In theory it is possible to plant large trees up to the size of fully grown, mature trees but in practice there are many restraints on what can be done. Nurseries in Britain and Europe grow enormous trees, up to 9m (30ft) high and with trunks 60cm (2ft) in circumference. In addition it is sometimes possible to move fairly mature trees using tree spades but often the trees will need preparing well in advance of the move. Moving any of these into a garden and planting them is a skilled and exceptional activity.
Access to most gardens is a problem. Heavy equipment is needed to move and plant mature trees and to remove the spoil which large rootballs produce. In addition the ground must be free of underground services and the water table must be suitable for the particular variety of tree. As the tree would have a large canopy vulnerable to movement by strong winds it would need specialist guying either by cables or by ground anchors.
The price of planting a mature tree is, of course, likely to be large both because of the long period of care needed to raise it and because of the expense of moving and planting it. In addition skilled aftercare is needed to ensure that the signs of distress in a tree are noticed before a situation becomes critical and the tree dies. Despite that it is a fairly cheap and straightforward job to plant trees up to around 4-6metres (13-20ft) high which are grown in large containers. These are grown in very large numbers by nurseries and can often be moved and planted by a couple of strong and skilled people. Of course they will also need proper aftercare to maximise their chances of survival.
Showing posts with label tree planting. Show all posts
Showing posts with label tree planting. Show all posts
Thursday, 17 September 2009
Wednesday, 22 October 2008
PLANTING A WINDBREAK
There are many situations where creating a garden is made very difficult by strong winds. These in themselves can make it hard to establish more sensitive plants but if the winds carry salt from sea water or are particularly cold the challenge is even greater. Planting a windbreak can dramatically reduce the winds suffered by both our plants and ourselves.
The first thing to remember in establishing a windbreak is that it is better to filter the wind rather than create a solid barrier. A wall or a building might at first seem like the best way to protect an area, but solid barriers create eddies and turbulence around them which may be worse for plants and for you. We are all familiar with the strength of winds between city buildings. In a similar way walls which create immediate barriers to wind also produce strong eddies and swirls of wind around them. Plants tend to filter the wind rather than deflect them so that the strength of the wind is reduced rather than simply moved to another place. They are also less expensive and generally more attractive than walls, generally improve with time and may need less maintenance.
In planting a windbreak you will need to start with a good idea of the predominant wind in your neighborhood. For most places there is a direction from which the majority of winds arrive. For instance most of the UK is subject to predominant winds from the south west although damaging cold winds can also come from other directions. For a garden located on a cliff or headland there may be frequent strong winds from more than one direction. Whichever you suffer from you will need to know about them in advance so that the trees you plant will be in the right place. It may take years to establish the windbreak so it is definitely worth getting this right the first time.
The general principle when planting a windbreak is to establish a row of large trees with dense smaller trees and shrubs either side of it on the windward and leeward sides. These smaller trees and shrubs greatly add to the overall filtering effect. As a general rule the effectiveness of an established windbreak usually stretches on the leeward side of the break for a distance which is around 5-10 times the height of the trees, but there may be some effect up to around 25 times the height. So if your trees are 30ft high the windbreak may be effective for more than 2-300 ft.
To choose plants which will do the job in your difficult situation the first thing to do is to look at the trees and shrubs which are already thriving in your neighbourhood. You may find that there is Sycamore and this is one of the few situations in which the planting of these tough trees can be easily justified in the UK. Generally they are considered a "weed tree" as they are very invasive and support little wildlife compared with native species.They are however a traditional windbreak for hill farms and exposed settlements and can provide the same function for a garden. They will of course lose their leaves in the winter and so a large evergreen tree species should be added to the windbreak. Austrian Pines, Pinus nigra, are excellent in this situation as they are resistant to strong winds and salt and do not need good soils. For an understorey of smaller trees and shrubs you would again be well advised to find out what thrives already in your neighbourhood. Near to the sea likely evergreen candidates will be Griselinia, Arbutus, Holly, Hebes, Eucalyptus gunnii, Olearia, Berberis darwinii, Phormium and Cordyline. Many of these will not thrive in cold and exposed sites. Evergreen shrubs for colder areas might be Eleagnus, Euonymus,Mahonia, Myrica, Rhododendron, and Viburnum. Deciduous trees for both situations may include Rowans and Whitebeams, Birches , Ashes , Beeches, Alders, and Willows. Shrubs could include Fuchsia riccartonii, Rosa rugosa and Gorse.
Of course planting and establishing trees in exposed conditions is also a problem. Our natural instinct is to stake them high and tie them three or four feet above ground level. However there is a problem with this. We should think of the trunks of trees in some respects as being like the muscles of an animal's body. The more they flex and are challenged the stronger they become. Therefore if we stake a tree high and then, after several years, untie it from the stake we will often find that it has not built up sufficient strength to stand alone. Our aim should be to stake it low so that it can still flex but the rootball can't move and loosen the roots. It is sufficient here to say that the tree should either have a low stake at an angle to the tree trunk, have two low stakes joined by a crossbar or should be secured by ground anchoring. Whichever system is used the stake should not go through the rootball, the above ground ties should be loosened a little each year and the tree roots should not be allowed to dry out for a year or two at least. Ground anchoring is a specialized way of securing a tree by tieing its rootball in a non-damaging way below ground. If done correctly the rootball won't move and nothing except the tree is visible above ground. It is an ideal way of planting a tree but requires rather more skill and expense than the conventional ways using stakes.
A good windbreak will take some years to establish but within it a surprising range of delicate and sensitive plants can often survive and, in addition, we humans usually feel a good deal more comfortable as well.
The first thing to remember in establishing a windbreak is that it is better to filter the wind rather than create a solid barrier. A wall or a building might at first seem like the best way to protect an area, but solid barriers create eddies and turbulence around them which may be worse for plants and for you. We are all familiar with the strength of winds between city buildings. In a similar way walls which create immediate barriers to wind also produce strong eddies and swirls of wind around them. Plants tend to filter the wind rather than deflect them so that the strength of the wind is reduced rather than simply moved to another place. They are also less expensive and generally more attractive than walls, generally improve with time and may need less maintenance.
In planting a windbreak you will need to start with a good idea of the predominant wind in your neighborhood. For most places there is a direction from which the majority of winds arrive. For instance most of the UK is subject to predominant winds from the south west although damaging cold winds can also come from other directions. For a garden located on a cliff or headland there may be frequent strong winds from more than one direction. Whichever you suffer from you will need to know about them in advance so that the trees you plant will be in the right place. It may take years to establish the windbreak so it is definitely worth getting this right the first time.
The general principle when planting a windbreak is to establish a row of large trees with dense smaller trees and shrubs either side of it on the windward and leeward sides. These smaller trees and shrubs greatly add to the overall filtering effect. As a general rule the effectiveness of an established windbreak usually stretches on the leeward side of the break for a distance which is around 5-10 times the height of the trees, but there may be some effect up to around 25 times the height. So if your trees are 30ft high the windbreak may be effective for more than 2-300 ft.
To choose plants which will do the job in your difficult situation the first thing to do is to look at the trees and shrubs which are already thriving in your neighbourhood. You may find that there is Sycamore and this is one of the few situations in which the planting of these tough trees can be easily justified in the UK. Generally they are considered a "weed tree" as they are very invasive and support little wildlife compared with native species.They are however a traditional windbreak for hill farms and exposed settlements and can provide the same function for a garden. They will of course lose their leaves in the winter and so a large evergreen tree species should be added to the windbreak. Austrian Pines, Pinus nigra, are excellent in this situation as they are resistant to strong winds and salt and do not need good soils. For an understorey of smaller trees and shrubs you would again be well advised to find out what thrives already in your neighbourhood. Near to the sea likely evergreen candidates will be Griselinia, Arbutus, Holly, Hebes, Eucalyptus gunnii, Olearia, Berberis darwinii, Phormium and Cordyline. Many of these will not thrive in cold and exposed sites. Evergreen shrubs for colder areas might be Eleagnus, Euonymus,Mahonia, Myrica, Rhododendron, and Viburnum. Deciduous trees for both situations may include Rowans and Whitebeams, Birches , Ashes , Beeches, Alders, and Willows. Shrubs could include Fuchsia riccartonii, Rosa rugosa and Gorse.
Of course planting and establishing trees in exposed conditions is also a problem. Our natural instinct is to stake them high and tie them three or four feet above ground level. However there is a problem with this. We should think of the trunks of trees in some respects as being like the muscles of an animal's body. The more they flex and are challenged the stronger they become. Therefore if we stake a tree high and then, after several years, untie it from the stake we will often find that it has not built up sufficient strength to stand alone. Our aim should be to stake it low so that it can still flex but the rootball can't move and loosen the roots. It is sufficient here to say that the tree should either have a low stake at an angle to the tree trunk, have two low stakes joined by a crossbar or should be secured by ground anchoring. Whichever system is used the stake should not go through the rootball, the above ground ties should be loosened a little each year and the tree roots should not be allowed to dry out for a year or two at least. Ground anchoring is a specialized way of securing a tree by tieing its rootball in a non-damaging way below ground. If done correctly the rootball won't move and nothing except the tree is visible above ground. It is an ideal way of planting a tree but requires rather more skill and expense than the conventional ways using stakes.
A good windbreak will take some years to establish but within it a surprising range of delicate and sensitive plants can often survive and, in addition, we humans usually feel a good deal more comfortable as well.
PLANTING A TREE
The principles of tree planting are similar whatever the size of tree. The idea is to try to disturb the tree as little as possible, place it in an appropriate hole and in a situation to which it is suited. An acid loving tree should not be planted in chalky soil, nor a sensitive tree in an exposed location. Some trees need good drainage or are less tolerant of frost or sea spray. Aftercare and staking are then designed to help it settle in. Larger trees of course will need more expert handling and those in pots over about 70litres in size may need moving and planting using machinery.
To prepare for planting, a hole a little larger than the pot needs to be prepared. In heavy clay this would need to be broken up around the edges and bottom to prevent it from turning into a sump filled with water which would suffocate the tree roots. In other soils this is not necessary. Neither is it necessary to feed the tree at planting or provide rich compost as it is useful to encourage the tree's roots to search for nutrients by growing into the surrounding soil. The tree should be planted so that the ground level is close to the level of the surface of the compost in the pot.
STAKING. Most trees will need some staking to prevent the wind from rocking the tree loose. It's necessary to take into account both the size of the tree and how exposed it will be to strong winds. Tree sizes are usually measured by their girth (which is their circumference in cms at 1m above the ground) if they have a single stem or by their height and pot size. For most trees up to around 16cm girth in a normal garden situation staking is by using a single stake driven in at around 45degrees and facing into the predominant wind which is often from the south west in the United Kingdom. The stake must be driven firmly into the ground avoiding the rootball as far as possible. It will usually cross the stem of the tree about 60cm above the ground. A well cushioned adjustable tree tie is attached and it should be loosened as the tree grows. Generally it can be removed after 2 or 3 years. For larger trees double staking is used (and occasionally guying and ground anchoring for larger trees or difficult situations) which consists of using two tall vertical stakes.These would be either side of the stem and outside the tree's rootball. The stakes are joined by a cross-piece which is attached to the tree by a cushion and tree tie. For very flexible young trees it may be necessary to use a taller single stake which can be reduced in height as the tree establishes. The general principle is that trees get stronger by flexing and adapting to adverse circumstances just as the muscles of an animal do. Over-staking therefore tends to produce weaker trees in the long run.
AFTERCARE It is surprising the extent to which weeds and grasses can compete with tree roots for nutrients and water. For trees planted into lawns or meadows therefore it is important to leave a clear circle about 1m in diameter until the tree is well established.. Mulching with a mulch mat or with about 50mm of bark can help both to keep weeds down and to maintain moisture levels in the soil. It is of course essential not to let the rootball dry out for at least the first year (see below). Pruning of laterals (small side branches coming from the main stems) and of dead or diseased branches can be carried out at planting.
WATERING. It is always important to remember that a large percentage of the losses in the first year or two are caused by allowing the roots of the tree to dry out. Periods of drought are especially dangerous. However watering little and often can encourage the roots of the tree to stay near the surface instead of spreading to seek new sources of water. The spreading of the roots will also, of course, stabilize the tree long after the stakes have been removed. For these reasons it is sometimes better to water trees through tubes sunk at the time of planting which provide water to the roots a foot or two below the surface. Failing this, surface watering systems such as leaky hoses can be useful especially when combined with mulches (although there are also trees, even species such as yew native to our better drained soils, which do not thrive if the soil is damp and mulched around their roots).
To prepare for planting, a hole a little larger than the pot needs to be prepared. In heavy clay this would need to be broken up around the edges and bottom to prevent it from turning into a sump filled with water which would suffocate the tree roots. In other soils this is not necessary. Neither is it necessary to feed the tree at planting or provide rich compost as it is useful to encourage the tree's roots to search for nutrients by growing into the surrounding soil. The tree should be planted so that the ground level is close to the level of the surface of the compost in the pot.
STAKING. Most trees will need some staking to prevent the wind from rocking the tree loose. It's necessary to take into account both the size of the tree and how exposed it will be to strong winds. Tree sizes are usually measured by their girth (which is their circumference in cms at 1m above the ground) if they have a single stem or by their height and pot size. For most trees up to around 16cm girth in a normal garden situation staking is by using a single stake driven in at around 45degrees and facing into the predominant wind which is often from the south west in the United Kingdom. The stake must be driven firmly into the ground avoiding the rootball as far as possible. It will usually cross the stem of the tree about 60cm above the ground. A well cushioned adjustable tree tie is attached and it should be loosened as the tree grows. Generally it can be removed after 2 or 3 years. For larger trees double staking is used (and occasionally guying and ground anchoring for larger trees or difficult situations) which consists of using two tall vertical stakes.These would be either side of the stem and outside the tree's rootball. The stakes are joined by a cross-piece which is attached to the tree by a cushion and tree tie. For very flexible young trees it may be necessary to use a taller single stake which can be reduced in height as the tree establishes. The general principle is that trees get stronger by flexing and adapting to adverse circumstances just as the muscles of an animal do. Over-staking therefore tends to produce weaker trees in the long run.
AFTERCARE It is surprising the extent to which weeds and grasses can compete with tree roots for nutrients and water. For trees planted into lawns or meadows therefore it is important to leave a clear circle about 1m in diameter until the tree is well established.. Mulching with a mulch mat or with about 50mm of bark can help both to keep weeds down and to maintain moisture levels in the soil. It is of course essential not to let the rootball dry out for at least the first year (see below). Pruning of laterals (small side branches coming from the main stems) and of dead or diseased branches can be carried out at planting.
WATERING. It is always important to remember that a large percentage of the losses in the first year or two are caused by allowing the roots of the tree to dry out. Periods of drought are especially dangerous. However watering little and often can encourage the roots of the tree to stay near the surface instead of spreading to seek new sources of water. The spreading of the roots will also, of course, stabilize the tree long after the stakes have been removed. For these reasons it is sometimes better to water trees through tubes sunk at the time of planting which provide water to the roots a foot or two below the surface. Failing this, surface watering systems such as leaky hoses can be useful especially when combined with mulches (although there are also trees, even species such as yew native to our better drained soils, which do not thrive if the soil is damp and mulched around their roots).
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