How Do Tilia cordata Greenspire Trees Cope with Drought Stress Regarding Their Biomass Allocation and Ecosystem Services?

Zhang Zhang,Stratopoulos Stratopoulos,Rötzer Rötzer,Pretzsch Pretzsch

doi:10.3390/f10080676

Abstract

In the context of climate change, drought is likely to become more frequent and more severe in urban areas. Urban trees are considered to play an important role in fixing carbon, improving air quality, reducing noise and providing other ecosystem services. However, data on the response of urban trees to climate change, particularly to drought, as well as the relationship between their below- and above-ground processes in this context, are still limited, which prevents a comprehensive understanding of the role of urban trees in ameliorating some of the adverse effects of climate change and their ability to cope with it. To investigate whole-plant responses to water shortages, we studied the growth of Tilia cordata Greenspire, a commonly planted urban tree, including development of its roots and stem diameter, leaf parameters and the harvested biomass. Our results showed that this cultivar was susceptible to drought and had reduced biomass in all three compartments: branch (30.7%), stem (16.7%) and coarse roots (45.2%). The decrease in the root:shoot ratio under drought suggested that more carbon was invested in the above-ground biomass. The development of fine roots and the loss of coarse root biomass showed that T. cordata Greenspire prioritised the growth of fine roots within the root system. The CityTree model’s simulation showed that the ability of this cultivar to provide ecosystem services, including cooling and CO2 fixation, was severely reduced. For use in harsh and dry urban environments, we recommend that urban managers take into account the capacity of trees to adapt to drought stress and provide sufficient rooting space, especially vertically, to help trees cope with drought.

Highlights

In the future, drought is projected to occur more frequently under the warmer conditions associated with the progression of climate change [1]
For use in harsh and dry urban environments, we recommend that urban managers take into account the capacity of trees to adapt to drought stress and provide sufficient rooting space, especially vertically, to help trees cope with drought
Obtaining comprehensive knowledge about how urban trees react to and cope with dry conditions can be of utmost importance for ecosystem services in cities

Summary

Introduction

Drought is projected to occur more frequently under the warmer conditions associated with the progression of climate change [1]. In association with increasing urbanisation, extreme heat events have become more prevalent than in previous decades, which reduce environmental quality [2,3,4]. Urban trees can mitigate environmental degradation by storing carbon, purifying the air, reducing storm water and providing other ecosystem services [5,6,7]. Urban trees can be a key component in the adaptation of cities to climate change [8]. In recent decades, the use of urban trees for various purposes has drawn increasing interest from researchers [9]. Nowak et al [10] studied how urban trees can filter pollutants that have adverse effects on human health. Velasco et al [12] reported that carbon sequestration depends

Objectives

Methods

Findings

Discussion

Conclusion