Some thoughts on the rehabilitation of sugar cane land into natural like grassland in the coastal regions of northern KwaZulu-Natal

A brief overview

In my professional opinion I believe it is an illusion to believe that in the short term one can recreate natural like grassland on a large scale. I believe that the best and most cost effective method is to set the process into motion, to guide it, to manage it and to keep it free of invasive aliens as best as can be done. Clearly the more the money that is invested into the project the quicker the results will be, but the higher cost can never be justifed.

Aloe maculata and berkheya spiciosa growing in my grassland at Mount Moreland

Unless one works in a cost effective manner together with nature in today’s economic climate it is going to be impossible to justify the expense of re-habilitation.  

If I was set with the task of re-habilitation of a large tract of sugar cane land into natural like grassland I would set about the task using the system and methods described in the rest of this brief article.

In my opinion there are many approaches that would deliver acceptable results and that there is no absolute right or wrong. We do not know for sure what was there before sugar cane but can give it a guess based on experience, local knowledge and looking at sites in surrounding areas with untouched or minimally damaged grassland. There could very clearly be elaborate and colorful designs put forward by office experts where nature will not comply with the designers wishes. Designs that would dazzle but that could never be implemented no matter how much money one invests into them. When dealing with nature there are certainly no guarantees that any expert can give. Regardless of our skills or lack of skills nature will have the last say the sooner we realize this the more successful we will be and the more money we can save arriving at an acceptable result.

As a case study I propose the re-habilitation of portions of sugar cane lands at the new Durban King Shaka International Airport as I know this area well having flown many hours low over the leveled areas since work was started on the site in about April 1971. I also often landed on the site long before the present airport was built. I now live at Mount Moreland immediately south of the airport. In addition I have been involved in the project in one way or another including planning of the re-habilitation since 3 August 2007.

On site during construction King Shaka International Airport Durban

After the initial earthworks were completed at the then La Mercy Airport the project was abandoned without any re-habilitation work whatsoever being implemented on site. Within a relatively short space of time weeds and grasses colonized the site and over the years many of the local grasses and grassland plants found there way onto the site.

Method

There are as many possible methods as the days in the year, which method is correct and which method is not can probably never be evaluated, clearly on a large scale cost will be a major factor so any method that works with instead of against nature saving cost is going to be the way to go.

Before attempting to engage in rehabilitation activities one must first try to reconstruct in ones own mind the nature and annual life cycles of the grasslands of the past, some indications can still be found in the rural areas nearby that have not been affected by sugar cane farming.

In my professional opinion the method that requires the least human intervention and the maximum use of natural processes to bring about the re-creation of natural like grassland is going to be the only sensible and economical approach in the short, medium and long term. This approach certainly will not give the quickest results but will most certainly be financially justifiable and will give a good result in the end.

In most of the areas not directly associated with the airport such as the runway, terminal and service areas where earth works were undertaken the growing of sugar cane continued on a lease basis in many areas right up to this day badly depleting marginal sandy soils of the last of their nutrients until they were in many cases finally abandoned.

Albuca setosa growing in my grassland at Mount Moreland

Starting the process

Harvest the sugar cane wait for he sugar cane to start growing when there is sufficient growth to be able to deliver a lethal dose of Glyphosate spray the cane and let nature continue the process.

Annual weeds

Since the natural vegetation was destroyed and sugar cane was first planted on this land from about the 1850´s no other crop has been grown on it. Over time the sugar cane has acted as a huge trap trapping vast amounts of windblown seed of invasive alien weeds including vast amounts of annual weeds which are now stored in the soil seed bank. Due to the sugar cane inhibiting the germination of the weed seeds most never germinated those that did germinate soon died as the cane grew and robbed them of light. When the sugar cane is finally removed and the factors inhibiting the germination of the weed seed has been removed the annual weed seeds germinate in their countless millions after the first rains. Small quantities of local perennial grasses mainly Panicum maximum also germinate together with the weeds after the sugar cane is removed and they receive sunlight, once the weeds have completed their life cycles and have produced their seeds and have died the grasses have a chance to grow, to cover the ground and to produce their own seeds in turn. If left to nature after a few cycles the grasses gain the upper hand and the annual weeds almost disappear, to be an insignificant component of the resulting grassland. These same annual weeds can also be found in the few remaining natural grasslands in the immediate vicinity and when portions of these seemingly stable natural grasslands are disturbed masses of these same annual weeds germinate, slowly to be naturally suppressed by the natural grasses and other plants.

As far as attempting to eradicate annual agricultural weeds such as Bidens pilosa, Bidens bipinnata, Conyza bonariensis, Ageratum conycoides etc. by chemical or mechanical means in rehabilitation and alien plant eradication projects at the King Shaka International Airport or elsewhere in the greater Durban area is concerned, I in my professional opinion believe that it is an impossible task due to many factors beyond our control.

Ageratum conycoides the most numerous annual weed at this time of year

Inappropriate use of the herbicide Glyphosate and poor cultural practices on surrounding farmlands and derelict and poorly managed land around the city has greatly increased the number of these agricultural weeds, which release their windborne seeds to re-infesting the areas that have been cleared. In my professional opinion a good healthy cover of natural grasses and grassland plants is the only sensible solution to suppress the numbers of these unwanted weeds.

This process does however not occur where perennial alien weeds are concerned and if left to nature they generally quickly become dominant making it necessary to remove them.

If left to nature it would be many years and some not at all before many of the other grasses and grassland forbs make their way to the site therefore some help is going to be needed to help them to get on site and to help them to establish themselves.

Obtaining and growing seed

Obtaining most of the seed needed to re-introduce the required plants both grasses and forbs to the site is going to present many problems as very few are available commercially and many aer close to impossible to grow using conventional methods. Here is where a very good knowledge of our local plants in particular knowing how to grow them and introduce them into the grasslands and innovative thinking based on this knowledge is going to be vital to the success of the project.

Berkheya speciosa in my garden at Mount Moreland

With many of the plants that need to be introduced into the grassland seed is neither able to be collected in the wild or the plants do not take kindly to propagation and cultivation so a good knowledge of the plants is essential and innovative methods need to be employed to be able to introduce them into the grasslands. So as to protect my specialist know how in this area I am not going to go into any detail in this article.

The planting of certain grass seeds in particular some of the grasses with long awls such as grasses in the genus Hyparrhenia presents problems all of its own for instance they can not be planted by seeding machines because they tie themselves together in tight bunches and can from my own experience only be hand distributed unless the awls can somehow be removed from the seed without damaging the seed.

Hyparrhenia hirta growing in my grassland see the very long awls on the seed

Management of developing grassland

Management of developing grassland poses many questions as to the correct management of the emerging natural grassland for instance at some point in time additional species need to be introduced and this is going to be very difficult if there is a thick cover of Panicum maximum that dominates the landscape not allowing other grasses and Forb seeds to germinate and grow just as was the case with the sugarcane dominating the landscape before it. Fire is clearly a tried and tested method to remove the dense grass cover once per year but I believe this is both damaging and inadequate if done alone in particular on developing grasslands. Burning removes moribund grass very effectively, promotes the germination of seed, it promotes the growth and variety of grassland forbs but looses nutrient to the atmosphere. Burning certainly helps control the rampant growth of the dominant pioneer species in this area Panicum maximum.

Burning alone removes large amounts of carbon returning it back to the atmosphere in addition to other vital minerals and organic compounds which are lost to a system which has already been impoverished due to over 150 years of sugar cane cultivation.

Burning of developing grassland following the removal of sugar cane

Domestic livestock

In the natural grassland as had occurred on site before the arrival of the white man who removed it and planted sugar cane the grasslands of this region were formed by the interaction of grazing and browsing animals both wild and domesticated and the actions of man who in the absence of natural fire set fire to the grassland after the first spring rains.

It long believed that the Nguni cattle, goats and sheep arrived in southern Africa with the Nguni-speaking people, ancestors of today's Zulu, Xhosa and Swazi people.  However, recent research has revealed that the cattle were probably introduced into southern Africa by the Khoisan-speaking people in around 600 and 1400 AD this is much earlier than originally thought. The Nguni-speaking arrivals in southern Africa quickly assimilated the cattle skills and husbandry techniques of the Khoisan. 

Since then, these animals have played an important environmental role in the development of the grasslands in the areas that were settled by these people. 

It is clear in my mind that animals must be part of the equation as they not only remove grasses and other plants allowing for light to periodically reach the level of the soil which fosters a much larger varieties of plants to establish and to maintain themselves this I have observed in the wild and proven in experiments that I have performed. In addition to periodically removing unwanted top cover in controlled grassing vast numbers of organic compounds and nutrients are returned to the impoverished soil. As it is not practical to do controlled grazing with wild animals and because domestic livestock also played and important role in managing the rolling grasslands of KwaZulu-Natal before the arrival of the white man I propose the use of Nguni cattle, Nguni goats and imvu the Zulu sheep to do this valuable task for us. Large herds of wild grazing and browsing animals and pastoral activities by native tribes has clearly had a large impact on forming the natural grasslands in this region before Europeans arrived and ripped most of it up to plant mono-cultures of sugarcane which have in most regions almost completely replaced the extensive grasslands of the past.

The major perennial invasive aliens such as Lantana camara, Solanum mauritianum and Chromaleana odorata that tend to invade this site will have to be dealt with using conventional means.

The invasion of woody species will mostly be taken care of by the annual burning of portions of the grassland.

In areas with deep poor sandy soils which are readily colonized by the forest indicators, Melinis repens, Helichrysum kraussii Chrysanthemoides monilifera, Albizia adianthifolia should probably not be forced into becoming grasslands but be allowed to do what nature is clearly indicating is the natural option.

Gladiolus ecklonii growing in my grassland at Mount Moreland

Conclusion

Keep your plan simple if you want to be sure not to fail.

At the end of the day the final production will be determined by a combination of specialist knowledge, a good feel for the intricate workings of the natural environment, time, luck and the workings of mother nature. No man can plan such a rehabilitation project in an office in a far off place to give an exact result with absolute certainty. We are working with nature and anyone who says that they can give a precise result years down the line is either a charlatan or is God himself

Click here to see Rehabilitation at King Shaka International Airport Durban

Michael Hickman
Ecosystem Manager

Landscape Design Specialist

www.ecoman.co.za

michael@ecoman.co.za

03.05.14

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A garden without wildlife is hardly a garden at all

Ever changing ever new

Our average affluent north Durban suburban garden owner has the most  uninteresting sterile garden possible planted to a very limited number of sterile unchanging plants such as Philodendron selloum cv. Xanadu, bright coloured crotons Codiaeum variegatum, dust collecting Dianella tasmanica variegata, Ophiopogon japonica, Ophiopogon jaburan variegata a never changing boring landscape. Masses of boring single straight stemmed palms, yellow leaved Duranta erecta Sheena's Gold ™ which have been trimmed into hedges, balls and who knows what, to me a plant that is this colour is  critically ill and needs to be removed. All to be finished of with horrible gaudy purple border bedding plants such as purple setcreasea Tradescantia pallida and Rheoe Tradescantia spathacea

Croton Codiaeum variegatum

The Croton Codiaeum variegatum above is very clearly a magnificent plant that has its uses but it never changes how it looks which in time becomes overpowering and boring and in particular it is sterile, it attracts no wildlife at all it could very easily be replaced in the garden with an identical copy made of plastic and few if any people would be any the wiser. These magnificently colourful plants most certainly do not bring life into the garden.

Change and variety are the spices of life and that applies in particular when planning a garden either exotic or indigenous if one would like to create tranquillity in the garden and to provide the greatest of benefit for the user and observer.

In a Proudly South African living garden planted to our local South African plants there are never two days that are the same, it is ever changing, ever interesting, the  bright yellow bloom of a Hibiscus calyphyllus or Hibiscus surattensis here this morning gone this afternoon a flush of blooms the following day.

 

Hibiscus surattensis  bright and beautiful ever changing never the same.

Dietes grandiflora and Dietes iridioides which come to their full glory for a single day in the spring and early summer months after a drop in atmospheric pressure, then wait for the next drop in pressure to repeat the spectacle. A blaze of blue from the Agapanthus Agapanthus praecox spp.orientalis for a few weeks during midsummer, a blaze of orange from the aloes during the winter to be followed by a blaze of red from the coral tree Erythrina lysistemon announcing the early spring that attract birds and insect 

A brightly coloured butterfly here and brightly coloured bird over there plucking a bright berry from a Psychotria capensis bush. A brightly coloured carpenter bee sucking nectar from the flower of a Justicia betonica, dragonflies doing their amazing aerial displays, interesting and brightly insects every where.

A brightly coloured carpenter bee Xylocopa caffra sucking nectar from the flower of a Justicia betonica

A bright coloured bird flying overhead to alight and pluck a bright red berry from a Psychotria capensis in full fruit in the winter. An interesting and colourful bug sitting on a flower, interesting colourful insects everywhere you look in the garden. A Striped Skink Trachylepsis striata sunning its self on a stone and one up on the roof garden waiting for a fat fly to pass by, a blue headed tree agama Acanthocercus atricollis sunning itself on the trunk of a tree

A spectacled Weaver Ploceus ocularis building its nest on a Strelitzia tree Strelitzia nicolai outside my kitchen door.

These things are seldom seen and experienced in your regular traditional Durban garden with its mostly sterile tropical and subtropical plants that appear to never change from season to season, day to day, week to week, year to year, never changing always the same. Many of these gardens may just as well be made of brightly coloured plastic and concrete for all the life that they bring into the garden. Well manicured bright un-natural colours, coarse textures.

  

A well designed garden planted exclusively to our local indigenous plants will be green and tranquil full of interest, full of beauty, with green that comes in every texture, form and shade is ever changing ever new. Every day there is a new surprise, as flower buds burst open to expose a splash of brilliant colour, sometimes lasting only a few hours and sometimes weeks on end then back to the tranquillity of green to soothe the soul.

A very easy plant to propagate and to grow is this magnificent pendulous Gladiolus cruentus a rare critically endangered local gem seldom if ever seen in cultivation in South Africa

A brightly coloured sun bird gently alights on a leonotis intermedia to sip nectar before flitting off to another brightly coloured plant or to hawk a passing insect in mid air.

During the day bright orange paradise flycatchers with their long tail feathers dart out under the canopies of the trees to catch a passing fly and as the sun dips its head below the horizon tiny little bats appear doing tight aerobatics under the same trees to hawk the insects that they feed on.

I look out the window and see a bright coloured Locust Zonocerus elegans which feeds on the milk weed plant Gomphocarpus physocarpus which is also the host plant to the African Monarch Butterfly.

A bright coloured Locust Zonocerus elegans resting on the flower of a grass aloe, Aloe cooperii

A bronze back manikin alights on a grass stem to pluck a seed head of Panicum maximum to build his nest,  later I see him return to collect the fluffy flower heads of natal redtop grass Melinis repens to line it with.

A bright red African Fire Finch arrives on the ground just outside my kitchen door to look for seed and insects.

African Fire Finch Lagonosticta rubricata

The sound of the Crested Barbet that has his home in a nest box I placed in a tree directly opposite my kitchen window only a few metres away, the sound of  Painted Reed Frogs in a small pond of arums in the evening a garden which is a haven for wildlife in all its forms both day and night with interest without end, is this not what a garden should be.

Painted Reed Frog Hyperolius marmoratus

To maximise the life in a garden it must be planned with as large a variety of interesting local plants to create habitat, which provides shelter, breeding and feeding opportunities for all manner of creatures both great and small. Thereafter we need to do little more to encourage life into our gardens, if the conditions are right wildlife will come and stay of its own. The bigger the variety of plants and habitat types the greater the numbers of creatures that will be attracted. The garden must have water, it must have lawn to serve as green pathways and to separate the different elements of the garden. Do not forget a bench here a table and chairs there so that one can sit and relax and enjoy the garden and its wildlife.

African Monarch butterfly Danaus chrysippus on the flower of it´s host plant the Milk Weed Gomphocarpus physocarpus

There is no reason why a garden that is maximised for wildlife should not be planned and planted to the highest standards of landscape design incorporating only our local plants and a slightly different order to what has traditionally been accepted here in South Africa and much of the world.

When it comes to maintenance the garden must still be well manicured just as the sterile traditional garden in particular at the entrance and near to the house but it will need to be a slightly different order, the beds will still need to be edged, the lawn mowed and the weeds removed, no one wants to be greeted by a mess. However the maintenance must not show a misguided sense of order it must not be carried out with sensitivity and not to the detriment of the life in the garden.

All the photos that I used in this article have been taken in my own garden at Mount Moreland north of Durban.

Michael Hickman

Landscape Design Specialist

www.ecoman.co.za

michael@ecoman.co.za

05.04.14

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Forest Toad Tree Tabernaemontana ventricosa an ideal tree for a small garden

Forest Toad Tree

Tabernaemontana ventricosa

Umkhahlu, Ukhamamasane (Zulu)

Belongs to the plant family Apocynaceae.

Natural Distribution and Habitat

Tabernaemontana ventricosa  has a disjunct distribution from Ghana, eastern Nigeria, western Cameroon, eastern Democratic Republic of the Congo, Kenya, Tanzania, Zambia, Mozambique, Zimbabwe and South Africa in the coastal areas of KwaZulu-Natal where it grows in riverine forests and the forest under storey.

Description 

This small to medium-sized tree can reach a maximum height of 15 m, but averages between 4 and 8 m. Tabernaemontana ventricosa can have one or more straight trunks with smooth greyish-brown bark. The tree is low branching with smooth, dark green young branches turning a pale brown when mature. The leaves are large oblong and shiny dark green in colour, the flowers are salver-shaped, white and sweet smelling. The unusual fruits have two pods joined at the base they are dark green and smooth, sometimes with wrinkles and light green speckles or markings they split open to reveal fleshy orange pulp with embedded seeds in June to August.

Use in the landscape

Tabernaemontana ventricosa with its small size, clean tidy growth habit, glossy dark green foliage, attractive sweet smelling white flowers and unusual fruits, is excellent for the landscape designer of gardener to plant in any garden or landscape design. For those wanting to plant it to bring nature back into their indigenous garden it is an excellent choice because apart from being an ideal landscape feature plant it also attracts birds, insects and small mammals into your garden.

Although Tabernaemontana ventricosa grows naturally mostly as an under story plant and prefers shade to partly shady conditions it will grow in the full sun in a garden if it is sheltered from the wind and it gets plenty of water, where it will flower much more profusely than if grown in shade.

Tabernaemontana ventricosa is frost sensitive, preferring more tropical areas with mild winters.

Tabernaemontana ventricosa will happily grow in wet places where many other plants may not grow.

Ecological importance

Birds, animals such as fruit bats and monkeys eat the fruit. The leaves are browsed by game in particular bushbuck, the sweet smelling flowers attract various insects.

Propagation and Growing

Tabernaemontana ventricosa can easily be grown from fresh seed and grows relatively fast under favorable conditions.

Tabernaemontana ventricosa seedlings grows best in humus rich well drained sandy soils.

Plant in a large hole and mix in a good amount of compost, well rotted manure, and a balanced fertiliser. Mulch well and water regularly, especially during the first year or two for optimum growth.

Cultural Uses 

The bark of this tree is said to be used for bringing down a fever, the latex is applied to wounds and sore eyes to promote healing and in KwaZulu-Natal the seeds, bark and roots are used to treat nervous complaints and high blood pressure.

The pulp of the ripe fruit is edible.

Michael Hickman

28 March 2014

Indigenous Landscape Design Specialist http://www.ecoman.co.za