Biosecurity in Forestry: A Case Study on the Status of Invasive Forest Tree Species in Southern Africa

by
B.I. Nyoka
Forest Research Centre
Harare, Zimbabwe
March 2003

Forest Biosecurity Working Papers

Forestry Department
Food and Agriculture Organization of the United Nations

Forest Resources Development Service
Forest Resources Division
Forestry Department

Working Paper FBS/1E
FAO, Rome, Italy

Table of Contents

Disclaimer

The FAO Forestry Department Working Papers report on issues and activities related to the conservation, sustainable use and management of forest resources. The purpose of these papers is to provide early information on on-going activities and programmes, and to stimulate discussion.

This paper is one of a series of FAO documents on forestry-related biosecurity issues. The study was carried out in June 2002, and was financially supported by a special contribution of the FAO-Netherlands Partnership Programme on Biodiversity.

The designations employed and the presentation of material in this publication do not imply the expression of any opinion whatsoever on the part of the Food and Agriculture Organization of the United Nations concerning the legal status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries.

Quantitative information regarding the status of forest resources has been compiled according to sources, methodologies and protocols identified and selected by the author, for assessing the diversity and status of forest resources. For standardized methodologies and assessments on forest resources, please refer to FAO, 2001. State of the World’s Forests 2001; and to FAO, 2001. Global Forest Resources Assessment 2000 (FRA 2000). FAO Forestry Paper No 140.

Official information can also be found at the FAO Internet site (<http://www.fao.org/forestry/Forestry.asp>).

Comments and feedback are welcome.

For further information please contact:

Pierre Sigaud, Forestry Officer (Forest Genetic Resources)	Gillian Allard, Forestry Officer (Forest Protection)
Forest Resources Division	Forest Resources Division
Forestry Department	Forestry Department
FAO, Viale delle Terme di Caracalla	FAO, Viale delle Terme di Caracalla
00100 Rome, Italy	00100 Rome, Italy
Fax: + 39 06 570 55 137	Fax: + 39 06 570 55 137
Email: [email protected]	Email: [email protected]

For citation:

Nyoka, B.I., 2003. Biosecurity in forestry: a case study on the status of invasive forest trees species in Southern Africa. Forest Biosecurity Working Paper FBS/1E. Forestry Department. FAO, Rome (unpublished).

ABBREVIATIONS AND ACRONYMS USED IN THE TEXT

EXECUTIVE SUMMARY

ACKNOWLEDGEMENTS

1. INTRODUCTION

2. DEFINITION OF INVASIVE TREE SPECIES

3. STATUS OF INVASIVE TREE SPECIES IN SOUTHERN AFRICA

3.1 SOUTH AFRICA

3.1.1 Background
3.1.2 Invasive alien tree species and extent of invasion
3.1.3 Environmental and economic impact of invasive tree species
3.1.4 Control of invasive trees
3.1.5 Awareness and potential conflicts of interest

3.2 ZIMBABWE

3.2.1 Background
3.2.2 Invasive alien tree species and extent of invasion
3.2.3 Environmental and economic impact of invasive tree species
3.2.4 Control of invasive tree species
3.2.5 Awareness and potential conflicts of interest

3.3 ZAMBIA

3.3.1 Background
3.3.2 Invasive tree species and extent of invasion
3.3.3 Environmental and economic impacts of invasive tree species
3.3.4 Control of invasive tree species
3.3.5 Awareness and potential conflicts of interest

4. CHARACTERISTICS OF INVASIVE TREE SPECIES

5. PROTOCOLS FOR SCREENING NEW TREE INTRODUCTIONS FOR INVASIVE POTENTIAL

6. CASE STUDIES OF TWO INVASIVE ALIEN TREE SPECIES IN SOUTHERN AFRICA

6.1 PINUS PATULA IN SOUTHERN AFRICA

6.1.1 Natural distribution
6.1.2 Introduction in southern Africa
6.1.3 Biology of Pinus patula
6.1.4 Extent of invasion in southern Africa
6.1.5 Economic importance
6.1.6 Control of Pinus patula invasions

6.2 ACACIA MEARNSII IN SOUTHERN AFRICA

6.2.1 Natural distribution
6.2.2 Biology of Acacia mearnsii
6.2.3 Introduction in southern Africa
6.2.4 Extent of Acacia mearnsii invasions
6.2.5 Economic importance
6.2.6 Control of invasions

7. DISCUSSION

REFERENCES CITED AND OTHER LITERATURE USED

APPENDIX