Summary 1.Resprouting of woody species after above-ground damage may help plants to persist longer at a given site and quickly reoccupy disturbed sites, thereby strongly influencing forest dynamics. Resprouting has been discussed from two adaptation perspectives: recovery from damage by catastrophic disturbance and survival in frequently disturbed shaded understorey. However, few studies have comprehensively dealt with both adaptation types to understand resprouting strategies. 2. To understand the adaptive significance of resprouting, we assessed the size dependence of resprouting ability after stem clipping for 24 deciduous broad-leaved species, including shrubs, subcanopy and canopy trees, in a cool-temperate forest in Japan. The community assembly includes species adapted to past catastrophic disturbances (e.g. fire, logging) and to stable forest with intermittent treefall (currently the dominant disturbance). We correlated resprouting ability with lifehistory strategies based on demographic parameters and plant functional traits, such as leaf mass per area (LMA), leaf toughness and wood density. 3. All the studied species could resprout in juveniles, and resprouting ability increased as stump size increased. Most sub-canopy and canopy trees lost their ability to resprout after attaining a particular stump size, whereas shrub species retained the ability to resprout throughout their lifetimes. 4. The relative growth rate, LMA and foliar nitrogen did not greatly influence the resprouting ability of a species. In contrast, species with smaller maximum size, lower leaf toughness and lower wood density had better juvenile resprouting ability. This better resprouting ability may have evolved because these characteristics make them more vulnerable to shaded understorey. However, species with larger maximum size and lower leaf toughness retained their ability to resprout to a larger size. 5. Synthesis. A better resprouting ability is related to the ability to survive frequent disturbances, in juveniles, which are characteristics of both forest understorey and frequent fire or drought. To retain resprouting ability until grown seems to be an adaptation to survive infrequent large disturbances. Light-demanding species, which generally have better resprouting ability than shade-tolerants both in juveniles and adults, are adapted to disturbances of various scale and frequency; however, shadetolerants could survive well in the understorey due to a combination of stronger physical defences and resprouting ability.

Summary1. Many woody plants resprout to restore above-ground biomass after disturbances or to survive in stressful environments. Resprouting requires carbohydrate storage, but the general relationship between resource allocation patterns and resprouting ability remains unclear because it can be influenced by the disturbance regime to which species have adapted. 2. We studied deciduous broadleaved trees that coexist in a Japanese cool-temperate forest to investigate the relationships among the biomass and total non-structural carbohydrate (TNC) allocation patterns of saplings, resprouting ability and functional traits. The study species comprised 16 singlestemmed species that only resprout when above-ground biomass loss occurs and eight multistemmed species that resprout regardless of whether above-ground damage occurs or not. 3. Single-stemmed species with better juvenile resprouting ability had larger roots, whereas multi-stemmed species with better juvenile resprouting ability did not necessarily depend on below-ground reserves. 4. Species that retain their ability to resprout until a larger size had a higher root TNC content as saplings, suggesting that they can survive major disturbances such as fire and coppicing by resprouting supported by TNC stored in their roots. 5. Species with shade-tolerant traits (i.e. low foliar nitrogen indicating low photosynthetic capacity, high wood density indicating high defensive investment) had small below-ground TNC reserves irrespective of resprouting types. On the other hand, multi-stemmed species with high wood density and high LMA (indicating high photosynthetic capacity) had small aboveground TNC reserves. Contrary to our hypothesis, a species' maximum size did not relate to the size of its below-ground reserves. 6. By considering the differences in resprouting types, we suggest more complex control of resprouting than was formerly proposed. Variation in the resprouting ability of single-stemmed species was based on a trade-off between below-ground reserves for resprouting and shade-tolerant traits. However, multi-stemmed species can vigorously resprout irrespective of the size of its below-ground reserves. Their multi-stemmed architecture, well-defended wood, high photosynthetic capacity or large above-ground carbohydrate reserves seem to respectively contribute to their persistence. Such variation in the resprouting strategy based on a trade-off between shade tolerance and resource storage would promote species coexistence under a range of disturbance regimes and light environments.

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Japanese cedar (Cryptomeria japonica) is the most important timber species in Japan; however, its pollen is the primary cause of pollinosis in Japan. The total number of pollen grains produced by a single tree is determined by the number of male strobili (male flowers) and the number of pollen grains per male strobilus. While the number of male strobili is a visible and well-investigated trait, little is known about the number of pollen grains per male strobilus. We hypothesized that genetic and environmental factors affect the pollen number per male strobilus and explored the factors that affect pollen production and genetic variation among clones. We counted pollen numbers of 523 male strobili from 26 clones using a cell counter method that we recently developed. Piecewise Structural Equation Modeling (pSEM) revealed that the pollen number is mostly affected by genetic variation, male strobilus weight, and pollen size. Although we collected samples from locations with different environmental conditions, statistical modeling succeeded in predicting pollen numbers for different clones sampled from branches facing different directions. Comparison of predicted pollen numbers revealed that they varied >3-fold among the 26 clones. The determination of the factors affecting pollen number and a precise evaluation of genetic variation will contribute to breeding strategies to counter pollinosis. Furthermore, the combination of our efficient counting method and statistical modeling will provide a powerful tool not only for Japanese cedar but also for other plant species.

1. Understanding ontogenetic differences in plant defenses and herbivory damage is crucial for obtaining a better understanding of plant life-history strategies, community assembly, and dynamics. Although many studies have compared plant defenses or herbivory damage between ontogenetic stages (e.g. sapling vs. adult), how the effects of plant characteristics on leaf herbivory damage change during plant ontogeny has rarely been examined across species or in a speciesrich natural community. 2. To elucidate the effects of plant characteristics, we compared the relationships of leaf herbivory by insects with stem density, plant size, and leaf traits between saplings and adults for almost all co-occurring woody species (56 species, ranging from rare to abundant) in a Japanese temperate forest.3. In most species, adults were larger, fewer in number, and had leaf traits that were potentially less favorable to herbivores (e.g. stronger, or with more phenolics). In contrast, we observed species-specific directions of changes in herbivory damage between adults and saplings with plant phylogeny or density having no clear effect. The relationships between some plant traits and herbivory damage were ontogeny dependent, indicating a shift from chemical to physical defense as plants mature, although most of the species characteristics studied were highly correlated between stages. Such ontogeny-dependent relationships between plant traits and herbivory damage could cause variation in the ontogenetic changes in herbivory damage among species depending on the value of plant traits. Moreover, the direction and magnitude of the effects of ontogenetic differences in species traits on the ontogenetic differences in herbivory damage varied depending on the traits. Together, these factors could have caused the observed ontogenetic changes in herbivory damage among species. Synthesis.Our study demonstrated how relationships between plant characteristics and herbivory damage can change ontogenetically across many coexisting woody species in a forest community, suggesting that plant traits may perform | 2773