Step 7. Establishing fit for purpose trees
All trees need regular maintenance to survive and grow and to perform their functions on the farm.
In the early years weed control is important to ensure good growth.
Pruning can enhance wood properties and reduce branch drop impacts on fences.
Thinning some trees over time can accelerate growth of retained trees, reduce stresses and maintain stand health during droughts and reduce the time timber trees take to reach a saleable size.
To provide shelter and shade
Orientation, porosity, and height of a shelterbelt determine the extent and area of reduced wind speed and protection for animals. Orient belts of trees to block winds during the most damaging times of year. Choose taller growing trees to protect a larger area of the paddock. Dense plantings have low wind speeds close to the belt but a smaller area of reduced speeds overall. Plant at moderate density (25-50%) to reduce windspeed over the largest area.
Where possible plant so a road or laneway borders the shelterbelt. This makes good use of the competition zone and internal or boundary fencing. Plant on the south side of laneways and roads to allow sun in winter to dry these areas.
Shelterbelts also provide shade but paddock trees are better for reducing heat stress as they provide shade without blocking airflow.
Shelterbelts can include timber trees. If you would like to grow timber trees in shelterbelts increase the width of belt to improve tree form and height growth through competition and provide more options for harvesting and maintaining shelter following selective removal of trees for timber.
To increase biodiversity
Establish environmental plantings in wider belts that connect existing vegetation on farm assist with improving biodiversity. Planting around dams, riparian areas, and rock outcrops are also recommended.
Tips of managing for biodiversity AND…
- Shelter: Understory and ground cover provide good shelter and habitat. See ANU’s fact sheet for much more detail.
- Carbon: Depending on the balance you want to achieve consider increasing the proportion of big trees to understory and keeping belts less than 40 m wide.
- Timber: Use native species and incorporate understory in the design
There are many resources available to assist in biodiversity focused planting on farms:
- ANU’s Sustainable Farms, https://www.sustainablefarms.org.au/
- Birds Australia, https://birdlife.org.au/projects/birds-on-farms/
- Wheen Bee Foundation https://www.wheenbeefoundation.org.au/our-work/projects/bee-friendly-farming/
For carbon sequestration
Site conditions (rainfall, location on slope and soil type, soil depth and water holding capacity) have a large impact on carbon sequestration. Estimates of carbon sequestration on your property in different types of planting can be generated using the model FullCAM. This requires some technical skill. The LOOC-C calculator developed by CSIRO (link) provides an initial estimate.
Species selection also has a large impact on carbon sequestration. Plant trees that grow quickly and reach a taller height at maturity, examples include shining gum and radiata pine. Planting more trees rather than understory shrubs can also increase sequestration.
Plantings configuration also influences carbon sequestration rate. Belts less than 40 m wide can sequester more carbon per unit area than trees planted in a block. On 3 sites in Victoria with varying productivity, the modelled average sequestration over 25 years for environmental plantings was about 40% more in belts than blocks.
Timber and carbon goals go well together on the right sites since high wood production is sequestering more carbon. Carbon on the farm is reduced when trees are harvested but some is stored in timber products. With sufficient area, harvesting a portion of the trees for timber in stages over time can maintain overall farm carbon stocks. More generally, staged planting can maintain carbon sequestration rates over a longer period, rather than all trees peaking at one time.
For details on sequestration rates in various context, how this might compare to farm emissions, and information on requirements for selling carbon or using it to reduce net farm emissions refer to the carbon sequestration fact sheet at https://piccc.org.au/research/project/TreesOnFarm.html
If you are located within 200 km of a sawmill or chip export facility and your property has good access for harvesting equipment, timber revenue increases the likelihood of a good return on investment in tree planting. Timber can be produced from trees in blocks or belts. Choose the right species for the market near your property (for example, radiata pine, blue gum, shining gum, sugar gum or durable eucalypt species).
Trees need to be managed to meet market needs. For example, to produce sawlogs, thinning will concentrate growth on crop trees to reach a minimum size more quickly. The final crop might be about 200 trees per hectare (85 per acre). These may need early, regular pruning to reduce branches that degrade sawlog quality. Blue gum or shining gum grown for wood chips need less management.
Good resources of incorporating timber production into your farm operation are available including Forestry Australia’s Farm Forest Line, Tree Alliance for Tasmania, and the Forest Industries Hubs website which maps the 11 regions and includes links to each. A timber industry partnership can provide finance and management support for establishing timber plantations for example the ActivAcre program in Tasmania.
Indicate on your property map where planting might possibly occur, remembering to ensure any plantings won’t be impacted (or impact!) current ‘flows’ on your property.