Accumulation of Urban Insect Pests in China: 50 Years’ Observations on Camphor Tree (Cinnamomum camphora)

Abstract

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 CO 2 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.

On the link between tree size and ecosystem carbon sequestration capacity across continental forests

“…We caution that large uncertainties in future climate and land-use conditions, and in the rates of young and middle-aged subtropical forest production, limit mid-and long-term estimations of terrestrial C uptake and stock. The regional forest C sink could likely decline if selective-log or clear-cut wood harvesting rises to meet demands for wood and biofuels (Fang, Yu, et al, 2018;Zhao et al, 2013b), for example, or if disasters, such as fire (Hood et al, 2018), pests (Xiang et al, 2020), and extreme weather (Zhao et al, 2020), increase stand dynamics and stand-replacing disturbance. In addition, global environmental changes, including the increasing nitrogen deposition and rising atmospheric CO 2 concentration, may interact to shift growth allometry and modify future age or height-related trajectories of ecosystem C stock and fluxes during stand development (Tong et al, 2020;Zhao et al, 2009;Zhao et al, 2013aZhao et al, , 2013b.…”

The Effect of Landscape History on the Urban Environment: Past Landscapes, Present Patterns

“…Current evidence suggests that thousands of urban trees have already died in South Africa, with millions more threatened (Potgieter et al 2020). Research on 50-year trends of pest outbreaks on the indigenous Camphor tree (Cinnamomum camphora) in Chinese urban areas indicates that urbanisation and its associated effects increase urban pest outbreaks, with some areas severely affected (Xiang et al 2020).…”

Coordination of leaf hydraulic and economic traits in Cinnamomum camphora under impervious pavement

“…Cinnamomum camphora is an evergreen broad-leaved tree species widely distributed in the southern part of the Yangtze River Basin in China. This tree species is not only a typical green tree species in China, but also a well-known fast-growing afforestation tree species in other parts of the world [ 32 ]. C. camphora often dominate subtropical forests in China, so they play an important role in the ecological benefits of subtropical forest ecosystems.…”