Horse Chestnut (Aesculus hippocastanum L.) Urban Habitat - Pollution Influence on Some Phenotypic and Morphological Characteristics

Fran Poštenjak,Karlo Poštenjak

doi:10.15177/seefor.12-14

Abstract

Background and purpose: Horse chestnut (Aesculus hippocastanum L.) may be found in most urban areas in Croatia. Over the years it showed to be resistant to various negative urban influences. In this research we tested trees on randomly selected streets with intense traffic in smaller towns. The main goal of this research was to establish the link between pollution and tree growth and to analyze to what extent pollution influences the increase in the measured parameters. Materials and methods: The research was done in 7 settlements, in towns with the population of up to 75 000 inhabitants. The measured parameters were the morphological characteristics of trees, shoots, leaves and nuts. From the selected branches we measured the annual shoot (thickness and length), leaves, the number of flowers and nuts. The crown transparency was assessed according to the ICP Forest method. Results and conclusions: The phenotype of the urban Horse chestnut significantly differs from its natural phenotype, and it is transformed by multiple radical pruning, what may be seen in the following ratios: the diameter at breast height tree height, trunk height tree height, crown height – tree height, crown width – crown height. The most significant characteristic of the tree is the vitality expressed by crown-damage classes. On the selected trees the worst crown damage class was “3b” and the best was “0”. The measured parameters of yearly shoot characteristics were defined. All measured parameters (trees, shoots, leafs and nuts) show significant differences from the given average values.

Highlights

Common, Horse chestnut’s (Aesculus hippocastanum L.) natural habitat is Central Europe - from Bulgaria to Greece [1]
The phenotype of the urban Horse chestnut significantly differs from its natural phenotype, and it is transformed by multiple radical pruning, what may be seen in the following ratios: the diameter at breast height - tree height, trunk height - tree height, crown height – tree height, crown width – crown height
The phenotype of the urban horse chestnut tree significantly differs from its natural phenotype, and it is transformed with multiple radical pruning - what may be seen in the following ratios: (I) diameter at breast height (DBH) - tree height, (II) trunk height – tree height, (III) crown height – tree height, (IV) crown width – crown height

Summary

Introduction

Horse chestnut’s (Aesculus hippocastanum L.) natural habitat is Central Europe - from Bulgaria to Greece [1]. The species has intense juvenile height growth. It is very sensitive and highly demanding to chemical, physical and biological stand parameters, such as the soil parameters, especially humus, while less demanding to insolation and temperature [2]. In Croatia, Horse chestnut trees may be found in urban areas, parks and alleys in all three regions: the Pannonian, Dinaric and the Mediterranean [3]. The reason for planting horse chestnuts as one of the main urban species lies in the exceptional aesthetics and management characteristics. Horse chestnut (Aesculus hippocastanum L.) may be found in most urban areas in Croatia. The main goal of this research was to establish the link between pollution and tree growth and to analyze to what extent pollution influences the increase in the measured parameters

Objectives

Methods

Results

Conclusion