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Questions Do neighbourhood interactions in trees result in discernible spatial and phylogenetic signals among their nearest neighbours in a montane evergreen and deciduous forest? Are neighbourhood patterns of different species associated with their abundances and traits? Location Badagongshan National Nature Reserve, Hunan, China. Methods We used four nearest‐neighbour indices: average spatial distance to the nearest conspecific cohort‐mate (SNCC), average spatial distance to the nearest conspecific adult (SNCA), average phylogenetic distance to the nearest heterospecific cohort‐mate (PNHC), and average phylogenetic distance to the nearest heterospecific adult (PNHA). We focused on 77 abundant species in a 25‐ha plot. We evaluated whether the changes in SNCC, PNHC, SNCA and PNHA deviated significantly from expected values of spatially random mortality during two life stage transitions. Results For more than one‐fourth of the tested species, the changes in SNCC and PNHC deviated significantly from the expectations of random mortality. Nearly one‐third of the tested species showed greater SNCC at the juvenile stage than expected of random mortality, which may be mainly explained by conspecific tree competition for space and resources. Approximately 60% and 40% of the tested species showed significantly smaller SNCA and PNHA than expected by random mortality, respectively, which suggests the effects of facilitation and habitat filtering. In addition, abundant and taller species were suppressed by conspecific cohorts to a greater degree than locally rarer and shorter species. Deciduous species were more negatively influenced by conspecifics and closely related heterospecifics than evergreen species. Conclusions Our study focused on long‐term responses of individual species to their conspecific and phylogenetic neighbourhoods and revealed the associations between species traits and neighbourhood patterns. Such trait–neighbourhood interactions provide support for stabilizing mechanisms driving species coexistence in this species‐rich subtropical forest. Using a null model approach, this study examines conspecific and phylogenetic interactions with nearest neighbours and reveals the associations between species traits and neighbourhood patterns in a montane evergreen and deciduous forest in China. Our study highlights the role of trait–neighbourhood interplays in the local stable coexistence of different species in species‐rich forests.

Many morphological, physiological and ecological traits of trees scale with diameter, shaping the structure and function of forest ecosystems. Understanding the mechanistic basis for such scaling relationships is key to understanding forests globally and their role in Earth's changing climate system. Here, we evaluate theoretical predictions for the scaling of nine variables in a mixed‐age temperate deciduous forest (CTFS‐ForestGEO forest dynamics plot at the Smithsonian Conservation Biology Institute, Virginia, USA) and compare observed scaling parameters to those from other forests world‐wide. We examine fifteen species and various environmental conditions. Structural, physiological and ecological traits of trees scaled with stem diameter in a manner that was sometimes consistent with existing theoretical predictions – more commonly with those predicting a range of scaling values than a single universal scaling value. Scaling relationships were variable among species, reflecting substantive ecological differences. Scaling relationships varied considerably with environmental conditions. For instance, the scaling of sap flux density varied with atmospheric moisture demand, and herbivore browsing dramatically influenced stem abundance scaling. Thus, stand‐level, time‐averaged scaling relationships (e.g., the scaling of diameter growth) are underlain by a diversity of species‐level scaling relationships that can vary substantially with fluctuating environmental conditions. In order to use scaling theory to accurately characterize forest ecosystems and predict their responses to global change, it will be critical to develop a more nuanced understanding of both the forces that constrain stand‐level scaling and the complexity of scaling variation across species and environmental conditions.

Tree mortality is one of the most influential drivers of forest dynamics, and characterizing patterns of tree mortality is critical to understanding forest dynamics and ecosystem function in the present era of global change. Here, we use a unique data set of mortality in a temperate deciduous forest to characterize rates and drivers of mortality. At the 25.6‐ha Center for Tropical Forest Science—Forest Global Earth Observatory forest dynamics plot at the Smithsonian Conservation Biology Institute (Virginia, USA ), we conducted two full tree censuses in 2008 and 2013 and then tracked mortality over the next 2 years (2014 and 2015). Overall, the mortality rate, m , of stems ≥10 cm diameter was 1.3–2.1%/yr. Biomass mortality, M , was 1.9–3.4 Mg·ha −1 ·yr −1 at the stand level (0.6–1.1%/yr of biomass), less than biomass gains from growth and recruitment, resulting in net live biomass accumulation. Small stems died at the highest rate; however, contributions to M increased toward larger size classes. Most species had m  < 2%/yr and M  < 0.25 Mg·ha −1 ·yr −1 (<3%/yr of biomass), whereas two to four species had anomalously high mortality rates during each census period, accounting for 15–24% of m ( n  = 2, Cercis canadensis , Ulmus species) and 39–75% of M ( n  = 4 Quercus species). Stems that died, whether or not in association with mechanical damage, tended to grow more slowly in preceding years than surviving stems and, for certain shade‐intolerant species, tended to be in neighborhoods with higher basal area. These findings show how relatively fine‐scale mortality processes contribute to stand‐level compositional change and carbon cycling. The mortality patterns reported here will provide a valuable basis for understanding future disturbance events within eastern deciduous forests and for comparing across forest types.

Background tree mortality is a complex process that requires large sample sizes and long timescales to disentangle the suite of ecological factors that collectively contribute to tree stress, decline, and eventual mortality. Tree mortality associated with acute disturbance events, in contrast, is conspicuous and frequently studied, but there remains a lack of research regarding the role of background mortality processes in mediating the severity and delayed effects of disturbance. We conducted an empirical study by measuring the rates, causes, and spatial pattern of mortality annually among 32,989 individual trees within a large forest demography plot in the Sierra Nevada. We characterized the relationships between background mortality, compound disturbances (fire and drought), and forest spatial structure, and we integrated our findings with a synthesis of the existing literature from around the world to develop a conceptual framework describing the spatio‐temporal signatures of background and disturbance‐related tree mortality. The interactive effects of fire, drought, and background mortality processes altered the rate, spatial structuring, and ecological consequences of mortality. Before fire, spatially non‐random mortality was only evident among small (1 < cm DBH ≤ 10)‐ and medium (10 < cm DBH ≤ 60)‐diameter classes; mortality rates were low (1.7% per yr), and mortality was density‐dependent among small‐diameter trees. Direct fire damage caused the greatest number of moralities (70% of stems ≥1 cm DBH), but the more enduring effects of this disturbance on the demography and spatial pattern of large‐diameter trees occurred during the post‐fire mortality regime. The combined effects of disturbance and biotic mortality agents provoked density‐dependent mortality among large‐diameter (≥60 cm DBH) trees, eliciting a distinct post‐disturbance mortality regime that did not resemble the pattern of either pre‐fire mortality or direct fire effects. The disproportionate ecological significance of the largest trees renders this mortality regime acutely consequential to the long‐term structure and function of forests.

The composition of animal species and interactions among them are widely known to shape ecological communities and fine-scale (e.g., < 1 km) monitoring of animal communities is essential for understanding the relationships among animals and plants. Although the co-existence of large- and medium-sized species has been studied across different scales, research on fine-scale interactions of herbivores in deciduous broadleaf forests is limited. Camera trapping of large- and medium-sized mammals was carried out over a 1 year period within a 25 ha deciduous broadleaf forest dynamics plot in the Qinling Mountains, China. Fourteen species of large- and medium-sized mammals, including six carnivores, six ungulates, one primate and one rodent species were found. Kernel density estimations were used to analyse the diel or 24 h activity patterns of all species with more than 40 independent detections and general linear models were developed to explore the spatial relationships among the species. The combination of overlapping diel activity patterns and spatial associations showed obvious niche separation among six species: giant panda ( Ailuropoda melanoleuca David), takin ( Budorcas taxicolor Hodgson), Reeves’s muntjac ( Muntiacus reevesi Ogilby), tufted deer ( Elaphodus cephalophus Milne-Edwards), Chinese serow ( Capricornis milneedwardsii David) and wild boar ( Sus scrofa Linnaeus). Long-term fine-scale monitoring is useful for providing information about the co-existence of species and their interactions. The results demonstrate the importance for fine-scale monitoring of animals and plants for improving understanding of species interactions and community dynamics.

The population structure and dynamics of Castanopsis cuspidata var. sieboldii were studied to evaluate vegetative and sapling regeneration in an old‐growth, evergreen broad‐leaved forest exposed to low‐severity typhoon disturbances by annual typhoons on the Tsushima Islands in Japan. The density of individuals ≥5 cm d.b.h. was 38.0 ha−1 in 1990; 7.9% were multiple‐stemmed individuals. Over the 7‐year study period (1990–1997), the number of individuals decreased, although the number of stems increased. Over 30% of apparently dead individuals were reconstituted by sprouting stems. Compared with sprout regeneration, sapling regeneration rarely occurred and was only observed in canopy gaps. Most individuals had at least one sprout shoot (H ≥30 cm, d.b.h. <5 cm), and the number and size of sprout shoots increased as the size of the individuals increased. During the study period, larger individuals with stem breakage tended to produce sprout stems. The density of saplings was 1074 ha−1 and they were more abundant in canopy gaps than under closed canopies, but large saplings were very rare even in canopy gaps. The population of C. cuspidata var. sieboldii consisted primarily of single‐stemmed individuals with a few multiple‐stemmed individuals providing a sprout bank. Larger individuals responded to the low severity typhoon disturbances and formed sprout stems. Although many saplings were observed, regeneration occurred more often by sprout formation than by growth of saplings. Thus, sprout regeneration is an important mode of regeneration, which allows this pioneer‐like species to maintain its population in this forest.

From 1991-2000, we examined the dynamics of the forest canopy and major tree populations in a 2-ha permanent plot of subalpine old-growth coniferous forest dominated by Picea jezoensis var. hondoensis, Abies mariesii, Tsuga diversifolia, Abies veitchii, and Betula ermanii in the Ontake Forest Reserve, central Japan. During the 9-y study period, the rates of canopy gap formation and closure were 0.89%·y⁻¹ and 0.63%·y⁻¹, respectively; mortality and recruitment rates were 2.74% ·y⁻¹ and 1.02%·y⁻¹, and the rates of basal area loss and gain were 1.26%·y⁻¹ and 0.80%·y⁻¹. The rates of mortality and recruitment of P. jezoensis var. hondoensis, T. diversifolia, and B. ermanii were clearly lower than those of A. mariesii and A. veitchii. Plots of mortality rate versus size class showed different patterns among species. Mortality of all stems was lower in the canopy and higher in the understory, while the proportion of stems killed by disturbances increased with height. The spatial pattern of dead stems in the upper layer was related to new gaps, but recruited stems were not concentrated in either old or new gaps. Entre 1991 et 2000, nous avons étudié la dynamique de la voûte forestière et celle des principales populations d'arbres constituant une ancienne forêt coniférienne subalpine dominée par Picea jezoensis var. hondoensis, Abies mariesii, Tsuga diversifolia, Abies veitchii et Betula ermanii. L'étude a été effectuée au sein d'une parcelle permanente de 2 ha située dans la réserve forestière d'Ontake, dans le centre du Japon. Au cours de la période de suivi, les taux de formation de trouées dans la voûte forestière et de fermeture de celle-ci ont été respectivement de 0,89 % et de 0,63 % par an. Pour leur part, les taux de mortalité et de recrutement ont été de 2,74 % et de 1,02 % par an et les taux de perte et de gain de la surface terrière ont été de 1,26 % et de 0,80 % par an. Les taux de mortalité et de recrutement de P. jezoensis var. hondoensis, T. diversifolia et B. ermanii ont été nettement inférieurs à ceux de A. mariesii et A. veitchii. Les graphiques du taux de mortalité en fonction des classes de taille ont mis en évidence différents patrons entre les espèces. La mortalité de l'ensemble des tiges du sous-bois a dépassé celle des tiges de la voûte forestière, alors que la proportion de tiges décimées par des perturbations s'est accrue avec la hauteur. Le patron spatial des tiges mortes des strates les plus élevées est relié aux trouées les plus récentes, mais les nouvelles tiges ne sont pas concentrées dans les vieilles ou les nouvelles trouées.

From 1991-2000, we examined the dynamics of the forest canopy and major tree populations in a 2-ha permanent plot of subalpine old-growth coniferous forest dominated by Picea jezoensis var. hondoensis, Abies mariesii, Tsuga diversifolia, Abies veitchii, and Betula ermanii in the Ontake Forest Reserve, central Japan. During the 9-y study period, the rates of canopy gap formation and closure were 0.89%·y- 1 and 0.63%·y- 1 , respectively; mortality and recruitment rates were 2.74%·y- 1 and 1.02%·y- 1 , and the rates of basal area loss and gain were 1.26%·y- 1 and 0.80%·y- 1 . The rates of mortality and recruitment of P. jezoensis var. hondoensis, T. diversifolia, and B. ermanii were clearly lower than those of A. mariesii and A. veitchii. Plots of mortality rate versus size class showed different patterns among species. Mortality of all stems was lower in the canopy and higher in the understory, while the proportion of stems killed by disturbances increased with height. The spatial pattern of dead stems in the upper layer was related to new gaps, but recruited stems were not concentrated in either old or new gaps.