Permaculture - 21 Pioneer Species
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Transcript of Permaculture - 21 Pioneer Species
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Pioneer Species - Re-establishing Woodland
We hear lots of reports about the destruction of the tropical rainforests, yet few people seem to realise
that huge areas of Britain were deprived of their tree cover many centuries ago. It seems difficult to
imagine when you travel in the countryside nowadays, but until humans arrived in Britain 97% of the
country used to be covered in forest!
Forest clearance began with the need for fuel coupled with the desire for grazing and arable land as
humans turned from hunter/gatherers to farmers. It gradually gathered pace as the human population
grew and the need for wood increased, firstly for construction, ship building etc. and later for fuelling
the industrial revolution.
With modern machinery it takes just a few minutes to chop down a tree that might have been growing
for several hundred years. Remove all the trees in an area and it can become very difficult for the trees
to re-establish themselves, especially if the land is exposed such as near the coast or at higher
elevations. Yet trees are the natural vegetation for almost all of this country and without them we will
lose much of our wildlife as well as causing environmental destruction in the form of soil erosion,
flooding etc.
In the winter of 1990 - 1991 we planted out almost 15,000 native trees on a very windswept site in
Cornwall. These trees in general have grown away satisfactorily, if rather slowly. By the end of 1996
they tended to average about 1.5 metres in height. However, there were huge differences between the
different species with some still less than 1 metre tall and, at the other end of the scale, others were
more than 5 metres tall.
Seeing these huge differences set me thinking about the way we were attempting to restore the tree
cover on this site. Talking it over with a visiting Australian who designs permaculture sites in Australia
and South America, I came to understand a little more about putting permaculture ideas into practice.
In conventional gardening there are certain species of plants just sitting there waiting to invade our
freshly turned soil. These plants are either aggressively self-sowing, or they have aggressive root
systems, or even worse they have both attributes. We call them weeds, but these are natures pioneers
and some of her strongest survivors. Many of these plants are annuals or herbaceous perennials, and
perhaps their seeds have been laying dormant in the soil for many years, buried too deep to be able to
germinate. Digging the soil will have bought some of these to the surface where the light will stimulate
germination. Others of these weeds will have very light seed that is carried by the wind and so can
travel quite large distances in their search for suitable conditions to grow in. These plants will soon
clothe the bare soil, protecting it from erosion and starting the process of regenerating it to its natural,
or climax, vegetation. If you leave almost any land alone for sufficient time in Britain you will end up
with a woodland growing there.
My Australian friend was taking advantage of this by deliberately introducing these pioneer species
into his designs. However, instead of using these annuals and perennials, he would short-circuit the
system by using those trees and shrubs that have the ability to invade land and act as pioneers. For
example, if he was taking over a barren site, he would immediately plant it out with fast-growing
leguminous trees. In his part of the world, these trees could grow 6 metres or more tall within 3 years
of sowing the seed! By planting them fairly densely (at about 5 metre spacing), by the end of the first
growing season he would have a mini woodland already 2 metres or more tall. Then, amongst these
legumes he would start to plant out those species he really wanted to grow on the site. These plants
would immediately start to benefit from the protection and the nitrogen that the legumes were
providing.
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By the end of the third year the new plantings would be established and growing away nicely. The site
would be getting rather crowded and so he would start to cut down some of the fast-growing legumes,
using the wood for fuel, construction or whatever and shredding everything that was left to be used as a
mulch.
This is a marvellous method of restoring land to tree cover, especially in the more difficult situations
where most woodland trees will struggle to survive, and it can also be used on a smaller scale toprovide nourishment and protection for herbaceous plants. There are many species suitable for this in
Britain, though don't expect the same rates of growth that can be achieved in warmer climates.
When deciding on which species to use as pioneers, it is important to take all the characteristics of your
land and the way you intend to use it into account, and also to understand the habits of the different
pioneer plants. Looking firstly at the habits of the plants, species such as the alders (Alnus species) and
sea buckthorns (Hippophae species) are very good companion plants that will enrich the soil around
them and improve the growth of neighbouring plants. Thus these species are ideal for using in the way
described above and can be planted in quite large quantities on the site. However, other species such as
the poplars (Populus species) and willows (Salix species) have very vigorous root systems that will
compete strongly with other plants. When using these as pioneers it is better to plant them in a more
compact way such as a hedge or shelterbelt - this will soon provide shelter on the land for your other
trees without creating competition problems. Other species, such as the sycamore (Acer
pseudoplatanus) are more neutral in their effect on other species and can be used in small quantitiesdotted around the site, thus ensuring plenty of diversity. When detailing the species to be used as
pioneers, they will be divided into these three sections.
The second important factor to take into account is the land and its intended use. For example, if you
have a very poor soil then you are going to want to concentrate on species that will improve the soil
condition - these will generally be those plants in the first section below. If you land is on a slope, and
erosion is a problem, then you will need to look for those species with vigorous root systems. If you are
close to the coast then you will probably need plants that can tolerate maritime exposure. If your land is
quite high up then you might need to be looking for those species that will tolerate cold, strong winds.
There are many other factors to take into account here, but space does not allow it in this leaflet. In the
end it is up to your own judgement of the site - try not to rush this judgement but give yourself time to
be with the land and come to understand its nature. If you feel that you do not have enough experience
to do this, then try to enlist the help of a more knowledgeable gardener in your area - preferablysomeone with an understanding of permaculture.
Detailed below are a few of the trees and shrubs that we have found to make good pioneer species. This
list is by no means exhaustive, but it does indicate the potential that exists.
Thesoilenrichers(Those species that can be used in quantity and interplanted
with your other trees.)
Alnus species. The alders are perhaps the best species that
can be used as pioneers - they really have everything going
for them. They are fast-growing even in severe exposure - we
have had some species reach 6 metres in height within 5
years of sowing the seed. They enrich the soil with nitrogen
and their heavy leaf-fall in the autumn greatly increases the
humus content of the soil. They are short-lived, and their
seedlings are unable to establish themselves in shady
conditions - thus they will never hang around to make a
nuisance of themselves once they have done their job. Any
members of the genus can be tried, most of which require a
moist to wet soil if they are to really thrive. Those species weespecially recommend are:-
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A. cordata. The italian alder tolerates drier soils than other members of the genus, it also holds on to its
leaves later into the autumn, thus giving extra protection from autumn gales.
A. glutinosa. Our native alder is not as fast growing as some other members of the genus, but it can
still reach 4 metres in height within 5 years. Being native, it has the added advantage of being more
useful for wildlife. The alder is also a superb source of dye materials, with brown, red, green, pink,
yellow and cinnamon hues being obtained.
A. rubra. The red alder grows amazingly quickly, even in extreme exposure. We have plants that have
reached 7 metres in height within 5 years.
Hippophae species. This is another genus that is very useful
for re-establishing woodland. The plants are, in general, fast-
growing though they may take a year or two to get going.
They enrich the soil with nitrogen and will succeed even in
extreme maritime exposure. In addition their fruit is
incredibly nutritious and has been shown to have a wide
range of medicinal applications, including in the prevention
and treatment of cancer. Many members of this genus suckervery freely and so are not suitable for small areas, though this
suckering habit means that the plants are ideal for stabilizing
sandy soils or steep slopes. This makes them ideal plants for
providing shelter near the coast and they are some of the most
wind-resistant species that we grow. For more information
see the Plant Portrait - Hippophae about the plant. We would
particularly recommend the following two species:-
H. rhamnoides. Our native sea buckthorn growswild by the coast. The fruit is very sharp, but is
exceedingly rich in vitamin C and makes an
excellent preserve.
H. salicifolia. The willow-leaved sea buckthorn isone of my most favourite plants. It is not hardy inthe colder areas of the country, but where the
climate suits it the plant will grow quickly and
provide very good yields of fruit. This fruit is not as
sharp as the native sea buckthorn, though it is still a
strong lemon flavour. It can also be picked from
middle August and will hang on the tree until early winter.
Lupinus arboreus. The tree lupin comes from California and
is only hardy in the milder areas of the country. In areas
where it is suited, it makes an excellent pioneer species for
the smaller garden. It grows about 1.5 metres tall, and will do
that in its first year from seed. Very tolerant of maritime
exposure, it will quickly create sheltered conditions to allow
less tolerant plants to become established, and will also feed
them with some of the nitrogen formed on its roots by
bacteria. The tree lupin will grow well on very poor sandy
soils and its root system will help to bind the soil together,
preventing erosion. The plant is quite short-lived - it flowers
so freely that it quite literally flowers itself to death.
However, it also self-sows freely if the seed is in a sunny
position, so it will maintain itself until such time as the other
plants are established and shade it out.
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Theneutralspecies(Those which can be interlanted in smaller quantities to add diversity.)
Acer pseudoplatanus. sycamore has gained a bad reputation
as an aggressive weed tree that can prevent native trees such
as oak from maintaining themselves. However, recent
research has shown that, in the longer term of 200 years or
more, sycamore is not really such a bad species and, indeed,
when we planted our native woodland the Forestry
Commission insisted that we put in 10% sycamore to help the
native species.
One real drawback with using this species as a pioneer is that
it does not know when to go away and will continue to sow
itself around long after the woodland has become established.
However, it is still a useful species to use in the right
situations, such as near the coast and does have a number ofother uses including the sap which can be used to make a
sweet drink and the leaves which impart a sweet flavour to
food if they are wrapped around the food when baking.
The wood is also of reasonable quality and so perhaps the
best way of using this species as a pioneer is to grow it for 10
years or so until the other trees are getting going, and then to
gradually remove it over the next few years and utilize the
wood.
Betula species. The birches are, in general, fast-growing trees
that often invade bare land. They will withstand considerablewind exposure, but do not tolerate the more heavily exposed
areas, becoming severely wind-pruned in such situations.
Like the alders, they have the benefit of not hanging around
too long once they have done what is asked of them, and they
do not regenerate well in the shady conditions of a woodland.
Unfortunately they do not have all the other benefits of the
alder, but they can be grown in considerably drier conditions
than the alder as well as tolerating areas with periodic
inundation. Another disadvantage of the birches is that their
thin branches are blown about in the wind and can act as
whips if they are within reach of other trees, this can cause
quite noticeable damage to these trees.
There are many species in this genus, and any of those thatreach tree-size can be tried as pioneer plants, but we would
especially recommend the native species,B. pendula, the
silver birch, andB. pubescens, the downy birch. Apart from
being superb trees for wildlife, these two very similar species
also have a very wide range of uses. These include the sap,
which can be taken off in the spring and used to make sweet
drinks, beer or vinegar. The bark is very weatherproof and
can be used to make drinking vessels, roofing tiles and so
forth. A tar-oil is obtained from the white bark in spring and
has fungicidal properties and is also used as an insect repellent and a shoe polish. The young branches
are very flexible and are used to make whisks, besoms etc. They are also used in thatching and to make
wattles. The leaves are a good addition to the compost heap, helping to improve fermentation. This list
is far from exhaustive, but does give an indication of the value of these species.
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Sambucus nigra. The elder is a wonderfully useful native
plant for almost any situation. Whilst it will look rather
battered, it will even grow in severe exposure and provide
enough shelter to help the woodland trees become
established. Unlike many other pioneer species, it will not
know when to say goodbye, but will hang around in small
numbers, especially along the edges of the woodland. This isa good thing, however, because it does have so many uses
both for us and the many other creatures that use it. Just a few
of its uses include the fruit which is edible, though few
people could enjoy it raw. However, it makes a superb
preserve and is widely used for making wine. The flowers
can also be used in wine-making or as a flavouring in cooked
fruits etc., though I prefer eating them raw. So long as you
make sure to remove all the insects that are likely to be
lurking in the flowers, they make a very refreshing munch on
a summers day.
There are so many non-food uses of this plant that it is hard
to know what not to include here. Therefore, because of lack
of space I am going to restrict myself to just one. If, like me,you are the sort of person who, when in a group of people are
always the first one to be bitten by midges or horseflies then
this is the plant for you. Simply rub the leaves over areas of bare skin and the biting beasties will leave
you alone for 2 hours or more - then simply top up the dose. You might find that you have a somewhat
unique aroma, but you will only get the very occasional bite from a midge that has lost its sense of
smell.
Sorbus species. Several members of this genus make
excellent pioneer species. They are in general very wind
resistant, though not totally happy in strong maritime
exposure when the winds often carry salt. They are also quite
tolerant of soil types, though do not like drought conditions
and will fare badly in dry soils. Those species we particularlyrecommend are:-
S. aria. Our native whitebeam can reach 12 metres in height
and is an excellent pioneer on chalk soils, though it is also
quite tolerant of other soil types. It is also very tolerant of
maritime exposure. The fruit can be eaten raw or cooked - it
makes a nice jam though most people would not want to eat
very many raw. However, it you blett it, which involves
storing the fruit in a cool dry place until it is almost but not
quite going rotten, then the fruit develops a delicious taste,
somewhat like a luscious tropical fruit.
S. aucuparia. Another native, the mountain ash grows to 15
metres tall and succeeds at higher elevations than any other
British tree and so is an excellent pioneer for upland areas.
The fruit is very acid and few people would be able to eat
more than one - though it makes an excellent jam. We use
this fruit mainly for another purpose - the birds love it and
will eat it in preference to apples, with which it ripens at the
same time, and so this is a very good plant to grow in or near
orchards.
S. decora. The American showy mountain ash grows to about 10 metres and does well on poor soils.
Its fruit is slightly better than S. aucuparia and we occasionally eat it raw.
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Thegreedyspecies(Those which have aggressive tendencies and are best used in more compact areas such as hedges.)
Populus species. Many species of poplar are fast growing
and make good pioneers, though most members of the genus
will not thrive in very windy sites and all of them are quiteaggressively rooting and so do not help to feed the soil or
other plants growing in it. They are also rather large trees and
many of the species will sucker freely, so they are not
suitable for smaller gardens. You need to be careful when
planting poplars near buildings, especially in clay soils,
because their root systems can dry the soil and cause
subsidence. Poplars usually require a rich soil if they are to
thrive and will not do well in drier conditions. Those species
we recommend include:-
P. alba. The white poplar will succeed in drier and poorer
soils than most members of the genus, and is also quite
tolerant of maritime exposure, though it dislikes strong coldwinds.
P. balsamifera. The balsam poplar scents the air for quite a
distance in the spring as its aromatic buds expand. These
buds are often used medicinally, their aromatic oils being
especially useful in the treatment of chest complaints. In
sheltered conditions, try the hybrid 'TT32' which can grow 3 metres or more in a year!
P. tremula. The aspen is a native species which will grow in poorer soils than most poplars and is also
quite wind tolerant. It will do very well in cold wet soils and, if you get the sub-species P. tremula
davidiana it will also succeed in very alkaline conditions. It does sucker freely, however, and so can
become a bit of a nuisance.
Rubus fruticosus. Our native blackberry is a species that
very often invades cultivated land, and will soon gain a
strong hold if left alone for a few years. It usually arrives first
as a seed in the droppings of birds or other creatures and then
rapidly spreads by forming new roots wherever the tips of the
shoots touch the ground. Almost before you know it, there
will be dense, impenetrable thickets that spread 2 metres or
more in every direction each year. As long as the trees you
want to grow there are fairly vigorous, and are allowed to get
their heads above the blackberries, then they will normally
thrive.
Whilst I would not normally recommend this species if you
are trying to create an edible woodland garden, it can be very
useful when establishing a native woodland. The dense
growth and prickly stems will protect the trees from the
predations of deer and rabbits and, eventually, the maturing
trees of the woodland will cast lots of shade on the
blackberries which, together with root competition, will
greatly reduce the vigour of the blackberries and even
eliminate them in places.
Most people know that blackberry fruits are edible, amongst
the plants other uses you can eat the young shoots in spring
and can also make quite a nice tea from the dried leaves. Afibre obtained from the stems has been used to make twine.
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Salix species. There are many species of willow that can be
used as pioneer plants - apart from the first one listed below
we will only mention the native species here. If you do not
live in Britain then you would be advised to look at your own
native members of this genus in preference to those listedhere. Willows are, in general, fast growing trees or shrubs
and several species are very tolerant of extreme exposure.
They do require a rich soil, though, and will not be very
happy unless there is plenty of moisture. Like many other
pioneer plants, their seeds are very light and can be carried
for considerable distances so they will often find their way to
bare sites. They are also quite short-lived, and will not
regenerate well once there is shade caused by the developing
woodland. Their main drawback is their extensive root
system. Whilst this can be an advantage on slopes where the
roots will hold the soil together and prevent erosion, there
will also be considerable competition with other plants for
nutrients.
All the willows mentioned here have similar uses - that is
their stems are very pliable and can be used for making
baskets etc. Also, the inner bark contains substances from
which the pain-killer aspirin is made. Instead of buying in
this drug, you can simply make a tea of the bark - but check
with a good herbal book, or a herbalist, before doing this to
ensure you get the dosage right.
One of the main advantages of using the willows is their cheapness. They are very easy to propagate by
cuttings - you simply stick a bit of stem in the soil and it will root and grow away like no-ones
business. Thus you only need to buy a few plants and then take cuttings every winter in order to
increase your stock. The species we would most recommend include:-
S. 'Bowles hybrid'. This plant is a male cultivar, and so will never be able to regenerate unlessyou take cuttings. It grows incredibly quickly to its maximum height of 5 metres, and even in
the strongest maritime exposure and will be providing good shelter in its third year.
S. alba. The white willow will grow quite rapidly and can eventually reach 20 metres or morein height.
S. aurita. The eared sallow is a very tough creature that is often the first woody plant toinvade wetter land and is also useful in reclaiming poor soils. It will only grow up to 3 metres
tall, but is exceedingly useful, especially when encouraging natural regeneration of native
woodland. Unlike the other willows mentioned here, the stems are of little use for basket
making. S. caprea, the goat willow growing up to 10 metres tall, and S. cinerea, the common
sallow growing up to 5 metres tall, are very similar species with the same uses.
S. pentandra. The bay willow will grow up to 10 metres tall. S. purpurea. The purple willow will reach about 5 metres tall and is a very good basket
willow.
S. viminalis. The common osier will reach 6 metres in height and can provide an abundanceof basket-making material.
You can also see the Woodland Garden Plants leaflet for ideas of things to plant to once you get your
woodland going.
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DatabaseThe database has more details on these plants: Acer pseudoplatanus, Alnus cordata, Alnus glutinosa,
Alnus rubra, Betula pendula, Betula pubescens, Hippophae rhamnoides, Hippophae salicifolia, Lupinus
arboreus, Populus alba, Populus balsamifera, Populus tremula, Rubus fruticosus, Sambucus nigra, Salix'Bowles hybrid', Salix alba, Salix aurita, Salix pentandra, Salix purpurea, Salix viminalis, Sorbus aria,
Sorbus aucuparia, Sorbus decora.
PlantsForAFuture2011http://www.pfaf.org