Temperate Forest In Japan Research Articles

Fungal content of ectomycorrhizal tips: comparison among 13 tree species

To better understand soil carbon cycling in forest ecosystems, we studied the proportion of fungal sheath area (FSA) in the cross-sectional ectomycorrhizal area in 13 tree species. Ectomycorrhizal samples were collected from subalpine and temperate forests in Japan. The FSA values were in the range of 12% to 56% across all tree species, tree ages, and fungal species. In Abies firma and Quercus serrata, the FSA values were larger in mature trees than in seedlings, whereas no such differences were found in Pinus densiflora and Fagus crenata. In broad-leaved trees, because the plant tissue radii lay within a narrow range, the FSA was affected mainly by the fungal sheath thickness. In conifers, however, the plant tissue radii varied widely among genera, so the FSA was affected by both the plant tissue radius and the fungal sheath thickness. Our findings suggest that the fungal content of ectomycorrhizal tips differs among tree species and fungal species, so that both parameters must be considered in studies of forest carbon cycling. The estimates revealed that data gathering in each type of forest leads to more accurate estimates of the biomass of fungi in ectomycorrhizal tips.

Flowers adaptively face down‐slope in 10 forest‐floor herbs

Summary An animal‐pollinated plant living on a slope should orientate its flowers down‐slope towards the more open space if by doing so it receives more pollinator visits and thereby achieves increased reproductive success. We measured flower orientation relative to slope direction on individuals of 10 species of forest‐floor herbs in cool temperate forests in Japan. For one of these species, Erythronium japonicum, we also manipulated flower orientation to test experimentally for its effects on both male and female reproductive function. In all 10 species, flowers were preferentially orientated down‐slope. This pattern was more pronounced in plants growing on steeper slopes. Our manipulative field experiment in Erythronium japonicum demonstrated that pollen dispatch was highest in flowers orientated down‐slope. Additionally, flowers orientated up‐slope may have achieved a lower seed set on steep slopes. We conclude that down‐slope orientation of flowers was a general phenomenon among the species that we studied, and that this behaviour was adaptive in enhancing plant fitness through pollination.

Development of an automatic chamber system for long-term measurements of CO2 flux from roots

To separate CO2 efflux from roots (Rr) and soil (Rs), we developed a system to measure Rr continuously. Using this system, seasonal variation in Rr was obtained in a temperate forest in Japan. We measured Rs, CO2 efflux from mineral soil (Rm) and environmental factors simultaneously, and the characteristic and seasonality of Rr were analysed in comparison with Rs. Rr and Rs showed different responses to soil water content: Rs decreased with decreasing soil water content, whereas Rr peaked at relatively low soil water content. Rr/Rs decreased from 64.8% to 27.3% as soil water content increased from 0.075 to 0.225 cm cm-3. The relationship between respiration and temperature appears to change seasonally in response to phenological and biological factors. Rr showed clear seasonal variation as a function of soil temperature. During the growing period, Rr exhibited a higher rate at the same soil temperature than during other periods, which may be due to phenological influences such as fine root dynamics. Rs decreased during the summer despite high soil temperatures. The seasonal peak for Rs occurred earlier than that for soil temperature. Rr/Rs ranged between 25% and 60% over the course of the year.

Decomposition of organic chemical components in relation to nitrogen dynamics in leaf litter of 14 tree species in a cool temperate forest

AbstractDecomposition of lignin, holocellulose, polyphenols and soluble carbohydrates was investigated in relation to nitrogen (N) dynamics in leaf litter of 14 tree species. The influence of organic chemical components and N on litter mass loss rate was then evaluated for 14 litter types. The study was carried out over a 3‐year period on upper and lower parts of a forest slope in a cool temperate forest in Japan. The decomposition processes were divided into early and late phases based on N immobilization and mobilization. Mass loss rate of whole litter and organic chemical components was similar for the upper and lower sites. Litter mass loss was faster in the immobilization phase than in the mobilization phase in each of 14 litter types, which was ascribed to the decreased mass loss of holocellulose, polyphenols and soluble carbohydrates in the mobilization phase as compared to the immobilization phase. Mass loss rate of lignin was not different between the phases. Litter mass loss rate in the immobilization and mobilization phases was negatively correlated to lignin content and positively correlated to contents of polyphenols and soluble carbohydrates at the start of these phases, but was not correlated to holocellulose and N contents in either phase.

Limit values for decomposition and convergence process of lignocellulose fraction in decomposing leaf litter of 14 tree species in a cool temperate forest

AbstractWe examined limit values for decomposition and lignocellulose index (LCI, the ratio of acid‐soluble holocellulose to acid‐soluble holocellulose plus acid‐insoluble lignin and lignin‐like substances) in leaf litter decomposition of 14 tree species over 3 years. The study was carried out on upper (moder) and lower parts (mull) of a forest slope that showed different humus accumulation forms in a cool temperate forest in Japan. Limit values for accumulated mass loss of litter ranged from 46.8% to 94.1% and were not different between the sites. Limit values were positively correlated to initial LCI and lignin content. Final values of LCI of 14 litter types at the end of the study period showed a convergent trend among litter types at 0.25–0.26 as compared to their initial values (0.41 mean). The final LCI was not different between the sites. A review of limit values and initial and final values of LCI in leaf litter of temperate and boreal forests indicated that the limit values and final LCI in litter types in Japan were lower than those in Europe and North America, which can be primarily ascribed to lower initial LCI in Japan.

Accumulation and release of nitrogen and phosphorus in relation to lignin decomposition in leaf litter of 14 tree species

Immobilization and mobilization of nitrogen and phosphorus were investigated in relation to the nitrogen (L/N) ratio and lignin to the phosphorus (L/P) ratio as indicators of the nitrogen and phosphorus dynamics. The present study was carried out on upper and lower parts of a forest slope in a cool temperate forest in Japan. Net immobilization and net mobilization characterized the dynamics of nitrogen and phosphorus in 14 litter types and were related to the changes in the L/N and L/P ratio. The critical values of the L/N and L/P ratio at which the mobilization began were 23–25 and 500–620, respectively. In litter types with the L/N and L/P ratio higher than critical values, nitrogen and phosphorus were immobilized until the ratios reached at the critical values and then nitrogen and phosphorus began decreasing. In litter types with initial L/N and L/P ratios lower than or equal to the critical values, nitrogen and phosphorus were released from litter. The critical values of the L/N and L/P ratios showed convergent trends among litter types as compared to their initial values, and were approached to those of underlying humus layers. These results indicated the usefulness of L/N and L/P ratios as indicators of the nitrogen and phosphorus dynamics in the study site. The general validity of the L/N ratio as an indicator of nitrogen dynamics and the convergent trend of critical L/N ratio at 25–30 were demonstrated by a review of literature on lignin and nitrogen dynamics in 47 litter types in temperate and boreal forests.

Recovery of mycorrhizas of a fungus, Cenococcum geophilum, after urea treatment in warm temperate forests in Japan

We studied recovery of the ectomycorrhizal species Cenococcum geophilum (Cg) after urea treatment in two types of vegetation. The recovery was as quick as 6 months after the treatment and overlapped the fruiting period of ectomycorrhizal ammonia fungi. Ectomycorrhizas investigated as Cg belonged to a single species irrespective of treatment and vegetation type. Cg ectomycorrhizas were significantly more abundant in density in nontreated soil than in treated soil. Between vegetation types, Cg ectomycorrhizas were significantly more in density in broad-leaved deciduous forest than in broad-leaved evergreen forest. Moreover, Cg was dominant in the nontreated soils of the former type of forest.

Analytical estimation of the vertical distribution of CO 2 production within soil: application to a Japanese temperate forest

We present methods, based on an analytical solution to a diffusion equation, for estimating the vertical distribution of the rate of CO 2 production within soil. The first method assumes an a priori equation that represents the profile of CO 2 production. The second method divides the soil into four layers, from the ground surface to a depth of 80 cm; within each layer, constant CO 2 production is assumed. These methods were applied to a secondary deciduous temperate forest in Japan. Soil respiration and CO 2 concentrations within the soil pores were measured in the forest from March to December of 1998. The value of Q 10, the factor by which metabolic processes increase for each 10 °C increase in temperature, was estimated to be 2.55, using the soil temperature at a depth of 10 cm. The annual soil respiration was estimated to be 642 ± 91 g C m −2 y −1. The CO 2 concentration within soil pores increased with soil depth in every season, and showed temperature dependency at all depths, which was similar to the relationship between soil respiration and soil temperature. By applying the proposed methods, the profiles of the actual CO 2 concentrations within soil pores were well reproduced. Within soil, the amplitude of the seasonal variation in the CO 2 production rate was larger in the shallow soil layers than in the deep layers. The CO 2 production rate in the shallow soil layers was highly correlated with soil temperature, and its response to soil temperature was more sensitive than that estimated from the CO 2 efflux from the soil surface. It was found that the temperature sensitivity of the CO 2 production rate differed between the shallow and deep soil layers; this would affect the estimated value of Q 10. Adding to the necessity of distinguishing heterotrophic and autotrophic respiration, it is suggested that the way in which they are distributed vertically within soil is critical for predicting soil respiration, and should be included in the parameterization of soil respiration.

The time of urea treatment and its effects on the succession of ammonia fungi in two warm temperate forests in Japan

We studied the effects of the timing of urea treatment on the succession of ammonia fungi. In two evergreen Castanopsis cuspidata forests and in one deciduous Quercus serrata forest, we applied 343g urea to 25 and 15 plots of 0.5m2, respectively, at three different times of the year. Ten of the early-phase (EP) species, considered to be saprotrophic, and 6 of the late-phase (LP) ones, considered ectomycorrhizal, fruited. In both phases, the commencement, peak, and cessation of fruiting took place simultaneously among all the plots treated at the same time. The fruiting occurred in summer and autumn. Quantity and size of the fruit bodies was larger in the LP than in the EP species. Fruiting of EP species was affected by the treatment time and that of LP species by interaction of the treatment time and vegetation type. EP was short and occurred as one period, whereas LP was long and occurred as two or more fruiting seasons. We found that species composition, dominant species, and degree of its dominance in fruiting of the ammonia fungi are predictable for different treatment times of the year and different vegetation types.

Potassium, calcium, and magnesium dynamics during litter decomposition in a cool temperate forest

The dynamics of K, Ca, and Mg were investigated during the decomposition of 14 litter types over a 3-year period on the upper and lower parts of a forest slope in a cool temperate forest in Japan. Potassium dynamics were divided into initial leaching phase and late phase. Initial K concentrations for the initial phase were correlated with the rate of decrease in K concentration during the initial phase. The late phase was characterized by seasonal fluctuations in concentration: K concentration increased from April to November and decreased during the winter period. The pattern of change in Ca concentration was divided into initial increase phase and late decrease phase in some litter types, or consisted of the late phase only in other litters. Calcium concentration of the initial litter was not predictable for the pattern of change in Ca concentration nor the rate of change in Ca concentration during the initial phase. Initial Ca concentration for the late phase was correlated with the rate of change in Ca concentration during the late phase. The pattern of change in Mg concentration was divided into initial leaching phase and late immobilization phase. Initial Mg concentration for the initial phase was correlated with the rate of change in Mg concentration during the initial phase. At the lower site, initial Mg concentration for the late phase was correlated with the rate of change in Mg concentration during the late phase, while such a relationship was not observed at the upper site. Concentrations of K, Ca, and Mg showed a convergent trend at the end of the study period. The final concentration differed between the upper and lower sites.

Development and characterization of microsatellite markers for Fagus crenata Blume

AbstractMicrosatellite markers can yield high‐resolution genetic profiles for individual identification, and for parentage analysis, when evaluating gene dispersal in populations. Fagus crenata is an important dominant species in the cool temperate forests in Japan, and although many studies on the species have been conducted the patterns of gene dispersal via pollen and seeds are poorly understood. In order to be better informed about gene dispersal in Fagus crenata, we have developed 16 new microsatellite loci from an enriched library of genomic DNA. These 16 loci were highly variable, with 3–40 alleles per locus and an expected heterozygosity value of 0.11–0.98.

Screening for dioxin-degrading basidiomycetes from temperate and tropical forests

A total of 500 strains of basidiomycetes isolated from temperate forests in Japan and 379 strains from tropical forests in Indonesia were subjected to a laboratory screening for dioxin-degrading ability. At first, about 200 fungal strains were selected by their ability to decolorize Remazol Brilliant Blue R dye as an indicator of ligninolytic activities. Next, for excluding the factor of dioxin sorption by mycelia, we prepared two series of living cultures exposed either long-term or short-term to 2,7-dichlorodibenzo-p-dioxin (2,7-DCDD), and compared the decreases in the remaining amounts of this model compound. We chose Bjerkandera adusta strain VH57 as a promising new candidate for dioxin degradation, because it gave 40% difference in 2,7-DCDD levels between the two treatments after 30 days of exposure.

Variations in transpiration rate and leaf cell turgor maintenance in saplings of deciduous broad-leaved tree species common in cool temperate forests in Japan.

To clarify mechanisms underlying variation in transpiration rate among deciduous broad-leaved tree species, we measured diurnal changes in stomatal conductance (gs) and leaf water potential, and calculated the maximum transpiration rate (Emax), leaf-specific hydraulic conductance (K(s-l)) and difference between the soil water potential and the daily minimum leaf water potential (Psis - Psi(l,min)). Pressure-volume (P-V) measurements were made on leaves. Saplings of eight broad-leaved tree species that are common in Japanese cool temperate forests were studied. Maximum transpiration rate varied significantly among species. There was a statistically significant difference in Psis - Psi(l,min), but not in K(s-l). Species with large Emax also had large Psis - Psi(l,min) and gs. The results of the P-V analyses showed that species with a large Psis - Psi(l,min) maintained turgor even at low leaf water potentials. The similar daily minimum leaf pressure potentials (Psip) across all eight species indicate that Psip values below this minimum are critical. Based on these results, we suggest that the leaf cell capacity for turgor maintenance strongly affects Psis - Psi(l,min) and consequently Emax via stomatal regulation.

SEEDLING DEMOGRAPHY OF SWIDA CONTROVERSA: EFFECT OF LIGHT AND DISTANCE TO CONSPECIFICS

Some shade-intolerant trees with soil seed banks also have advanced recruits under a closed canopy. To determine the relative roles of advanced recruits and seed banks in regeneration, we studied the demography of seedling cohorts of the deciduous canopy tree, Swida controversa, in an old-growth temperate forest in Japan. Five cohorts that germinated in 1988–1992 were followed for 10 yr, relating their survival and growth to the environment. We measured distance to the nearest conspecific adult, initial local density of conspecific seedlings, herbaceous plant coverage, light intensity, and soil water content. Seed production occurred only in 1988 and 1990, but seedlings emerged every year from 1988 to 1992. Only increasing distance to the nearest conspecific adult had a significant, positive effect on seedling survival. Damping-off by fungal pathogens was the most common cause of seedling mortality, especially near conspecific adults. Growth of seedlings was significantly and positively affected by light level; rapid growth occurred mostly in a large gap (∼200 m2). Even here, however, the growth rate of seedlings decreased over time. A stochastic simulation suggested that the relative importance of soil seeds and advanced recruits changes with the distance. In sites <25 m from conspecific adults, colonization of gaps should occur via the soil seed bank, because seedlings do not survive at these distances. In sites farther away, advanced recruits were more important than the seed bank in colonizing gaps. We hypothesize that, in sites with an abundant population of S. controversa, regeneration would most likely originate from the soil seed bank, but in other sites regeneration would most likely be from advanced recruits.

Importance of physiological integration of dwarf bamboo to persistence in forest understorey: a field experiment

Summary Sasa spp., dwarf bamboo which dominate the undergrowth of temperate forests in Japan occur as clonal fragments in which ramets in light gaps to are connected to those in shaded understoreys by long rhizomes. We test whether persistence under shaded conditions is supported by translocation of assimilates from illuminated ramets. A dense population of Sasa palmata growing at an open site, was exposed to two light conditions (homogeneous: open–open and heterogeneous: open–shaded) and two rhizome connection treatments (intact and severed) in a full factorial design. Ramet mass, and the mass of many parts of the clonal fragments, was much lower in the shade than in the open, but this effect was less marked when the rhizome connection was intact than when it was severed. Clone parts in shade may therefore be supported by translocation from connected clone parts in the open, with such physiological integration enhancing persistence where light supply is heterogeneous as in the gap–understorey continuum. Above‐ground biomass was reduced sooner than that below ground. Clonal fragments of S. palmata recover via dormant buds on rhizomes, whose longer persistence would therefore enhance performance of the clonal fragment. Specific leaf area (SLA) was greater in shade than in the open, irrespective of rhizome connection, suggesting that individual leaves show morphological plasticity independently of only physiological integration.

Relationship between leaf characteristics, tree sizes and species distribution along a slope in a warm temperate forest

The relationships between some leaf characteristics, tree size and species distribution were investigated for evergreen tree species along a slope in a warm temperate forest in Japan. Tree species were classified into three groups based on their dominance on the slope: ‘ridge species’ that were aggregated in an uppersite, ‘valley species’ that were aggregated in a lowersite, and ‘uniform species’ that were distributed almost uniformly. The ridge species had a more positive leaf carbon isotope ratio than the valley species, which suggests that the ridge species have larger water use efficiency than the valley species. This may give some advantage to the ridge species over the valley species in the uppersite where water availability would be limited. However, the ridge species had smaller leaf nitrogen content on a mass basis and larger leaf mass per area than the valley species, which suggests that the ridge species had a smaller mass‐based leaf photosynthetic capacity than the valley species. This may be disadvantageous to ridge species in the lowersite, because smaller leaf photosynthetic capacities cause lower leaf carbon gain and thus lower growth than the valley species. These differences in leaf characteristics between the ridge and the valley species were affected by microenvironments, and were also partly affected by the difference in species specific responses to microenvironments on the slope.

Seasonal Changes in the Diet of Japanese Giant Flying Squirrels in Relation to Reproduction

The diet of Japanese giant flying squirrels ( Petaurista leucogenys ) was studied in a temperate forest in Japan for 9 years, 1978–1990. These exclusively arboreal squirrels fed entirely on plant material. On the basis of 3,559 feeding records, 45 species of trees belonging to 21 families were identified in the diet. The families Fagaceae, Pinaceae, and Rosaceae were particularly important. Main food items were seeds (33.9%), leaves (26.2%), and staminate cones of conifers (12.4%). Foliage and flowers predominated in the diet in the first one-half of the year and various seeds in the second one-half. The proportion of mature leaves in the diet (a negative index of availability of food) was lowest in May and September and highest in February and July. May and September are periods of lactation or of foraging by weaned young, and February and July coincide with periods of pregnancy in the biannual reproduction.

The effects of organic carbon on acid rain in a temperate forest in Japan

From recent studies, we noticed that stemflow had an acidity that differed from that of precipitation or throughfall. Organic substances, supplied from the tree surface, would be one of the factors that modifies the acidity of rain. The objectives of this study were to determine the DOC concentration and to clarify the influence of dissolved organic carbon (DOC) on acidity in precipitation, throughfall and stemflow. Throughfall and stemflow were measured in sugi [Cryptomeria japonica D. Don], hinoki [Chamaecyparis obutusa Endl.] and kojii [Castanopsis cuspidata (Thumb.) Schottky.] stands. All samples were analyzed for their pH, electric conductivity (EC), major inorganic anions and cations and DOC concentration.

Life histories of four oribatid mite species in a mull type soil in a cool temperate forest in Japan

Life histories of four oribatid mite species in a mull type soil in a cool temperate forest in Japan

Taxonomic character of plant species in absorbing and accumulating alkali and alkaline earth metals grown in temperate forest of Japan

Absorption and accumulation of alkali (Li, Na, K, Rb, Cs) and alkaline earth (Mg, Ca, Sr, Ba) metals were investigated as taxonomic characteristics (in 62 plant species). Leaf and soil samples were collected from 9 sites in temperature forest in Japan and the above mentioned elements were analyzed. Considerable differences were found among species in their ability to accumulate alkali and alkaline earth metals. Very high concentrations of Li (45 ppm, D.W.), K (37×103 ppm), Rb (159 ppm) and Cs (8.2 ppm) were detected inLastrea japonica which were about 412, 12, 27 and 6 times higher than those of the species with the lowest concentrations. Na content was high inAcer micranthum (358 ppm) which was 16 times higher than species with the lowest concentration. Other species containing high levels of alkali metals wereHydrangea macrophylla, Struthiopteris niponica, Clethra barbinervis. Mean discrimination ratio (D.R.) for all investigated plant species for Li, Na, Rb, and Cs to K were 1.7, 0.44, 0.9 and 1.8 respectively. High concentrations of alkaline earth metals Ca (36×103 ppm), Sr (345 ppm), and Ba (241 ppm) were found in the leaves ofHydrangea paniculata which were about 31, 84, and 72 times higher than those for the species with the lowest concentration. Mg was very high inStruthiopteris niponica (83×102 ppm). Other species with high concentrations of alkaline earth metals belonged to the genus Viburnum. Mean D.Rs. for Mg, Sr, and Bavs Ca were 1.0, 0.7 and 0.08. Principal component analysis of interrelationships between the mineral content in leaf tissues indicated that these elements could be classified into 2 groups with respect to their accumulation behavior in plants. The alkali metals K, Li, Rb, and Cs behaved similarly in their accumulation in leaves but Na behaved independently. Alkaline earth metals Ca, Mg, Sr, and Ba were also found to behave similarly in their accumulation. Factors scores of 1st and 2nd components revealed three groups of plant species: alkaliphilic, alkaline earthphilic, and neutral (non-accumulators).