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We evaluated the phenology and litterfall dynamics of the mangrove Bruguiera gymnorrhiza (L.) Lamk along the Okukubi River, Okinawa Island, Japan. Over 3 years, this species showed the highest litterfall of leaves and stipules in summer and the lowest litterfall in winter. From Kendall’s coefficient of concordance, the monthly changes in leaf, stipule, and branch were strongly and significantly concordant among years. Leaf and stipule litterfall could be governed by monthly maximum wind speed, monthly day length, and monthly mean air temperature. Branch litterfall depended on monthly maximum wind speed and monthly rainfall, and increased exponentially with increasing monthly maximum wind speed. Mean total litterfall was 11.8 Mg ha−1 yr−1, with the largest component being leaf litterfall (65.8 %). Annual leaf litterfall per plot was almost constant regardless of the tree density of the plot. Mean leaf longevity was 18 months. Flower and mature propagule litterfall might be influenced by monthly mean air temperature, monthly day length and monthly mean air temperature. The average development periods from flower buds to flowers and flower buds to mature propagules were 1 and 8 months, respectively. Except for leaf and branch, all vegetative and reproductive organ litterfall had clear annual cycles. B. gymnorrhiza showed a positive correlation between leaf production and reproductive organ production.

Information on aboveground biomass of mangrove forest at Rawa Aopa Watumohai National (RAWN) Park is fundamental for the management of mangroves (Lumnitzera racemosa Willd.) in the park. Allometric relationships of partial or whole L. racemosa trees were examined using independent variables D30, DBH, and DB or quadratics D302H, DBH2H, and DB2H from different individuals of L. racemosa trees. Aboveground biomass was estimated by allometric equations and tree census data. Results showed that the best fit for allometric models of stem biomass (WS) and leaf biomass (WL) used the independent variable of DBH2H, while the best fit for branch biomass (WB) used quadratic DB2H. The quadratic DBH2H is the most reliable parameter for estimating aboveground biomass of L. racemosa trees. Aboveground biomass of L. racemosa varied among stands, ranging from 26.23 to 191.01 ton ha−1. Biomass density of L. racemosa forest varied from 4.07 to 29.80 ton ha−1 m−1. The high aboveground biomass of L. racemosa indicates its high...

This study was conducted to quantify and compare the above- and belowground biomass, litterfall and net primary productivity of three mangrove species in the family Rhizophoraceae: Bruguiera gymnorrhiza, Kandelia obovata, and Rhizophora stylosa, in Manko Wetland, Okinawa Island, Japan. A total of thirty five plots were monitored over five years. The studied mangrove stands of all three species were mostly dominated by a large number of small sized trees. Total above-ground biomass of B. gymnorrhiza, K. obovata, and R. stylosa was 64.9,111.6, and 208.290.6 Mg ha−1, respectively. There was no significant difference in AGB between B. gymnorrhiza and K. obovata, but AGB of both of these species differed significantly from that of R. stylosa. Similarly, there was no significant difference in total BGB between B. gymnorrhiza and R. stylosa, but BGB of both of these species differed significantly from that of K. obovata AGB and BGB of K. obovata increased with increasing basal area of this species. On the other hand, in case of AGB and BGB of B. gymnorrhiza and R. stylosa, it did not show any relationship with basal area of the respective species. The average annual rate of above-ground biomass increment was 15.7 Mg ha−1 yr−1 in the R. stylosa stands. Hence, R. stylosa stands recored a higher AGNPP (43.8 Mg ha−1 yr−1) than B. gymnorrhiza (17.7 Mg ha−1 yr−1) and K. obovata (22.3 Mg ha−1 yr−1). Annual total litterfall rates for B. gymnorrhiza, K. obovata, and R. stylosa during the five-year period was 10.1, 9.9, and 12.3 Mg ha−1 yr−1, respectively. The annual rate of NPP in the R. stylosa stands was greater than that of two other species. R. stylosa was the most productive tree in the mangroves of Manko Wetland area in terms of dry matter production.

The vegetative and reproductive phenology of the subtropical mangrove species Rhizophora stylosa was investigated at Manko Wetland, Okinawa Island, Japan. We assessed phenology using litterfall data over four years. Leaf and stipule litterfall occurred throughout the year, with distinct seasonal patterns. Kendall’s coefficient of concordance, W, revealed that the monthly changes in leaf and stipule litterfall were strongly and significantly concordant among years. Leaf litterfall was significantly correlated with monthly maximum wind speed and monthly day length, and stipule litterfall was significantly correlated with monthly mean air temperature and relative humidity. Branch litterfall showed no clear monthly pattern and correlated well with monthly maximum wind speed. Mean total litterfall was 11.2 Mg ha−1 year−1, with the largest component being vegetative organs (78.7 %). Flower, fruit, and propagule litterfall were all highest in summer and lowest in winter. The W values revealed that most reproductive organs in litterfall had significant monthly trends. Flower and fruit litterfall were significantly correlated with monthly day length and monthly mean air temperature, respectively. The average development periods from flower buds to flowers, fruits, and mature propagules were approximately 2–3 months, 4–5 months, and 11–12 months, respectively. Except for branches, all vegetative and reproductive components of litterfall had approximately one year cycles.

This study evaluated the litterfall dynamics of the mangrove Bruguiera gymnorrhiza along the Okukubi River, Okinawa Island, Japan. Leaf and stipule litterfalls occurred throughout the year, with respective distinct monthly patterns, and could governed by monthly day length as well as monthly maximum wind speed and monthly mean air temperature, respectively. Branch litterfall depended on monthly maximum wind speed and increased exponentially with increasing monthly maximum wind speed. Flower and propagule litterfalls might be influenced by monthly mean air temperature and monthly day length, respectively. Leaves contributed the most to total litterfall and represented 71.0 and 68.7% of total litterfall in the first and second years, respectively. Annual leaf litterfall per plot was almost constant regardless of the tree density of the plot. Bruguiera gymnorrhiza showed a positive correlation between leaf production and reproductive organ production.

Analuddin K, Septiana A, Sharma S, Hagihara A. 2016. Crown shape dynamics of dense mangrove Kandelia obovata standsin Manko Wetland, Okinawa Island, Japan. Biodiversitas 17: 865-872. The objectives of this study were to elucidate the crown structure dynamics for dense mangrove stands, and to know the crown shape maintenances and its important role for ensuring the stability and vitality the crowded mangrove forest. The growth parameters of K. obovata Shue, Liu & Yong stands, such as tree height H (m), height at the lowest living leaves HL (m), crown length CL (m) and crown width CW (m), were measured in the summer from 2004 to 2008. The crown shape dynamics were analyzed. The results showed that the HL was significantly increased with increasing H, which suggests thatthe crown changed to be dumpy as the stands grew. However, the CL of young stands increased and then decreased continuously as the stands grew, while the CL of mature stands decreased from 2004 to 2007 and then increased in 2008. Meanwhile, the CL/CW ratio of young stands decreased as the stands grew, while the CL/CW ratio of mature stands decreased and then increased, which imply that dense Kandelia obovata trees might transform their crown shape for reducing of competition for light among trees. Therefore, these resultssuggested that the crown shape of dense mangrove treesare dynamics as developing stands.

Vegetative and reproductive phenology of the subtropical mangrove Bruguiera gymnorrhiza was investigated at Manko Wetland, Okinawa Island, Japan. Phenology was assessed using litterfall data over 4 years. Leaf and stipule litterfall occurred throughout the year, with distinct seasonal patterns. Kendall’s coefficient of concordance, W, revealed that the monthly changes in leaf and stipule litterfall were strongly and significantly concordant among years. Leaf litterfall was linked to monthly day length and maximum wind speed, and stipule litterfall was linked to monthly mean air temperature, monthly rainfall, and maximum wind speed. Branch litterfall showed no clear monthly pattern, but tended to vary with monthly maximum wind speed. Mean leaf longevity was 19 months. Mean total litterfall was 10.1 Mg ha−1 year−1, with the largest component being vegetative organs (58 %). Flower and propagule litterfall were highest in autumn and summer, respectively, and lowest in winter. The W values revealed that, of the reproductive organs, only flower litterfall had a significant monthly trend. Flower litterfall was correlated with monthly mean air temperature and relative humidity. The average development periods from flower buds to flowers and from flowers to mature propagules were approximately 1 and 8 months, respectively. It took 9 months to produce mature propagules from flower buds. Except for branches, all vegetative and reproductive components of litterfall had clear annual cycles.

Data on leaf phenological traits and longevity of mangroves are important for improved understanding of the adaptation strategies, growth, and productivity of these trees. We studied leaf phenological traits and longevity of Rhizophora stylosa, Bruguiera gymnorrhiza, and Kandelia obovata monthly from April 2008 to March 2009. Both tree sampling (direct observation) and litterfall (indirect observation) were used. All leaves and branches of each sample tree were numbered and marked with tags at the beginning of the experiment. Peaks of leaf recruitment and death occurred in July and June, respectively, for B. gymnorrhiza and K. obovata but both occurred in July for R. stylosa. Leaf recruitment for all the species was lowest in January; leaf death was minimum in December for R. stylosa and B. gymnorrhiza, and in January for K. obovata. Leaf recruitment for the three species was significantly correlated with monthly mean air temperature and monthly hours of sunshine. K. obovata and R. stylosa leaf death was correlated with monthly mean air temperature, monthly hours of sunshine, monthly mean air vapor pressure deficit, and monthly rainfall; B. gymnorrhiza leaf death was not correlated with any environmental factors. Specific leaf area for R. stylosa (45.4 ± 1.0 cm2 g−1) and K. obovata (48.6 ± 0.8 cm2 g−1) was not significantly different, but means for these two species were significantly different from that for B. gymnorrhiza (71.0 ± 2.8 cm2 g−1). Mean leaf longevity was 13.9 months for R. stylosa, 17.2 months for B. gymnorrhiza, and 12.1 months for K. obovata. Different measured variables between B.gymnorrhiza and the other two species may have been because of the growth strategy and shade tolerance of B.gymnorrhiza. Mean leaf longevity increased with increasing mean annual air temperature.

This study was conducted to evaluate and compare the litterfall dynamics of three mangrove species in the family Rhizophoraceae: Rhizophora stylosa, Kandelia obovata, and Bruguiera gymnorrhiza, in Manko Wetland, Okinawa Island, Japan. Over 3 years, these species showed highest litterfall of leaves and stipules in summer and the lowest litterfall in winter. Litterfall of flowers and fruits peaked in July for R. stylosa, and in August and again in October–November for K. obovata. Litterfall of flower buds, flowers, and propagules occurred throughout the year for B. gymnorrhiza, but was highest in summer. Litterfall of propagules was highest in September and May for R. stylosa and K. obovata, respectively. Kendall’s coefficient of concordance revealed that the monthly changes for leaf, stipule, flower, and fruit litterfalls of all the species were strongly and significantly concordant among the years. The conversion rate of flowers to propagules was 2.3 % in R. stylosa, 5.9 % in K. obovata, and 10.3 % in B. gymnorrhiza. Total annual litterfall in R. stylosa was significantly different from K. obovata and B. gymnorrhiza; however, the latter two species showed no significant differences. Leaves contributed the most to the total litterfall of all three species, and represented 58.4, 54.0, and 50.4 % of the total litterfall for R. stylosa, K. obovata, and B. gymnorrhiza, respectively. Except for branches and flower bud primordia, all other components of litterfall had clear annual cycles for all three species. Rhizophora stylosa and K. obovata showed a negative correlation between leaf production and reproductive organ production, but B. gymnorrhiza tended to increase leaf production with increasing reproductive organ production.

According to the Weller’s allometric model, the slope of the self-thinning exponent αx of a partial organ was calculated from the allometric constants θx and δx obtained from the allometric relationships of mean tree height H ¯ ( ∝ w ¯ x θ x ) and of organ mass density d ¯ ( ∝ w ¯ x δ x ) to mean organ mass w ¯ x . The self-thinning exponent, αx(=1/{1 − (δx + θx)}), was estimated to be 1.519 for stem, 1.515 for branch, 1.095 for leaf, and 1.482 for aboveground. The αx-value obtained from the estimates θx and δx cannot be used for its significance test because these two estimators are dependent of each other. The allometric relationship of the mean occupied area per tree s ¯ ( = 1 / ρ ∝ w ¯ x ϕ x ) to w ¯ x gives the self-thinning exponent αxk, calculated as 1/ϕx, which is mathematically and statistically (by ordinary least squares) equivalent to 1/{1 − (δx + θx)}. The ϕx-value was 0.6582 for stem, 0.6601 for branch, 0.9129 for leaf, and 0.6748 for aboveground mass. The ϕx-value was not significantly different from 2/3, but it was significantly different from 3/4 for stem, branch, and aboveground. This means that self-thinning exponents for woody parts were not significantly different from 3/2. This result suggests that the self-thinning exponent was close to 3/2 rather than 4/3. On the other hand, the ϕL -value for leaf was significantly different from both 2/3 and 3/4, but it was not significantly different from 1.0. This means that stand leaf biomass was constant regardless of population density. The self-thinning exponent for leaf had a negligible effect on that for aboveground because of the small amount of leaf mass compared with the combined mass of the woody organs. Therefore, the present results based on the allometric model of partial organs roughly support the 3/2 power law for aboveground self-thinning. For overcrowded Bruguiera gymnorrhiza stands, self-thinning could be explained by a simple geometric model rather than a metabolic model.

Mangroves in the subtropical area of Japan are growing to their northern limits, yet little is known of their phenology. The aim of the present study was to understand both vegetative and reproductive phenology patterns, such as leaf emergence, leaf fall, bud setting, flowering, fruiting and propagule setting, in the mangrove Kandelia obovata. The phenology of this species was assessed using litter-fall data for 5 years. Leaf and stipule litter-falls continued with a clear monthly pattern throughout the years. New leaf production and leaf fall peaked in summer, immediately after the propagules fell. Leaf and stipule litter-falls were linked to monthly sunshine hour, and monthly mean air temperature and monthly mean air relative humidity, respectively. Kandelia obovata had a distinct flowering period, with the flowering phenophase starting in spring and continuing into summer. Fruit initiation started at the end of summer and continued into autumn, whereas propagule production occurred during winter and spring. Flowering of K. obovata was influenced by monthly sunshine hour and monthly mean air temperature, whereas fruit and propagule litter-falls were not linked to any climatic factors. The present results showed that a small portion (4.4%) of flowers developed into propagules. The average development period from flower buds to mature propagules was approximately 11 months. Kendall's consistency coefficient suggested that the monthly trends in vegetative and reproductive litter-fall components, except for branches, did not change significantly among years.

Organic matter fluxes into marginal wetland areas require to be quantified given their support for the detrital components. Following their study for 5 years in a mangrove ( Kandelia obovata ) stand near the northernmost limit of the species’ distribution in East Asia, leaf and stipule litterfalls exhibited a clear monthly pattern, with maximum values in July and minimum values in February. In this region, mangroves experience a distinct seasonal climate characterised by low temperatures and frequent typhoons. Propagule litterfall was largest in April and May, whereas no propagule litterfall occurred in summer. Kendall’s coefficient of concordance revealed that the monthly trends of litterfall did not significantly differ among years (branch, p p −2 yr −1 , of which leaf litterfall constituted 49.3–67.9%. Higher annual total litterfall was caused by high production of branch litterfall during typhoons. Stipule litterfall (an indicator of new-leaf flush) decreased with increasing levels of flower/fruit and propagule litterfalls and mean annual leaf litterfall per tree decreased with increasing tree density among plots. Annual leaf litterfall per plot was almost constant regardless of tree density and mean leaf longevity was estimated to be 12.04 ± 0.04 month.

The allometric relationships of mean tree height to mean organ mass w were studied in Bruguiera gymnorrhiza stands. According to Weller's allometric model, the self-thinning exponent α was estimated to be 1.11 in leaf, 1.55 in wood and 1.47 in aboveground. The self-thinning exponent α in leaf was not significantly different from 1.0, which showed that the stand leaf biomass was constant regardless of the population density ρ. The α was not significantly different from 3/2 in wood and aboveground, which concluded that the 3/2 power law of self-thinning holds in overcrowded B. gymnorrhiza stands.

The crown foliage dynamics of Kandelia obovata (S., L.) Yong were investigated, including leaf recruitment, survival and leaf growth. Newly flushed leaves occurred successively throughout the year, with a maximum in July and a minimum in January. The highest leaf death was in August, whereas it was the lowest in January. The relative mortality rate of leaves seemed to depend on the season when new leaves flushed. The growth pattern of leaves varied among seasons. The maximum leaf area was significantly larger in winter than in autumn, but showed no significant difference between the winter and the other seasons. The half-expansion period and the intrinsic rate of increase were respectively longer and lower in winter than in the other seasons. Therefore, leaves flushed in summer grew faster in their initial stage and attained their maximum leaf area sooner than those flushed in winter. This most likely results from the difference in temperature between summer and winter. The crown leaf area was almost stable throughout the year, as if homeostatic control is likely to function. Stipule litterfall decreased significantly with increasing flower and propagule litterfalls, indicating that a high production of flowers and propagules results in low leaf recruitment. This may be because flower production and propagule growth impose a severe burden on K. obovata.

The floristic composition, woody species diversity, and spatial distribution of trees in a subtropical evergreen broadleaf forest on Ishigaki Island, Japan, were investigated based on architectural stratification. Five architectural layers made up the forest stand. The floristic composition was almost similar between the third and the bottom layers, whereas it was almost exclusive between the top and the lower four layers. The fourth layer contained the highest potential number of species (90). Castanopsis sieboldii, Daphniphyllum teijmannii, Neolitsea aciculata, and Distylium racemosum were typical facultative shade species that appeared in all layers. Ardisia quinquegona was the most dominant species, as it had the highest importance value at the stand level; it was also considered a small climax species because of its disappearance in the top layer but higher importance value in the lower four layers. The values of Shannon’s index H’ and Pielou’s index J’ were 4.36 bit and 0.69, respectively, for the entire stand; these values tended to increase from the bottom layer upward, except for the H' -value of the top layer. Furthermore, woody species diversity was higher in the upper strata than the lower strata. The spatial distribution of trees was random in each layer, except in the bottom layer where trees were aggregately distributed. The degree of overlap in tree habitats differed among layers, and the results suggested that trees in the second layer could capture moderate light, while light could not easily penetrate the lower three layers. Therefore, most species in the lower layers must be shade-tolerant. The mean tree weight of each layer decreased from the top layer to the bottom layer, whereas the corresponding tree density increased. We concluded that this trend might be a general phenomenon in subtropical evergreen broadleaf forests of the Ryukyu Archipelago, and we designated this trend as the quasi mean tree weight-density trajectory of forest stratification. The relationship of mean tree height to tree density for the upper two layers supported Yamakura’s quasi -3/2 power law system.

Information on mangrove stand development is rare because long-term monitoring data is often lacking. Such information is important in order to plan management measures effectively. Novel approaches based on existing datasets are required to bridge this gap of knowledge. This study uses a unique combination of field data analyses with simulation experiments in order to demonstrate how information on mangrove dynamics can be extracted if data are sparse. The paper provides a baseline characterization of stand development in a monospecific pioneer mangrove stand of Kandelia obovata. Point pattern analyses revealed that in the young stage, self-thinning has started but has not yet lead to a regularity of spatial tree distribution in the entire stand, and trees located in smaller clumps hinder each other in growth but do not lead to a significant size class differentiation. However, after ca. 2 decades the self-thinning and the size class differentiation start to become more visible. A mutual inhibition of growth was observed within 2 m circular distance (r) in the young stage and within 3 m distance after two decades of stand development as confirmed by the negative values of mark correlation function. As a stand grows older the spatial pattern of individuals become more regular from a clustered pattern. In order to understand and predict the future stand development, simulation experiments were carried out by means of the individual-based model KiWi. © Author(s) 2013., SCOPUS: ar.j, info:eu-repo/semantics/published

In case of mangroves, little information is available on seasonal crown leaf area growth and leaf survival. Therefore, it is necessary to investigate the dynamics of crown foliage to understand the productivity of mangroves. The present study describes the crown foliage dynamics of Bruguiera gymnorrhiza (L.) Lamk., Okinawa Island, Japan, which is the northern limit of its distribution. This study was carried out from April 2008 to March 2009. The crown foliage dynamics includes the leaf recruitment and survival. The production and fall of leaves were investigated by a direct observation of a sample tree of B. gymnorrhiza as well as by an indirect observation of litterfall measurement. The numbers of surviving and dying new leaves were totaled monthly. Newly flushed leaves occurred successively throughout the year, with a maximum in July and a minimum in January. The highest leaf death was in June, whereas the lowest was in December. The crown leaf area was almost stable throughout the year, having a peak in December. The homeostatic control of the crown foliage area may also be accompanied by the regulation of leaf recruitment and death. Therefore, the present results suggest the existence of integrated mechanisms between the internal and external factors maintain the crown foliage area

Background Progress of forest production in response to the environment requires a quantitative understanding of leaf area development. Therefore, it is necessary to investigate the dynamics of seasonal crown foliage in order to understand the productivity of mangroves, which play an important role in the subtropical and tropical coastlines of the world. Method Crown foliage dynamics of the mangrove Rhizophora stylosa were studies to reveal patterns of leaf recruitment, survival and seasonal leaf area growth. Results Flushing of leaves occurred throughout the year, but both flushing and leaf area growth pattern of leaves varied with season. Maximum flushing occurred in summer, but leaf areas did not differ significantly with season. The half-expansion period is longer, and the intrinsic rate of increase was lower in winter. Summer flushed leaves grew faster at their initial stage and reached their maximum area over a shorter period of time. The difference in temperature and air vapor pressure deficit (VPD) between summer and winter contributed to the present dynamics of foliage patterns. The mean leaf longevity was estimated to be 13.1 month. The crown foliage area was almost stable throughout the year. Conclusions Homeostatic control of the crown foliage area may be accompanied by the existence of ecophysiological mechanisms in R. stylosa. Integrating crown foliage dynamics into forest models represents an important step towards incorporating physiological mechanisms into the models for predicting growth responses to environmental changes and for understanding the complex responses of tree growth and litter production.