Alien Tree Removal Lesson Notes

Alien Tree RemovalPoster 7

Lesson Notes

Notes for the Educator

Congratulations on obtaining your Water Wise education notes from Rand Water. The following notes focus on ALIEN TREE REMOVAL and explain the concepts dis-played in the poster, and include activities that can be done as school activities or as part of a training course.

The notes have been designed to be adaptable to various learning groups. The pack is aimed at Grade 9 learners in the senior phase, with particular focus on the Natu-ral Science learning area. However the content can be expanded upon for the more advanced groups or condensed for groups that need only the basic concepts.

The facilitator first needs to determine the group’s needs, desired learning out-comes and the resources available. They can then decide how best to use the post-er and notes. The notes include suggested activities that tie in with the outcomes based curriculum. The content and activities also touch on the critical and devel-opment outcomes found in our constitution.

Acknowledgements:

Lesley Henderson from South African National Botanical InstituteKay Montgomery from Wordlink Media

Contents

Introduction 1

- What makes a plant become

an invader? 4

- Why are invaders not invaders

in their home countries? 3

- Problems caused by IAPs 4

- Law

- Invasive Alien Plant categories 8

Category 1 8

Category 2 8

Category 3 9

- Alternatives to IAPs 11

- What is a catchment? 12

-Benefitsofindigenousplants 12

- Water invaders 13

How can these water IAPs be removed? 13

- How to remove IAPs 14

Manual control 15

Chemical control 17

Safetyprecautions 20

Biological control 21

- Healthy wetlands 23

- Rehabilitation 24

POSTER 7

Lesson 1 INTRODUCTION

Invasive alien species occur everywhere and affect everyone, not only ecologically but economically too. Invasive alien species can be animals, birds, insects, but with-in these notes the focus is on Invasive Alien Plants (IAPs). Not all alien plants are problematic; only those listed as invasive alien plants should be removed from your gardens. Everybody has a role to play in the management of IAPs.

Alien plants• are any plants brought into South Africa from other countries. These include plants brought in on purpose for gardens, farming or forestry. Some plants are accidentally introduced, e.g. their seeds were amongst the hay brought in for horses. Of these aliens, whether introduced on purpose or by ac-cident, certain species have escaped from cultivation, reproducing and spread-ing without human help. Exotic and alien mean much the same thing, but the word ‘alien’ is the preferred term when referring to problem plants. Aliens that become serious problem plants are known as Invasive Alien Plants (IAPs). Cur-rently, there are 198 listed IAPs, and this list will probably be added to in the near future.

Alien Tree Removal - Poster 7 - Lesson 1 - Page 1

Alien Tree Removal

Numbers on the poster correspond with numbers in lesson notes

2

1

3

4 56

7

8

9

101112


Naturalised plants• such as cosmos, blackjack and khakibos have found a niche (typically they occur in disturbed areas such as roadsides and building sites), and flourish there but do not present a serious threat to local biodiversity.

Naturalised• plants are able to reproduce and spread without human help and be-come established as part of the local flora in a place other than their place of ori-gin. Sometimes alien plants become naturalised plants and become nuisances, as they are tenacious enough to spread without human assistance. Naturalised species are alien species that can reproduce consistently and sustain popula-tions for at least 10 years without human intervention. These species do not necessarily spread over large areas.

A • weed is a plant that grows where it is not wanted, and can therefore be an indigenous or alien species. An unwanted plant growing in your garden is just called a weed, but the 198 listed IAPs are called “declared weeds and invaders”.

Khakibos (Tagetes minuta)

Alien• has a similar meaning to exotic (ie. from another country), but the word “Alien” is commonly used to describe plants that are not indigenous to South Af-rica (from another country) and have become problematic (spreading rapidly, threatening the existing plant species).

Invaders• are those few alien species that reproduce and spread, unassisted by man, into areas where they are not wanted. For a species to become an invader it has to:

- Arrive - Survive - Thrive

Biodiversity• refers to a rich mix of different types of living organisms – including animal and plant species Biodiversity makes up the structure of the ecosystems and habitats that support essential living resources, including wildlife, fisheries and forests.

Indigenous• refers to a plant or animal that occurs naturally in the place in which it is currently found.

An IAP species that has established or spread outside of its natural distribution range is therefore a threat to the ecosystems and habitats it has invaded. IAPs cause problems because they are more competitive than the indigenous plants and tend to take over areas previously inhabited by indigenous species. IAPs affect the environment in terms of bio-physical, economic and social dimensions.

What makes a plant become an invader?

IAPs are successful because they no longer have their natural enemies around which controlled their growth and spread in their natural habitats. IAPs can there-fore grow faster and stronger that the existing indigenous plants. Many IAPs are fast growing and usually have a strong root system, taking large amounts of water and nutrients from the soil, and therefore depriving indigenous plants of nutrients, water and sunlight.

IAPs are the single biggest threat to plant and animal biodiversity. IAPs threaten productive land such as nature reserves and agriculturally valuable areas that could be used for cultivation or grazing. IAPs generally consume more water than the natural veg-etation such as fynbos and grassland species. It is estimated that IAPs use up to 7% of the water that would normally flow into rivers. IAPs such as black wattles and certain pine trees usually have deep rooted systems that allow them to access reserves of water found deeper in the soil, which the shallower rooted grassland species cannot reach.

What makes an alien plant become an invader?Absence of natural enemies.•Similar conditions to native country.•Vegetative reproduction.•Prolific seed production, long-lived seeds.•Effective seed dispersal mechanisms, such as water, wind and birds. •

Why are invaders not invaders in their home countries?

The invaders are kept in control in the countries they come from by:Climate: the climate in their home country may not be as favourable to their •growth as is the climate in many parts of South Africa.


TAKE NOTE

IAPs also have the ability to spread and reproduce quickly and easily. Many IAPs can spread by vegetative reproduction, such as the grey pop-lar that produces root suckers or the prickly pear cactus where a whole new plant can grow from a piece of stem. IAPs also produce prolific amounts of seed that are long-lived, and use seed dispersal mechanisms such as water, wind and birds that spread the seeds far and wide.

Existing ecological conditions: other plants in their home environment compete •with them, while these competitors are not present in South Africa.

Seasonal pests and disease: their natural enemies keep their growth in check, •but in South Africa these IAPs have no or very few enemies. This allows them to grow freely without being attacked as they would in their natural environ-ment.

Problems caused by IAPs About 750 tree species and 8000 herbaceous species have been introduced into South Africa, of which 198 have been identified as IAPs. These plants grow in our homes, gardens, fields and parks, consuming up to 7% of our annual water sup-ply, displacing indigenous plants, causing fires and soil erosion and endangering many of our animals. These invading alien plants have become established in over 10 million hectares of land in South Africa, and if left unmanaged, the problem will double within 15 years. IAPs reduce our ability to farm; intensify flooding and fires; increase soil erosion, destruction of rivers, siltation of dams and estuaries, replace natural vegetation and upset natural ecosystems. The cost of controlling IAPs in South Africa is estimated at R600 million a year over 20 years.

Group workDivide the following points amongst small groups. Each group must discuss the problem and the effects on the environment. The group must also discuss various solutions to the problem. The group must present the problem and its effects as well as solutions back to their class mates.

Invade land •IAPs have invaded 10 million hectares of South Africa or an area the size of KwaZulu Natal (8% of South Africa’s land).

Waste valuable water •IAPs are often high water users that come from areas where there is a more abundant supply of available water for plants. IAPs generally have a deeper and more vigorous root system as compared to the surrounding wetland/grassland vegetation where they are found, allowing them increased access to the available water. IAPs tend to grow along river banks and create thickets which slow the flow of rivers and intensify flooding.


GautengNorth West

Northern Cape

Free State

Eastern Cape

Kwazulu Natal

Western Cape

Limpopo

Mpumalanga

ACTIVITY

Displace natural indigenous species •The IAPs take over the area, leaving little or no space for the indigenous species that naturally occurred there.

Threaten biodiversity •As the IAPs push out the indigenous species of plants, so the insect, bird and animal life are negatively influenced as their food or host plants are no longer available.

Use soil nutrients •IAPs grow fast and therefore use up large amounts of soil nutrients, reducing the nutrients available for indigenous plants.

Change the composition of soil •IAPs such as the Australian wattles (Acacia spp.) belong to the legume family and therefore change the composition of soil by fixing nitrogen and making nitrates available to the soil. Indigenous plants such as fynbos are adapted to sandy nitro-gen-poor soils and therefore cannot survive in the enriched soils. Australian Acacias (Wattles) have no thorns and should not be confused with the South African Acacias, which have thorns.

1 Soil erosion IAPs sometimes prevent other species from growing underneath them, by block-•ing the required sunlight, creating nutrient-poor soil, and also because the IAPs secrete chemicals into the soil which discourage plant growth, this is known as allelopathy. This leaves the soil bare and prone to soil erosion. Soil is washed into the river during rainstorms, which leads to poor water quality and siltation of dams (this reduces a dams storage capacity).

Donga erosion

Decrease in agricultural production •IAPs that are crop weeds can reduce the success of crops, by depleting the soil of water and nutrients, and by contaminating harvests with their own seeds.



2FuelforfiresIAPs are usually soft woods like Pine, and tend to grow in dense thickets. These catch fire easily and the fire is hotter than normal because there is more matter available to burn, which intensifies the damage caused by fires. IAPs that have been cut down need to be cleared from the area, or else they can become a fire hazard. Many IAPs seeds germinate after fires, and therefore areas that have been burnt need to be sprayed with a herbicide to kill seedlings.

Toxic to humans and livestock •IAPs such as Oleander and Seringa are poisonous to livestock if the leaves or ber-ries are eaten. Some can be irritants to humans and animals, such as the leaves and stems of Pampas grass which can cause a mild skin irritation.

Host insects•IAPs such as bugweed host the fruit fly which attacks commercial fruit crops caus-ing financial loss.

Monoculture•IAPs form dense stands of the same plant and exclude other species.

Working for Water

This isanational campaignaimedat changing theattitudesandbehaviourof the

SouthAfricanpublictowardsIAPs.ThiscampaignisaninitiativeledbytheDepart-

mentofWater&EnvironmentalAffairs.Theorganisationemploysunemployedpeo-

pletoliterallyhackandcuttheirwaythroughalienplants.Sinceitsinceptionithas

createdthousandsofjobs.About52%ofthepeopleemployedbyWorkingforWater

arewomen,mostlysinglemoms.

hint

Biodiversity means that there is a pool of species (differentplants, animalsandinsects)thatexistinanareatogetherforeachother’s benefit and aredependentoneachother.

LAW

South Africa has acts and legislative documents that are relevant for the control and management of IAPs. Landowners are under a legal obligation to control invad-ing alien plants occurring on their properties. This obligation exists as a result of the various laws. The relevant laws identified at this stage are the following:

The common law relating to neighbours and nuisance;•Section 151(1) of the National Water Act 36 of 1998;•Section 28 of the National Environmental Management Act, 107 of 1998;•Section 31A of the Environment Conservation Act 73 of 1989;•Municipal by-laws and the National Veld and Forest Fire Act 101 of 1989;•Regulations in terms of the Conservation of Agricultural Resources Act 43 of •1983. National Environmental management biodiversity act 10 of 2004.•

These laws make provision for the conservation of natural resources of South Af-rica through:

Maintaining the production potential of land;•Combating and preventing erosion;•Preventing the weakening or destruction of the water sources;•Protecting the vegetation;•Combating weeds and invader plants;•Preventing the spread of unwanted plants. •

The Conservation of Agricultural Resources Act, 1983 (Act No. 43 of 1983) (CARA) is used to control the devastation caused by IAPs as well as their spread. CARA identifies 198 Invasive Alien Plants which are divided into three categories. Each category prescribes different courses of action or remedies depending on the seri-ousness of the threat caused by the identified IAPs within the category.

Currently these categories are being revised. The new categories have not been finalised but the suggestion is that Category 1 be divided into 1a = priority species for control; 1b = species to be controlled as part of a management programme; 2 = same as current; species requiring permits and permitted only in demarcated areas; 3 = same as current; no further planting, propagation, importation or trade. For updated information please refer to the SANBI website at www.sanbi.org. The revised list is expected to be finalised in 2009/2010. The revised regulations lists 348 species and a further 100 species have been proposed which need further in-vestigation before they can be listed or removed from consideration.


TAKE NOTE

Not all IAPs present equal problems in all provinces. For example, Camphor trees need only be removed in KwaZulu- Natal, Mpumalanga and Limpopo.

According to The Conservation of Agricultural Resources Act: •An invader plant• is defined as “any kind of plant which has been declared an in-vader plant, and includes the seed of such plant and any vegetative part of such plant which reproduces itself asexually”.A weed• is defined as “any kind of plant which has been declared a weed, and includes the seed of such plant and any vegetative part of such plant which re-produces itself asexually”.

INVASIVE ALIEN PLANT CATEGORIES

Please note these categories will be revised as soon as new legislation is approved.

Category 1Alien plants which have been declared as “weeds” and which are not allowed to oc-cur on land or on inland water surfaces (other than biological control reserves). (These invasive alien plants are causing major problems due to their invasiveness and must be removed and destroyed immediately).

What are Category 1 plants? These are “declared weeds”.

They may not occur on any land or on any inland water surface throughout the •Republic of South Africa.These plants must be controlled, or eradicated where possible (except in biologi-•cal control reserves). No person may:•

Sell, agree to sell, offer, advertise, keep, exhibit, transmit, send, convey or deliver for sale, or exchange for anything or dispose of to any person in any manner for a consideration, any weed, or in any manner whatsoever disperse or cause or permit the dispersal of any weed from any place in the Republic of South Africa to any place in the Republic of South Africa.

Category 2These are commercially valuable or utility plants which may be grown in areas that have been specifically demarcated for this purpose e.g. forestry plantations. These IAPs may be grown in demarcated areas, where they must be controlled. A permit is required in order to grow and have these plants on your property and most ho-meowners will find it difficult to get a permit, therefore it is best to remove these plants. These plants are prohibited within 30 m of the 1:50 year flood line of water courses or wetlands unless authorisation is obtained.


TAKE NOTE


What are Category 2 plants? These are “declared invader plants”

Generally they are plants grown for commercial purposes but may also be used •as a woodlot, shelter belt, building material, animal fodder, soil stabilisation or other beneficial function that may determined.They may only be allowed to grow in demarcated areas under controlled condi-•tions.Import of propagative material and trading allowed only by permit holders.•Prohibited within 30 m of the 1:50 year floodline of watercourses or wetlands •unless authorisation obtained.

Category 3 These are plants which may no longer be planted. Individuals of these IAPs that already exist need not be removed, but new plants may not be planted. No propaga-tion or trading of these is allowed and such plants may not occur within 30 metres of the 1:50 year flood line of a river, stream, spring, natural channel in which water flows regularly or intermittently, lake, dam or wetland.

What are Category 3 plants?These are “declared invader plants”.

They may continue to grow where they already exist; •However, no new planting or trade or propagating of these plants is permitted.•Prohibited within 30 m of the 1:50 year floodline of watercourses or wetlands, or •as directed by the executive officer.

All three categories are permitted in biological control reserves which are areas spe-cially designated for the breeding of biological control agents.

Flood line refers to how high floodwaters have reached in a period of time. Flood zones are determined by the level of water that has been reached during a period of time. Therefore a 1:50 year flood line depicts the highest level reached by flood waters in 50 years. Therefore for building and planting purposes it has become common practice that construction occurs above this flood line in order to avoid damage to property when flooding occurs. Regulations for category 2 and 3 states that IAPs may not occur within 30m of the 1:50 year flood line.

Today 20-40 Yearslater

The effects of IAPs on water sources

TAKE NOTE

The following table lists IAPs that are commonly found in gardens and must be re-moved immediately. Alternatives are listed


Moth catcher (Araujia sericifera)

IAP

Mickey mouse bush (Ochna serrulata)

Bugweed (Solanum mauri-tianum)

Marmalade bush (Streptosolen)

Alternative

Lantana (Lantana camara)

False olive (Buddleja saligna)

Red Sesbania(Sesbania punicea)

Plumbago (Plumbago auricu-lata)

Oleander (Nerium oleander)The double-flowered hybrid of Oleander is allowed.

Pride of de kaap (Bauhinia galpinii)

Role play: Team up with another classmate and then each take turns playing the role of gar-den centre sales person and customer.

Explain to the customer: - What is an IAP? - Name the act that governs IAPs. - How many categories of IAPs are there? - Describe the action that this act prescribes for each category? - What harm do IAPs cause?


ACTIVITY

Alternatives to IAPsOnce you have removed the IAPs from your garden, replace them with alternative plants. This will make your garden look pleasing again, and prevent soil erosion from occurring. There are many Water Wise, low maintenance plants ideal for re-placing invasive plants.

Cabbage tree (Cussonia paniculata) is ideal for replacing the prickly pear (Opuntia spp.) – Category 1. This frost hardy tree is drought resistant and loves a sunny position.

Cape honeysuckle (Tecoma capensis) is an alternative for lantana (Lantana camara) – Category 1. This fast growing, drought resistant shrub attracts birds and butter-flies to the garden.

Mickey mouse bush (Ochna serrulata) is a good alternative for red sesbania (Sesbania punicea) – Category 1. This shrub can be grown in small gardens in a sunny position where it will attract birds and butterflies.

Pride of De Kaap (Bauhinia galpinii) is an attractive alternative for oleander (Nerium oleander) – Category 1. It is a fast growing, spreading shrub that prefers a sunny position. Remember that there is an oleander hybrid that is allowed.

Plumbago (Plumbago auriculata) is a good alternative for bugweed (Solanum mauri-tianum) - Category 1. Fast growing and fairly drought resistant, this scrambling shrub makes an attractive informal hedge.

Weeping wattle (Peltophorum africanum) can be planted in place of Spanish broom (Spartium junceum), yellow bells (Tecoma stans) and yellow oleanders (Thevetia peru-viana) which are all Category 1 plants. This shade tree has a non-aggressive root system and grows fair quickly in fertile soil.

Honey euryops (Euryops virgineus) can be used to replace pom pom weed (Campulo-clinium macrocephalum).

Zebra grass (Miscanthus capensis “Zebrinus”) is used to replace pampas grass (Cortode-ria selloana)


ACTIVITY

hint

Other terms that are used to describe a catchment are: drainage basin; catch-ment area; catchment basin; drain-age area; river basin; water basin and watershed.Allmeanthesamething.

WHAT IS A CATCHMENT?

3 A catchment is an area of land where water from rain or snow melt drains down-hill into a body of water, such as a river, lake, reservoir, estuary, wetland, sea or ocean. A catchment includes both the streams and rivers that direct the water as well as the land surfaces from which water drains into those channels.

A catchment acts like a funnel, collecting all the water within the area covered by the basin and channeling it into a waterway. Catchments are separated from adja-cent basins by a ridge, hill or mountain (known as a water divide).

BENEFITS OF INDIGENOUS PLANTS

Indigenous plants have adapted with time to the climate in the region within •South Africa where they occur and they are suited to the local soil, rainfall and temperature conditions.If indigenous plants become extinct other forms of life that depend on these spe-•cies (as a source of food or as a host) may also be under threat and die out.Maintaining rich, diverse and indigenous landscapes encourages tourism there-•by boosting the economy.

DiscussionWhy should government and land owners spend time and resources to give atten-tion to IAPs when there seems to be more pressing problems like people needing access to clean water, sanitation and energy?

Drainage basin

WATER INVADERS

Water is one of our most valuable resources. Aggressive IAPs can negatively trans-form vast bodies of water.

IAPs invade wetlands, rivers, dams and estuaries causing problems such as:Oxygen deficiencies in the water;•Dense vegetation that blocks inlet channels;•Restricting access of boats (fishing, river transport, recreational activities);•Increasing rate of siltation of rivers;•Increasing loss by evapo-transpiration;•Preventing waves from forming;•Providing breeding sites for mosquitoes and snails that carry diseases such as •malaria and bilharzia;Leaves of floating weeds prevent sunlight from penetrating the water and this •affects the entire food chain, causing the deterioration of aquatic biodiversity.

How can these water IAPs be removed? Control involves removing the plants present and the seedlings which emerge and replacing them with alternative species to limit re-growth and re-invasion. Several follow up actions are required to remove all seedlings. Many of these plants can regenerate from small pieces of leaf or stem, and these plantlets must be removed as well.

Remove the following aquatic IAPs from your garden; do not leave behind any part of the plant (stem, leaf, seed) all of which can regenerate. Put the IAPs in a sealed plastic bag and safely dispose of them. In larger areas it may be necessary to apply a herbicide to kill the plants.


Herbicide spraying to prevent re-growth

Category 1

Category 3

Take a look at your pond at home or at school to ensure that it is free from any inva-sive water plants. Follow the methods below if invasive plants (terrestrial species) are present.

HOW TO REMOVE IAPS


hint

Invasive Alien Plants invade land that could ratherbeusedforfarming.

TO DO

Giant reed (Arundo donax)

Sword fern (Nephrolepis exaltata)

Parrot’s feather (Myriophyllum aquaticum)

Pickerel weed (Pontederia cordata)

Water Lettuce (Pistia stratiotes)

Methods used to remove IAPs can be manual, chemical or biological. Usually a combination of control measures is used in order for removal to be successful.

Manual control: Do not allow IAPs to become established in any area, or to set seed. Remove them while they are still young. Control should begin before the species has an oppor-tunity to establish itself and set seed to save time and money. Many IAPs can be removed manually:

4 Tree fellingFell the tree, leaving the stump as flat and as close to the ground as possible. Mix a herbicide and apply it to the phloem, cambium and outer sapwood on the cut-stump. 5 Bark strippingBark must be removed from the bottom of the stem to a height of 0.75-1.0 m. All bark must be removed to below ground level for good results. Bush knives or hatch-ets should be used for debarking.

8 FrillingUsing an axe or bush knife, make angled cuts downward into the cambium layer through the bark in a ring. Ensure to make the cuts around the entire stem and ap-ply herbicide into the cuts.Manual control methods are more effective when used in conjunction with chemi-cal control methods.

7 Chop the plant or tree down using a hatchet or a panga. When chopping or sawing a plant or tree down, it is vital to immediately apply a herbicide to the cut stump, so that the withdrawing sap will carry the poison down to the roots and kill the plant. Otherwise, the stump will coppice, and in a short time the problem will be back again.


Chop the plant or tree down using a panga, a hatchet or brush cutter.

Saw the plant or tree with a chainsaw or bow saw

When seedlings appear, pull them out as soon as possible. Use a tree popper to re-move shrubs and smaller trees.


6 Ring barking is a technique that involves removing a ring of bark around a tree trunk. Ring barking interferes with the circulation of the tree and results in it slowly dying. Remove a 30 to 40 cm strip of bark around the base of the tree trunk to ground level. Ring-barking removes the cambium/phloem, a layer just beneath the bark, which carries food from the leaves down to the roots. The roots will eventually die thereby killing the tree. In some species chemicals must also be applied.

TAKE NOTE

hint

The Tree Popper is a simple tool that uses the concept of leverageand can be used by a single person toremoveplants.Itcomprisesofarubbergripandafootpiecefirmlyheld together by a circlip. Thesetwopartsformapliers-likejawthatisusedtogriptheplantstem.

A Tree Popper

The first Jacaranda tree was imported into Pretoria from Brazil in 1888. Today some 70 000 of the trees grace parks, gardens and streets. These are category 3 plants, i.e. existing ones may remain but new ones may not be planted.

Chemical methods


Apply herbicides. Use only registered approved herbicides that control or prevent re-growth

Combining the methods: Two or more methods of control can be used at the same time, e.g. me-chanical and chemical. You can slash a young Black Wattle and then spray a registered herbicide onto the stump

hint

Herbicidesareagroupofchemicalswith the ability to interrupt plant growth or metabolism to the extent that it either kills the plant or reduces itcompetitiveness.

Notes:

Jacaranda tree

SprayingHerbicides are being used in many different ways. These include full cover sprays, band applications, and the distribution of granules, cut stump treatments, basal stem treatments as well as stem injections. Some herbicides are selective and can be used, for example to target grasses or broad leafed species, leaving other plants unharmed.

Types of chemicalsGroup 1Are non-selective chemicals and can act on most plant groups. These chemicals de-grade rapidly without long-term environmental effects. For stump-type treatments and foliar applications many chemicals are available the most popular one being glyphosate which is used for general garden applications. Examples of these are Roundup, Ridder and Mamba. Always carefully follow the application instructions on the label of the chemical you use, this is an important safety precaution.


hint

Herbicides (suchasRoundup,Ridder and Garlon) can be sprayed on plants less than 2 m in height for quick results(especiallyusefulwhentreatingsmallshrubsorseedlings).

Certain chemicals are only registered to work on specific plants. Any chemical can be used on any plant but there is no guarantee of the result if the plant is not listed on the label. Always ask an expert for advice when using chemicals. Group 2Work selectively only on broad leafed plants, which can be advantageous when spraying in grassed areas. When apply-ing this solution a wetter must be added so that the mixture is absorbed more ef-fectively by the plant. Examples of this group are Garlon or Triclon.

TAKE NOTE


Chemical treatmentRoots of established trees or shrubs1.

To kill the roots of trees and large shrubs a systemic herbicide can be used. It is absorbed by the roots and then translocated to the rest of the plant thereby killing it.

Cut stump method 2. Fell the tree, leaving a stump as flat and as close to the ground as possible. Mix a herbicide and apply it to the phloem, cambium and outer sapwood on the cut-stump. The phloem is on the outer rim of the tree or shrub; on larger trees it should only be applied to the outer portion of the cut made in the stem.

Chemical treatment on frilling or ringbark3. If a tree cannot be cut down, spray or paint herbicide into the continuous frills chopped into the bark, or apply herbicide to the bottom cut of a ringbarking.

Basal stem treatment4. For smaller trees and shrubs, paint a herbicide onto the exposed base of the tree trunk and any exposed roots. Paint the herbicide up to a height of 25cm above ground level. In the case of multi-stemmed trees, each individual stem should be painted. The herbicide will enter the tree’s circulation and eventually kill the tree.

Foliar spraying5. In the case of re-growth from stumps (also know as coppicing), mix a herbicide and spray it on the re-growth. Allow the re-growth to reach a height of 50cm before treatment. Ensure that a full cover spray is achieved but avoid drift to adjacent plants.

Cut stump method

Frilling method

Stem injecting method

Notes:

Safety precautions

At all times take extreme care when 1. handling any poison and especially concentrates.

Always follow the instructions on 2. the label.

Protective clothing should be worn 3. (eg. gloves, mask, apron, eye protection)

After use wash hands with plenty of 4. soap and water.

All chemicals, concentrated or diluted5. must be kept in a safe place – out of the reach of children.

All containers into which the herbicide 6. is stored or mixed into should be clearly marked.

Store chemicals away from pets, 7. children and food and in a clearly marked area.

Avoid spraying herbicides on 8. indigenous or other desirablevegetation.

Never decant or store chemicals in 9. old bottles, especially cool drink bottles.


hint

Check that the herbi-cide being used is reg-istered for the plantbeing treatedand forthat specific type oftreatment.

ACTIVITY

Debate why IAPs should be removed when some communities rely on the fire wood as a resource in order to survive. What are the benefits of IAP removal? Are there any envi-ronmentally friendly alternatives to wood?

Biological controlCertain Invasive Alien Plants (IAPs) have natural enemies, insects and or diseases, which only affect them and can therefore be used as a control method. Biological control is commonly used to control aquatic invasive alien plants. New biological control agents are tested in controlled conditions, sometimes over a period of years, to make sure that it only focuses on the problem plant and will not itself become a problem pest.

Water hyacinth clogs waterways and affects wildlife and people.


Notes:


HEALTHY WETLANDS

Wetlands are difficult to define because of their great variation in size and location. The most important features of wetlands are waterlogged soils (temporary, season-al or permanent), unique types of soil and distinctive plants adapted to water-sat-urated soils. Marshes, bogs, swamps and vleis are examples of wetlands. Wetlands in all forms perform a range of key functions and provide humans with many life sustaining products.

9 Many wetlands act to:Reduce floods•Replenish ground water•Control erosion•Purify water•Retain sediment•Regulate stream flow. •

Over half of the wetlands in South Africa have been destroyed by draining for farm-ing or development, pollution, the overharvesting of reeds and peat, and incorrect burning practices. Others have been invaded by alien plants and can no longer func-tion properly. So? It is important to save what is left and keep them free of IAPs.

10 We cannot continue to pollute wetlands, drain them, starve them of water and exploit them unsustainably for food and shortsighted economic development, with-out expecting to pay a heavy price in the long term.

11 Water is absolutely essential to all animal and plant life. Wetlands are biodi-versity rich. They support plants and animals that are specifically adapted to wet-lands. Each wetland type supports different communities of plants and animals. For example, mud flats are ideal for small wading birds such as sanderling, curlew sandpiper and red knot, and large hunting birds such as pelicans and cormorants

TAKE NOTE

Otter

Mongoose

Plants play a significant role in the quality of water found in wetlands. Wetland plants are adapted to water saturated conditions. They filter surface water runoff, capturing sedimentation. They also act as purifiers, removing toxins and pollut-ants from the water. Healthy wetlands include vegetation such as bulrushes, red hot pokers, vlei lilies and sedges.

Dragonflies are a sign of a healthy wetland, as their nymphs need good quality wa-ter to live in.


TAKE NOTE

People use wetlands for recreational activities such as bird watching, water sports and fishing. The products from wetlands provide a source of food as well as economic benefits as many rural community members make crafts from wetland materials, such as reed mats. The use of wetland and other natural resources must be carefully monitored to ensure they are not depleted.

Notes:

Bulrushes Red hot poker

REHABILITATION

12 Once an area has been cleared of IAPs the area is bare and is prone to higher rates of erosion. Grass can be used to stabilise banks and prevent erosion. One such grass is Vetiver grass. Vetiver grass is not indigenous to South Africa AND CAN BE INVASIVE but it is not considered as an invasive species because it only grows where it is planted, and is sterile – IT SPREADS VEGETATIVELY. Indigenous spe-cies should be used.

Vetiver grass has a strong, fibrous root system that penetrates several meters be-low the ground to bind soil tightly. It can withstand fire, drought and slopes of more than 45°. Vetiver grass forms dense and permanent cover that slows surface water run off thereby improving soil moisture and nutrient retention.

Vetiver grass is a perennial grass that requires little maintenance. It does not spread to become a weed and reproduction occurs vegetatively. Planting dense vig-orous ground covers reduces the rate of erosion and reduces surface water runoff. This method of rehabilitation is ideal for disturbed areas.

Planting indigenous alternatives are other forms of rehabilitation of disturbed ar-eas, where IAPs have been problematic.


Some wetlands have green water be-cause it is full of tiny green algal cells. The algae multiply very fast especially when the water contains lots of nutri-ents (often as a result of pollution). The algal cells block out the sunlight and rooted plants are unable to grow.

DID YOU KNOW?

Vetifer grass

Decoration material made from by-products of alien invasive plant material

ForinformationandideasonWaterWisegardeningcalltheRandWatercustomerservicecentreon0860101060,orvisitthehomeand

gardensectionoftheirwebsiteat

www.randwater.co.za

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Alien Tree Removal Lesson Notes

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