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Forest carbon stocks and sinks (CSSs) have been widely estimated using climate classification tables and linear regression (LR) models with common independent variables (IVs) such as the average diameter at breast height (DBH) of stems and root shoot ratio. However, this approach is relatively ineffective when the explanatory power of IVs is lower than that of unobservable variables. Various environmental and anthropogenic factors affect target variables that cause the correlation between them to be chaotic. Here, we designed a knife set (KS) approach combining LR models and the wandering through random forests (WTF) algorithm and applied it in a specific case of Phyllostachys edulis (Carrière) J. Houz. (P. edulis) forests, which have an irregular relationship between their belowground carbon (BGC) stocks and average DBH. We then validated the KS approach performed by cluster computing to estimate the aboveground carbon (AGC) and BGC stocks and the total net primary production (TNPP). The estimated CSSs were compared to the benchmark of the methodology that applied Tier 1 in the Intergovernmental Panel on Climate Change (IPCC) Guidelines for National Greenhouse Gas Inventories via 10-fold cross validation, and the KS approach significantly increased precision and accuracy of estimations. Our approach provides general insights to accurately estimate forest CSSs relying on evidence-based field data, even if some target variables are divergent in specific forest types. We also pointed out the reason why current fancy models containing machine learning (ML) or deep learning algorithms are not effective in predicting the target variables of certain chaotic systems is perhaps that the total explanatory power of observable variables is less than that of the total unobservable variables. Quantifying unobservable variables into observable variables is a linchpin of future works related to chaotic system estimation.

The extent of damage to Pinus thunbergii trees in coastal forests resulting from the tsunami caused by the Great East Japan Earthquake in 2011 differed depending on the local environment. The height (H) of P. thunbergii was generally limited in stands closer to the coastline and these trees could fail due to the force of the tsunami. The resistance forces of coastal forests to tsunamis are expressed as critical turning moments and measured by tree-pulling experiments. However, few studies have focused on the differences in the critical turning moment between stands with locally different environmental conditions among P. thunbergii coastal forests. We determined the differences in the critical turning moments of P. thunbergii in two contrasting sites having different distances from the coastline. We also estimated the tolerance of P. thunbergii in the two sites against loading from tsunami. Two experimental plots, sea-side and land-side, in a coastal P. thunbergii forest were established with different depths of the water table belowground and wind forces. In both plots, the aboveground traits, including the diameter at breast height (DBH), and H × DBH2 of P. thunbergii, were positively correlated with the critical turning moments. In particular, when P. thunbergii had the same H × DBH2 between the plots, there were no differences in the critical turning moments. This result suggested that P. thunbergii at the sea-side had acclimated for 50 years to their environment by changing shallow tap roots for shallower belowground water and developing horizontal roots for strong winds. The depth of the center point of rotation was significantly deeper and was positively correlated with moments in the land-side plot, suggesting changes from a tap root system to a plate root system in the sea-side plot with a shallower water table. The estimated loading from the tsunami with a 2 m wave height was over the critical turning moments for both plots. P. thunbergii trees at the sea-side plot could be more susceptible to overturning by lower-height waves than at the land-side plot because of differences in aboveground traits of H × DBH. We propose that the practical management of coastal forests is to create an embankment by raising the ground level to develop tree growth with capable of enhanced resilience to tsunamis.

To develop a scoring system that can adequately predict a successful guidewire crossing (S-GC) of below-the-knee (BTK) chronic total occlusions (CTOs) in angiographic evaluation.A retrospective, multicenter, nonrandomized study examined 448 consecutive BTK CTOs in 299 patients treated with endovascular therapy in seven Japanese medical centers from April 2012 to April 2020. The cohort was classified into two groups: an S-GC group and a failed guidewire crossing group.The final logistic regression model created by a backward stepwise multivariate logistic regression model included five variables: "No outflow of the target vessel," "CTO length ≥200 mm," "Reference vessel diameter 2.0 mm," "Calcification at the proximal entry point," and "Blunt type at entry point." Optimisms were adjusted using 1000 bootstrap samples with replacement and candidate's risk score models developed according to optimism-adjusted correlation coefficients of risk factors. Choosing the best model as the Japanese-BTK (J-BTK) CTO score by comparing the optimism-adjusted area under receiver-operating characteristic curves it was decided to assign one point to "Blunt type at the proximal entry point," one point to "Calcification at the proximal entry point," one point to "Reference vessel diameter 2.0 mm," one point to "CTO length ≥200 mm," and two points to "No outflow of the target vessel." This rule was then used to categorize BTK CTOs into four grades with varying probabilities of S-GC: grade A (J-BTK CTO score of 0 and 1), grade B (score of 2 and 3), grade C (score of 4 and 5), and grade D (score of 6). Rates of S-GC in each grade (grades A, B, C, and D) were 97.3%, 76.8%, 19.3%, and 0%, respectively. Lesions categorized as grade C or D have a lower chance of S-GC. Internal validation was performed using the Hosmer-Lemeshow test (P = .99).The J-BTK CTO score predicts the probability of an S-GC of BTK CTOs and stratifies the difficulty of endovascular therapy for BTK CTOs in angiographic evaluation.

In temperate and boreal forest, the production of extraradical mycorrhizal hyphae (EMH) is a major pathway for the plant – soil carbon (C) flux. For warm-temperate forest, however, scarcely available field data provide inconclusive evidence for the drivers of EMH production dynamics. In this study, we measured the seasonal variation in EMH production in Japanese warm-temperate Chamaecyparis obtusa (arbuscular mycorrhizal evergreen) and Quercus serrata forest (ectomycorrhizal broad-leaf), and assessed the relationship of EMH production to air temperature, global solar radiation, and soil water content. EMH productions of six consecutive two-month periods were estimated from hyphal lengths (HLs) and hyphal carbon masses (HCs) in 360 hyphal in-growth mesh bags and corrected for non-mycorrhizal HLs and HCs in 72 control bags from root-trenched areas. Seasonal variations in HL and HC productions of EMH were significant in both forest types. HL and HC productions of EMH were significantly related to air temperature which drives plant C assimilation in both forest types. We, thus, present evidence for coupling of EMH production to plant C assimilation in warm-temperate forest, regardless of the dominating mycorrhizal type.

Regeneration by sprouting in secondary forests is a necessary technique not only for the utilization of forest resources, but also for maintaining forest health by regrowth and avoiding slope instability caused by over-sized aboveground biomass. The strength of soil reinforcement by roots generally decreases during the tree death process in deforestation, such as clear-cutting, whereas root system strength temporarily decreases in trees that regenerate sprouting after cutting. However, quantitative evaluation of decreasing soil reinforcement by roots and slope stability has not been conducted during regeneration. In this study, we evaluated changes in the number of roots and root distribution up to 3 years after cutting in the regeneration process of Quercus serrata, a major dominant species of secondary forests in warm and cool temperate zones in Japan. We also estimated soil reinforcement by roots: additional cohesion from roots using the root bundle model, and slope stability based on a factor of safety by dividing the effect of the tree root system into vertical and horizontal cohesion with soil physical properties. After cutting at the height of approximately 0.2 m, the aboveground sprouting branches immediately regenerated, whereas the belowground root system gradually decayed. The additional cohesion from roots in trees before cutting was calculated as 34.6 kPa, whereas it decreased significantly to 21.7 kPa in living stumps 3 years after cutting. The value for the factor of safety with a saturated soil thickness of 0.7 m was calculated as 1.20 in soil under trees before cutting, whereas it decreased significantly to 1.11 in soil under living stumps in the 3 years after cutting. The safety factor's value to 0.99 in soil under dead stumps, which did not regenerate sprouts within 3 years after cutting. We concluded that the probability of slope failure was significantly greater in the dead stumps than in the living stumps and could vary depending on the dynamics of above- and below-ground parts, including fine roots.

Tree root diameter and root distribution are crucial factors for root reinforcement in forest soils and can be estimated using nondestructive ground-penetrating radar (GPR). However, no studies on estimating root reinforcement have been performed using GPR. The aim of this study was to evaluate root reinforcement using GPR in thinned and unthinned stands of Cryptomeria japonica in Andisols. Roots in each stand were detected using a 900 MHz GPR and the diameter and horizontal distribution of roots were estimated. Roots were also excavated to compare their GPR estimates. The relationships between root diameter and tensile force were established through field pullout tests. Finally, root reinforcements in each stand were estimated using the recently proposed root bundle model (RBM). There were no significant differences in the diameter frequency distribution of roots estimated between thinned and unthinned stands, determined using either the GPR or excavation methods. The detection frequency of the number of roots >5 mm in diameter using GPR was 27.2%, but it increased to 58.7% for roots >10 mm. The waveform indexes, determined using the sum of time intervals between zero crossings (ΣT) of all reflection waveforms of GPR, had a significant linear relationship with the diameters of excavated roots, indicating that waveform index could be used to estimate root diameter using the GPR index in these stands. Furthermore, the relationship between the root tensile force (F) and- root diameter (d) was estimated as F = 15.69 d1.75 (R2 = 0.87). The root reinforcements at the center of gaps between individual trees were estimated to be 23.4–32.9 kPa in the thinned stand and 8.8–23.9 kPa in the unthinned stand using GPR. These values ranged from 31.9% to 170.7% of those obtained by using the excavation method. There were no significant differences in root reinforcement between thinned and unthinned stands, regardless of the method used. This study revealed that GPR, together with diameter-tensile force relationships, can nondestructively estimate root reinforcement in managed forests. This protocol can be applied to manage forests to evaluate the effects of management on belowground roots.

Understanding how extraradical mycorrhizal fungal hyphae (EMH) regulate the cycling and retention of plant-assimilated carbon (C) in forest soils requires estimation of the production, mortality, and decomposition of EMH. To do this, the use of mass-balance models in combination with hyphal in-growth mesh bags (“in-growth bags”) was proposed in recent studies. However, poor knowledge on the decomposition of field-grown EMH prevents confirmation of assumed EMH decomposition dynamics. In this study, we determined the decrease in hyphal length density of field-grown EMH of arbuscular mycorrhizal fungi (AM) over eight months in in-growth bags incubated in a warm-temperate Chamaecyparis obtusa forest, to study EMH decomposition under field conditions. We used exponential decay models to describe the changes in the decomposition rate of EMH over the incubation time, between EMH diameter classes, and between seasons. A rapid decrease of the decomposition rate of EMH within two months from 2.5 to 0.1 month−1 was estimated, corresponding to an increase in half-life from 0.3 to 7 months. Furthermore, significant differences in the initial maximum decomposition rate were estimated between fine (1.6 month−1; minimum half-life: 0.4 months) and coarse EMH (3.1 month−1; minimum half-life: 0.2 months) and between incubations during spring-summer (April and August; 2.7 month−1; minimum half-life: 0.3 months) and autumn-winter (October and February; 1.1 month−1; minimum half-life: 0.6 months). This large variability in the decomposition rates of EMH of AM fungi has to be considered in mass-balance models to estimate C fluxes between plants, soil, and the atmosphere.

Background: Snaclecs affect the hemostasis of snakebite victims upon envenomation. Results: Rhinocetin, a novel snaclec, inhibits integrin α2β1-dependent functions of human platelets and endothelial cells. Conclusion: The actions of rhinocetin are consistent with hemorrhagic symptoms upon envenomation. Significance: Due to its inhibitory actions on integrin α2β1, rhinocetin may have potential diagnostic and therapeutic values., Snaclecs are small non-enzymatic proteins present in viper venoms reported to modulate hemostasis of victims through effects on platelets, vascular endothelial, and smooth muscle cells. In this study, we have isolated and functionally characterized a snaclec that we named “rhinocetin” from the venom of West African gaboon viper, Bitis gabonica rhinoceros. Rhinocetin was shown to comprise α and β chains with the molecular masses of 13.5 and 13 kDa, respectively. Sequence and immunoblot analysis of rhinocetin confirmed this to be a novel snaclec. Rhinocetin inhibited collagen-stimulated activation of human platelets in a dose-dependent manner but displayed no inhibitory effects on glycoprotein VI (collagen receptor) selective agonist, CRP-XL-, ADP-, or thrombin-induced platelet activation. Rhinocetin antagonized the binding of monoclonal antibodies against the α2 subunit of integrin α2β1 to platelets and coimmunoprecipitation analysis confirmed integrin α2β1 as a target for this venom protein. Rhinocetin inhibited a range of collagen-induced platelet functions such as fibrinogen binding, calcium mobilization, granule secretion, aggregation, and thrombus formation. It also inhibited integrin α2β1-dependent functions of human endothelial cells. Together, our data suggest rhinocetin to be a modulator of integrin α2β1 function and thus may provide valuable insights into the role of this integrin in physiological and pathophysiological scenarios, including hemostasis, thrombosis, and envenomation.

To estimate net ecosystem exchange (NEE) and net ecosystem production (NEP) in a forest situated on complex terrain, we evaluated the sensitivity of the estimates of NEE to the choice of a friction velocity (u*) correction for the estimation of flux on calm night. And compared these estimates with estimates based on biometric data using a warm-temperate deciduous and evergreen mixed forest in Japan. Biometric approaches were based on analyses of autotrophic carbon pools and heterotrophic carbon fluxes (NEP) versus changes in two major carbon pools (ΔC). To estimate ΔC, we calculated contributions to the soil carbon pool by litter and coarse woody debris (CWD) independently. The 3-year mean annual NEE from 2000 to 2002 was −1.23 MgC ha−1 year−1 (a negative flux indicates carbon gain). Estimated ΔC and NEP were 1.73 and 0.91 MgC m−2 year−1, respectively (a positive flux indicates carbon gain). The increment of live biomass contributed 76% of total ΔC. Estimated NEP varied widely due to large spatial variation in soil respiration. A realistic u* threshold was 0.4 m s−1. The estimated NEE value was larger than NEP. The change in NEE as a function of the u* threshold was marked, and most of the measured data (about 80%) could be eliminated by using the 0.4 m s−1 u* threshold. These results seem to be caused by the loss of most nocturnal respiration as a result of horizontal advection or drainage flow (because the study site was located on complex terrain). This tendency was consistent for towers located on a ridge and in a valley.

We measured the rates of respiration from snags and logs (“coarse woody debris”, CWD) of Japanese red pine ( Pinus densiflora Sieb. et Zucc.) to examine the rate of decomposition and CO 2 efflux from these materials in a temperate secondary broad-leaved forest in Japan. At this site, a high quantity of CWD of P. densiflora had accumulated as a result of pine wilt disease during the 1970s. Respiration rates were measured using a dynamic closed chamber method combined with an infrared gas analyzer. We measured the respiration rate of 7 samples of snags and 10 samples of logs from August 2003 to January 2004. The responses of the respiration rates of snags ( R snag ) and logs ( R log ) to changing temperature were both exponential and the responses to water content were quadratic, and the same function could be used to estimate annual values of both R snag and R log . Intensive measurements of water contents of snags and logs showed a marked difference in water content. The mean water content of snags was 20% of log water content. This difference was likely responsible for the observed difference in annual R snag and R log . The decay rate constants estimated from the respiration rates measurement of snags and logs were 0.019 and 0.081 year −1 , respectively. Despite being lower than R log , R snag was a significant compartment of the CWD carbon budget at this site.