Larix Kaempferi Research Articles

Transcriptome and Proteins Analysis Reveals the Gene Regulatory Processes Mediated by LaAP2L1, an AP2/ERF Transcription Factor, Functioning in Fast-Growing Heterosis in Larix kaempferi

Transcriptome and Proteins Analysis Reveals the Gene Regulatory Processes Mediated by LaAP2L1, an AP2/ERF Transcription Factor, Functioning in Fast-Growing Heterosis in Larix kaempferi

Inheritance of wood color, decay resistance, and polyphenol content of heartwood in full-sib families of Japanese larch (Larix kaempferi (Lamb.) Carr.)

Abstract Japanese larch (Larix kaempferi) is an important plantation species in Japan as well as in Europe. The inheritance of wood color (L*, a* and b*), mass loss by a white-rot fungus (Trametes versicolor) and a brown-rot fungus (Fomitopsis palustris), and polyphenol content (as the taxifolin equivalent) in heartwood were examined for 75 trees in 15 full-sib families of L. kaempferi. The mean values of all trees were 74.5 in L*, 8.4 in a*, 23.0 in b*, 18.3 and 26.0% in mass loss by T. versicolor and F. palustris, and 0.045 µmol/mg in polyphenol content. The narrow-sense heritability (h 2) showed higher values in heartwood color (h 2 = 0.70–0.87), but mass loss and polyphenol content showed relatively lower values (h 2 = 0.00–0.33). Significant negative correlations were found between polyphenol content and mass loss by white-rot and brown-rot fungi. In addition, the polyphenol content of heartwood was significantly correlated with the color of heartwood. Similar results were obtained in genetic correlations. Thus, it is concluded that parents with lower L* and higher a* and b* in heartwood could produce progenies with higher polyphenol content in heartwood, thereby leading to higher decay resistance.

Seasonal phosphorus and nitrogen cycling in four Japanese cool-temperate forest species

PurposeIn plant-soil systems, phosphorus partitioning during the annual cycle related to nitrogen partitioning remains largely unknown. The present study aims at assessing the soil-plant P allocation patterns of four tree species along four phenological stages and its relationship with tissues and soil N concentrations.MethodsCryptomeria japonica, Larix kaempferi, Fagus crenata and Robinia pseudoacacia trees were selected to sample coarse roots, sapwood, foliage, litter and soil during four phenological stages where total and Olsen extractable P and nitrogen content were measured respectively.ResultsIntra- and inter plant tissue nitrogen correlated well with phosphorus during the four phenological stages, especially root nitrogen. Fagus and Robinia were phosphorus limited, Larix was nitrogen limited and Cryptomeria co-limited. All species reabsorbed phosphorus and nitrogen from foliage prior to leaf abscission and stored nitrogen in roots and sapwood. Phosphorus storage was solely found in sapwood of Robinia. Soil dissolved ammonium correlated positively with nitrogen reabsorption efficiency during the green leaf stage, while single soil nutrient variables did not correlate with phosphorus reabsorption efficiency.ConclusionsPlant tissues nitrogen partitioning correlated well with their respective phosphorus partitioning and the increase of soil NH4+ correlated positively with nitrogen reabsorption efficiency, regardless of tree species during the green leaf stage. The results of this study show the intricate relationship that exists between nitrogen and phosphorus in the soil-plant continuum as well as the tree species specific internal cycling of these nutrients.

Determination of charring thickness of wood by residual strength analysis

This study was conducted to propose an accurate measurement method of charred thickness in structural glued laminated timber (glulam) exposed to standardized fire temperature conditions for evaluation of the fire resistance of Japanese larch (Larix kaempferi) structural glulam. The compressive strength of the test piece collected from the structural glulam exposed to the standardized fire temperature for two hours was analyzed. The results showed that there was residual strength of 14% in the boundary area between sound and charred part. Therefore, the thickness of charred part should be calculated as approximately 4.5 mm less than what is measured visually. The cell wall thickness between sound-, boundary-, and charred-part exposed to high temperature was observed under a microscope. Higher temperature resulted in a thinner tracheid cell wall, and the radial tissue was broken down. The transformation of the boundary part of these microstructures progressed gradually until full carbonization of wood occurred. Based on compressive strength tests and microscopic observation in the boundary part of specimens exposed to high temperature, the current visual assessment of charred thickness measurement is safe in terms of structural aspect but not efficient in terms of wood utilization point of view due to exception of load carrying area of the member.

Mycosphaerella laricis-leptolepidis (needle cast of Japanese larch)

Mycosphaerella laricis-leptolepidis (needle cast of Japanese larch)

The Change in Permeability of Larch Boxed-Heart Timber During Drying After High Temperature and Low Humidity Treatment

Abstract Japanese larch (Larix kaempferi) boxed-heart timbers with the dimension of 100 × 100 × 1,000 mm were dried after being steamed at 100°C and 0°C wet-bulb depression for 5 hours, and then dried at 120°C and 30°C wet-bulb depression for 8, 12, and 16 hours, respectively. The radial permeability of the surface layers of the timbers during drying was measured to discover the moisture movement mechanism in the transverse direction. The radial permeability in the surface layers of pretreated timbers decreased and tended to decrease as pretreating time increased. The decreased permeability can be attributed to the reduced distance between microfibrils inside the surface layers of pretreated timbers attributable to the pretreatment. This reduced distance decreases the moving rates of the bound water and water vapor from the inner part to surface layers of pretreated timbers during drying. Therefore, the average drying rate of pretreated timbers was decreased.

Upgrading of Picea glehnii, Larix kaempferi and Abies sachalinensis seeds by gravity separation using a wind sorter

Upgrading of Picea glehnii, Larix kaempferi and Abies sachalinensis seeds by gravity separation using a wind sorter

Differential water-use and growth responses of Pinus densiflora and Larix kaempferi seedlings to microclimate manipulation

Our study assessed how physiological traits and the growth of seedlings of Pinus densiflora and Larix kaempferi, representative coniferous species of Korea, are affected by warming and precipitation manipulation. A warming and precipitation manipulation experiment was conducted with 1- and 2-year-old seedlings using infrared heaters, transparent panels, and an irrigation system. Plant physiological activities were monitored using a portable photosynthesis measurement system, and seedling growth was investigated by measuring the dry weight of harvested biomass. P. densiflora, an isohydric species, showed an overall decrease in physiological activities under the warming treatment in the first (germination) year. In particular, stomatal conductance decreased to prevent excessive water loss, with minimal decreases in photosynthetic activity, and increased the water-use efficiency in the first year. L. kaempferi, an anisohydric species, maintained stomatal conductance under the warming treatment. Both species maintained physiological activities with their distinct responses to heat in the second year, while the seasonal variation pattern changed in 2-year-old P. densiflora seedlings. The dry weight of L. kaempferi seedlings increased under warming; however, it decreased by warming combined with increased precipitation. These results can enhance the understanding of seedling responses to microclimate manipulation according to the different water-use by species and seedling age. Under the future climate change, these responses should be accounted for in management of seedlings in nurseries or newly afforested areas.

Дифференциация климатипов лиственниц (Larix spp.) в географических культурах в лесостепи Средней Сибири

Дифференциация климатипов лиственниц (Larix spp.) в географических культурах в лесостепи Средней Сибири

Impact of COVID-19 on sales volume and prices of Japanese larch and Todo fir logs

Impact of COVID-19 on sales volume and prices of Japanese larch and Todo fir logs

Characterization of Larix kaempferi seeds selected by near-infrared spectroscopy for germination and post-germination growth in nursery containers

ABSTRACT Demand for nursery stock of Japanese larch (Larix kaempferi) is growing. Containerized seedlings are expected to meet this demand. However, the conventional methods are labor intensive and time consuming because one-year-old bare-root seedlings are transplanted to containers. In this study, we selected seeds using a spectroscope and examined two propagation methods, direct sowing on nursery container (direct sowing) and sowing on a small plug tray followed by transplantation to a container (plug transplant), to shorten the nursery period of 2 years. Germination rate increased in the selected seed when compared with the unselected seed (χ2 test). The days to germinate (DtG) shortened with the use of heavier seeds, and the one-year-old seedlings grew taller as the DtG decreased. However, transplantation from plug trays had negative effects (generalized linear model (GLM) and analysis of variance (ANOVA). On the other hand, large volume cell had positive effects on root collar diameter (GLM and ANOVA). The results revealed that the nursery periods were shortened by using large volume cell, irrespective of the seedling type (direct sowing or plug transplant).

Effect of film liner packaging with chlorine dioxide on the storage quality of containergrown or bare-root seedlings at cold or frozen temperatures in sawtooth oak and Japanese larch

Effect of film liner packaging with chlorine dioxide on the storage quality of containergrown or bare-root seedlings at cold or frozen temperatures in sawtooth oak and Japanese larch

Long-term bending properties of cross-laminated timber made from Japanese larch under constant environment

Cross-laminated timber (CLT) has been used extensively in timber construction. CLT panels are typically used in roofs and floors that carry a continuous load, and it is important to examine the long-term loading capacity of CLT. However, studies that focus on the long-term loading capacity of CLT are limited. To this end, we conducted long-term out-of-plane bending tests on seven-layer CLT made from Japanese larch (Larix kaempferi) under constant environmental conditions, investigated creep performance and duration of load, and experimentally analyzed creep rupture behavior. The mean estimated relative creep after 50 years was 1.49. The sample showed a satisfactory resistance to creep as a building material. The duration of load of most of the specimens in this study was shorter than the conventional value of small clear wood specimens. Specimens had a lower duration of load capacity than solid lumber. According to the results of survival analysis, a loading level of 70% or more caused the initial failure of specimens. Creep rupture of most of the specimens occurred at less deflection than displacement at failure in the short-term loading test. Additional studies focusing on the effects of finger joints, transverse layers, and width of a specimen on creep rupture behavior are suggested.

Early Growth Responses of Larix kaempferi (Lamb.) Carr. Seedling to Short-Term Extreme Climate Events in Summer

Extreme climate events such as heat waves, drought, and heavy rainfall are occurring more frequently and are more intense due to ongoing climate change. This study evaluated the early growth performance of one-year-old Larix kaempferi (Lamb.) Carr. seedlings under open-field extreme climate conditions including experimental warming and different precipitation regimes. We recorded the survival rate, root collar diameter, height, biomass, shoot-to-root ratio, and seedling quality index using nine treatments (three temperature levels, i.e., control, warming by 3 °C and by 6 °C, × three precipitation levels, i.e., control, drought, and heavy rainfall) in July and August 2020. The survival rate of seedlings did not differ between treatments, showing high values exceeding 94% across treatments. The measured shoot height was largest under warming by 3 °C and high rainfall, indicating that moderate warming increased seedling height growth in a moist environment. Heavy rainfall decreased stem volume by 21% and 25% under control and warming by 6 °C treatments, respectively. However, drought manipulation using rain-out shelters did not decrease the growth performance. Overall, extreme climate events did not affect the survival rate, biomass, shoot-to-root ratio, and seedling quality index of L. kaempferi. We thus conclude that, regarding growth responses, L. kaempferi seedlings may be resistant to short-term extreme warming and drought events during summer.

Analysis of Anatomical Characteristics for Wood Species Identification of Commercial Plywood in Korea

International efforts to prevent illegally logged wood are expanding around the world. The “Legal Wood Trade Promotion System” was enacted in Korea in 2019 to strengthen the legal import and distribution of commercial wood in Korea. Since then, this system has promoted and ensured that the imported wood and wood products are legal with respect to the country of origin, wood species, and harvested area. As verification methods, DNA analysis technology and anatomical analysis using a microscope are mainly used in conjunction. Therefore, in this study, wood species of plywood were identified by analyzing the anatomical characteristics of various wood products for the first time. Douglas fir (Pseudotsuga menziesii (Mirb.) Franco.) and larch (Larix kaempferi (Lamb.) Carriere) plywoods (7, 9 ply) were obtained from four companies that supply plywood in Korea. After cutting each company

Upgrading the fuel properties of hydrochar by co-hydrothermal carbonisation of dairy manure and Japanese larch (Larix kaempferi): product characterisation, thermal behaviour, kinetics and thermodynamic properties

This study investigated co-hydrothermal carbonisation (co-HTC) of dairy manure (DM) and wood shavings from Larix kaempferi, commonly known as the Japanese larch (JL) to enhance the fuel properties of the resulting hydrochar. The JL was mixed with the DM at 25, 50 and 75 wt.% ratios. Co-HTC was conducted at 260 °C for 20 min. The resulting hydrochars were characterised based on the physicochemical properties and the thermal behaviour. Results showed that the hydrochar solid biofuel properties improved as the ratio of JL was increased. The produced hydrochars were in the region of lignite and closed to the region of the coal with increased fixed carbon, carbon contents and lowered H/C and O/C ratios. Hydrochar with ash content of 7.2 ± 0.5% was obtained at 75 wt.% JL. In addition, the HHV of hydrochar increased remarkably to 26.4 ± 0.02 MJ/kg as the mass ratio of the JL was increased. The surface morphology of the hydrochars were altered and became distinct while the specific surface area (SSA) and the total pore volume (TPV) of the hydrochars increased at increasing the mass ratio of the JL. The surface functional groups were also altered by the co-HTC process. A decline in the combustion performance was observed after the HTC process but improved at 75 wt.% JL after the co-HTC process. The kinetic analysis also revealed that the activation energy decreased after the HTC process but increased to a higher value at 50 wt.% JL after the co-HTC process. Therefore, hydrochar production by co-HTC of DM and JL has proved to be an effective and promising solid biofuel source.Graphical abstract

Disentangling the direct and indirect effects of canopy and understory vegetation on the foraging habitat selection of the brown bear Ursus arctos

Elucidating the factors affecting the foraging habitat selection of wildlife can further our understanding of the animal–habitat relationships and inform wildlife conservation and management. Canopy and understory vegetation may directly or indirectly affect the foraging habitat selection of carnivores through changes in habitat structure and prey availability, respectively; however, the relative importance of these two effects remains largely unknown. Dwarf bamboo Sasa kurilensis is a predominant understory plant that suppresses regeneration in the forests of northern Japan. The purpose of this study was to disentangle the direct and indirect effects of canopy forest type Larix kaempferi plantation versus natural mixed forest) and dwarf bamboo on foraging habitat selection of a large carnivore, the brown bear Ursus arctos. In the Shiretoko World Heritage, brown bears dig for cicada nymphs during summer. We evaluated the frequency of brown bear foraging on cicadas by investigating traces of digging for cicada nymphs. A structural equation model was used to statistically disentangle the direct and indirect effects of vegetation. Our results demonstrated that canopy and understory vegetation directly and indirectly affected foraging habitat selection of brown bears. Dwarf bamboo negatively affected cicada nymph density, which positively affected brown bear digging. This suggests that dwarf bamboo also had indirect negative effects on brown bears. Forest type had significant direct and indirect effects via change in cicada nymph density on foraging behavior in brown bears. Forestry managers in northern Japan, including the study site, try to remove dwarf bamboo for assisting natural regeneration. Removal of dwarf bamboo by scarification might not only promote natural regeneration, but also provide a beneficial foraging habitat for bears.

Embryogenic callus induction from immature zygotic embryos and genetic transformation of Larix kaempferi 3x Larix gmelinii 9.

To date, there are few reports of the successful genetic transformation of larch and other conifers, mainly because it is difficult to transform and integrate exogenous genes. In this study, hybrid larch Larix kaempferi 3x Larix gmelinii 9 cones were collected on June 27, July 1, July 4, July 7 and July 16, 2017. Embryogenic callus induction was studied using a combination of different plant growth regulators and concentrations. The results showed that July 1 was the best stage; the highest induction rate was 10.83%, which cultured in BM medium (Button medium, which formula was listed in S1 Table) with 1.0 mg/L 2,4-D (2,4-dichlorophenoxyacetic acid) and 0.2 mg/L KT(kinetin). When cultured on a proliferation medium for 12 days, proliferation was the fastest, reaching 323.08%, which could also maintain the freshness and vitality. The suitable pre-culture medium for somatic embryogenesis was 1/4 BM medium containing 10 g/L inositol and 60 g/L sucrose. The combination of 45 mg/L ABA (abscisic acid) and 75 g/L PEG4000 (Polyethyene glycol 4000) could promote the number of somatic embryos, and reached the maximum, 210 140 per 1 g FW. The genetic transformation was carried out by the Agrobacterium-mediated transformation method with embryogenic callus cultured for 12 days. The results showed the optimal OD600 of the infection solution(suspension of A. tumefaciens) was 0.5, co-culture time was 2 days, and screening concentration of Hyg (hygromycin B) was 4 mg/L. In this study, the transformation rate of resistance callus was 32.1%. It provides a reference for low genetic transformation efficiency of larch at present. This study could be beneficial for the innovation and breeding of larch by genetic engineering and provides a certain basis for rapid propagation of excellent larch germplasm resources and genetic engineering breeding of larch and other conifers.

Short-term physiological responses of Larix kaempferi seedlings to spring warming and drought manipulation

Excessively high temperatures and droughts after winter dormancy can affect the physiological responses of plant seedlings. In the present study, an open-field experiment was conducted to investigate the impact of spring warming and drought treatments on the short-term physiological responses of 1-year-old Larix kaempferi seedlings. The warming treatment was designed to increase the air temperature by 4 °C compared to that of the temperature control plots and was carried out for seven days each in the second and fourth week of May 2020. Moreover, the drought treatment was designed to completely block precipitation for four weeks in May 2020. After the first warming treatment period, stomatal conductance, transpiration rate, and net photosynthetic rate decreased by 35.16%, 29.53%, and 13.34% in the temperature warming plots compared to those in the temperature control plots, respectively. After the resting stage, stomatal conductance and transpiration rate increased by 101.47% and 72.80% in the temperature warming plots compared to those in the temperature control plots, respectively. Stomatal conductance, transpiration rate, and net photosynthetic rate tended to decrease in the drought treatment. The total chlorophyll content did not change under the warming treatment, but it increased by 20.29% in the drought treatment plots compared to that in the precipitation control plots in the fourth week; this may have resulted from chlorophyll hormesis. Furthermore, the correlation and principal component analyses showed that seedling physiological responses and environmental conditions were closely related. We found that spring warming and drought treatments can reduce stomatal conductance, transpiration rate, and net photosynthetic rate, thus affecting seedling growth. This study is expected to be the basis for more in-depth studies on the effects of warming and drought treatments on the growth and phenology of L. kaempferi seedlings.

Influence of adhesive and layer composition on compressive strength of mixed cross-laminated timber

Different types of wood can be used for making cross-laminated timber (CLT), which is useful as a structural material. Therefore, to assess the viability of mixed cross-laminated timbers prepared with different adhesives, their compressive strength performances were evaluated. Laminae of Japanese larch, red pine, and yellow poplar were used to manufacture eight types of mixed CLTs, which were then tested in a universal testing machine for obtaining the compressive strength. The results were then compared to those obtained from the finite element (FEM) simulation of the CLTs at proportional limit load. The compressive strength of CLTs consisting of Japanese larch laminae, with a high modulus of elasticity, tended to increase. Mixed CLT with polyurethane adhesives showed an average compressive strength that was 14% lower than that of larch CLT, while mixed CLT consisting of red pine and yellow poplar showed an average compressive strength that was 18% lower than that of the larch CLT. The CLT prepared with phenol-resorcinol-formaldehyde adhesive yielded the highest compressive strength among the three adhesives. The FEM-predicted strengths were found to be close to the actual values in all specimens. The obtained results will be useful for selecting material and adhesive for future endeavors.