Tree Guards | Agroforestry

Bambra Tree Sleeves
Protection from wallabies and sheep

Developed by Rowan Reid

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Tree guards need to match the purpose: I like to graze sheep between our young trees to reduce the fire threat and control weeds. We also have problems with wallabies. The guards need to be cost effective and easy to assemble. There was nothing on the market that met my needs so I then set about designing a better option.

My guard uses a 1.2m length of light plastic tube (cut from a roll) which is fed over a 2m long post and fixed with 3 cable ties.

The stake has to be flexible so it returns to the upright position when battered by wind or stock. This encourages greater stem diameter growth compared to a solid post. A flexible guard is also of less value as a rubbing post for sheep. I have tried a number of options and originally settled on and 2m length of 20mm electrical conduit cut from 4m lengths. These are flexible and durable enough to be used a number of times.

But, in a dry season it is hard to thump the conduit into the ground. I have now found a better post. It is a 2m long 8mm diameter fibreglass rod with coating to prevent it degrading over time. The fibreglass is easier to bang into the ground than the conduit and, being thinner, allows more room for the tree in the tube.

Setting up the guard

These photos show the process. The seedling is planted first. Then I use a metal pipe to thump the fibreglass post into the ground about 5cm away from the tree. Then I slide the tubing over the post and fix with 3 cable ties. If the seedling is very small (as in this case) I use a short stick or piece of conduit to hold the tube in place and protect the seedling. Before fixing the tubing be sure that the post DOES NOT rest in the crease. If it does the tubing will close flat and can prevent hot air rising up the tube. By fixing it between the creases the tube is held open.

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The highly palatable River Sheoak growing well in the flexible tree sleeve.

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I leave the guard on until the tree is large enough to stand up for itself. Then I remove the post but leave the plastic tubing on for another year or so to protect the bark from stock. Before the trunk fills the tube I cut the plastic off.

This system seems to work for a range of tree species including both natives and exotics. Fungal disease and aphids are occasional problems and it is important to regularly inspect the trees for broken poles or torn plastic. The guards are less effective on very windy sites and pushing the post into the ground is difficult if it is very dry or rocky. The guards do allow easy follow-up weed control which is important for the slower growing species.

20mm electrical conduit and cable ties can be purchased from Hardware stores or electical supplies. Use the black cable ties (UV stabalised).

I now sell the fibreglass posts ($2.25 each) and 270m long rolls of the plastic tube ($135) plus postage. Thats 60c/1.2m tall tree guard. I can cut off shorter lengths if required. GO TO SHOP

 

Things to watch when setting up the guard:

* I use a homemade 'thumper'. For the 20mm conduit you'll need 2inch gal pipe (about 1m long) with a threaded cap - start slow and guide the conduit in with your foot taking care it is straight. For the 8mm fibreglass post I have a 20mm gal pipe with a cap.

* Rotate the tubing so the post DOES NOT rest in the crease. If it does the tubing will close flat. By fixing it between the creases the tube is held open

* Use a screwdriver to punch holes through the plastic tubing so you can put cable ties at the bottom, middle and top.

* Pull the cable ties very tight being sure there is a small gap at the bottom (say 20mm) to allow air to enter the tube

* If planting small seedlings use a short stick pushed into the ground opposite the post to stop the tubing moving over the seedling

* Check regularly: ensure the tubing is not blocked with grass/leaves, replace if the post is broken, etc.

 

Tree sleeves are not the solution for everyone - they are expensive, labour demanding and not suitable on rocky soils. But, if you don't want to have to poison or shoot native wildlife and want to graze the site with sheep they may be an option.