Since China experienced a rapid and unprecedented process of urbanization and climate change from 1978 onwards, pest outbreaks were frequently reported on urban forests, which reflects a significant imbalance between natural regulation and human control. Based on information extracted from all journal articles and reports about insect pests on camphor tree (Cinnamomum camphora) in urban China, we characterized historical patterns and trends in pest outbreaks over large areas. Our results suggested that (1) most distribution areas of C. camphora in urban China had pest records (14 provinces) over the last 50 years, especially at the south-eastern coastal areas; (2) pests on camphor tree in urban China showed an accelerated growth since the 1990s; and (3) pests on camphor tree in urban China were characterized by native and leaf-feeding species. Urbanization seems to positively correlate with urban pest outbreaks. Changes of urban pest outbreaks could largely be described by synchronic changes of socio-economic indicators, of which CO₂ emissions as metric tons per capita is the most significant predictor, followed by GDP and human population. Thus, managers and city planners should allocate resources to socio-economic-related pest outbreaks for a sustainable ecosystem.

Due to manganese mining and slag accumulation, the geological structure of the wetland polluted by heavy metals in Xiangtan Manganese Mine area was seriously damaged, hence biodiversity loss, severe soil, and water pollution, as well as serious heavy metal pollution to food, vegetables, and other natural sources. In order to restore the ecological environment of the mining area, in 2015, the ecological restoration test of heavy metal polluted wetlands in the mining area was carried out. The results showed that the Mn content of different parts of Koelreuteria paniculata root from high to low order: fine root > small root > medium root > large root. The Mn content of different parts of Elaeocarpus decipiens root from high to low order: large root > medium root > small root > fine root. The order of Mn content in plants of the wetland restoration from high to low is as follows: Canna warscewiezii > Thalia dealbata > Boehmeria > Pontederia cordata > Typha orientalis > Nerium oleander > Softstem bulrush > Iris germanica > Acorus calamus > Arundo donax > Phragmites australis; The order of Internal Cu content from high to low is as follows: Acorus calamus > Thalia dealbata > Softstem bulrush > Canna warscewiezii > Typha orientalis > Arundo donax > Boehmeria > Iris germanica > Pontederia cordata > Nerium oleander > Phragmites australis; Zn content from high to low order is as follows: Canna warscewiezii > Acorus calamus > Thalia dealbata > Typha orientalis > Pontederia cordata > Arundo donax > Softstem bulrush > Iris germanica > Boehmeria > Phragmites australis > Nerium oleander; Cd content from high to low order is as follows: Phragmites australis > Softstem bulrush > Thalia dealbata > Nerium oleander > Boehmeria > Canna warscewiezii > Acorus calamus > Iris germanica > Typha orientalis > Pontederia cordata > Arundo donax. The results of this study have provided a theoretical basis and decision-making reference for the evaluation of heavy metals polluted wetland restoration, protection, and reconstruction effects and the selection of ecological restoration modes.

The asymptotic height (H_max) and the size‐scaling exponent (β), proxies of tree size and important forest architectural parameters of the relationships between height and tree diameter of forests, play important roles in the carbon (C) stocks and fluxes of forest ecosystems. However, the patterns and drivers of these values in continental China are not well known. Based on a national forest database of China, we explored the geographic patterns and ecological drivers of H_max and β and their dynamic relationships with the C sequestration capabilities of the studied ecosystems, including the C stock and allocation, net ecosystem productivity (NEP), and mean ecosystem C turnover time. At the ecosystem scale, the H_max values ranged from 10.37 to 37.07 m, with a mean value of 25.41 m, showing a decreasing trend with increasing latitude. However, β ranged from 0.598 to 0.73, with a mean value of 0.66, showing an increasing trend with latitude. The spatial patterns of the forest H_max and β at the national scale were largely controlled by the mean annual temperature, mean annual precipitation, and forest age. These patterns were verified using biomass and forest C sequestration data, showing that the total vegetation C stock as a whole, in aboveground or belowground components, was significantly and positively correlated with H_max (p < 0.05), revealing apparent “faster first, slower later” increasing trends with H_max (R² = 0.759, 0.821, and 0.527, respectively). In addition, for forest >20 m, NEP showed a significant strong negative correlation with H_max (by −0.967% per 1 m of H_max, R² = 0.504, p < 0.05), and a 10‐m increase in H_max resulted in a decrease in mean ecosystem C turnover time by 16.9% (7.43 years). Taller forests might indeed be expected to have higher autotrophic respiration consumption rates but lower mean ecosystem C turnover time and NEP values than shorter forests. The discovery that community‐level asymptotic height could be used as a comparative predictor of ecosystem C sequestration capacity and its difference among forest biomes underpins the fundamentals of ecological theories and modeling, which has important implications for forest restoration, policy, and management.

Chinese trees adapted to wet, warm, highly heterogeneous, and dynamic light environments might be expected to systematically differ from other non‐Chinese trees based on stem allometry and life em allo. However, our understanding of the extent to which how differentiation in forest architecture and species size influences tree allometry relates to fundamental physiological and ecological trade‐offs, climate, forest structure, and function is limited. We quantified height–diameter allometries and growth increments of 13,594 individuals of 151 tree species across China. Although trees grew statistically indistinguishably from the theoretically predicted exponent, the height–diameter allometries for trees in China deviated from tree patterns in other continental forests worldwide. Chinese trees showed substantially lower heights at a given diameter for larger trees and asymptotic heights (33.05 m), with values were 5.5% to 43.3% lower than those estimated for continental rain forest trees in South America, Australia, Southeast Asia, and Africa. In total, 149 of 151 species showed significant nonlinearity of height–diameter allometry with asymptotic heights ranging from 6.33 to 50.54 m; additionally, half (74/149 species) fell in the range of 20–33.5 m, averaging 21.98 ± 8.70 m (SE) for canopy trees. In subsets of canopy trees sampled from larger‐statured species and deciduous trees, the approximated maximum heights were 14–42% larger than those of smaller‐statured and evergreens and those in other wet and warmer regions found worldwide. These results suggest flexible phenotypic responses of height–diameter allometries to heterogeneous light conditions along understory‐canopy gradients. Average growth rates, varying from 0.02 to 0.78 cm/yr (mean of 0.25 cm/yr), were positively related to the asymptotic height, diameter at inflection, and allometric intercept but negatively correlated with the shape of the asymptotic curve and allometric slope. Species with asymptotic heights above 30 m or inflection sizes larger than 20 cm clearly depicted higher growth rates than smaller ones.

The impacts of ice-storms on forests have received growing attention in recent years. Although there is a wide agreement that ice-storms significantly affect forest structure and functions, how frequent ice-storms and subsequent salvage logging impact productivity of subtropical coniferous forests in the future still remains poorly understood. In this study, we used the Ecosystem Demography model, Version 2.2 (ED-2.2), to project the impact of salvage logging of ice-storm-damaged trees on the productivity of Cunninghamia lanceolata-dominated coniferous forest and C. lanceolata-dominated mixed coniferous and broadleaved forests. The results show that forest productivity recovery is delayed in coniferous forests when there is no shade-tolerant broadleaved species invasion after ice-storms, and C. lanceolata could continue to dominate the canopy in the mixed coniferous and broadleaved forests under high-frequency ice-storms and subsequent salvage logging. The resistance and resilience of the mixed coniferous and broadleaved forests to high-frequency ice-storms and subsequent salvage logging were stronger compared to coniferous forests. Although conifers could continue to dominate the canopy under shade-tolerant broadleaved species invasion, we could not rule out the possibility of a future forest community dominated by shade-tolerant broadleaf trees because there were few coniferous saplings and shade-tolerant broadleaf species dominated the understory. Our results highlight that post-disaster forest management should be continued after high-frequency ice-storms and subsequent salvage logging in C. lanceolata forests to prevent possible shade-tolerant, late successional broadleaf trees from dominating the canopy in the future.

The impacts of drought and/or warming on forests have received great attention in recent decades. Although the extreme drought and/or warming events significantly changed the forest demography and regional carbon cycle, the seasonality quantifying the impacts of these climate extremes with different severities on the productivity of subtropical coniferous forests remains poorly understood. This study evaluated the effects of seasonal drought and/or warming on the net primary productivity (NPP) of subtropical coniferous forests (i.e., Cunninghamia lanceolata and Pinus massoniana forests) from Hengyang–Shaoyang Basin in southern China using the Ecosystem Demography model, Version 2.2 (ED-2.2) and based on the datasets from forest inventory, meteorological reanalysis, and remotely sensed products. The results showed that the goodness of fit of the DBH-height allometric equations was better than that of the default in ED-2.2 after model calibration; the ED-2.2 model qualitatively captured the seasonality of NPP in the subtropical coniferous forests; and the mismatch between simulated annual NPP and MODIS-NPP (MOD17A3HGF) became smaller over time. The effect of seasonal drought on NPP was greater than that of warming; the decline rate of NPP gradually increased and decreased with time (from July to October) under the seasonal drought and warming scenarios, respectively; NPP decreased more seriously under the combined drought-warming scenario in October, with an average decrease of 31.72%, than the drought-only and warming-only scenarios; seasonal drought had an obvious legacy impact on productivity recovery of subtropical coniferous forests, but it was not the case for warming. With the increase in drought severity, the average values of soil available water and NPP together showed a downward trend. With the increase in warming severity, the average values of canopy air space temperature increased, but NPP decreased. Seasonal drought and/or warming limit forest production through decreasing soil moisture and/or increasing canopy air space temperature, which impact on plant photosynthesis and productivity, respectively. Our results highlight the significance of taking into account the impacts of seasonal warming and drought when evaluating the productivity of subtropical coniferous forests, as well as the significance of enhancing the resistance and resilience of forests to future, more severe global climate change.