Simulating Water-Use Efficiency of Piceacrassi folia Forest under Representative Concentration Pathway Scenarios in the Qilian Mountains of Northwest China

Shouzhang Peng,Yunming Chen,Yang Cao

doi:10.3390/f7070140

Abstract

The current study used the Biome-Bio Geochemical Cycle (Biome-BGC) model to simulate water-use efficiency (WUE) of Piceacrassi folia (P. crassifolia) forest under four representative concentration pathway (RCP) scenarios, and investigated the responses of forest WUE to different combinations of climatic changes and CO2 concentrations in the Qilian Mountains of Northwest China. The model was validated by comparing simulated forest net primary productivity and transpiration under current climatic condition with independent field-measured data. Subsequently, the model was used to predict P. crassi folia forest WUE response to different climatic and CO2 change scenarios. Results showed that (1) increases in temperature, precipitation and atmospheric CO2 concentrations led to associated increases in WUE (ranging from 54% to 66% above the reference climate); (2) effect of CO2 concentration (increased WUE from 36% to 42.3%) was more significant than that of climate change (increased WUE from 2.4% to 15%); and (3) forest WUE response to future global change was more intense at high elevations than at low ones, with CO2 concentration being the main factor that controlled forest WUE variation. These results provide valuable insight to help understand how these forest types might respond to future changes in climate and atmospheric CO2 concentration.

Highlights

The fifth assessment report (AR5) of the Intergovernmental Panel on Climate Change (IPCC)showed that the earth’s overall carbon dioxide (CO2 ) concentration has increased from 280 parts per million by volume at the beginning of the Industrial Revolution in the 1850s to the present level of 400 ppm [1,2]
We used Biome‐BGC to model the stem volume size of P. crassifolia forests at other sites based on simulated stem carbon [17]
The model presented a favorable performance in simulating stem carbon of P. crassifolia forests

Summary

Introduction

The fifth assessment report (AR5) of the Intergovernmental Panel on Climate Change (IPCC)showed that the earth’s overall carbon dioxide (CO2 ) concentration has increased from 280 parts per million by volume (ppm) at the beginning of the Industrial Revolution in the 1850s to the present level of 400 ppm [1,2]. The report projects that global surface mean temperature will increase by. 1 ̋ C–3.7 ̋ C in the late 21stcentury relative to the 1986–2005 period under the various representative concentration pathway (RCP) scenarios [3]. These factors will likely result in significant changes in vegetation function over large fractions of the global land surface [4,5]. Forests cover nearly one-third of the earth’s land area and contain up to 80% of the total above-ground terrestrial carbon and 40%. Understanding how forest ecosystems will respond to global changes in the future is imperative.

Methods

Results

Discussion

Conclusion