Bamboo Density Research Articles

Minimally destructive bamboo property estimation of Phyllostachys makinoi using drilling resistance method

Drilling resistance amplitude was used to estimate properties such as density, modulus of elasticity (MOE), and modulus of rupture (MOR) in Phyllostachys makinoi bamboo. The purpose of this study was to replace subjective visual estimation with a scientific method, using drilling resistance to estimate bamboo maturity, thereby providing a basis for selecting high-quality bamboo materials. The results indicated significant linear correlations between both average and maximum drilling amplitudes and bamboo density, MOE, and MOR. The coefficients of determination (R²) for average and maximum drilling amplitude with bamboo density ranged between 0.55 and 0.56, and a significant linear correlation was also observed between average and maximum drilling amplitudes (R² = 0.75). Additionally, the profile curve of drilling resistance amplitude varied significantly across the thickness of the bamboo culm. From the culm surface inward (bamboo skin, flesh layer, and cavity layer), the amplitude rose rapidly, reaching a peak at approximately 28% of culm thickness, then gradually decreased, with a secondary reduction observed around 67% of the thickness, eventually reaching the hollow core. Based on these findings, maximum drilling amplitude could serve as an indicator of bamboo density and may be applied as a minimally destructive technique

Size and canopy characteristics of community reserves determine primate occupancy in the state of Meghalaya, India, and implications for its conservation.

Globally, the effective protected area network is one of the last resorts for conserving biodiversity. The nature of protected areas depends on the land ownership of the respective countries including India. The landholding in the northeastern states of India remains with native people, thus, 'Community Reserve' (CR) was introduced in 2003. Considering the high number of CR in Meghalaya that are home to many threatened primates, understanding their role in conserving the primates was crucial. We conducted day and night trail surveys in 32 CR of Meghalaya, and a questionnaire survey of local people for their perception of primates. We sampled basal area, tree density, canopy cover, canopy height, bamboo density, and human activity in each CR to test their influence on the occupancy of primates. We recorded the Western hoolock gibbon Hoolock hoolock, capped langur Trachypithecus pileatus, Northern pig-tailed macaque Macaca leonina, Assamese macaque Macaca assamensis, Rhesus macaque Macaca mulatta, and Bengal slow loris Nycticebus bengalensis. The primate richness and abundance were higher in the CR of Garo Hills than in the Khasi and Jaintia Hills. The gibbons had the highest patch occupancy, which was followed by capped langur, Assamese macaque, and pig-tailed macaque. Large-sized CR determined the occupancy of gibbons and Assamese macaques. Canopy cover positively influenced the occupancy of three primates except the Assamese macaque, whereas the canopy height had a positive association with three species of primates. The basal area, and tree density, negatively affected the occurrence of Assamese macaque, northern pig-tailed macaque, and capped langur. Macaques were the most hunted primates. The differential occurrence and abundance in different hill systems may be due to hunting and habitat size rather than habitat quality. Habitat restoration would improve the habitat quality with the involvement of communities to assist in retaining and avoiding the local extinction of primates.

Environmental Factors Affecting the Density and Growth of New Bamboo Through Quantification Theory

Environmental Factors Affecting the Density and Growth of New Bamboo Through Quantification Theory

Evaluating the splitting capacity of timber beams loaded perpendicular to grain by bolted connections with steel plate: Experimental study and theoretical calculation

Timber structures have advantages such as green environmental protection and low-carbon energy conservation. Bolted connection with steel plate as one of the most commonly used dowel-type connections is widely used in timber structures. Nevertheless, the splitting capacity of timber beams loaded perpendicular to the grain by bolted connections with steel plate is influenced by various factors, leading to significant differences in calculation formulas and outcomes. On the basis of preliminary experimental research, a total of 113 timber beams and 6 bamboo glulam beams with steel plate bolted connections, loaded perpendicular to the grain, were tested and categorized into two main groups, with the consideration of the materials used for members and the total width of bolted connections. It was found that the splitting capacity of bolted connections loaded perpendicular to the grain increased along with the increase of material density of wood and bamboo. Essentially, a linear correlation was observed between the splitting capacity and the material density. In addition, the splitting capacity increased with an increase in the total width of connections and that the splitting capacity tended to be constant when the total width of connections reached a certain amount. Based on the test results and the current calculation model for splitting capacity, a modified model for calculating the splitting capacity of bolted connections loaded perpendicular to the grain was proposed. Notably, the average ratio of the calculated splitting capacity to literature-reported experimental results is 0.975. More importantly, the modified model, considering a comprehensive set of factors, offers broader application and improves usability for engineering designers.

Habitat Characteristics of the Endangered Himalayan Red Panda in Panchthar–Ilam–Taplejung Corridor, Eastern Nepal

The Panchthar–Ilam–Taplejung Corridor in Eastern Nepal, managed through community forestry, is a crucial habitat for the Himalayan red panda, an endangered carnivore threatened by forest degradation and illegal trade. We deployed the altitude line intercept and ten-tree plotless methods to evaluate the distribution of Himalayan red pandas and the environmental factors affecting them within four community forests, namely Singhadevi, Chitre-Hile, Chhipchhipe, and Kalikhop-Dadehli, of the corridor. We established a total of 23 transects and 92 plots, identifying 41 plots with evidence of the Himalayan red panda’s presence. The sign occurrence revealed a clumped distribution of the species across all four community forests. The Himalayan red panda signs were observed between 2200 m and 2700 m above sea level (asl) and the majority of them were from habitats with a moderate slope within elevations of 2400 m to 2500 m asl. The primary sites for the defecation were large horizontal tree branches (78.12%), followed by forest ground (15.62%) and rocks (6.25%). The dominant tree species in their habitats included Lithocarpus pachyphylla (Importance value index, IVI = 45.05), Symplocus theifolia (IVI = 37.19), Symplocos pyrifolia (IVI = 20.99), Quercus lamellosa (IVI = 19.25), and Magnolia campbellii (IVI = 17.25). Among the thirteen environmental variables examined, proximity to water, distance to road, bamboo density, and Normalized Difference Vegetation Index were identified as the major factors influencing the Himalayan red panda’s distribution. This research provides crucial insights to develop site-specific habitat management plans for community forestry.

Assessment of Density and Anatomical Features of Young and Old Bambusa vulgaris (Schrad. ex J.C. Wendl.) Culm Heights as Sustainable Structural Material in Ghana

This study sought to assess the density and anatomical features of young and old Bambusa vulgaris Schrad. ex JC Wendl. culm heights and, therefore, evaluate their influence on the utilization potential of the culm as a sustainable structural material. Bambusa vulgaris culm of 2-year and 4-year-old were harvested and prepared to the required length of 6 meters for the study. Basic density and anatomical features were carried out. The results showed that the basic density of old bamboo ranges from 652.91 kg/m³ to 729.06 kg/m³, while the young bamboo ranges from 342.33 kg/m³ to 509.52 kg/m³. The vascular bundle arrangement was found to be in Type III and Type IV for the culm heights of both young and old bamboo. The average vascular bundle radial diameter ranged from 761.13 μm to 890.78 μm for the old culm and 727.16 μm to 844.83 μm for the young culm. The average vascular bundle tangential diameter ranged from 499.44 μm to 533.49 μm for the old culm and 425.56 μm to 483.56 μm for the young culm. The radial diameter of the metaxylem vessel of the old culm ranged from 216.81 μm to 54.74 μm, while 214.23 μm to 73.86 μm were for the young culm. Parenchyma tissues ranged from 35%– to 70% for the old bamboo culm and 45% to 75% for the young bamboo culm. Vessel proportion ranged from 6%–12% for the old culm while the young culm ranged from 5%–11%. Fiber proportion ranged from 22% to 54% for the old culm and 19% to 44% for the young culm. Old bamboo had better vascular bundle properties than that of young bamboo. The density is significantly correlated positively to the anatomical properties. Old bamboo is more suitable to be used as the engineered composite material due to its better anatomical features across the culm wall thickness.

Swelling Behaviour of Bamboo (Phyllostachys pubescens)

Bamboo is a plant with various applications. As a natural, renewable material that exhibits good mechanical performance, it seems to be an interesting alternative to wood, which has become a scarce and expensive commodity. However, comprehensive knowledge of its properties is necessary to maximise its potential for various industrial purposes. The swelling behaviour of bamboo is one of the features that has not yet been sufficiently investigated. Therefore, in this research, we aimed to measure and analyse the swelling pressure and kinetics of bamboo blocks. The results show that similar to wood, the swelling kinetics of bamboo depend on its density: the denser the tissue, the higher the maximum swelling value recorded. The maximum tangential swelling measured was about 5%–6%, which is lower than the value for the most commonly used wood species. Swelling pressure ranged from 1.16 MPa to 1.39 MPa, depending on the bamboo density: the denser the sample, the shorter the time required to reach maximum swelling pressure. Like in wood, the smallest linear increase in size due to swelling was observed in the longitudinal direction (0.71%). However, opposite to wood, more pronounced swelling was recorded in the radial direction (over 7%) than in the tangential direction (nearly 6%). The results show that bamboo’s swelling behaviour makes it a good material for use in variable humidity conditions, being more favourable than the unmodified wood of many species.

Leaf traits are good predictors of woody species distribution after bamboo expansion in a mountain forest

The expansion of bamboo into neighboring plant communities is a common phenomenon in nature reserves. However, the role of climate factors and plant functional traits in the distribution of woody species after bamboo expansion remains unclear. Six functional traits of leaves of 180 individuals of 52 species, soil properties and air temperature were measured along an elevational gradient with different bamboo densities on Mt. Fanjingshan, Tongren City, Guizhou. Then, the direct and indirect effects of climate, soil properties, leaf traits and bamboo density on woody species distribution were detected. Our results showed that leaf traits were represented by two independent dimensions. The first dimension (PC1) is represented by the trade-off between the pairs leaf P, leaf N and leaf dry matter content, leaf C, representing nutrient use efficiency (NUE). The second dimension (PC2) was positively associated with leaf area, specific leaf area and leaf N, representing the leaf economics spectrum (LES). Climate, soil, leaf traits and bamboo density significantly explained 18% and 21% of the variance in species importance values for all species and evergreen species, respectively, but not for deciduous species. Air temperature had a positive indirect impact on the species importance value of all species via a negative direct impact on PC2, and air temperature affected the evergreen species importance value in two indirect ways: the first was to affect the species importance value positively and indirectly via PC2; the second was to affect the species importance value positively and indirectly through PC2 and PC1. However, bamboo expansion alone had no significant direct or indirect effects on species distribution. These results suggest that leaf traits are good predictors of woody species distribution after bamboo expansion in a mountain forest, and the effects of bamboo expansion are dependent on tree growth type, air temperature and leaf traits.

Variation in a Darwin Wasp (Hymenoptera: Ichneumonidae) Community along an Elevation Gradient in a Tropical Biodiversity Hotspot: Implications for Ecology and Conservation.

Understanding how biodiversity varies from place to place is a fundamental goal of ecology and an important tool for halting biodiversity loss. Parasitic wasps (Hymenoptera) are a diverse and functionally important animal group, but spatial variation in their diversity is poorly understood. We survey a community of parasitic wasps (Ichneumonidae: Pimplinae) using Malaise traps up a mountain in the Brazilian Atlantic Rainforest, and relate the catch to biotic and abiotic habitat characteristics. We find high species richness compared with previous similar studies, with abundance, richness, and diversity peaking at low to intermediate elevation. There is a marked change in community composition with elevation. Habitat factors strongly correlated with elevation also strongly predict changes in the pimpline community, including temperature as well as the density of bamboo, lianas, epiphytes, small trees, and herbs. These results identify several possible surrogates of pimpline communities in tropical forests, which could be used as a tool in conservation. They also contribute to the growing evidence for a typical latitudinal gradient in ichneumonid species richness, and suggest that low to medium elevations in tropical regions will sometimes conserve the greatest number of species locally, but to conserve maximal biodiversity, a wider range of elevations should also be targeted.

Physical, mechanical, chemical, and durability assessment of water leaching treatment of bamboo

Water leaching is a traditional bamboo treatment method in which fresh bamboo poles are immersed in running water for at least 30 days to leach out water-soluble substances such as starch and carbohydrates. This method is easy to apply and does not require additional chemicals. Although water leaching is widely applied, its influence on the physical, mechanical, and chemical properties of bamboo and its effect on the durability of bamboo against termites has not been fully explored through experimental methods. This paper assesses the effects of water leaching treatment on bamboo and identifies the potential and limitations of this treatment. A 23% reduction in the density of bamboo after water treatment was found, which can be related to the removal of water-soluble extractives from the material. A significant (15%) increase in the modulus of rupture and a 20% increase in the modulus of elasticity were identified using a three-point bending test after water treatment while keeping a similar fibre volume fraction. Water leached bamboo had less dimensional stability and higher water absorption than untreated bamboo. As the density of the bamboo decreased, more space became available in its bundles for water. A darkened surface was observed after treatment, but no chemical modifications were found through FT-IR spectroscopy. Termites can use cellulose as a source of food, and the removal of starch from bamboo did not improve its resistance against this insect. On the contrary, the free space created after treatment favoured the action of the termites, leading to a higher mass loss percentage for treated bamboo. The water leaching system should not be used as the only treatment method in bamboo being utilized for structural purposes, and the reduction of dimensional stability and the darkened surface must be considered when using the bamboo for furniture and handicraft applications.

Forest degradation caused by dwarf bamboo overabundance reduces soil C, N and P stocks in giant panda habitat

Although forest degradation caused by dwarf bamboo overabundance has a significant effect on the survival of wild giant pandas, the degradation process and its impact on soil C, N and P stocks remain unclear. By investigating the vegetation structure and physicochemical analysis of litter and soil, we explored the changes in soil organic carbon (SOC), total nitrogen (TN), available nitrogen (AN), total phosphorus (TP) and available phosphorus (AP) stocks and the driving forces at three degradation levels triggered by dwarf bamboo overabundance in an important giant panda habitat—the subalpine coniferous forest. Dwarf bamboo overabundance following forest logging prevented tree regeneration, resulting in simplified a vegetation structure; even after 23 years of natural recovery, the clear-cut forestlands remained in the shrub stage, and the tree density and basal area were only 1.6% and 38%, respectively, of those in primary subalpine coniferous forest. With increasing degradation intensity, the litter stock and litter quality showed a decreasing trend, as did the SOC, N and P stocks in the litter layer and topsoil. The vegetation structure and litter quality together explained more than 90% of the variance in the C, N and P stocks (SOC: 97.3%, TNsoil: 93.5%, ANsoil: 96.2%, TPsoil: 97.2% and APsoil: 97.0%), and litter quality had greater explanatory power than the vegetation structure. The SEM analysis results showed that the increase in dwarf bamboo density caused by the reduction in tree basal area affected the litter C/N and C/P ratios, and ultimately reduced the SOC, Nsoil and Psoil stocks. This study highlights that dwarf bamboo overabundance not only causes forest degradation but also reduces the carbon sequestration function of giant panda habitat, leading to the loss of soil N and P. We suggest that reducing bamboo abundance can promote the recovery of the soil carbon, nitrogen and phosphorus stocks in degraded giant panda habitats.

Phenotypic diversity of bamboo Schizostachyum lima (Blanco) Merr. population grown in several critical habitats on Lombok Island, Indonesia

Abstract. Aryanti E, Arumingtyas EL, Azrianingsih R, Arisoesilaningsih E. 2023. Phenotypic diversity of bamboo Schizostachyum lima (Blanco) Merr. population grown in several critical habitats on Lombok Island, Indonesia. Biodiversitas 24: 2788-2796. This study aims to analyze the phenotypic diversity among populations of Schizostachyum lima (Blanco) Merr. grown in several critical habitats on Lombok Island. Sampling was conducted to record clump growth and habitat properties of 38 sites grouped based on the clump density using PAST 4.11 and ArcGIS 10.8.2 software. Sampling was conducted to record clump growth and habitat properties of 38 sites grouped based on the clump density using PAST 4.11 and ArcGIS 10.8.2 software. The results showed that habitat 1 was the most critical land and had the lowest fertility, but it provided a qualified bamboo as a raw material for the artisanal straw industry. The results showed that habitat 1 was the most critical land and had the lowest fertility, but it provided a qualified bamboo as a raw material for the artisanal straw industry. Bamboo density reached 46 culms per clump and had the smallest culms diameter of 13 mm. Bamboo density reached 46 culms per clump and had the smallest culms diameter of 13 mm. The soil comprised 90% sand, with SOC 0.9 g.kg-1, total N 0.08 g.kg-1, and CEC 8.3 me.100 g-1. The soil comprised 90% sand, with SOC 0.9 g.kg-1, total N 0.08 g.kg-1, and CEC 8.3 me.100 g-1. Meanwhile, habitat 6 and habitat 7 were lesser critical, consisted of 66% of sand, showed the best soil fertility, and mean SOC 4.98 g.kg-1, total N 0.30 g.kg-1, CEC 27.23 me.100 g-1, density 151 culms, and biggest culms diameter 33 mm. Meanwhile, habitat 6 and habitat 7 were lesser critical, consisted of 66% of sand, showed the best soil fertility, and mean SOC 4.98 g.kg-1, total N 0.30 g.kg-1, CEC 27.23 me.100 g-1, density 151 culms per clump, and biggest culms diameter 33 mm. The other habitats varied in soil quality and bamboo growth properties. It was revealed that the high culms density, diameter, height, and internodal length were significantly increased in the high soil CEC, SOC, and total N. Furthermore, the SOC and total N content significantly correlated with the wall thickness.

Free-ranging livestock cause forest understory degradation in giant panda (Ailuropoda melanoleuca) habitat

Free-ranging livestock are common in reserves established for giant pandas (Ailuropoda melanoleuca), which rely almost exclusively on bamboo in the montane forests of southwestern China. Previous studies have showed that overgrazing by livestock had led to a reduction in bamboo abundance. However, there is limited knowledge of how livestock impact the structure of the understory vegetation. Conducted in the Wanglang National Nature Reserve with a livestock exclosure experiment, our study aimed to fill this gap by examining the impact of livestock grazing on two important elements of forest understory bamboo and moss in giant panda habitat, and quantifying their recovery after excluding livestock. Measurements of bamboo and moss showed that both elements were severely degraded. With a closer examination, we found moss growth was worse in areas with dense bamboo or no bamboo at all, but better when there were many dead stems in bamboo clump, suggesting bamboo exerted both negative competition and positive shelter effects from livestock trampling on moss. Livestock exclusion with fence indeed exempted bamboo and moss from continuous damage which were exemplified by more bamboo shoots inside the fence and significantly decreased moss height outside the fence. However, we observed no recovery of damaged bamboo and moss inside fenced quadrats in two years. Neither the sprouted bamboo shoots matured into stems after the growing season, nor the height of moss increased. Collectively, our results suggested that long-term livestock grazing drastically altered understory layer of bamboo and moss and interactions in between, and there was hardly recovery of the understory bamboo and moss in a short term. Therefore, we recommend artificial intervention with bamboo and moss planting in severely degraded areas and long-term monitoring of understory vegetation to restore the habitat of giant panda.

Determinations and performance investigations of hybrid composite properties for hydrokinetic turbine blades

In this experimental study, hybrid composite properties for hydrokinetic turbine blades were determined, and its performance was examined. The reinforcements included glass fiber, treated and untreated highland bamboo fiber, reinforced polyester-based composites and their hybrid composites, as well as row bamboo (bamboo culm). The row bamboo was prepared on the bamboo culm’s outer surface to get rid of any leftovers, before cutting in accordance with the specimen test standards. In order to make hybrid composite materials, polyester resin was mixed with fibers in the proportions of bamboo fiber/glass fiber (50%/50%), and fiber/matrix (30%/70%). The composite containing glass fiber has a flexural strength that is 12% and 21% higher than materials reinforced with alkali-treated and untreated highland bamboo fiber reinforced composites respectively. The alkali treatment of highland bamboo fiber improved its physical-mechanical properties, making it suitable for use different application. Alkaline treatment boosts the composite’s tensile and compressive strength by 37% and 3.4% for composite reinforced with untreated bamboo fiber, and 10.2% and 23.8% for composite reinforced with glass fiber, respectively. The fiber density of highland bamboo was increased by removing less dense non-cellulosic components (hemicellulose and lignin). However, the fiber’s moisture absorption is the main issue in using it in a composite that works submerged in water. This study investigated whether incorporating glass fiber in highland bamboo-glass fiber polyester hybrid composite reduces the composite material’s water uptake. A reduction was found, however, the density was increased. It is challenging to employ row bamboo for the construction of hydrokinetic turbine blades as water ingress of the composite must be avoided even in the presence of erosion caused by cavitation and impact with foreign bodies in the water.

Stepwise modification with 2,3-epoxypropyltrimethylammonium chloride cationization and rosin acid impregnation to improve water repellency and mold-proof property of bamboo

As its abundant reserves and good physical properties, bamboo is deemed to be a promising feedstock material for construction and home furnishing. However, the hydrophilicity of bamboo and its rich nutrients make it susceptible to mold infection. In this study, bamboo firstly reacted with 0, 3, 6, 9, and 12 wt times of 2,3-epoxy-propyltrimethylammonium chloride (EPTAC) in NaOH/Urea solution, respectively, and then impregnated with rosin acid. Effects of modification on structure, thermal stability and water repellency of bamboo were identified by FT-IR, XRD, XPS, SEM, TGA, contact angle measurement and water absorption coefficient, respectively. A comparative study of mold-proof properties of original and modified bamboo was conducted as inoculation of Aspergillus niger, Penicillium citrinum and Trichoderma viride on samples. The results indicated that the sample obtained from a mass ratio (EPTAC to bamboo) of 9 had the highest substitution degree, charge content and ion exchange capacity as compared to samples obtained from other EPTAC dosages. After modification, the density of bamboo increased by 43.3%, which exhibited considerable thermal stability. Impregnating this sample with rosin acid improved its water-repelling and anti-swelling efficiency to 10.91% and 27.83%, respectively. Compared with the original bamboo, anti-mold property of EPTAC modified bamboo to three fungi was notably improved and achieved rate 1 mold coverings. Impregnation-modified bamboo with rosin acid enhanced the anti-mold property, achieving a rate of 0 mold covering. The research provides a feasible way to improve the mildew resistance of bamboo and promote the utilization of rosin.

RCompetence Between Endangered Wild Animals: an Example of Takin (Budorcas Taxicolor Bedfordi) and Panda (Ailuropoda Melanoleuca)

The study was conducted in tow locations are: (1) Taibai Mountain natural reserve (107°22’-107°51’E and 33°49’-34°05’N) and (2) Zhouzhi natural reserve (108° 14′-108° 18′ E, 33° 45′-33° 50′ N). To examine and analyze the impact of Golden takin behavior on the Giant panda activity in winter habitat and analyze their interactions at Taibai Mountain and Zhouzhi natural reserve. For habitat survey, randomly walked within the study areas with different vegetation types to search for signs of each species. The presence of Golden takin and Giant panda was identified based on their fresh droppings. Once fresh droppings were found and a sampling plot of 20 m x 20 m was established and centered on the droppings location. Two (2 m × 10 m) were set at different locations within the 20 m × 20 m plot, and observations were made according to the type of habitats including type of trees, bamboo type, bamboo cover, bamboo density, canopy, shrub cover and herb cover. At Taibai Mountain, a total of 12 infrared cameras were placed on tree stems at 1 m height, the laying density of cameras is 4 sets / km2 and other 20 infrared cameras were mounted at Guangtoushan in Zhouzhi natural reserve,to monitor Golden takin and Giant panda movement. Camera traps data were collected every three months depending on the status of battery and the weather conditions. Takin displayed the highest peak activity at periods of 16:00-18:00 pm (48.03%) and 16:00-18:00 pm (39.29%) in 2013-2014 and 2014-2015, respectively, while for Panda the highest peaks of activity were recorded at periods of 14:00-16:00 pm (24.58%) and 12:00-14:00 pm (26.13%) in 2013-2014 and 2014-2015, respectively. At Zhouzhi natural reserve, Takin showed also highest peak of activity at periods of 16:00-18:00 pm (23.48%) and 16:00-18:00 pm (38.48%) in 2014-2015 and 2015-2016, respectively, whereas the highest peak activity for Panda were recorded at periods of 12:00-14:00 pm (19.15%) and 12:00-14:00 pm (18.22%) in 2014-2015 and 2015-2016, respectively.

Changes in the abundance and species diversity of Collembola community along with dwarf bamboo density gradient in a mountainous temperate forest of Japan

Understory vegetation plays an important role in forest ecosystems by providing protection from soil physicochemical stresses or disturbance. Consequently, this type of vegetation may help maintain soil biodiversity and functions. However, the effects of understory degradation on soil faunal communities is not well understood. This study investigated the effects of the declining understory dwarf bamboo density in cool-temperate Japanese deciduous forests on the community composition of soil Collembola; by comparing partitioned community dissimilarity indices and trait components to detect the processes shaping community under understory degradation. For the species richness and diversity of Collembola community, unimodal quadratic model to dwarf bamboo density was selected as best model among all measured environmental properties, whereas, for Collembola abundance, linear negative relationship to dwarf bamboo density was selected as best model. For Collembola trait compositions, dwarf bamboo density model was not selected, although those of soil C and hardness were selected. The nestedness component in community dissimilarity increased with greater dwarf bamboo density differences between plots, whereas the replacement component was not significant. This suggests that the decreasing dwarf bamboo density might induce reduced niche space of whole Collembola community. In the range of mid to high density of dwarf bamboo, the higher density of dwarf bamboo declined the species diversity of the Collembola community, whereas the abundance still increased, probably because of the competitive exclusion by the dominant Folsomia octoculata under less disturbed habitat condition in high understory and litter coverage. Our results implied that the changes in the abundance and species diversity of Collembola community to understory density gradient were controlled both by abiotic niche reduction and biotic competitive exclusion without life-form trait selection.

Climate, Soil, and Plant Controls on Early-Stage Litter Decomposition in Moso Bamboo Stands at a Regional Scale

Moso bamboo (Phyllostachys edulis) is currently distributed across a wide geographical area in East Asia. As a common bamboo species occurring along a broad environmental gradient, there is a need to understand how environmental and biotic drivers affect belowground processes at large scales. In this study, we investigated the influence of climate, soil properties, stand characteristics, and organic matter input parameters as potential drivers of the initial decomposition process in Moso bamboo stands at a regional scale. Using the Tea Bag Index method, we estimated the initial decomposition rate (k) and stabilization factor (S; potential long-term carbon storage) from standard litter incubated at 13 sites across southern Japan and Taiwan. We found that both decomposition parameters were strongly affected by the climate. The climatic conditions during the incubation period better explained the variance in k. In contrast, the long-term climate was more important for S. Notably, temperature and precipitation interactively affected the initial decomposition rates. This interaction showed that in warmer sites, precipitation increased k, whereas in cooler sites, precipitation had no effect or even decreased k. Soil parameters had no influence on k and only had minor effects on S. A structural equation model showed that the stabilization factor was indirectly affected by stand density, which suggests that higher bamboo densities could increase litter stabilization by increasing above-and below-ground organic matter input. Our study highlights the central role of climate in controlling decomposition processes in Moso bamboo stands on a broad scale. Moreover, differences in stand structure can indirectly affect potential soil carbon storage through changes in organic matter input and soil conditions.

Bamboo flattening technology ebables efficient and value-added utilization of bamboo in the manufacture of furniture and engineered composites

Bamboo flattening, a novel and efficient bamboo processing and utilization technology, can effectively flatten bamboo culms into crack-free board. The technology enables the efficient and value-added utilization of bamboo in the manufacture of furniture and engineered composites. In this study, we compared the effects of three types of flattening technologies on the macro-mechanical, macro-physical, micro-morphology, and micro-mechanical properties of untreated, softened a flattened bamboo samples. As expected, the hemicellulose and cellulose concentrations of the saturated steam treated sample (18.05% and 38.9%, respectively) were less than those the untreated sample (21.3% and 40.1%, respectively). Moreover, scanning electron microscopy (SEM) analysis showed that the notched flattening technology (NFT) inserted indents and grooves on the bamboo surface. However, the “non-notched flattening technology (NNFT)” only compressed the bamboo tissue. The flattening process increased the equilibrium moisture content and density of bamboo. The enhanced density, lignin content, and cellulose crystallinity index enhanced the bamboo cell wall properties. The non-notched-flattened bamboo board exhibited a higher cell wall modulus of elasticity and hardness (20.1 and 0.89 GPa, respectively) than the untreated bamboo samples (13.7 and 0.49 GPa, respectively). The enhanced bamboo cell wall mechanical properties of the non-notched-flattened bamboo board. Finally, we explored the practical applications, economic benefits, and limitations of the current “Non-notched bamboo flattening technology”.

Study on the correlation between the puncture impact performance of arc-shaped bamboo splits and bamboo ages

The unique hierarchical gradient structure of bamboo from the macro to nano scales and its remarkable combination of vascular bundles and parenchyma provide its high strength and toughness. Bamboo is an excellent engineering material that is widely used in construction and transportation, and its impact performance is an important indicator that reflects its structural stability. In this study, the finite element method was used to analyze the mechanical characteristics of bamboo splits under impact in simulations, and arc-shaped bamboo splits were tested to assess impact performance under puncture, thus, clarifying the relationship between bamboo age, density, and chemical composition and fracture load. As the bamboo age increased (from 2 to 4 and 8 years), the maximum impact load of bamboo first increased and then decreased. The maximum impact load of 4-year-old bamboo was 4373 N, which was 1.79- and 1.70-fold that of 2- and 8-year-old bamboo, respectively. Although the maximum impact load of 2-year-old bamboo was lower than that of 4-year-old bamboo, it nevertheless withstood secondary loads after fracture and was highly tough. Specimens exhibited both transverse and intergranular impact fractures, but the latter category comprised most of the fractures. The crack deflection, fiber stripping, and crack bridging caused by the gradient structure of bamboo enhanced its fracture load. There were clear correlations between the maximum load of bamboo impact and the density, moisture content, and chemical composition of bamboo. The establishment of structure–activity relationships between the bamboo impact load and physicochemical properties can guide the engineering applications of bamboo and provide a reference for biomimetic materials.