How we plant trees at
Westonbirt Arboretum
A picture story
At Westonbirt, Penny our propagator prepares around 300 trees a year
for the tree team to plant. They get the best planting treatment possible
to give them the greatest chance of success.
Penny and Mark decide where the trees will be planted, taking into
account soils, light, colours, sizes, ages of trees surrounding,
susceptibility of disease and of course the picturesque style of the
arboretum. They do this all throughout the year, making notes and
coming up with ideas. They look at the list of 300 or so trees they have
to plant that year and think of where they should go.
Penny and Mark then put in a post where the tree will be planted.
All the equipment (and trees) are gathered together
ready for planting.
The tree team find the site, match the tree and double check the site is ok
They check that there will be enough space for a mower to get round and
whether they need to do any other work to make the site suitable.
They use triangulation to plot the location of the tree. This is so that it
can be mapped on the tree database. The first step is to measure a
straight line from two nearby trees whose location is already known
(any ones with a black label).
The next step in triangulation is to measure the distance
from the tree to the line at right angles.
These numbers are recorded on the sheet to triangulate the tree’s
location.
Once the tree has been plotted the planting can begin. If grass is
growing there then the turf is removed to stop the grass
competing with the growing the sapling.
A circular area is dug over. This circle is about a spades length (from
handle to blade) in radius. This is to provide the roots with lots of dug
over ground to expand into.
A smaller hole is then dug at the centre of this circle for the tree to be
placed into, and the tree is taken out of it’s airpot.
The airpot has helped the tree develop lots of lateral roots which
increases its chances of survival.
The root ball is gently rubbed to get rid of the formation that the airport
left behind.
The tree is then placed in the hole and checked to see that it is level
with or slightly above the level of the ground. If it is below the level of
the ground it could suffer from water logging.
When the tree is in place it is firmed into the ground
using hands and toes.
The tree is given a “wobble” to make sure it is secure
and that the root ball doesn’t wobble underground
(which would indicate unwanted air pockets).
Now the tree is ready to have a cage put around it. The size of the cage
is decided according to the spread and height of the tree.
The tree cage has five stakes supporting it.
They are pushed into the ground with a post-banger.
The netting comes on a roll and is rolled out around the stakes.
It is around 1.2m tall and protects the tree from rabbits and deer
browsing and bark ringing.
It is cut to the right length with secateurs.
It is attached to itself with a “pig ringer”.
This creates little loops of wire that connects the netting together.
It is not stapled to the posts – this way it can be lifted up off the stakes
for weeding and pruning to be done.
The tops of the stakes are sawn off to make them flush with the netting.
Bark chip is added to mulch the tree. It will keep weeds suppressed
and help save moisture in the summer.
The mulch goes on the outside of the netting a little way too.
That helps keep weeds down so that the mower
doesn’t have to mow too close to the cage.
A temporary tag is put on the tree so that it can be identified by staff /
volunteers putting out black tree labels.
The date the tree was planted is written down for our records.
The finished job. Hopefully this tree will survive well in the future.
It will be put on a list of “unestablished trees” to be checked each year
for around five years until it is thought to have fully established itself
into the arboretum!