Large-sized Trees Research Articles

The role of Molecular Markers in Improvement of Fruit Crops

Markers have been used over the years for the classification of plants. Markers are any trait of an organism that can be identified with confidence and relative easy, and can be followed in a mapping population on another hand markers be defined as heritable entities associated with the economically important trait under the control of polygenes. Morphological markers can be detected with naked eye (naked eye polymorphism) or as difference in physical or chemical properties of the macromolecules. In other words, there are two types of genetic markers viz. morphological markers or naked eye polymorphism and non-morphological markers or molecular markers. Morphological markers include traits such as plant height, disease response, photoperiod, sensitivity, shape or colour of flowers, fruits or seeds etc. Molecular markers include biochemical constituents. Morphological markers have many limitations for being used as markers particularly in fruit crops because of long generation time and large size of fruit trees besides being influenced by environment. Consequently, molecular markers could be appropriate choice to study and preserve the diversity in any germplasm. Molecular markers have diverse applications in fruit crop improvement, particularly in the areas of genetic diversity and varietal identification studies, gene tagging, disease diagnostics, pedigree analysis, hybrid detection, sex differentiation and marker assisted selection.

Seasonal variation in the size-dependent respiration of mangroves Kandelia obovata

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 404:31-37 (2010) - DOI: https://doi.org/10.3354/meps08505 Seasonal variation in the size-dependent respiration of mangroves Kandelia obovata A. T. M. Rafiqul Hoque1, Sahadev Sharma1, Rempei Suwa2, Shigeta Mori3, Akio Hagihara2,* 1Graduate School of Engineering and Science, University of the Ryukyus, Okinawa 903-0213, Japan 2Faculty of Science, University of the Ryukyus, Okinawa 903-0213, Japan 3Forestry and Forest Products Research Institute, Tsukuba 306-8687, Japan *Email: amyh@sci.u-ryukyu.ac.jp ABSTRACT: Despite the potential importance of mangrove forests in carbon cycling and coastal ecology, information on mangrove respiration is scanty. Aboveground nighttime respiration of mangrove Kandelia obovata trees at the northernmost limit of their distribution was measured monthly throughout a year to investigate size-dependence and seasonal variation in respiration. Six sample trees of different sizes were selected from a completely closed canopy stand. Respiration rate (r) of K. obovata trees at a monthly mean temperature increased with increasing mass (m). This tendency was described by means of the power function r = fmh, where f is the multiplying coefficient and h is the scaling exponent. The exponent values ranged from 0.723 to 1.085. In the cool winter (dormant season), the exponent h was close to 1.0, while in the warm summer (growing season) the exponent was closer to 3/4. Respiration varies more between seasons in small-sized trees than in large-sized trees. The relative increase in respiration from the winter dormant season to the summer growing season was large in the small-sized trees compared with that in the large-sized trees. The variation in respiration between the 2 seasons is explained on the basis of theories about resource harvesting and transport. Separation of summer respiration into growth and maintenance components is suggested to better understand the dependence of respiration on size and temperature. Corrigendum KEY WORDS: Power function · Mass · Surface area · Summer respiration · Winter respiration Full text in pdf format PreviousNextCite this article as: Hoque ATMR, Sharma S, Suwa R, Mori S, Hagihara A (2010) Seasonal variation in the size-dependent respiration of mangroves Kandelia obovata. Mar Ecol Prog Ser 404:31-37. https://doi.org/10.3354/meps08505 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 404. Online publication date: April 08, 2010 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2010 Inter-Research.

SIMPLE MODELS FOR SCALING IN PHYLOGENETIC TREES

Many processes and models — in biological, physical, social, and other contexts — produce trees whose depth scales logarithmically with the number of leaves. Phylogenetic trees, describing the evolutionary relationships between biological species, are examples of trees for which such scaling is not observed. With this goal, we analyze numerically two branching models leading to nonlogarithmic scaling of the depth with the number of leaves. For Ford's alpha model, although a power-law scaling of the depth with tree size was established analytically, our numerical results illustrate that the asymptotic regime is approached only at very large tree sizes. We introduce here a new model, the activity model, showing analytically and numerically that it also displays a power-law scaling of the depth with tree size at a critical parameter value.

Preparation of the taper tables for Japanese larch (Larix kaempferi Carr.) applicable to large size trees in Hokkaido

Preparation of the taper tables for Japanese larch (Larix kaempferi Carr.) applicable to large size trees in Hokkaido

Structure and species composition of novel forests dominated by an introduced species in northcentral Puerto Rico

The African tulip tree, Spathodea campanulata Beauv., is an introduced species forming novel forest types in Puerto Rico. These forests develop naturally after deforestation, agricultural use and land abandonment, and there are many questions as to their ecological characteristics. We sampled structure and species composition of large, small, and juvenile trees (≥10, ≥2.5 to <10, and <2.5 cm diameter at breast height, respectively) in nine secondary forests dominated by S. campanulata on alluvial, karst, and volcanic substrates in northcentral Puerto Rico. No differences were found in S. campanulata forest structure between substrates. Of a total of 79 species found, 17 were introduced. Forests on karst and alluvium had the highest and lowest global species richness, respectively. Species richness increased from large to small to juvenile trees in most sites, but more so on karst. The percentage of introduced species was inversely related to species richness of tree size classes on all substrate types. The dominance of S. campanulata in the large tree size class was highest and lowest in alluvial and volcanic sites, respectively, and decreased from large to small to juvenile trees on all substrate types. Species richness of S. campanulata forests is lower than that of native forests on equivalent substrates. Although land use history affects composition, the juvenile tree species established in S. campanulata forests seems to correspond to the geological substrate were sites are found. This study shows S. campanulata restores forest structure and native tree species on abandoned agriculture and grazing lands in Puerto Rico. Management of these novel forests should consider them as resources were natural processes have the potential of making them more diverse.

Ecological Significance of Crown Functional Traits Across Size Classes and Disturbance Environments in Eight Pioneer Species in a Sri Lankan Rain Forest

Information on tree crown characteristics has been used in forestry to assess tree and ecosystem health and productivity. Although there are well known differences in crown functional traits between light-demanding pioneer species and later successional species, data is limited usually to regeneration phases. Further, information on variation between species within the pioneer guild is needed in order to select pioneer species for facilitation of reforestation, more shade demanding species, and for monitoring and evaluation of such efforts. In this study we assessed three crown functional characteristics—crown surface area, crown volume, and live crown ratio—in eight pioneer species commonly found in the tropical rain forests of Sri Lanka: Alstonia macrophylla Wallich ex G. Don, Dillenia triquetra (Rottb.) Gilg, Macaranga indica Wight, Macaranga peltata (Roxb.) Muell, Melastoma malabathricum L., Schumacheria castaneifolia Vahl, Trema orientalis (L.) Blume, and Wendlandia bicuspidata Wight & Arn. We modeled the influence of species, tree size, and environmental factors on these crown functional traits in seedling, sapling, and larger tree size classes using generalized linear models. We found that the disturbance environment was only influential at the larger tree size class. For smaller size classes, the majority of the variation in crown characteristics was explained by tree size characteristics. In larger trees, among the three functional traits, live crown ratio showed the strongest relationship with the disturbance environment and crown surface area and crown volume had higher correlation with tree height and diameter. While crown characteristics were influenced by species irrespective of size class, in the larger trees species varied in their relationship between tree crown functional traits and the disturbance environment. In larger trees, four species—M. indica, D. triquetra, S. castaneifolia, and W. bicuspidata, which are more commonly found in small gaps—had stronger relationships between crown surface area, live crown ratio and canopy openness than T. orientalis and M. peltata, which are more commonly found in large canopy openings, and A. macrophylla and M. malabathricum, two generalist species. The small gap specialists may develop deeper crowns to overcome the short duration of direct light in small gaps and more efficiently utilize lateral light which is a larger fraction of total light in these environments compared to large canopy openings. The differences among species must be considered in selecting pioneers for reforestation efforts and designing silvicultural treatments. We recommend a step wise introduction of species starting with the more high light restricted and generalist pioneers followed by the small gap restricted species and finally the late successional species.

Can you see green? Assessing the visibility of urban forests in cities

The Green View index was developed to evaluate the visibility of urban forests. It was estimated through a combination of field surveys and photography interpretation and tested in Berkeley, California. The results showed that the overall Green View value in Berkeley was 24.79%. It has a strong correlation ( R 2 = 0.86) with the canopy cover of tree/shrubs, which was 31.49%. Besides the absolute amount of canopy cover, Green View is also influenced by the distribution pattern of trees. The ANOVA analysis indicated that the size of trees, the distance between trees and viewers, the existence of vegetation other than trees and shrubs all had a significant impact on values of Green View. The study shows that the use of large-size trees is important for creating a view with more greenery in a city. Green View can be used to evaluate the visual impact of various planning and management practices on urban forests.

Simulating Multiaged Coast Redwood Stand Development: Interactions between Regeneration, Structure, and Productivity

Abstract Multiaged management regimes and harvesting scenarios were simulated in coast redwood (Sequoia sempervirens [D. Don.] Endl.) stands using models of stand growth and yield (CRYPTOS) and stocking assessment (redwood MASAM). Various stocking and age-class combinations were modeled on site index 100 and 130 ft (50 years). Results demonstrated how the number of cohorts, upper limit of stocking, and cohort densities affected growth and yield. Board foot volume increment reached a plateau in stands with a prescribed upper limit of stocking above leaf area index 7.2 to 8.6. Productivity did not differ between stands with two to five cohorts producing the same tree size at harvest. It was affected by stand structure when a cutting cycle of 20 years was prescribed in stands with three to five cohorts. Stands with the same density returned to the upper limit of stocking much sooner on better sites. Prolonging the cutting cycle by reducing stand density resulted in larger tree sizes at harvest and greater productivity. The growth of trees remaining after cutting 10–50% of stand basal area and growth of new stump sprouts were also simulated. Stands quickly returned to preharvest stocking after light cutting, implying that heavy or frequent light cutting is needed to sustain growth and vigor of regeneration in multiaged coast redwood stands.

Ecological Thresholds in the Savanna Landscape: Developing a Protocol for Monitoring the Change in Composition and Utilisation of Large Trees

BackgroundAcquiring greater understanding of the factors causing changes in vegetation structure - particularly with the potential to cause regime shifts - is important in adaptively managed conservation areas. Large trees (≥5 m in height) play an important ecosystem function, and are associated with a stable ecological state in the African savanna. There is concern that large tree densities are declining in a number of protected areas, including the Kruger National Park, South Africa. In this paper the results of a field study designed to monitor change in a savanna system are presented and discussed.Methodology/Principal FindingsDeveloping the first phase of a monitoring protocol to measure the change in tree species composition, density and size distribution, whilst also identifying factors driving change. A central issue is the discrete spatial distribution of large trees in the landscape, making point sampling approaches relatively ineffective. Accordingly, fourteen 10 m wide transects were aligned perpendicular to large rivers (3.0–6.6 km in length) and eight transects were located at fixed-point photographic locations (1.0–1.6 km in length). Using accumulation curves, we established that the majority of tree species were sampled within 3 km. Furthermore, the key ecological drivers (e.g. fire, herbivory, drought and disease) which influence large tree use and impact were also recorded within 3 km.Conclusions/SignificanceThe technique presented provides an effective method for monitoring changes in large tree abundance, size distribution and use by the main ecological drivers across the savanna landscape. However, the monitoring of rare tree species would require individual marking approaches due to their low densities and specific habitat requirements. Repeat sampling intervals would vary depending on the factor of concern and proposed management mitigation. Once a monitoring protocol has been identified and evaluated, the next stage is to integrate that protocol into a decision-making system, which highlights potential leading indicators of change. Frequent monitoring would be required to establish the rate and direction of change. This approach may be useful in generating monitoring protocols for other dynamic systems.

Cell lineage tree models of neurogenesis

The production of neurons to form the mammalian cortex, known as embryonic cortical neurogenesis, is a complex developmental process. Insight into the process of cell division during neurogenesis is provided by murine cortical cell lineage trees, recorded through experimental observation. Recurring patterns within cell lineage trees may be indicative of predetermined cell behaviour. The application of mathematical modelling to this process requires careful consideration and identification of the key features to be incorporated into the model. A biologically plausible stochastic model of evolution of cell lineage trees is developed, based on the most important known features of neurogenesis. Tractable means of measuring lineage tree shape are discussed. Symmetry is identified as a significant feature of shape and is measured using Colless's Index of Imbalance. Distributions of tree size and imbalance for large tree sizes are computed and results compared to experimental data. Several refinements to the model are investigated, when the cell division probabilities are weighted according to cell generation. Two models involving generation-dependent cell division probabilities produce imbalance distributions which are the most consistent with the available experimental results. The results indicate that a stochastic cell division mechanism is a plausible basis of mammalian neurogenesis.

Field Evaluation of 64 Rootstocks for Growth and Yield of ‘Kensington Pride’ Mango

Despite an abundance of polyembryonic genotypes and the need for rootstocks that improve scion yield and productivity, simultaneous field testing of a wide range of mango (Mangifera indica L.) genotypes as rootstocks has not previously been reported. In this experiment, we examined the growth and yield of ‘Kensington Pride’ on 64 mango genotypes of diverse origin during the first four seasons of fruit production to identify those worth longer-term assessment. We also recorded morphological characteristics of seedlings of 46 of these genotypes in an attempt to relate these measures to subsequent field performance. Tree canopy development on the most vigorous rootstocks was almost double that on the least vigorous. Growth rates differed by more than 160%. Cumulative marketable yield ranged from 36 kg/tree for the lowest yielding rootstock to 181 kg/tree for the most productive. Yield efficiency also differed markedly among the 64 rootstocks with the best treatment being 3.5 times more efficient than the poorest treatment. No relationship was found between yield efficiency and tree size, suggesting it is possible to select highly efficient rootstocks of differing vigor. Two genotypes (‘Brodie’ and ‘MYP’) stood out as providing high yield efficiency with small tree size. A further two genotypes (‘B’ and ‘Watertank’) were identified as offering high yield efficiency and large tree size and should provide high early yields at traditional tree spacing. Efforts to relate the morphology of different genotype seedlings to subsequent performance as a rootstock showed that nursery performance of mango seedlings is no indication of their likely behavior as a rootstock. The economic cost of poor yields and low yield efficiencies during the early years of commercial orchard production provide a rationale for culling many of the rootstock treatments in this experiment and concentrating future assessment on the top ≈20% of the 64 treatments. Of these, ‘MYP’, ‘B’, ‘Watertank’, ‘Manzano’, and ‘Pancho’ currently show the most promise.

PEACH PLANTING SYSTEMS IN SOUTHERN ITALY: ECOPHYSIOLOGICAL ASPECTS AND TECHNICAL DEVELOPMENTS

PEACH PLANTING SYSTEMS IN SOUTHERN ITALY: ECOPHYSIOLOGICAL ASPECTS AND TECHNICAL DEVELOPMENTS

PhyloWidget: web-based visualizations for the tree of life

PhyloWidget is a web-based tool for the visualization and manipulation of phylogenetic tree data. It can be accessed online or downloaded as a standalone application. A simple URL-based API allows databases to easily link to and customize PhyloWidget for interactively viewing medium- to large-sized trees. PhyloWidget is available for online use or download at http://www.phylowidget.org/.

High litterfall in old-growth and secondary upper montane forest of Costa Rica

Tropical upper montane forests usually comprise trees of small stature with a relatively low aboveground productivity. In contrast to this rule, in the Cordillera de Talamanca (Costa Rica), tall trees (>35 m in height and more than 60 cm in diameter) are characteristic for the upper montane old-growth oak forests which are growing at an altitude of almost 3,000 m close to the alpine timberline. For these exceptional forests, productivity data are not yet available. In this study, we analyzed litterfall and its components (tree leaves, litter of epiphytic vascular and non-vascular plants, mistletoes, twigs and other canopy debris) in three forest stands belonging to different successional stages and related seasonal changes in litterfall to micrometeorological variables. The studied stands were early-successional forest (10–15-year-old), mid-successional forest (40-year-old), and old-growth forest. The stands are dominated by Quercus copeyensis and are located at 2,900-m altitude. Total litterfall was highest in the mid-successional forest (1,720 g m−2 y−1), and reached 1,288 g m−2 y−1 in the old-growth forest and 934 g m−2 y−1 in the early-successional forest. Litter mass was dominated by leaves in all stages (56–84% of total litterfall). In the old-growth forest, however, twigs and small canopy debris particles (33%), epiphytes (6%), and mistletoes (5%) also contributed substantially to litter mass. Leaf litterfall showed a clear seasonal pattern with a negative correlation to monthly precipitation and highest values in the dry season (January–April). However, the strongest correlation existed with minimum air temperature (negative), probably because temperatures already dropped at the end of the rainy season, when precipitation had not yet declined and leaf shedding already increased. In contrast, litterfall of epiphyte mass, and twigs and other debris was mostly dependent on occasional strong winds. We conclude that the upper montane oak forests of the Cordillera de Talamanca are exceptional with respect to the large tree size and the relatively high productivity as indicated by litterfall. Litter mass was especially high in the mid-successional and old-growth forests, where the observed annual totals are among the highest recorded for tropical forests so far.

Presence of the cytolytic protein enterolobin in different developmental stages of Enterolobium contortisiliquum seeds

Enterolobin is a 52.9 kDa, cytolytic, inflammatory and insecticidal protein present in Enterolobium contortisiliquum (Vell.) Morong, a Brazilian large-sized tree. This protein was previously described to occur in different forms of association (monomeric and oligomeric forms). In the current work, we investigated the presence of enterolobin forms of association and hemolytic activity in maturing, germinating and germinated seeds. Immunoblotting analysis revealed the presence of the monomeric form of enterolobin in all phases under study, whereas the dimer was detected in developing seeds in the second half of the maturation period, during germination and in the early post-germination phase. The trimeric form of enterolobin appeared one week after the dimer and could be detected up to half of the average germination time of the E. contortisiliquum seeds. The highest hemolytic titers due to enterolobin activity were found in mature and germinating seeds. Apparently, there was no modification in molecular mass of the enterolobin monomer during seed maturation and germination, suggesting the absence of a precursor form. The results also show that enterolobin was not utilized in germination and initial post-germination phases, which are critical in development and seedling establishment. Enterolobin availability could enable it to perform an important physiological role, including plant defense.

Predicting stand damage and tree survival in burned forests in Catalonia (North-East Spain)

The study developed models for predicting the post-fire tree survival in Catalonia. The models are appropriate for forest planning purposes. Two types of models were developed: a stand-level model to predict the degree of damage caused by a forest fire, and tree-level models to predict the probability of a tree to survive a forest fire. The models were based on forest inventory and fire data. The inventory data on forest stands were obtained from the second (1989-1990) and third (2000-2001) Spanish national forest inventories, and the fire data consisted of the perimeters of forest fires larger than 20 ha that occurred in Catalonia between the 2nd and 3rd measurement of the inventory plots. The models were based on easily measurable forest characteristics, and they permit the forest manager to predict the effect of stand structure and species composition on the expected damage. According to the stand level fire damage model, the relative damage decreases when the stand basal area or mean tree diameter increases. Conversely, the relative stand damage increases when there is a large variation in tree size, when the stand is located on a steep slope, and when it is dominated by pine. According to the tree level survival models, trees in stands with a high basal area, a large mean tree size and a small variability in tree diameters have a high survival probability. Large trees in dominant positions have the highest probability of surviving a fire. Another result of the study is the exceptionally good post-fire survival ability of Pinus pinea and Quercus suber.

Tree-Level Models for Predicting Lumber Volume Recovery of Black Spruce Using Selected Tree Characteristics

Abstract Four model forms (linear, polynomial, power, and exponential) and their extensions with different independent variables were studied for their predictive ability for lumber volume recovery from black spruce (Picea mariana [Mill.] B.S.P.) trees at two types of sawmills (a stud mill and a random length mill) using basic tree characteristics (dbh, tree height, and stem taper). Of the three tree characteristics, dbh was identified as having the most predictive ability for lumber volume recovery. We found that all models predicted lumber volume recovery more precisely for small-sized and medium-sized (≤23 cm) trees than for large-sized (&amp;gt;03E23 cm) trees. In terms of the selected statistical criteria such as adjusted R2, root-mean-square error (RMSE), predicted error sum of squares (PRESS), and prediction error, the best models for predicting lumber volume recovery were considered to be the following forms for both types of sawmills: (1) the second-order polynomial function with dbh alone, (2) the polynomial function with an interaction term of squared dbh and tree height, and (3) the power function with dbh and tree height. For both types of sawmills, the three final fitted model forms accounted for over 91% of the total variation. Model validation using independent data from a stud mill indicated that by using measured tree characteristics the three model forms were able to accurately and precisely predict lumber volume recovery, especially from small- and medium-sized trees.

Restoration of the urban forests of Tokyo and Hiroshima following World War II

The urban forests of Tokyo and Hiroshima were devastated by American bombing during World War II. Approximately 160 km 2 of Tokyo were burned by more than 100 fire bombings, while an area of 12 km 2 was leveled and burned by one atomic bomb in Hiroshima. Tokyo's street tree population was reduced from 105,000 to approximately 42,000 by the end of the war. In the years immediately following the war, the street tree population dropped to 35,000 in Tokyo due to a combination of further tree mortality and the cutting of trees for fire wood. No estimates of pre-war street tree populations are available for Hiroshima. Examination of pre- and post-atomic bombing photographs of Hiroshima suggests an even higher percentage of the trees in the city were destroyed. Post-war reconstruction of the urban forests of each city developed along different pathways. Plans for the redevelopment of Tokyo were rejected by the general public who wanted a return to pre-war conditions. Few streets were widened to accommodate traffic and allow for new street tree planting. Plans for new parks were shelved or only partially achieved. Some streets were replanted by private citizens. Initial survival rates of replanting were low. Trees in Tokyo's municipal tree nurseries, which had not been converted to vegetable gardens during the war, were often larger than the optimal size for transplanting, but were used as no other trees were available. A more concerted effort to reconstruct the urban forest came following the 1959 decision to site the 1964 Olympic Games in Tokyo. Many streets were widened and planted with trees. New tree-lined boulevards were also created. In contrast, Hiroshima sponsored an international competition for the design of a Peace Park and a major tree-lined boulevard. Several wide streets were built with space for street trees. Major plans were also drawn to create greenways along the rivers and to build additional parks. Trees were initially donated by local farmers and nearby towns for planting the parks and the boulevard since municipal tree nurseries had been converted to vegetable gardens during the war. Survival rates were very low due to the rubble content of the soil and difficulties in watering the transplanted trees. Strong support from the mayors of Hiroshima contributed to the success of urban forest reconstruction in Hiroshima. The historical significance of the destruction caused by the first atomic bomb to be dropped on an urban area also contributed to Hiroshima citizens' will to reconstruct both the city and its urban forest. Species and location of trees determined the survival of trees after war in both cities. Species with strong resprouting ability and thick bark survived the bombing and fire. In Tokyo trees located in open areas avoided the fire, while in Hiroshima trees standing behind tall concrete buildings were shielded from radiation and the heat wave. In addition to the difficulties faced during the city-wide replanning process, constraints of urban forest recovery included severe financial restriction, short supply of proper large-sized trees for planting and lack of labor for planting and post-planting tree care. Hiroshima used public participation and community involvement to restore the urban greenery successfully and, until today, has maintained a program to conserve the trees that survived the atomic bomb.

Maintenance of Inbreeding Depression in a Highly Self-Fertilizing Tree, Magnolia obovata Thunb

Inbreeding depression is a major selective force that maintains outcrossing in flowering plants. If the long life and large mature size of trees cause high inbreeding depression via mitotic mutations and half-sib competition, these characteristics may increase inbreeding depression sufficiently to maintain traits that facilitate outcrossing even with high primary selfing rates (proportion of selfed ovules). Here, I report the maintenance of inbreeding depression in a population of a tree (Magnolia obovata Thunb.) with primary selfing rates greater than 0.8 resulting from geitonogamy. The progenies exhibited inbreeding depression for germination, seedling survival, and seedling mass (δ = 0.29–0.38), but no significant difference between crossing type in seedling height. Cumulative inbreeding depression for early survival (from zygote to 2-year-old stage) estimated from these results and from prior data on embryonic survival was high (δe = 0.91). The fixation index at maturity based on six allozyme loci was low (Fis = 0.08), indicating that significant inbreeding depression for late survival results in a low level of inbreeding with respect to gene transmission to the next generation. From these results, I estimated that inbreeding depression for late and lifetime survival equaled 0.69 and 0.97, respectively. These results suggest that M. obovata trees maintain high inbreeding depression at both early and late life stages, resulting in a low level of inbreeding despite a high primary selfing rate. The high inbreeding depression can be explained by previous theories and is consistent with the predicted maintenance of inbreeding depression in highly self-fertilizing tree populations. The inbreeding load due to the high primary selfing rate represents a cost of this tree’s pollination system for outcrossing, which is based on automimicry and mass flowering.

Distribution, size-structure and suppressed condition of Japanese black pine (Pinus thunbergii Sieb. et. Zucc.) trees constituting in a coastal forest preserved as a place of scenic natural beauty

Distribution, size structure and suppressed condition of pine trees constituting of a coastal forest preserved as a place of natural beauty were investigated in order to obtain information for maintenance of the forest. Study site is located on the southwest part of Awaji Island, Hyogo prefecture, Japan. Location, diameter at breast height and height of tree, height of lowest branch and height of lowest leaves of large-sized and middle-sized pine trees were recorded. The number and density of large-sized pine trees were 120 and 4.0/ha. The number and density of middle-sized pine trees were 189 in 9.3 ha and 20.3/ha. The mean dbh and mean height of trees of large-sized trees were 2.6 times and 1.2 times of middle-sized pine trees. The ratio of height to diameter of pine trees decreases as height of trees increase. The size-structure of trees in the present study was quite different from other coastal pine forests which constitute even aged trees. The 68.3% of large-sized and 69.3% of middle-sized pine trees were suppressed by small pine trees which prevent sunlight from penetrating to leaves of large-sized and middle-sized pine trees. It is necessary to remove these trees in order to recover light condition. Many of these small pine trees were considered to be planted after the outbreak of pine wilt disease by the voluntary local people. The information that those planted trees might be cut down should be give to the people.