Choosing trees for small landholdings
Although planting a tree may seem relatively simple, getting the wanted results needs careful species selection with the end use in mind. The wrong tree in a poorly chosen position is not only a waste of money, but can be a nuisance or even dangerous.
Carefully consider why you want to plant trees. It is unlikely you will find one tree to do several jobs successfully, so consider specific plantings for particular purposes.
When choosing varieties of trees to plant on your property, three vital questions need to be answered:
Why are you planting trees? Choose tree varieties with the correct characteristics to suit your intended purpose. Trees have many uses on small landholdings, including:
- wind erosion control
- stock shelter
- nature conservation
- waterlogging control
- salinity control
- possible commercial production.
You must know what you want the trees to do for you, so you are clear as to what characteristics you need from the trees. Remember, there are no ‘miracle’ species that will do several very different tasks.
After it is clear why the trees are to be planted, think about where in the landscape you intend to plant the trees to achieve the particular task.
Where are the prevailing winds coming from? Where will the stock be that need the shelter? Where will they look best from the house or from the road?
Trees will struggle and may not survive if they are planted in an environment they are not suited to. For each specific location you intend to plant trees, you must consider the specific environmental factors of that area such as soil type and rainfall.
Even within the property boundary, although rainfall may not vary significantly, soil types must be checked at each site, as they can vary widely (e.g. well drained, dry or wet).
Use this information to determine what species will do the task best. Many large tree growing organisations such as the Forest Products Commission or Men of the Trees have tree selection catalogues. These are very useful, as they also list preferred rainfall, preferred soil types, mature height, growth habit, uses and a general description.
Observe the golden rules
Although the tree seedlings may not be particularly expensive, all the preparation, labour and maintenance add costs to tree planting.
To achieve a high survival rate, there are some golden rules that must be considered before choosing and ordering your tree species.
Plant in the correct rainfall zone
Rainfall is critical. Unless there is an unusual situation (such as a large freshwater seep at the site) select trees from similar or lesser rainfall zones to your planting site.
For example, if you are in a 650mm annual rainfall zone, plant trees suited to 650mm of rainfall or less. Don’t plant a tree suited to a 900mm rainfall zone.
Trees suited to a higher rainfall zone may survive for a few years but when their water usage peaks they may die if their annual moisture needs are not met.
Know your soils
Soils are also a very important consideration. Go to the planting site and dig a hole with a posthole digger or shovel, preferably to one metre deep, to find out what type of soil it is.
How deep is it to clay? How deep is the deep sand?
You don’t need to be a soils expert, as most nursery tree selection lists refer to light or heavy loams, clays, gravels or sand.
In some cases, such as limestone-based soils on the coast, the soil pH would also be important.
Ensure good site preparation
Site preparation is critical to success:
- Total weed control is essential for a one metre radius around each tree seedling and this area must remain weed free for at least one year after planting.
- Ripping the planting lines at least 40cm deep and preferably on the contour one year before planting will help root penetration. If ripping down a slope is unavoidable briefly lift the ripper out every 20m to avoid water erosion occurring in a continuous rip line.
- Rip and mound the soil in waterlogged or salt affected sites to provide seedlings with a more favourable growing environment whilst getting established.
- Site drainage may be necessary as trees should not be planted on a site that will sit in water for weeks. To avoid legal issues, you should discuss any drainage proposal with your local government authority and neighbours. In the case of drainage of saline land, approval from the Department of Primary Industries and Regional Development may also be required.
Plant local native species
Try to plant the local native species of your area if they are suitable to your requirements. The local native species are not the mature trees that were planted by someone many years ago, but the local remnant vegetation.
It is better to plant local native species because they:
- have adapted over thousands of years to the local climate and rainfall
- best suit the local wildlife
- are more suited to the local rainfall
- are more resilient to local diseases and insects
- perpetuate the local species.
However, local native species may not be suitable if the local environment has changed, for example because of salt encroachment.