Host plants of domesticated silkworms in tropical countries are attacked by an array of insect pests, disease pathogens and nematodes. In order to reduce resulting plant damage, chemicals have been extensively used. In recent years, products extracted/isolated from 47 plant species have been tested as replacements for or to minimize the use of hazardous chemicals. Bioefficacy of the extract in water or chemical solvent, crude seed/leaf oil, and cake is discussed, and integrated management of major and occasional pests and plant diseases is proposed in sericultural plants in order to produce chemical-free foliage.

The purpose of this study was to determine a suitable model for investigating the effects of climate factors on the area burned by forest fire in the Tahe forest region, Daxing’an Mountains, in northeast China. The response variables were the area burned by lightning-caused fire, human-caused fire, and total burned area. The predictor variables were nine climate variables collected from the local weather station. Three regression models were utilized, including multiple linear regression, log-linear model (log-transformation on both response and predictor variables), and gamma-generalized linear model. The goodness-of-fit of the models were compared based on model fitting statistics such as R², AIC, and RMSE. The results revealed that the gamma-generalized linear model was generally superior to both multiple linear regression model and log-linear model for fitting the fire data. Further, the best models were selected based on the criteria that the climate variables were statistically significant at α = 0.05. The gamma best models indicated that maximum wind speed, precipitation, and days that rainfall greater than 0.1 mm had significant impacts on the area burned by the lightning-caused fire, while the mean temperature and minimum relative humidity were the main drivers of the burned area caused by human activities. Overall, the total burned area by forest fire was significantly influenced by days that rainfall greater than 0.1 mm and minimum relative humidity, indicating that the moisture condition of forest stands determine the burned area by forest fire.

Uluguru forests are globally recognized as important biodiversity hotspots, but anthropogenic pressure threatens their value. This study examined species diversity, abundance, and structure of trees in the Uluguru forests. All trees of diameter at breast height (DBH) ≥ 10 cm were inventoried in seven forests ranging from 3 to 995 ha in area. A total of 900 stems, 101 species and 34 families were inventoried. Fabaceae was the most speciose family. Ehretia amoena Klotzsch was the most abundant species with relative abundance of 9.22 %. The forests differed significantly in species richness (26–93 species ha⁻¹), tree density (85–390 stems ha⁻¹), basal area (3–24 m² ha⁻¹) and Shannon-Wiener diversity (2.50–4.02). Forest area was significantly and positively correlated with species richness (r = 0.92) and species diversity (r = 0.95). Tree density showed significant positive correlation with species richness (r = 0.80) and basal area (r = 0.85). Milawilila and Nemele forests had highest floristic similarity (0.55) followed by Kimboza and Kilengwe (0.54) while the rest had similarity coefficients of less than 0.50. Despite legislative protection, many forests remain at risk and therefore the possibility to conserve highly valuable tree species via enhanced protection or cultivation must be considered.

In this paper we analyze and compare natural regeneration in shrub-tree community in three areas below Pinus caribaea stands and a natural area (cerrado sensu stricto). We also analyze the influence of biophysical and environmental variables on the distribution of regenerating shrub-tree species. The areas were analyzed and compared in relation to dispersal syndromes as well, being zoochory and anemochory the prevailing syndroms in the four areas. The sites below P. caribaea show a heterogeneous regeneration with the number of species ranging from 18 to 42. We analyzed the influence of the biophysical and environmental variables performing a canonical correspondence analyses, being found significant values for variables distance from remnant and basal area. The species Siparuna guianensis, Miconia albicans, Xylopia aromatica, Sclerolobium paniculatum, Casearia sylvestris and P. caribaea were the most importante ones in the four areas.

Restoring natural forests after field abandonment is a land management objective that fosters the recovery of forest biodiversity. We performed seeding and transplanting of native tree species 40 years after the abandonment of an arable field that became dominated by a dwarf bamboo (Pleioblastus chino (Franch. et Sav.) Makino) and by kudzu (Pueraria lobata (Willd.) Ohwi). By permutation tests, the removal of competing vegetation (gap creation) significantly increased the survival of three seeded species of Fagaceae and of eight transplanted species. In contrast, intact vegetation prevented most individuals of all species from surviving for 1 year after planting. The lack of natural recruitment of Fagaceae in the nonseeded subplots indicated that seed limitation was a cause of the slow afforestation. Although litter accumulation in gaps at the time of seeding slightly increased survival for late-germinating Quercus myrsinifolia Blume and Castanopsis sieboldii (Makino) Hatus. ex T. Yamaz. et Mashiba, the effect was not consistent among plots and was not statistically significant. Our results suggest that for successful afforestation using native trees in abandoned fields, it will be necessary to remove competitive native species to avoid severe limitations on microsite availability and that simultaneous tree establishment by seeding or transplanting should be implemented to accelerate the establishment of native tree species.

Carbon (C) sequestration through plantations is one of the important mitigation measures for rising levels of carbon dioxide and other greenhouse gases in the atmosphere. This study aimed to assess C stocks and their sequestration rate, and to develop allometric models for estimation of C stocking in age-series young teak (Tectona grandis) plantations (1, 5, 11, 18, 24 and 30 years) by using biomass and productivity estimation and regression, respectively. These plantations were raised in tropical moist deciduous forests of Kumaun Himalayan tarai. Total C stocks estimated for these plantations were 1.6, 15.8, 35.4, 39.0, 61.5 and 73.2 Mg ha⁻¹, respectively. Aboveground and belowground C storage increased with increasing plantation age; however, the range of their percentage contribution showed little variation (87.8–88.2 and 11.7–12.7 %, respectively). The rate of C sequestration for these respective plantations was 1.06, 6.95, 5.46, 5.42, 3.39 and 5.37 Mg ha⁻¹ a⁻¹. Forty percent of the aboveground annual storage was retained in the tree while 60 % was released in the form of foliage, twigs, and fruit litter. In the case of total (tree) annual production, 43 % was retained while 57 % was released as litter including root. C stock, C sequestration rate, accumulation ratio (1.4–18.1), root:shoot C ratio (0.61–0.13) and production efficiency (0.01–0.18) were comparable to some previous reports for other species and forests. These data could be useful in deciding the harvesting age for young teak with respect to C storage and sequestration rate. Four allometric models using linear regression equations were developed between biomass (twice the C stock) and diameter, girth, and height of the tree at different ages. The diameter model was found more suitable for C stock prediction in similar areas.

Population of the rare and endangered species Ammopiptanthus mongolicus (Maxim.) Cheng f. declined rapidly in China’s arid region and Central Asia. There is an urgent need to protect this species, which is particularly important in maintaining biodiversity throughout the arid region of northwestern China. By analyzing the infrared thermal images based on plant-transpiration transfer coefficient (h _at) and photosynthetic parameters, we made quantitative and accurate diagnoses of the plant growth and health status of A. mongolicus. Using an LI-COR6400 photosynthesis system, we measured the net photosynthetic rate (P _n), stomatal conductance (G _s), and transpiration rate (T _r). Infrared thermal images obtained in the field were processed by ENVI4.8 software to calculate surface temperatures of the plant subjects. We found that the plant transpiration transfer coefficient of A. mongolicus was in the order of old plants >young plants >intermediate-aged plants. Declining health levels of young, intermediate, and old plants were divided into three categories: <0.4, 0.4–0.7, and >0.7. The coefficient showed a significant negative correlation with T _r, G _s, and P _n, indicating that they can simultaneously reflect the state of plant growth. By establishing h_at and photosynthetic parameters in regression model Y = a-blnx, we can accurately diagnose plant growth and decline of plant health conditions.

Many plants exhibit heterophylly; the spatially and temporally remarkable ontogenetic differences in leaf morphology may play an adaptative role in their success under diverse habitats. Thus, this study aimed to gain insights into differences in leaf functional traits of heterophyllous Syringa oblata Lindl., which has been widely used as an ornamental tree around the world under different light intensities in East China. No significant differences existed in specific leaf area (SLA) between lanceolate- and heart-shaped leaves. Differences in the investment per unit of light capture surface area deployed between lanceolate- and heart-shaped leaves may be not obvious. This may be attributing to the fact that single leaf wet and dry weight of heart-shaped leaves were significantly higher than those of lanceolate leaves but leaf length and leaf thickness of heart-shaped leaves were significantly lower than those of lanceolate leaves. The SLA of shade trees was significantly higher than that of sun trees. The investment per unit of light capture surface of shade trees was lower than that of sun trees, making it possible to increase light capture and use efficiency in low-light environments. The phenotypic plasticity of most leaf functional traits of lanceolate leaves was higher than those of heart-shaped leaves because the former is the juvenile and the latter is the adult leaf shape during the process of phylogenetic development of S. oblate. The higher range of phenotypic plasticity of leaf thickness and leaf moisture for sun trees may be beneficial to obtain a more efficient control of water loss and nutrient deprivation in high-light environments, and the lower range of phenotypic plasticity of single leaf wet and dry weight, and SLA for shade trees may gain an advantage to increase resource (especially light) capture and use efficiency in low-light environments. In brief, the successfully ecological strategy of plants is to find an optimal mode for the trade-off between various functional traits to obtain more living resources and achieve more fitness advantage as much as possible in the multivariate environment.

Betulin, oleanolic acid, and betulinic acid are naturally occurring pentacyclic triterpenoids that have significant medicinal value. Considerable amounts of these triterpenoids are available in the outer bark of white birch. In this study, we used ultrasound-assisted extraction (UAE) to extract triterpenoids from birch bark rapidly and with high efficiency. Using high performance liquid chromatography (HPLC), three types of triterpenoids were separated and detected. We examined the differences among triterpenoids extracted from diploid versus tetraploid white birch. Then, we used factor analysis to screen out tetraploid white birches with comprehensively excellent performance. The results indicate that the optimum conditions for extraction include the use of ethanol as an extraction solvent, a solid-to-liquid ratio of 0.1 g/10 ml, ultrasonic power set at 100 W, a temperature of 60 °C and an extraction time of 15 min. A reversed-phase C18 column (4.6 mm × 250 mm × 5 μm) with a column temperature of 30 °C and the mobile phase composed of A (acetonitrile) and B (0.1 % aqueous phosphoric acid, v/v) at a flow rate of 0.5 ml/min were used, and the detection wavelength was 195 nm. No significant difference was observed between diploid and tetraploid white birch in terms of the content of three types of triterpenoids (at a confidence level of 0.05). As triterpenoid content, height, and DBH (diameter at breast height) are strongly interrelated, we used factor analysis to evaluate all individuals, and we screened out six plus trees with excellent comprehensive characters.

Oligo-carrageenans (OCs) obtained from pure carrageenans extracted from marine red algae stimulate growth by enhancing photosynthesis and basal metabolism in tobacco plants and Eucalyptus trees. In addition, OCs stimulate secondary metabolism, increasing the level of metabolites involved in defense against pathogens. In this work, we analyzed the effect of OC kappa on the increase in height, in activities of basal metabolism enzymes involved in carbon, nitrogen and sulphur assimilation, ribulose 1,5 biphosphate carboxylase/oxygenase (rubisco), glutamate dehydrogenase (GDH) and O-acetylserine thiol-lyase (OASTL), and in the level of growth-promoting hormones, the auxin indole acetic acid (IAA) and the gibberellin GA₃, in pine (Pinus radiata) trees treated with OC kappa at concentrations of 1 and 5 mg mL⁻¹ and cultivated for 9 months without additional treatment. Pines treated with OC kappa at 1 mg mL⁻¹ showed a similar increase in height but displayed a higher increased in total chlorophyll, activities of rubisco, GDH and OASTL and level of IAA and GA₃ than those treated with OC kappa at 5 mg mL⁻¹. Thus, OC kappa stimulates growth and basal metabolism and increases the level of growth-promoting hormones in pine trees, mainly at 1 mg mL⁻¹.

Pinus densiflora var. zhangwuensis grows fast, and its drought and salinity resistance are better than Pinus sylvestris var. mongolica. We compared cold hardiness and mechanisms of cold hardiness between the two species, to provide a theoretical basis for promoting and applying P. densiflora var. zhangwuensis in cold regions. A cold stress experiment was carried out on 3-year-old plantlets of P. densiflora var. zhangwuensis and P. sylvestris var. mongolica after hardening at five temperature regimes, 5, −10, −20, −40, and −60 °C, respectively. Some indices of needle samples for both species were measured, such as relative conductivity (REL), maximum photochemical efficiency (F_v/F_m), malondialdehyde (MDA), catalase (CAT), proline (Pro), soluble sugar (SS), and stomata density. REL and MDA values of both species after hardening had the same trend of increasing, but the trend was opposite in F_v/F_m value with increasing cold stress. Compared with P. sylvestris var. mongolica, the P. densiflora var. zhangwuensis had smaller increases in REL and MDA, and a smaller decline in F_v/F_m during cold stress. Compared to the control, REL growth of P. densiflora var. zhangwuensis and P. sylvestris var. mongolica at −60 °C were 0.41 and 0.60, and MDA growth was 29.94 mol g⁻¹ FW and 47.80 mol g⁻¹ FW, and F_v/F_m declines were 0.08 and 0.27. Half-lethal temperatures (LT₅₀) calculated by logistic equation for P. densiflora var. zhangwuensis and P. sylvestris var. mongolica were −58.23 and −50.34 °C, respectively. These data suggest that cold resistance of P. densiflora var. zhangwuensis is stronger than that of P. sylvestris var. mongolica. Cold-resistance mechanisms of the two species differed. In response to cold stress, P. sylvestris var. mongolica had strong osmotic adjustment ability because of higher Pro and SS content, while P. densiflora var. zhangwuensis had strong antioxidant ability due to stronger CAT activity. Stomata density and diameter of P. densiflora var. zhangwuensis were smaller, as were single leaf area and number of leaves per plant, both characteristics promoting survival in a cold environment. Greater shoot height and total biomass of seedlings of P. densiflora var. zhangwuensis might be another reason for its stronger cold tolerance.

Populus species are important resources for industry and in scientific study on biological and agricultural systems. Our objective was to enhance the frequency of plant regeneration in Himalayan poplar (Populus ciliata wall. ex Royle). The effect of TDZ alone and in combination with adenine and NAA was studied on the regeneration potential of petiole explants. The explants were excised from Himalayan poplar plants grown in glass-houses. After surface sterilization the explants were cultured on shoot induction medium. High percentage shoot regeneration (86 %) was recorded on MS medium supplemented with 0.004 mg L⁻¹ TDZ and 79.7 mg L⁻¹ adenine. The regenerated shoots for elongation and multiplication were transferred to MS + 0.5 mg L⁻¹ BAP + 0.2 mg L⁻¹ IAA + 0.3 mg L⁻¹ GA₃. Root regeneration from shoots developed in vitro was observed on MS medium supplemented with 0.10 mg L⁻¹ IBA. Himalayan poplar plantlets could be produced within 2 months after acclimatization in a sterile mixture of sand and soil. We developed a high efficiency plant regeneration protocol from petiole explants of P. ciliata.

Pterocarpus indicus Willd is a tropical woody legume that holds promise for plantation forestry. Two glasshouse experiments were undertaken on two soil types to determine the phosphorus (P) concentration ranges in the foliage of P-stressed and healthy plants, and to define critical P concentrations for the diagnosis of deficiency and toxicity. There was a narrow range in rates of P fertilizer, supplied as Ca(H₂PO₄)₂·H₂0, between deficiency and toxicity compared to other tree species. The relationship between shoot yield and P concentration in the youngest fully expanded leaf enabled critical P concentrations for the diagnosis of deficiency (0.17 %) and toxicity (0.41 %) to be determined at 90 % maximum yield from linear regressions fitted to the data. The foliar P concentration ranges for deficiency and toxicity were similar to other nitrogen-fixing trees. The defined P concentration ranges and the critical P concentrations for the diagnosis of P deficiency and P toxicity should be useful for monitoring the P status of nursery stock and the health of young seedlings after out-planting.

It is important to understand seasonal heavy metal accumulation in different parts of plants in order to develop the best phytoremediation practices for contaminated soils. For this purpose we exposed, 1 year old A. victoriae seedlings to ZnSO₄ in 4 different concentrations: 0, 50, 250 and 500 mg Zn L⁻¹ for 45 days over two growing seasons. Subsequently, bioaccumulation of Zn in different plant tissues (roots, shoots and leafs) was assessed by Atomic Absorption Spectroscopy (AAS) for two periods. In addition, various growth attributes (dry biomass, shoot and root lengths, plant appearance) and functional traits (leaf area, chlorophyll a, b and total) were measured. The accumulation of Zn was influenced by the Zn concentration in the growth medium and the number of growing seasons. The amounts of Zn concentrated in the root tissues might indicate A. victoriae as a good option for phytostabilization of soils contaminated by Zn. We recommend that if A. victoriae is used for phytoextraction purposes, then it should be harvested at the end of the first growing season (fall) because at this time the concentrations of Zn in the above-ground parts will be maximal.

To better understand the effects of forest succession on soil microbial activity, a comparison of soil microbial properties and nutrients was conducted between three forest types representing a natural forest succession chronosequence. The study compared a pine (Pinus massoniana) forest (P _F), a pine and broadleaf mixed forest (M _F) and an evergreen broadleaf forest (B _F), in the Yingzuijie Biosphere Reserve, Hunan Province, China. Results showed that soil nutrients in the M _F and B _F plots were higher than in the P _F plots. The range in microbial biomass carbon followed a similar pattern with B _F having the greatest values, 522–1022 mg kg⁻¹, followed by M_F 368–569 mg kg⁻¹, and finally, P _F 193–449 mg kg⁻¹. Soil nutrients were more strongly correlated with microbial biomass carbon than basal respiration or metabolic quotient. Overall, forest succession in the study site improved soil microbial properties and soil fertility, which in turn can increase primary productivity and carbon sequestration.

Significant CO₂ fluxes from snow-covered soils occur in cold biomes. However, little is known about winter soil respiration on the eastern Tibetan Plateau of China. We therefore measured winter soil CO₂ fluxes and estimated annual soil respiration in two contrasting coniferous forest ecosystems (a Picea asperata plantation and a natural forest). Mean winter soil CO₂ effluxes were 1.08 µmol m⁻² s⁻¹ in the plantation and 1.16 µmol m⁻² s⁻¹ in the natural forest. These values are higher than most reported winter soil CO₂ efflux values for temperate or boreal forest ecosystems. Winter soil respiration rates were similar for our two forest ecosystems but mean soil CO₂ efflux over the growing season was higher in the natural forest than in the plantation. The estimated winter and annual soil effluxes for the natural forest were 176.3 and 1070.3 g m⁻², respectively, based on the relationship between soil respiration and soil temperature, which were 17.2 and 9.7 % greater than their counterparts in the plantation. The contributions of winter soil respiration to annual soil efflux were 15.4 % for the plantation and 16.5 % for the natural forest and were statistically similar. Our results indicate that winter soil CO₂ efflux from frozen soils in the alpine coniferous forest ecosystems of the eastern Tibetan Plateau was considerable and was an important component of annual soil respiration. Moreover, reforestation (natural coniferous forests were deforested and reforested with P. asperata plantation) may reduce soil respiration by reducing soil carbon substrate availability and input.

Soil polarization in pure forest stands affects the stability and sustainable development of the ecosystem. The most effective approaches to the prevention of soil polarization may be the use of forage litter as fertilizer or the direct establishment of tree-grass communities. We investigated monospecific plantations of Populus simonii and Quercus liaotungensis. Such plantations have been established throughout the Loess Plateau of China. A 120-day decomposition incubation experiment with forest humus soil mixed with 7 common leguminous forage litter species was performed to study the uses of forage litter in controlling soil polarization in pure forests. The addition of forage litter of Astragalus adsurgens, Lespedeza bicolor, and Vicia villosa to the soil of pure P. simonii forest clearly improved the soil quality, these forage species are suitable for planting with P. simonii, whereas Melilotus officinalis, Medicago sativa, and Onobrychis viciifolia litter produced obvious deterioration, thus these forages should not be planted with P. simonii. Coronilla varia litter showed no significant influence. The addition of forage litter of M. sativa to the soil of pure Q. liaotungensis forest clearly improved the soil quality, and C. varia and V. villosa also yielded improvements but were slightly less effective than M. sativa litter, these forages are suitable to be planted with Q. liaotungensis. However, L. bicolor showed obvious deterioration, followed by O. viciifolia and A. adsurgens, and M. officinalis had no significant influence. These species should not be planted with Q. liaotungensis.

A simplified water balance model in conjunction with an evapotranspiration (ET) model and cumulative forest cover data were used to quantify the changes in annual water yield in response to reforestation in a large watershed, northeast China. Cumulative forest cover increased by 22 %, leading to a significant decrease in estimated annual water yield. Reforestation increased ET (P = 0.0144), resulting in a remarkable decrease (P = 0.0001) in estimated annual water yield according to the water balance model. Reforestation increased ET by 33 mm and decreased annual water yield by 38 mm per decade. The effect of reforestation on annual water yield can be quantified using a simplified water balance model in a large watershed, although our reforestation area was small (about 20 %) in relation to the total watershed area.

We investigated the spatial distribution (horizontal and vertical concentrations) of copper (Cu), lead (Pb), zinc (Zn), and cadmium (Cd) in five wetland types (mudflat, aquaculture wetland, water area, farmland wetland and mangrove) from three areas (Ningde, Fuding, and Xiapu), China. Cu concentrations in five wetland types descended in the order: farm wetland, mudflat, aquaculture, water area and mangrove. Pb concentrations decreased in the order: aquaculture, mangrove, farm wetland, mudflat, and water area. Zn content decreased in the order: farm wetland, water area, aquaculture, mudflat and mangrove, and Cd content decreased as follows: mangrove, aquaculture, water area, mudflat, and farm wetland. Comparison of the concentrations of the same heavy metals in different areas showed that the highest Cu (63.75 mg kg⁻¹) and Zn (152.32 mg kg⁻¹) concentrations occurred in Ningde coastal wetlands; Pb (110.58 mg kg⁻¹) and Cd (2.81 mg kg⁻¹) contents were highest in Fuding wetlands, and the average contents of all heavy metals were very low in Xiapu wetlands. Examination of the vertical distribution showed that the Cu content was high in all mudflat layers; Pb and Cd concentrations were highest in aquaculture and mangrove wetlands, respectively, and Zn content was highest in farm wetlands. The spatial distribution of Cu and Zn contents for different areas decreased as follows: Ningde > Fuding > Xiapu, for Pb and Cd were most concentrated in Fuding coastal wetlands. Concentrations of Zn and Cu were highly correlated, while Zn and Cu were not significantly correlated with Pb.

Disease-resistant genes play an important role in defending against a variety of pathogens and insect pests in plants. Most of the disease-resistant genes encode proteins with conserved leucine rich repeat and nucleotide binding site domains. In this study, we cloned and characterized gene-resistant analogs (RGAs) from Eucalyptus grandis using degenerate PCR, with primers specifically targeting these two domains. The amplified fragments were cloned into the pGEM-T vector and transformed into Escherichia coli. Among the 90 clones obtained, 13 were sequenced and compared with each other and with previously identified gene-resistant diseases. A BLASTX search in GenBank revealed high similarities among the conserved domains of these cloned genes with RGA genes. Some clones, however, showed no significant similarity with DNA sequences in GenBank. Southern blotting analysis identified several polymorphic RFLP loci between distinct genotypes. However, none of them co-segregated with the Puccinia psidii Winter resistance gene 1 (Ppr1) in a population study.

Whitebark pine (Pinus albicaulis) populations are in decline across the species’ range due to historic wildfire exclusion, mountain pine beetle (Dendroctonus ponderosae, MPB) outbreaks, and an invasive fungal pathogen causing the disease white pine blister rust (Cronartium ribicola, WPBR). Despite reliance on stand-replacing fires, information on whitebark pine regeneration occurrence is limited and the trajectory of future forests is largely unknown in some areas of the range. Regeneration densities were assessed in burned and adjacent non-burned areas at six high elevation locations in northwest Wyoming where stand-replacing fires occurred 8–32 years before the surveys. In these locations at the eastern extent of the species range, we assessed what site factors were associated with regeneration success. Whitebark pine regeneration density was greater and seedlings were older in non-burned compared to burned areas. Within burns, north aspects had more regeneration than south aspects. Potential seed source densities and other species’ regeneration were positively related to whitebark pine regeneration densities in burned areas. South facing slopes or grass covered areas may have either delayed or no regeneration of whitebark pine without the help of artificial planting.

A new species of the genus Rhynchina Guenée, 1854, R. tongmaia Pan and Han, sp. n. is described from China. This species is compared with a supercially similar congener, R. rivuligera Butler, 1889 with illustrations of their imagoes and genitalia.

We studied two clones of Eucalypt urograndis hybrid (Eucalyptus grandis × E. urophylla), GR283 and GR330, grown in Tumkur district of Karnataka (India), and felled 5–6 years old three trees of each clone. We recorded axial variations in heartwood content, bark properties, wood density and anatomical characteristics of wood including fibre length, fibre diameter, fibre wall thickness, lumen diameter, vessel frequency, vessel diameter and vessel element length. Clone GR283 had about 10 % heartwood, significantly lower than for clone GR330 (37 %). Basic wood density along the tree height varied significantly within and between the clones. We observed significant variations in fibre length, fibre diameter and wall thickness within and between the two clones. Vessel frequency and vessel element length did not vary but vessel diameter differed significantly between the clones. With a greater proportion of sapwood, clone GR283 can be utilized for paper and pulp applications. Clone GR330 had a higher proportion of heartwood and lower wood density and, hence, is more suitable for light-weight material applications.

We used principal component analysis (PCA) and compressed sensing to detect wood defects from wood plate images. PCA makes it possible to reduce data redundancy and feature dimensions and compressed sensing, used as a classifier, improves identification accuracy. We extracted 25 features, including geometry and regional features, gray-scale texture features, and invariant moment features, from wood board images and then integrated them using PCA, and selected eight principal components to express defects. After the fusion process, we used the features to construct a data dictionary, and realized the classification of defects by computing the optimal solution of the data dictionary in l ₁ norm using the least square method. We tested 50 Xylosma samples of live knots, dead knots, and cracks. The average detection time with PCA feature fusion and without were 0.2015 and 0.7125 ms, respectively. The original detection accuracy by SOM neural network was 87 %, but after compressed sensing, it was 92 %.

We determined the ultrasonic velocity and energy attenuation value of three tree species (basswood, elm, and fir) 1 per tree in different moisture content levels, using RSM-SY5 ultrasonic testing instrument, and analyzed the regularity of ultrasonic velocity and energy attenuation values with moisture content, respectively. The ultrasonic velocity of the three species decreased as moisture content increased, with the turning point at 32 % of moisture content. When the moisture content was more than 32 %, the growth curve of ultrasonic wave velocity was flattened. The moisture contents of all three species increased under the any point moisture content of 1–60 %. The differentiation degrees of energy attenuation value of three species were higher than the corresponding ultrasonic wave velocity, when the moisture content was less than 15 %. The differentiation degrees of the energy attenuation value of three species was higher than the corresponding ultrasonic velocity, when the moisture content was more than 15 %.

We focused on the optimization of corn-stalk skin flake-wood shaving composite technology. We studied the effects of material-mixture ratio, glue content, hot-pressing temperature, and hot-pressing time on the appearance, physical, and mechanical properties of the composite by the orthogonal experiment method. Our findings yielded highly significant results in all three cases: the effects of the material-mixture ratio on 2 h of thickness swelling (2hTS) and the modulus of rupture (MOR); the effects of glue content on 2hTS, internal bond strength, and modulus of elasticity (MOE); and the effects of hot-pressing temperature on MOR and MOE. Product optimization is achieved when the ratio of corn stalk skin flake to wood shaving is 3:7, the glue content is 12 %, the hot-pressing temperature is 150 °C, and the hot-pressing time is 4.5 min.

We studied the effect of salinity on nail-holding power in wood construction. In saline solution, the holding power of nails was less than in purified water. With the increase of salt concentration, the surface and side nail-holding power of the wood specimens both declined, but the differences between salinity treatments were not significant. However, compared to the surface and side nail-holding power, the power on the edge was generally less and the difference was not obvious in different salt concentrations. In the same salt concentration, with the extension of the processing cycle, the performance of holding power of nails showed a downward trend, expect the temporary rise in the middle.

Analyzing the ploidy levels of plants is important for identifying species, selecting parental lines, identifying the relationships between species, and determining evolutionary patterns. The genus Chrysanthemum is widely distributed throughout the world and exhibits different ploidy levels. We used flow cytometry to analyze the ploidy levels of nine species of Chrysanthemum L. collected from different regions and geographical locations in China. Three diploids from Henan and Wuhan provinces corresponded to Chrysanthemum lavandulifolium and two species of C. nankingense, while three tetraploids from various regions corresponded to C. indicum and two species of C. chanetii. Two hexaploids corresponding to C. vestitum were collected at Funiu mountain (Henan province), and C. zawadskii was collected at Huangshan mountain (Anhui province). We found that OTTO extraction buffer was suitable for extracting nuclei from most species, apart from C. zawadskii. Flow cytometry proved to be a simple, rapid, and highly accurate method for identifying ploidy levels in Chrysanthemum species.

Electrical impedance (EI) and phase angle (PHI) parameters in AC impedance spectroscopy are important electrical parameters in the study of medical pathology. However, little is known about their application in variation and genetic relationship studies of forest trees. In order to test whether impedance parameters could be used in genetic relationship analysis among conifer species, EI and PHI were measured in a seedling experiment test composed of Pinus tabuliformis, Pinus yunnanensis, and Pinus densata in a habitat of Pinus tabuliformis. The results showed that variations in both EI and PHI among species were significant in different electric frequencies, and the EI and PHI values measured in the two populations of P. densata were between the two parental species, P. yunnanensis and P. tabuliformis. These results show that these two impedance parameters could reflect the genetic relationship among pine species. This was the first time using the two AC impedance spectroscopy parameters to test the genetic relationship analysis between tree species, and would be a hopeful novel reference methodology for future studies in evolution and genetic variation of tree species.

The Marsh Grassbird Locustella pryeri is an uncommon songbird endemic to East Asia. Suitable nest-site selection can minimize nest loss, especially for open-cup and ground nesting passerines. We located and monitored 66 Marsh Grassbird nests during 2004–2006 in Zhalong National Nature Reserve, northeast China, to identify characteristics of preferred nest sites. Marsh Grassbird nested mainly at sites with dense vegetation cover, high undergrowth and dry standing reed stalks, as well as small shallow ponds or rivers. Nests were more successful when they were placed higher above ground in patches with greater litter thickness. Predation and flooding were the leading causes of nest failure, accounting for at least 33 and 25 % of 24 nests lost, respectively. We advocate retention of some unharvested reed patches and implementation of irrigation strategies that avoid increasing water levels during the breeding period (May–July) of Marsh Grassbirds.