Chinese celtis

Download PDF version 257kb

Chinese celtis (celtis sinensis)

Chinese celtis (celtis sinensis), also known as celtis or hackberry, is an invasive tree growing up to 20 m tall. It is a native of China, Japan and Korea and was introduced into Australia as an ornamental and shade tree.

Chinese celtis has become a major environmental weed in south-east Queensland, expanding rapidly over recent years into major infestations along riparian zones in the Sunshine Coast hinterland and the Ipswich area.

In north-eastern New South Wales, significant but controllable infestations occur in and near a number of urban areas. Old ornamental plantings act as a seed source, particularly around Kyogle where it was planted as an ornamental and shade tree 50 years ago.

NSW is still in a position to successfully control the existing limited infestations. To do this, coordinated control must begin now while the opportunity exists.

Distribution

Most established populations of Chinese celtis in the northern areas of NSW are in urban areas in both private gardens and public areas. Significant but controllable Chinese celtis infestations occur in bushland in and near Lismore, near Kyogle and the upper Richmond River Catchment, in the Tweed and in Coffs Harbour. It has also been found growing along the Manning River, at Taree and Bellingen.

Description

Chinese celtis is a large tree, with a spreading, moderately dense crown. It has a smooth, mottled grey bark with alternate, elliptical shaped leaves that are 4–7 cm long. The leaf margins are finely serrated in the upper half of the leaf.

In northern NSW it is deciduous or semi-deciduous in late winter and the dry early spring period.

Chinese celtis produces thousands of fleshy fruits that are approximately 7–8 mm in diameter. The fruits turn reddish brown to orange when ripe in autumn and early winter. Chinese celtis fruits during the same period as camphor laurel and similar birds feed on both species.

Habitat

Chinese celtis is reported to grow in a wide range of soils. It prefers moist riparian areas, but has been found growing in a range of habitats. Current infestations are largely in riparian zones in areas originally supporting subtropical and dry rainforests.

Chinese celtis infestations initially develop in disturbed areas of riparian vegetation and in previously cleared and regenerating riparian zones. Regenerating riparian areas, also infested with camphor laurel and privet, are widespread along the north coast of NSW.

Impact

Chinese celtis is an invasive environmental weed and a potential weed of agriculture because of its ability to become structurally dominant.

Chinese celtis has been recognised and listed as a serious environmental weed by bush regeneration groups, Councils and the National Parks and Wildlife Service.

It rapidly colonises disturbed bushland, forms dense thickets, replaces native shrubs and trees and dominates riparian vegetation.

The demonstrated ability of Chinese celtis in south-east Queensland to spread rapidly makes its control in north-eastern NSW a high priority. Failing to control Chinese celtis infestations at the same time as controlling camphor laurel may lead to it partially or totally replacing camphor laurel in some areas.

Spread

Chinese celtis seeds are spread by birds feeding on its fruit in autumn and early winter. Some of the same species of birds also feed during the same period on fruit of camphor laurel. This may significantly enhance the dispersal of Chinese celtis throughout the disturbed, regenerating riparian zones.

Chinese celtis has also been promoted and planted as a shade and street tree, which has assisted in its spread over the years. This tree should not be promoted or planted as a useful tree because of its potential as a weed.

Control and management

The first step in a control program is to assess the weed problem and situation. A well planned management plan for Chinese celtis will include revegetation of the site after treatment with local native species, control of other weed species that may be present (e.g. privet, camphor laurel) and follow-up maintenance and re-treatment of the site.

Manual control

Manual removal of isolated small seedlings can be attempted by hand pulling or digging them up. This is only practical for a small number of plants. Large trees may be cut down and the stump dug up and removed.

Care should be taken to avoid moving fruit to uninfested areas when manually removing mature trees.

Herbicide control

Herbicide control is effective using the cut stump, basal bark or stem injection techniques. The method used depends on the site situation, tree size, access and personal preferences.

Currently in NSW there are a number of registered herbicides and an AVPMA permit covering the use of herbicides for Chinese celtis control.

Read the relevant permits and labels before treatment and consult the Industry & Investment NSW publication, Noxious and Environmental Weed Control Handbook for further information.

Legislation

To prevent Chinese celtis naturalising and becoming a serious weed in NSW it has been declared a Class 3 noxious weed.

Declaration of the plant raises the profile of the weed species and enables the implementation of a coordinated control program. A Class 3 noxious weed must be fully and continuously suppressed and destroyed.

Responsibility for control of noxious plants on private land rests with the owner or occupier of the land. This responsibility extends to the middle line of any adjacent watercourse, river or inland water (tidal or non-tidal). Failure to control noxious plants can result in a notice being served to the landholder by the local council, court action and a fine.

Alternatively, the council may legally enter the land, eradicate the plants and charge the cost to the landholder.

Acknowledgements

Author: Rod Ensbey

This Primefact is an updated edition of Agnote DPI 425 Celtis: identification and control.