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

Permaculture - 21 Pioneer Species

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