responses to Throughfall Reduction in a Eucalyptus Plantation in Southern China

In subtropical plantations in southern China, how soil microbial communities respond to climate change-induced drought is poorly understood. A field experiment was conducted in a subtropical Eucalyptus plantation to determine the impacts of 50% of throughfall reduction (TR) on soil microbial community composition, function, and soil physicochemical properties. Results showed that TR reduced soil water content (SWC) and soil available phosphorus (AP) content. TR significantly altered 196 bacterial operational taxonomic units (OTUs), most of them belonging to Acidobacteria, Actinobacteria, and Proteobacteria, while there were fewer changes in fungal OTUs. At the phylum level, TR increased the relative abundance of Acidobacteria at 0–20 cm soil depth by 37.18%, but failed to influence the relative abundance of the fungal phylum. Notably, TR did not alter the alpha diversity of the bacterial and fungal communities. The redundancy analysis showed that the bacterial communities were significantly correlated with SWC, and fungal communities were significantly correlated with AP content. According to predictions of bacterial and fungal community functions using PICRUSt2 and FUNGuild platforms, TR had different effects on both bacterial and fungal communities. Overall, SWC and AP decreased during TR, resulting in greater changes in soil bacterial community structure, but did not dramatically change soil fungal community structure.

Value Chain Analysis of Eucalyptus Wood Products in the Blue Nile Highlands of Northwestern Ethiopia

Eucalyptus wood products contribute significantly to the income of smallholder growers in many parts of Ethiopia. This has incentivized smallholders to convert arable lands to Eucalyptus plantation. Given the limited attention and availability of empirical evidence, this study examined the Eucalyptus wood products value chain in terms of the actors engaged, the type and importance of channels, margins analysis and the overall value chain governance in the main Eucalyptus growing areas of the Blue Nile highlands of Northwestern Ethiopia in 2019/2020. Sources of data were randomly selected 388 Eucalyptus grower households and 166 Eucalyptus wood traders, complemented by an interview with key informants, group discussions and direct observations. The results reveal that a total of 2,051,114.75 m3 of Eucalyptus wood was produced in the study area and Eucalyptus plantations are expanding over crop lands at a rate of 102.35 ha a year on average. Many actors involved handle a large volume of wood in eight main channels with a high disparity in the shares of the margins. We found that Eucalyptus is the main source of cash earning, contributing about 45.76% to the total annual income of smallholder growers. Little policy attention, a lack of sectoral integration, missing infrastructure and an absence of modern wood processing factories are among the key challenges impeding the performance of the wood sector value chain. There are however existing opportunities for the development of the wood sector value chain such as favorable growing conditions and the spectacular growing demand for wood products. The study provides valuable insights about the wood sector value chain and actions towards ensuring sustainable value chains and the commercialization of the sector.

Eucalyptus plantation and its integrated supply chain in pulp and paper mill

Nowadays, demand of the pulp and paper production increases quickly. That increasing demand has led to demanding of eucalyptus plantation. That is why eucalyptus plantation has rapidly expanded and became the most planted tree species across the world over the last century. Not only because its unique characteristics, increasing of eucalyptus plantation also happened because its growing gives a socio-economic benefits, industrial benefits, and environmental impacts. However, increasing demand of eucalyptus certainly make availability of eucalyptus being determined, known as limited supply chain. Due to the increasing demand and limited supply chain, the eucalyptus wood supply should managed, by integrated the supply chain well. In this research study, the supply chain of eucalyptus wood for pulp and paper industry was diagnosed and divided into three degree, there are direct supply chain, extended supply chain, and ultimate supply chain. Four main stakeholders in this chain identified consisted of the eucalyptus seedling developers and sellers, the suppliers, the distribution centers, and the pulp and paper production plants.

Fulfilling Eucalyptus raw materials for pulp and paper production plants

Eucalyptus is one of the major species used for pulp and paper industry. As industries develop, the need for Eucalyptus supply increases. However, there are challenges plantation companies must specifically determining eucalyptus market price potential risks in eucalyptus plantation and how eucalyptus plantation impacts the surrounding environment.. Stakeholders on eucalyptus supply chain have risks which have to be mitigated. The eucalyptus seedling and developer and the supplier hold crucial role in providing good quality eucalyptus raw material for pulp and paper production plants. This research is conducted to explore on ways to mitigate each stakeholders risk, challenges plantation companies face in fulfilling eucalyptus raw material for pulp and paper production plants. There are four stakeholders in eucalyptus supply chain: eucalyptus seedling developer and seller, supplier, distribution centre and pulp and paper production plants. Some of the major risk stakeholders are facing in eucalyptus supply chain are: early cut of eucalyptus trees, farmers’ lack of understanding on growing eucalyptus properly, small stem size, fluctuating eucalyptus wood price and low stock quantity. Some of the minor risk stakeholders are facing: earthquake, over fertilization, overwatering, cold climate, and plant setting. There are four methods used to determine eucalyptus pricing: cost-based pricing, customer-based pricing, competition-based pricing, and statutory pricing. Eucalyptus consume high amount of water which can cause dry areas around eucalyptus plantation area and low groundwater reservoir.

Bird-plant interaction networks in native forests and eucalyptus plantations within a protected area

Frugivory is a plant-animal mutualistic interaction carried out mostly by birds. It consists in the bird consumption of fruits with later dispersion of the plants' seeds, helping in the vegetation regeneration. Frugivory can be affected by the habitat fragmentation and introduction of exotic species, which may alter the species interaction by extinction or competitor introduction. This study aimed to compare the structure of the network of frugivorous interactions between birds and plants in native forest and eucalyptus plantation. Birds were captured by mist nets and had their feces collected. Later, the seeds were identified in laboratory. The records of fruit consumption by birds in the zoochoric plant species present in the study area were also conducted. The data collected was used to build a network of interactions and identify the most important network metrics, species, and ecological functional groups in the studied environments. The results showed that the species composition, the connectivity of the relationships, the importance of the species for the interaction networks and the number of subgroups within the networks were highly similar between the native forest and the eucalyptus plantation. This could be explained by the favorable conditions that the studied eucalyptus plantations presented, such as the lack of anthropogenic activities, well-developed understory, and the presence of native surrounding vegetation, allowing practically the same seed dispersal capacity in both types of environments.