Tree growth response of Fokienia hodginsii to recent climate warming and drought in southwest China

Abstract

To date, few attempts have been made to assess the influence of climate change on forest ecosystems and on the relationship between tree growth and climate in humid areas of low latitudes. In this paper, we studied the response of tree growth and forest ecosystem to climate change by using Fokienia hodginsii tree-ring cores from the northern Yunnan-Guizhou Plateau, southwest of China. Tree growth correlates the highest (r = -0.64, p < 0.01) with mean temperature (July-September), but the coefficients were changing with time as revealed by a moving correlation analysis. Tree growth is significantly (p < 0.05) and positively correlated with January-April mean temperature from AD 1961-1987, while correlations with precipitation are insignificant. In contrast, from 1988 to 2014, tree growth correlated negatively with mean temperature of previous summer and positively with precipitation of previous August-September. This indicated that the limiting factors for tree growth have changed under different climate conditions. The meteorological data suggested that from 1961 to 1987 it was cold and wet in the study area and radial growth is limited by winter and spring temperatures. This restriction is weaker if the climate is appropriate in general. However, from 1988 to 2014, the combined effects of recent warming and decreasing precipitation have led to an increasing response of tree-ring width to drought. In addition, a large proportion of mature F. hodginsii mortality occurred from 2007 to 2013, which corresponds with a drastic reduction of radial growth (narrowest in recent 100 years). The recent drought, induced by decreasing precipitation and increasing temperature, may have passed the threshold which F. hodginsii could tolerate, causing tree growth reduction, tree growth-climate relationship change, as well as catastrophic tree mortality. All these changes may lead to further responses of the local ecosystem to climate change which should be highly regarded.

Increased Drought Sensitivity Results in a Declining Tree Growth of Pinus latteri in Northeastern Thailand

“…Increasing growth sensitivity to spring season moisture availability or drought conditions is becoming predominant during recent years for the Abies spectabilis and other conifer species in the central and western Himalaya, along with weakening responses to growing season temperatures [59][60][61]. Radial growth of Fokienia hodginsii in southwest China shows increasing responses to summer temperature (negative) and precipitation (positive) under a warming and drying climate [62]. Rahman et al (2018) [18] reported that radial growth of Chukrasia tabularis in the lowland forests in Bangladesh showed increased sensitivity to early growing season temperatures and atmospheric water demand in recent decades, probably due to a significant warming trend and an increasing dry season length.…”

Physiological and Growth Responses to Increasing Drought of an Endangered Tree Species in Southwest China

“…Drought-induced tree decline and mortality is increasing in many parts of the world, which could fundamentally alter the composition [35], structure [9], and biogeography [36] of forests. Recently, mature trees of the endangered species F. hodginsii from a natural forest in YGP in southwest China are undergoing large mortality events [12,26]. F. hodginsii growing in its range boundary is a good example of an endangered tree species that may be more vulnerable to drought.…”

“…Our tree-ring data was collected from living and dead trees (Table 1), sampled in November of 2014 and 2016 [12], at 1200-1270 m altitude range within the Xi Shui National Nature Reserve (Figure 1). Dead trees were collected in a precipitous slope in Wangxiantai (SCH01), a scenic area.…”

“…Trees were still standing and had no green needles remaining in their crown. It is known that most of these mature F. hodginsii trees died in recent years (2007 to 2013) [12,25,26]. Not all dead trees were sampled because of the rapid wood decay rate in this subtropical monsoon climate.…”

“…It is, therefore, critical to understand the influence of changing climate, especially drought, on F. hodginsii growth to predict its response to future environmental change, protection, and to provide sound management recommendation for the species in the future. A previous study has shown the drought-related response of F. hodginsii to climate change in southern China, but the physiological mechanisms causing tree death are still poorly understood, mainly due to a lack of historical information for the species [12].…”