Timber Plantations Research Articles

Long-term effects of planting density and site quality on timber assortment structure based on a 41-year plantation trial of Chinese fir

Stand density control coupled with site control is a key technique for cultivating large-diameter timber of Chinese fir trees, whose yield can be effectively increased by the optimal density and site management mode employed. This study aimed to evaluate the dynamic changes in timber assortment structure under differing initial planting densities and site quality based on growth data of a 41-year trial of Chinese fir plantations. Our results showed that the total timber yield and both large-diameter timber outturn and the outturn rate all increased with better site quality under the same initial planting density. Further, the outturn peak as well as outturn rate peak for both medium- and small-diameter timber was reached sooner with improved site quality. For the same site class, a lower initial planting density augmented the total timber outturn rate, and also resulted in less time required for the total timber outturn rate to reach a constant or maximum value. Finally, the total timber outturn rate of all density plots tended to be nearly identical. Using a high planting density increased the outturn of small-diameter timber, whose outturn peak was delayed in the denser plots. The bolstering effect of low density upon the growth of large-diameter timber was enhanced by higher site quality, with density-induced differences in large-diameter timber more pronounced; conversely, that promoting effect weakened under poor site quality conditions. The interaction between planting density and site index significantly influenced the growth of any timber assortment of Chinese fir in the early stage following its formation. Notably, the significant effect of site index on large-diameter timber lasted longer than that of other timber assortments. The optimal site conditions for cultivating large-diameter timber trees of Chinese fir consist of a site class ≥ 20 with a planting density limited to no more than 1667 trees/ha, whose stand rotation period must be over 26 years, so as to maximize the output of large-diameter timber yield. Our empirical findings will be helpful for the construction of an optimal cultivation mode for the density, site, and rotation age of large-diameter timber in Chinese fir plantations.

New Data of Morphological Variation in Microhyla gadjahmadai Atmaja et al., 2018 (Anura: Microhylidae) from West Sumatra

Microhyla gadjahmadai was first described by Atmaja et al. in 2018. For the newly described species category, there is not much information explaining this species and there has been no further research after this species was described, especially in West Sumatra. This study aims to provide information on variations in the morphological characteristics of M. gadjahmadai in West Sumatra, through morphological and morphometric analysis of 8 samples (1 adult male and 7 adult females) found in Puncak Anai (Dempo Anailand), Kanagarian Guguak, District 2x11 Timber Planting, Padang Pariaman Regency, West Sumatra. This study used the Visual Encounter Survey (VES) method. The result of the present study shows that no significant morphological differences between the holotype and paratype of Microhyla gadjahmadai and other specimens from West Sumatera. However, the present study reported that the morphological variations of this species.

Preserving large tracts of natural grassland promotes mammal species richness and occurrence in afforested areas

The global loss of biodiversity paired with the shortcomings of protected areas highlights the need to improve the conservation potential of human-modified lands. Although often referred to as “ecological deserts”, large spatial scales and long rotation periods make tree plantations a relatively stable and permeable environment that could provide an important link between fragmented natural habitats. Different intensities of afforestation within the same geographic grassland region provide an opportunity to test how transformation by commercial plantations affects local biodiversity. We conducted camera trap surveys at two sites characterised by different degrees of afforestation. We demonstrate a higher mammalian diversity and a higher probability of habitat use in less transformed areas, suggesting that preserving large tracts of native vegetation is vital when offsetting biodiversity loss from timber plantations, especially regarding grassland-specialist species. Community-level habitat use increased in more rugged areas, while in the highly transformed site, habitat use increased closer to indigenous patches and roads. Our research highlights the importance of maintaining comprehensive networks of protected units as part of a broader landscape management approach and identifies a major challenge for the forestry industry moving forward, with plantation stands being dominated by species that threaten the long-term sustainability of the crop itself.

Особенности клонального микроразмножения триплоидной осины с применением ростостимулирующих препаратов

The creation of fast-growing triploid aspen plantations in the area of wood processing enterprises has high importance in terms of increasing demand for deciduous wood associated with the development of board production and the prospects for the introduction of innovative technologies for deep processing of wood. The article presents the results of studies of triploid aspen clones of Kostroma origin at the stages of “introduction to in vitro culture”, “proper micropropagation”, and “rooting of microshoots” with the use of growth-regulating substances. At the “introduction culture to in vitro” stage, the most effective sterilizing agents were silver nitrate with the concentration of 0.2 %, Lysoformin 3000, 5 % applied for 15 min and sulema, 0.2 % used for 10 min. At the “proper micropropagation” stage, the total length of triploid aspen shoots did not differ significantly depending on the composition of the nutrient media studied but was slightly exceeded the options with Woody Plant Medium. An increase by 1.2–2.6 times was observed in the total length of triploid aspen microshoots in vitro, when the concentration of 6-benzylaminopurine in the nutrient medium was increased from 0.5 to 1.0 mg/L. The maximum value of the total length (5.6 cm) of tryploid aspen microshoots in vitro was observed on Woody Plant Medium at the 6-benzylaminopurine concentration of 1.0 mg/L and the presence of Epin-Extra preparation of 0.5 mg/L. At the “rooting of microshoots” stage the number, average, and total length of triploid aspen roots in vitro had no statistically significant differences depending on the nutrient medium composition. Increasing the concentrations of indole-3-butyric acid and indole-3-acetic acid from 1.0 to 2.0 mg/L in the nutrient medium increased the total length of regenerated plant roots of triploid aspen in vitro by 2.3–2.4 times. The maximum total length (5.1 cm) of triploid aspen roots in vitro was observed on Woody Plant Medium with indole-3-butyric acid at a concentration of 1.0 mg/L. Clonal micropropagation appears to be a perspective for accelerated production of elite planting material of triploid aspen for the purposes of laying out timber plantations. For citation: Makarov S.S., Bagaev E.S., Chudetsky A.I., Kuznetsova I.B., Lebedeva O.P., Antonov A.M. Features of Triploid Aspen Clonal Micropropagation Using Modern Growth-Stimulating Preparations. Lesnoy Zhurnal = Russian Forestry Journal, 2023, no. 2, pp. 183–194. (In Russ.). https://doi.org/10.37482/0536-1036-2023-2-183-194

Remnant habitat patches provide high value for a wide range of insect species in a timber plantation mosaic

Species present in transformed landscapes utilise resources from either the transformed patches, natural patches, or both. Depending on the degree to which species are specialised, species-specific responses to landscape transformation is both varied and dynamic. Understanding species-specific responses across a landscape is therefore essential to make informed conservation decisions. We investigate how spillover of stenotopic, cultural, and ubiquitous insect species respond to the different edge combinations present in a timber plantation mosaic. We use a multi-taxon approach, sampling two distinct insect assemblages (ground and foliage) across four different biotopes in a grassland-forest-plantation landscape in the Midlands of KwaZulu-Natal, South Africa, which forms part of the Maputaland-Pondoland-Albany biodiversity hotspot. We show that in this landscape, ecological networks consisting of natural grassland and forest supported high insect diversity in both ground and foliage assemblages. The foliage assemblage displayed stronger responses to the different biotope combinations than the ground assemblage. There was remarkably little spillover of habitat specialist species of either the ground or foliage assemblages from grassland or forest into the plantation stands. The few species associated with plantation stands (cultural species) had consistent levels of spillover across different types of plantation blocks, but not into the natural areas. Natural biotopes in this landscape conserved many habitat specialists, whereas plantations maintained low levels of diversity. Thus, we recommend that conservation practitioners consider the fidelity and spillover of the species present in the local landscape before designing conservation plans in these dynamic production landscapes.

The Role Of Inter-Sectors In Agroforestry Development In The Community Forest Environment, Pacitan District

Communities around the forest need to be encouraged in the development of forestry plants by the community either independently or with the assistance—of the government so that environmental sustainability can be adequately controlled. The development system carried out by the community, in general, is a hybrid system or better known as the agroforestry system. This study aims to identify sectors related to efforts to develop forestry plants.airly well-established economic condition. Development of forestry plants with this system . However, few people also develop a monoculture system, especially those with large enough land and who do not depend on the ground. Building role synergy between sectors supporting the development of forestry plantations is urgently needed to increase the quantity and quality of raw materials to meet the needs of the timber industry, both locally and nationally. Three critical sectors that must synergize in supporting the development of forestry plantations by the community are research and educational institutions, the government, and the market (industry). These three sectors are expected to be able to build attractive incentives for the community so that the community continues to preserve timber plants. Research and educational institutions can provide information and technology related to efforts to increase forestry plant production. Both information and technology from social, economic, and silvicultural or cultivation aspects. Information and technology produced by these research and educational institutions can be used as input and consideration for the government in formulating programs and policies related to developing timber plantations on private land. Through the formulation of its policies and work programs, the government is expected to initiate, facilitate and assist the community in developing forestry plants. Furthermore, the market sector, especially the timber industry, must be encouraged to create a conducive post-harvest climate so that the community continues to be motivated to increase the production of raw wood materials.

Paulownia (Paulownia elongata S.Y.Hu) – importance for forestry and a general screening of technological and material properties

ABSTRACT In Austria, paulownia (Paulownia spp.) has not been approved as a forest species. Because of the enormous annual growth and the promising mechanical and physical properties of this tree species, it is grown in short-rotation and value timber plantations in Central Europe. Previous studies have addressed the forestry and silvicultural aspects of different plant materials and issues in wood technology and wood physics based on small sample collections. Broad material screening for the technological evaluation of paulownia, samples obtained in large quantities from plantations, has not been conducted thus far. Therefore, this study aimed to provide a general overview of the technological, physical and mechanical properties of this wood species, in addition to basic forestry considerations. The wood samples for the experiments were obtained from an Austrian experimental plantation. In addition to wood drying, natural durability, workability and gluing, density and swelling/shrinking behaviour were investigated, and a comprehensive characterisation of all strength and stiffness properties was performed. The results will enable the modelling of paulownia wood to determine its static and dynamic loads, as well as the crash behaviour, using the finite element method (FEM) and well-founded assessments of the material’s workability.

Mapping China’s planted forests using high resolution imagery and massive amounts of crowdsourced samples

Tree planting has been suggested as a potentially effective solution for mitigating climate change. China has implemented the world’s largest afforestation and reforestation project since the 1970s, but high-resolution maps of China’s planted forests remain unavailable. In this study, we explored the use of multi-source remote sensing images and crowdsourced samples to produce the first high-resolution (30-m) map of China’s planted forests. We constructed a Google Earth Engine (GEE)-based mapping framework using spectral, temporal, structural, textural and topographic features derived from Landsat and Sentinel-1 time series imagery, Digital Elevation Model (DEM) and Chinese Forest Canopy Height (CFCH) data. Over 300,000 high-quality crowdsourced samples were collected for training the mapping pipeline. Validation against independent field samples indicated an accuracy of 84.93 % and an F1 score of 0.85. The uncertainty map of each pixel was also constructed and showed that the areas of low and medium uncertainties accounted for 38.27 % and 50.98 % of the total area, respectively, indicating the high estimation reliabilities of the planted forest map. We show that China’s planted forests in the year of 2020 had a total area of 769853.01 km2, accounting for 31.30 % of the world’s total planted forests. The majority (77.45 %) of China’s planted forests were located in the Eastern, Center-South, and Southwestern regions. By further assessing the performance of the image features used to map the planted forests, we found that temporal features are key to identifying the planted forests in East and Center-South of China, where they are mainly timber plantations. However, structural and textural features were more useful for locating the planted forests in North and Northeast of China, where are dominated by planted shelterbelts. Our study demonstrated that combining crowdsourced samples with high-resolution satellite images allows mapping planted forests with unprecedented resolution (30-m) across large areas. Our map could contribute to the sustainable management of China’s forests and a more accurate quantification of the carbon balance of China’s natural ecosystems.

The role of landscape and parent material on regolith under timber plantations at Highflats, KwaZulu-Natal, South Africa

Regolith is an important component of the Earth's critical zone. Little investigative work has been done in southern Africa on regolith characteristics as a component of the critical zone, and in particular the importance to forestry plantation productivity in the eastern hinterland of South Africa. Regolith cores were extracted from five positions across two slopes underlain by sandstone and tillite to characterize these regolith profiles and ascertain the effect of slope position and parent material on regolith development. Regolith profiles were characterized and analysed on hill crest and lower midslope positions at both sites. The profile descriptions noted the degree of weathering, rooting activity, and mineral composition. The deepest in situ weathering of regolith was found on the hill crest positions; sandstone crest (24.0 m) and tillite crest (8.2 m) respectively. The accumulation of colluviated sediment on lower slopes also resulted in a thicker regolith at the tillite site, despite the less intensely weathered bedrock. These findings were consistent with earlier geophysical and pedohydrological studies of the area and the regolith profiles are consistent with those described for a range of other sedimentary lithologies in similar regions in sub-tropical and tropical landscapes The results show that tree roots utilize the saprolite and saprock below soil horizons and the nature of these layers indicate the full regolith profile should be considered in the water and nutrient supply available to forest plantations. Current concepts of ‘effective rooting depth’, as widely used by South African forestry, are inadequate for understanding ecosystem processes in forest plantations.

Implementation of Bayesian inference MCMC algorithm in phylogenetic analysis of Dipterocarpaceae family

Dipterocarpaceae is one of the most prominent plant families, with more than 500 members of species. This family mostly used timber plants for housing, making ships, decking, and primary materials for making furniture. In Indonesia, many Dipterocarpaceae species have morphological similarities and are challenging to recognize in the field. As a result, the classification process becomes difficult and even results are inconsistent when viewed only from the morphology. This research will analyze the phylogenetic tree of Dipterocarpaceae based on the chloroplast matK gene. The aim of the research is to classify the phylogenetics tree of Dipterocarpaceae family using Bayesian inference algorithm. This research used the chloroplast gene instead of morphological characters which has more accurate. The analysis steps are collecting data, modifying the structure sequence name, sequence alignment, constructing tree by using Markov Chain Monte Carlo (MCMC) from Bayesian Inference, and evaluating and analyzing the phylogenetic tree. The results showed that the tree constructed based on the gene is different from the tree based on morphology. Based on the morphological, Dipterocarpus should be in the Dipterocarpeae tribe but based on the similarity of its genes, Dipterocarpus is more similar to the Shoreae tribe.

Effect of thinning on growth and shape of Castanea sativa adult tree plantations for timber production in Chile

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.

Screening of Ginkgo Individuals with Superior Growth Structural Characteristics in Different Genetic Groups Using Terrestrial Laser Scanning (TLS) Data.

With the concept of sustainable management of plantations, individual trees with excellent characteristics in plantations have received attention from breeders. To improve and maintain long-term productivity, accurate and high-throughput access to phenotypic characteristics is essential when establishing breeding strategies. Meanwhile, genetic diversity is also an important issue that must be considered, especially for plantations without seed source information. This study was carried out in a ginkgo timber plantation. We used simple sequence repeat (SSR) markers for genetic background analysis and high-density terrestrial laser scanning for growth structural characteristic extraction, aiming to provide a possibility of applying remote sensing approaches for forest breeding. First, we analyzed the genetic diversity and population structure, and grouped individual trees according to the genetic distance. Then, the growth structural characteristics (height, diameter at breast height, crown width, crown area, crown volume, height to living crown, trunk volume, biomass of all components) were extracted. Finally, individual trees in each group were comprehensively evaluated and the best-performing ones were selected. Results illustrate that terrestrial laser scanning (TLS) point cloud data can provide nondestructive estimates of the growth structural characteristics at fine scale. From the ginkgo plantation containing high genetic diversity (average polymorphism information content index was 0.719) and high variation in growth structural characteristics (coefficient of variation ranged from 21.822% to 85.477%), 11 excellent individual trees with superior growth were determined. Our study guides the scientific management of plantations and also provides a potential for applying remote sensing technologies to accelerate forest breeding.

Plus tree selection of Gao vang (Naucleo Orientalis) for big timber developing of indigenous plantations

The results of early growths assessment of the Gao vang experimental planting area at the stage 7 year old and the selection of plus trees for big timber plantations show that the average growths in diameter at breast height, crown diameter, total height and trunk volume of plus trees (TG) reached a value of 16.74 cm; 5.24m; 10.74m; and 118.20 dm3 per tree, respectively, exceeding the accompanying forest tree group (ĐR) of 1.60; 1.02; 1.15; and 2.82 times, respectively, under the same comparison criteria, environmental conditions and time. The forest tree groups including, ĐR1; ĐR2; ĐR3; ĐR4; and ĐR5 had a coefficient of variation (CV%) in diameter of 19.07; 18.41; 13.45; 17.90; and 17.18%. Growth speed in diameter of plus trees including, TG4; TG3; TG2; TG5; and TG1 reached a value of 2.31; 2.40; 2.40; 2.41; and 2.43 cm per year, respectively, growth farther other forests tree group by 1.55 to 1.59 times. Exceed level (%) in diameter of plus trees including, TG1; TG2; TG3; TG4; and TG5. Forest trees groups reached a value of 31.75; 30.72; 31.97; 31.52; and 30.89%, respectively, that were better than the accompanying forest tree groups and the standards of plus trees for big timber indigenous plantating development. In total, there are over 1360 Gao vang individuals measured and evaluated, but only 5 excellent trees in growth could be selected, that had a exceed level for diameter of over 30% compared to the accompanying forest tree group, a ratio of 0.36%, and a selective intensity of 0.99. The plus trees evaluated and selected are very valuable as propagation materials, contributing to providing information, scientific basis, quality seed sources, and diversifying the structure of forestry tree varieties for the goal of developing big timber plantations with native species.

Panel products from Melia dubia

The demand and supply gap for wood is showing an ever increasing trend and in order to counter act on this trend, efforts are made in all possible ways to substitute wood with suitable alternatives wherever possible and to shift the focus from natural forests to private plantations for sourcing the timber raw material for wood based industries. As part of this efforts, local timbers are being extensively studied for their suitability for producing wood based composites which could replace the solid wood without compromising in either aesthetic appearance or strength properties. Clones of Eucalyptus, Poplar, Silver oak etc. are a few timber species to name. Melia dubia is one such plantation timber suitable for farm forestry and agro forestry which is becoming trendy among present day farmers, private planters and wood based industries because of its fast growth, inherited anti-termite and anti-insect properties etc. This paper presents the research results of a series of studies conducted to find the suitability of Melia dubia for manufacturing Particleboard, Medium density fiberboards (MDF), Laminated Veneer Lumber (LVL) and Blockboard.Â

What drives the abundance of marsupial carnivores in production forest landscapes?

Production forest landscapes provide important habitat for wildlife but expose them to disturbances from forestry practices. Understanding how threatened carnivores use production forests can inform management practices to improve their conservation. While there have been many studies of eutherian carnivores in production forests, the use of these landscapes by marsupial carnivores is poorly understood. Using a network of remote cameras, we investigated the use of forestry landscape features by two endangered marsupial carnivores, Tasmanian devils (Sarcophilus harrisii) and eastern quolls (Dasyurus viverrinus). Devil and quoll abundance increased with the extent of timber plantations within production forest landscapes. Overall, devils were positively associated with higher tree density and eastern quolls with indicators of open habitat such as less understorey, fewer trees and more grassland. Within plantations, devil abundance increased with the volume of windrows (piles of woody debris from harvesting arranged in rows), as did eastern quoll abundance in pine plantations. Eastern quoll abundance was higher in pine plantations established on pasture than those established on cleared native forest land, and in eucalypt plantations, higher with windrows comprised of plantation debris. Neither species showed a strong response to logging-related features in native forest such as time since harvest, though eastern quolls were positively associated with log cover. Our results demonstrate that plantations provide valuable habitat for marsupial carnivores and that they can persist in harvested native forests. Windrows likely benefit devils and eastern quolls by providing denning, shelter and foraging opportunities, and should be managed as important habitat features for carnivores. These findings can be used by forest managers to guide decisions and help maintain threatened carnivore populations in human-modified landscapes.

There is glory in prevention! Regional spatio-temporal agrochemical runoff into aquatic ecosystems and its potential mitigation using multifunctional buffers

Study regionUruguay, South America Study focusRiparian ecosystems accumulate the impacts of land use change from extensively used grasslands to industrial cash crops in their watersheds and transport a proportion of pollution downstream. We modelled and assessed land use changes within different zones along Uruguayan freshwater ecosystems and estimated the potential risks of phosphorus and glyphosate runoff based on different land use scenarios. New hydrological insights for the region under studyWe found that ongoing intensification of grasslands, as well as the conversion to cropland and timber plantations, exerted high pressure on aquatic ecosystems. Phosphorus runoff is expected to increase by more than 40% and glyphosate runoff by 500%. Excluding intensified land use within the first 100 m of streams can reduce pollutant discharge by ≈ 20%. We propose an expansion of pollution monitoring from large to small streams. Results from modelling can contribute to decision making and to raising awareness among stakeholders involved in land management and planning.

Season of prescribed burns and management of an early successional species affect flower density and pollinator activity in a pine savanna ecosystem.

In the age of changing fire regimes, land managers often rely on prescribed burns to promote high diversity of herbaceous plants. Yet, little is known about how the timing of prescribed burns interacts with other ecological factors to maintain biodiversity while restoring fire-adapted ecosystems. We examined how timing of prescribed burns and removal of a dominant, early successional weedy plant yankeeweed (Eupatorium compositifolium) affect flower density and pollinator activity in an early-successional longleaf pine savanna restored from a timber plantation. During the first year of this study, plots received seasonal burn treatments, including unburned control, winter-dry, spring, and summer-wet season burns. During the second year of the study, data on flowers and pollinators were sampled across all plots. In the third year, these seasonal burn treatments were again applied to plots, and data were again collected on flowers and pollinators. In each burn treatment plot, we manipulated the presence of yankeeweed, including one control subplot (no removal) in which yankeeweed was not manipulated and one removal subplot in which yankeeweed was removed, and flowers and pollinators were measured. During the year between burns, flower density was highest in the summer-wet season burn treatment, significantly higher than in the unburned control, while pollinator activity was highest in the summer-wet and spring season burn treatments, significantly higher than the unburned control. During the year in which plots were burned again, flower density was highest in the spring season burn treatment, and pollinators most frequent in both spring and winter-dry season burn treatments, significantly higher than the unburned control. Removing yankeeweed enhanced pollinator activity but only in the year between fire applications. We conclude that prescribed burning enhances floral resource availability and pollinator activity, but the magnitude of these effects depends on when fires are applied. Additionally, removal of yankeeweed can enhance pollinator activity during years between prescribed burns.

Mitigating the Mistletoe Menace: Biotechnological and Smart Management Approaches.

Mistletoes have been considered a keystone resource for biodiversity, as well as a remarkable source of medicinal attributes that attract pharmacologists. Due to their hemiparasitic nature, mistletoes leach water and nutrients, including primary and secondary metabolites, through the vascular systems of their plant hosts, primarily trees. As a result of intense mistletoe infection, the hosts suffer various growth and physiological detriments, which often lead to tree mortality. Because of their easy dispersal and widespread tropism, mistletoes have become serious pests for commercial fruit and timber plantations. A variety of physical and chemical treatment methods, along with silvicultural practices, have shaped conventional mistletoe management. Others, however, have either failed to circumvent the growing range and tropism of these parasitic plants or present significant environmental and public health risks. A biocontrol approach that could sidestep these issues has never achieved full proof of concept in real-field applications. Our review discusses the downsides of conventional mistletoe control techniques and explores the possibilities of biotechnological approaches using biocontrol agents and transgenic technologies. It is possible that smart management options will pave the way for technologically advanced solutions to mitigate mistletoes that are yet to be exploited.

Janka Hardness Evaluation of Plantation-Grown Eucalyptus nitens for Engineered Flooring Applications

Hardness is commonly used to determine the suitability of a timber species for flooring applications. In this study, Janka hardness test is conducted on sawlog managed Eucalyptus nitens and regrowth forest Eucalyptus obliqua sourced from Tasmania, Australia. Plantation E. nitens timber is currently entering the Australian market and the feasibility of using this fast grown species in value added applications such as timber flooring is advantageous. Further to testing Janka hardness on solid timber samples, a regime of engineered timber flooring prototypes consisting of plantation E. nitens top layers, veneers and solid densified E. nitens boards were developed and subjected to Janka hardness test. The results were compared against solid E. obliqua flooring and a commercially available engineered flooring product with Tasmanian Oak top layer. The results showed that Janka hardness of plantation grown E. nitens, and E. obliqua currently available in the market are lower than the values published in the literature. This indicates that the material properties of fast grown plantation timber and regrowth forest material are different to the native forest timber properties published decades earlier. Furthermore, some of the tested engineered flooring prototypes showed similar behaviour to timber flooring products currently in market, suggesting that E. nitens engineered flooring would be suitable for domestic/light commercial flooring applications despite the general conception of unsuitability due to lower densities.

Calibration, validation and application of the SWAT model to determine the hydrological benefit of wetland rehabilitation in KwaZulu-Natal, South Africa

In South Africa, with highly variable and intense land-use practices, coupled with limited soil fertility and water resources, there has been a long history of encroachment of arable lands (sugarcane and timber plantations) into surrounding wetlands. Although wetland delineation within the timber and sugar sectors is well-defined in policy, and existing and proposed legislation, there are significant areas of non-compliance. The spatially-explicit Soil Water Assessment Tool (SWAT) was adopted to investigate the interactions of climate, land-use and soil on the water-use of natural and encroached wetlands. This paper documents the calibration, validation and application of the SWAT model on Quaternary Catchment (QC) U20G, which is a 498 km2 catchment that forms part of the uMngeni River basin. The SWAT-CUP parameter sensitivity and optimization model was tested with daily observed streamflow data for this catchment. Parameters were modified using the sequential uncertainty fitting (SUFI-2) analysis routine to calibrate the model. The simulated flow had a close fit to the observed flow with a regression coefficient (r2) of 0.87 and a Nash-Sutcliffe (NS) coefficient of 0.8. Through the buffer scenario analysis, the model showed that if the wetland and a 20-m buffer were to be returned to a natural state, there could be a 16% increase in the annual streamflow contribution, with an upper limit of a 60% increase in some hydrologic response units (HRUs). Thus there would be a hydrological gain if wetlands and sensitive buffer areas were to be cleared of commercial timber species and sugarcane.