Decadal changes in masting behaviour—directional changes in seed production with fluctuations on a decadal time‐scale—are attracting widespread attention in the context of global climate change. However, our mechanistic understanding of the effects of climate on seed production on a decadal scale is unsatisfactory, partly because of the insufficient statistical analyses of long‐term data on masting. We detected decadal changes in masting behaviour in the Japanese oak Quercus crispula based on long‐term data (38 years: 1980–2017) from the Kitakami Mountains of Japan. The moving average of seed production in a 20‐year sliding window increased, whereas the coefficient of variation decreased. A wavelet power spectrum, as well as a second‐order log‐linear autoregressive (AR) model showed that masting intervals shortened from 3‐ or 4‐year cycle to a 2‐year cycle. The moving average of seed production increased linearly as the moving average of temperature increased. Temporal variations of the two AR model coefficients as a function of temperature were well described by concave curves. Synthesis. By conducting the statistical analyses of a long‐term seed production dataset, we obtained significant evidence of decadal changes in the masting behaviour of the Japanese oak and showed that the shortening of the masting interval was associated with rising temperature. A resource allocation shift and an environmental veto were discussed as possible mechanisms underlying the decadal change.

Seed retention time (SRT), the time interval between seed ingestion and defaecation, is a critical parameter that determines the spatial pattern of seed dispersal created by an animal, and is therefore, an essential component of trait‐based modelling of seed dispersal functions. However, no simple predictive model of SRT for any given animal exists. We explored the linkage between animal traits and SRT. We collected previously published data on mean SRT for 112 species of birds, mammals, reptiles and fishes and investigated the general allometric scaling of mean SRT with body mass for each taxon. Moreover, we analysed the effects of food habit and digestive strategy on mean SRT for birds and mammals. In general, mean SRT increased with body mass in all four taxa, whereas the pattern of allometric scaling varied greatly among the taxa. Birds had a smaller intercept and larger slope than those of mammals, whereas reptiles had a much larger intercept and smaller slope than those of either birds or mammals. For birds, food habit was also detected as an important factor affecting SRT. We applied the allometric scaling that was obtained for birds to estimate mean SRT of extinct Mesozoic dinosaurs (Theropoda) – few of which are assumed to have acted as seed dispersers. SRT for large carnivorous theropods was estimated to be 4–5 days, when considering only body mass. The present study provides allometric scaling parameters of mean SRT for a variety of seed‐dispersing animals, and highlights large variations in scaling among taxa. The allometric scaling obtained could be a critical component of further trait‐based modelling of seed dispersal functions. Further, the potential and limitations of the scaling of animal SRT with body mass and a future pathway to the development of trait‐based modelling are discussed.

Understanding trade‐offs between demographic parameters is crucial when investigating community assembly rules in high‐diversity forests. To this end, we estimated mortality and growth parameters, and correlations among them, across entire size classes for 17 tree species ( Betula , Carpinus , Fagus , Quercus , Castanea , Acer , Cerasus , Swida , Kalopanax , and Styrax ) using a dataset over 18 years obtained from an old‐growth forest in Japan. Size classes were represented by 12 categories determined by age, height, and diameter at breast height (DBH) from new seedlings to stems of DBH >85 cm. We derived the annual mortality and growth for each species and class using estimates of transition probabilities between classes. Trade‐offs or synergies in growth and survival among species per size class were analyzed with and without the inclusion of phylogenetic relationships. Annual mortality showed U‐shaped patterns across size classes for species that could potentially reach a DBH ≥55 cm: 0.2–0.98 for seedlings, 0.002–0.01 at DBH 35–45 cm, and ca. 0.01 at DBH ≥55 cm. Other species demonstrated monotonically decreasing mortality toward specific maximum size classes. When phylogenetic information was included in analyses, the correlations between survival and growth changed across size classes were significant for some classes: As an overall tendency, synergy was observed in growth and survival for seedling to sapling classes, trade‐offs for juvenile to DBH 15–25 cm classes, and synergy again for larger classes. When phylogenetic information was not included, a significant trade‐off was observed only at DBH 5–15 cm. Synthesis . Trade‐offs at intermediate classes imply differentiation in demographic characteristics related to life history strategies. However, evolutionarily obtained demographic characteristics are not substantial drivers of niche differentiation in the study area. The polylemma of mortality, growth, and other parameters such as the onset of reproduction may also be important factors driving species‐specific demographic traits.

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An aggregated distribution of dispersed seeds may influence the colonization process in tree communities via inflated spatial uncertainty. To evaluate this possibility, we studied 10 tree species in a temperate forest: one primarily barochorous, six anemochorous and two endozoochorous species. A statistical model was developed by combining an empirical seed dispersal kernel with a gamma distribution of seedfall density, with parameters that vary with distance. In the probability density, the fitted models showed that seeds of Fagaceae (primarily barochorous) and Betulaceae (anemochorous) were disseminated locally (i.e. within 60 m of a mother tree), whereas seeds of Acer (anemochorous) and endozoochorous species were transported farther. Greater fecundity compensated for the lower probability of seed dispersal over long distances for some species. Spatial uncertainty in seedfall density was much greater within 60 m of a mother tree than farther away, irrespective of dispersal mode, suggesting that seed dispersal is particularly aggregated in the vicinity of mother trees. Simulation results suggested that such seed dispersal patterns could lead to sites in the vicinity of a tree being occupied by other species that disperse seeds from far away. We speculate that this process could promote coexistence by making the colonization rates of the species more similar on average and equalizing species fitness in this temperate forest community.