Biotic and abiotic factors causing the collapse of Robinia pseudoacacia L. veteran trees in urban environments.

Frank H Koch,Agnieszka Wilkaniec,Lidia Irzykowska,Łukasz Pardela,Krzysztof Wielgus,Włodzimierz Breś,Roma Durak,Beata Borowiak-Sobkowiak,Jadwiga Środulska-Wielgus,Dariusz Świerk

doi:10.1371/journal.pone.0245398

Abstract

Robinia pseudoacacia L. is an interesting example of how one plant species can be considered invasive or useful depending on its environment. In the past this tree species was planted for decorative purposes and for wood in Poland. For many years it was recommended in poor and degraded habitats because it facilitated late-successional plant species. The aim of this study was to verify if black locust can still be regarded as a resistant tree species in urban greenery. The health condition of old tree specimens growing along streets and in parks was compared. The occurrence of pests and pathogens on R. pseudoacacia trees was assessed and the content of mineral elements in leaves was examined. The research results showed that the health of black locust trees growing in the urban environment in Polish cities, especially along streets (in comparison to park sites), deteriorated significantly due to the interaction of harmful biotic and abiotic factors. Increased level of toxic metals (Fe, Zn, Pb, Mn and Cd) in plant tissues and the accumulation of pests and pathogens negatively influenced the health of R. pseudoacacia.

Highlights

The basic functions of greenery and the advantages of trees in urban ecosystems are widely known
Which factors deteriorate the health of black locust most? Which biotic and abiotic factors interact together and increase the trees’ stress? In order to achieve the research objective, we evaluated the most important factors influencing the condition of black locust trees in selected urban areas of three Polish cities
The strongest dependencies between the factors were found in Wrocław; the content of Fe, Mn and Cu in the leaves had the most negative effect on the health of the black locust trees growing along the streets of this city (Fig 1A)

Summary

Introduction

The basic functions of greenery and the advantages of trees in urban ecosystems are widely known. They have positive influence on the city landscape and health-promoting effects for the city’s population. The city is seen as one big ecosystem or as a complex of several individual ecosystems, e.g. parks and alleys [1]. The ecosystem functions of trees include decreasing ambient temperature, shading paved grounds, retaining rainwater, and removing air pollution [2,3,4,5,6,7,8].

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Conclusion