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... and every tree planted by hand !
Forestry Facts
South Africa has a plantation area of more than 1.5 million hectares, representing only 1.2% of
the land area. This percentage compares poorly to the 30% of the USA and the 67% of
Japan. One of the largest afforested areas in South Africa (an area of 0.6 million hectares) is
in the Mpumalanga province.
The Forestry Industry contribute 8.7% of the gross value of the country's agricultural output.
The plantation forests of South Africa uses just 3% of the country's total water resource.
Irrigation, which is the norm in the growing of many agricultural crops, is never utilised in forest
plantation management. The rainfall, therefore, need to be higher than 750 mm per annum to
sustain commercial forestry.
The Main Tree Species
Pines
(Softwoods) |
Tree,
Cone
and Needle |
Identification
Characteristics |
Pinus patula
(Jelecote Pine)
Indigenous to Mexico |
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Long (25 cm), light
green, drooping needles. Cones are pear-shaped and
the bark is orange-coloured.
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Pinus elliottii
(Slash Pine)
Indigenous to USA |
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Needles and bark darker than
that of Pinus patula and the needles do
not droop. Cone not as spiny as that of Pinus taeda.
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Pinus taeda
(Loblolly Pine)
Indigenous to USA |
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Needles and bark darker than
that of Pinus patula and the needles do
not droop. Cone is spiny, compared to Pinus elliottii.
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Timber
Usage:
Timber from thinnings are used for the manufacturing of pulp, boxes and crates.
Logs from mature (20-30 year old) trees are used for building and construction
timber.
High quality logs are used for veneer and furniture. |
Webmaster's
Note:
Foresters can tell these
three pine species apart with little more than a sideways
glance. But for the non-forester wishing to identify them,
follow this simple field test:
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If the needles droop, it is Pinus patula.
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If the needles don't droop, pick up a cone. Hold it in the palm
of your hand and squeeze it hard. If it hurts, it is Pinus
taeda - if not, it is Pinus elliottii.
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Eucalypts
(Hardwoods) |
Eucalyptus grandis
(Gum, blue-gum, grandis)
This fast growing tree is indigenous to Australia and is the
most common (almost exclusively) planted eucalypt tree in the
Sabie area. The
harvested tree stump will coppice (re-sprout) to form second
and more crops (rotations).
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Timer Usage:
Trees are generally harvested at 7
to 10 years and the timber is mainly used for pulp, mining timber and for telephone and
transmission poles. Timber from older trees (12 to 30 years) is used to produce fine furniture,
as can be seen in most South African schools.
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The Life Cycle of a Pine Tree
Pine cones are gathered from seed orchards where the parent trees have been specially selected for
their growth qualities and desirable timber characteristics. The seeds are extracted, treated
and sown into rigid plastic tubes. The seedlings are then grown in the tree nurseries until
planted out in the plantation.
Planting is done by hand at an espacement of 2.7m x 2.7m to yield an initial stocking of 1 370
trees per hectare. No fertilisers are used, but particular care is taken to match the tree
species with the soil type and environmental factors.
The trees are thinned out progressively, at about 5 year intervals, to allow the better formed and
more vigorous trees to develop faster. The lower branches are also pruned to produce knot free
timber.
When a final density of approximately 300 trees per hectare is reached the plantations are allowed to
grow undisturbed until ready for clear felling at 25 to 30 years. During the rotation age of up
to 30 years the trees are protected against forest fires, weed competition, forest pests and tree
diseases.
Sawlogs from the clear felled plantations are transported to sawmills by road where they are sawn
into boards, kiln-dried and graded to SABS (South African Bureau of Standards) specifications.
The sawmill recovery rate is less than 50% (i.e. less than half of the log intake is converted into
lumber - the rest ends up as sawdust, pulp chips or is burned as fuel to produce steam for the drying
kilns). A number of sawmills (including the largest sawmill on the African continent) are
located around Sabie.
Timber from early thinnings, as well as the thinner sections and toppings from clear-fellings are
collected for the pulp mill at Ngodwana for conversion to pulp and then to paper.
Pulp from
pine trees is generally processed into newsprint, or mixed with pulp from Eucalypt trees to produce
high quality paper.
Forest Fires
Forest owners spend an enormous amount of time and money in protecting timber plantations from
fire. Open strips of land, which separate blocks of trees, are constantly cleared of all
combustible material in order to create what is termed a fire-belt. Before each winter the air
around Sabie is occasionally hazy and smoke-filled as foresters prepare and burn fire-belts.
Fires are caused either accidentally, through carelessness, or through natural causes such as
lightning. Whatever the cause, fires can devastate forests, destroy the wildlife and ecology of
entire plantations and expose the ground to erosion.
On the high peaks overlooking the plantations are numerous fire lookouts. Some of these lookouts
are manned 24 hours a day and others are equipped with sophisticated, remote-controlled video cameras
that relay pictures to a central command centre.
Helicopters, water bomber planes and spotter aircrafts are also used whilst firefighting teams often
endanger their lives to combat forest fires.
War on Weeds
Weeds in plantations smother tree seedlings and reduce timber volumes, obstruct workers tending trees
and make harvesting difficult. In unplanted areas weeds interfere with the natural ecological
processes by smothering indigenous plants, changing the habitat for animals and birds, increasing the
fuel load for wild fires and altering the pattern of rainfall run-off and stream flow.
In the Sabie area the five main plantation weed species are;
- Bugweed (Solanum mauritianum)
An invasive alien shrub or small tree from Central America. This is a declared weed.
American bramble (Rubus cuneifolius)
This rambling, thorny scrub smother young trees and severely hamper access to plantations.
Lantana (Lantana camara)
An invasive alien shrub or climber from Central America. This is a declared weed.
Setaria grass (Setaria megaphylla)
Tuffs of Setaria grass grow up to 2 meters tall. This aggressive alien grass compete
with young trees for moisture and nutrients and increase the fire risk during the dry winter
months.
Black Wattle (Acacia mearnsii)
A useful Australian species in other parts of the country, but these trees are not grown
commercially in the Sabie area.
A large percentage of any forester's budget is devoted to weed control, using mechanical, chemical
and biological control methods. The Department of Water Affairs and Forestry have a very
successful "Working for Water" project with the aim to increase streamflow by reducing
weeds in water cathment areas, whilst at the same time creating much needed employment opportunities.
Forests and People
The plantation forests around Sabie have transformed previous grasslands and in so doing have created
an entirely new environment. On the one hand, this new environment is managed as a commercial
entity in which the highly technical business of timber growing, harvesting and processing takes place
as an essential ingredient in the supply of timber products to markets across the country. On
the other hand, these plantations areas are there to be enjoyed by the many visitors who seek to
escape to the tranquility of the country.
Forest owners have developed hiking trails and 4x4 routes through some of the most remote and dramatic
countryside that the escarpment can provide, for the enjoyment of the public. Elsewhere, scenic
points have been opened up and facilities provided for both tourists and for many artists and crafts
people who rely on roadside stalls to sell their work.
The progressive opening of forests to sport enthusiasts and tourists should be accompanied by a real
awareness of the ecosystems which make up the forest plantations. Mountain bikers, hikers,
motor ralyists, fishermen, birders, botanists, photographers and many others who enjoy our forest
environment should seek to preserve this valuable
asset for all.
Webmaster's
Note:
Timber companies are often fiercely criticized for ravaging
our indigenous grasslands with evergreen exotic trees that
consume more than their fair share of our valuable water
resources.
I have often wondered what the escarpment must have looked like a mere 100
years ago. I can imagine that the rolling grasslands must have looked
magnificent - perfectly in tune with mother nature.
But as I go about my daily routine of reading my newspaper, buying my
breakfast cereal in a cardboard box, filling my printer's paper tray
and tending to my personal sanitation and hygiene, I can not imagine being without
paper.
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The Role of the Forester
The science of growing and tending trees as a branch of forestry is called silviculture, a word which
describes the progressive elements of plantation management from planting through all stages of growth
to final harvest. This is the work of the the forester whose training equips him or her for
every aspect of forest management and control. Forestry is a highly technical profession where
timber yields are measured against numerous factors during the life cycle of a tree and it is the
responsibility of the forester to ensure that these returns are achieved.
The forester must be aware of forest pests (entomology) and tree diseases (tree pathology) which
he/she must control as far as is possible. He/she must manage the extraction of plantation
timbers by contractors and ensure that environmental damage is minimised and that the land is restored
for future plantings.
The forester must interact with authorities, tourism organisations and adjoining land owners to
establish the best possible protective policy for the plantations under his/her control. He/she
will also be aware of rare indigenous plant species growing in his/her area, such as cycads and tree
ferns which must be protected from trespassers and illegal plant dealers. The protection of bird
and game species is also an important part of a forester's work.
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Walks & Hikes
Forestry
