Tree planting
Correct tree selection is crucial to a successful planting. Trees must be suitable for the soil type, aspect and rainfall of the area. Trees from areas of high rainfall, such as the alps or a rainforest, will not survive in a location with low rainfall unless they are watered regularly.
The Wyndham area is a low rainfall zone with rocky and low nutrient soils. Trees that are to thrive in this area without additional help must be able to grow naturally in similar conditions.
Both native and exotic trees can be found which are suitable for conditions found in Wyndham, however, these types of trees will not be as successful as indigenous plants that grow naturally in the Wyndham area. Indigenous species have evolved to cope with the low rainfall and poor soils found in the district.
When is the best time to plant?
Late autumn and winter are the best times to plant trees in Wyndham because temperatures arent as hot and there is usually enough regular rainfall and less evaporation over this period to allow seedlings to establish new roots before the warmer weather starts in spring and summer.
In other areas of Melbourne, spring has traditionally been the recommended time to plant trees. However, Wyndham has an average rainfall of less than 550mm per year and an evaporation rate 2 times the annual rainfall. Unless the trees can be watered regularly over the warmer months, the higher temperatures and increased evaporation can severely stress seedlings, retarding growth or even killing them if they are planted during this time of the year.
How to assist trees in the summer
Mulch as much of the area around the trees as possible. This will dramatically reduce the amount of moisture lost from the soil through evaporation.
If the trees appear to be stressed, watering them for the first two years during the warmer months will assist in their survival. Long, deep watering will help to establish a deep root system. Frequent, shallow watering can result in trees developing a shallow root system, making them dependent on this type of watering and making them more unstable in high winds.
Why mulch?
Mulching has many benefits for trees and the soil. Mulch placed around trees will suppress weed growth, greatly reducing competition for valuable moisture, nutrients and light.
Mulch will begin to break down over time, leading to the release of nutrients into the soil and helping to condition the soil by the addition of organic matter.
Among the decomposing mulch, many different organisms live, including worms and soil fleas. These organisms provide a valuable food source for birds and lizards.
What are the different types of mulch and where can they be purchased?
Mulch can range from pea straw or leaves up to the coarser types such as wood-chips from branches or recycled timber.
The softer mulch material like straw and leaves will provide short-term weed suppression and a short-term nutrient source once the mulch has broken down. The harder mulch material such as wood chips can provide long-term weed suppression, taking much longer to break down.
Mulch can be sourced from landscape suppliers, specialist mulch suppliers and often from tree pruning companies.
Care should be taken when choosing mulch and the source of the mulch because it can be contaminated with a variety of weed propagules eg. seeds, root fragments, branch fragments, corms, bulbs, etc. and can add to your weed problem.
How do I calculate the area for mulch?
Measure in metres the length and width of the area to be mulched, then multiply this figure by the depth of the layer of mulch required eg. 0.075metres (7.5cms), 0.1metres (10cms) or 0.15metres (15cms). The final figure is the cubic metres of mulch required for the area, eg 7 metres long x 5 metres wide x 0.1 metres (10 cms) = 3.5 metres of mulch.
What depth do I mulch to?
Mulch depth is usually between 7.5cm to 15cm, depending on the type of mulch and the application. The deeper the mulch, the longer the period of weed suppression and nutrient release. Mulch depths over 15cm can have negative affects on the growth of the plants because it can reduce the amount of water filtering through the mulch and into the soil after rain or watering. If the mulch is too deep and is in contact with tree trunk, it can also cause collar rot.
Are rabbits in the area?
Rabbits are attracted to disturbed soil and planting trees will often attract rabbits even when there are other food sources around. Rabbits will dig at the roots of trees in search of food and they will also strip the bark off the trunks of young trees as a way of controlling the growth of their front teeth.
Placing guards around trees will prevent rabbits from digging at the plant roots and collaring the trunk but it won't stop them from eating the foliage when it grows over the top of the tree guard.
Rabbit-proof fencing is probably the best way to stop rabbits from eating or damaging young trees. Traditionally, a rabbit-proof fence is constructed from star pickets and/or wooden posts and chicken wire mesh attached to the fencing wire.
The mesh should be a minimum of 90cm high, with a 30cm skirt of mesh extending over the ground in the direction of the rabbit infestation. The mesh skirt is a vital component of the fence because it will prevent rabbits from digging under the fence and getting access to your trees. The mesh skirt should then be either pinned down at regular intervals or be secured by placing rocks /logs or other heavy material on it to keep it flat along the ground.
Rabbits will take advantage of any weak spot in the fence, such as any lifting of the mesh. The mesh should be checked regularly for any holes or breaches and be repaired as soon as they are located.