In the early stages of plantation planning, it is advisable to consult with local government concerning any legislative or planning constraints that may affect the selected site.
The regulations may differ by State (and even municipality), so you need to check locally. In Victoria, plantations greater than 40ha in size require a formal planning permit. Although plantations in Victoria of less than 40ha do not require formal planning approval, Shires do require the submission of a Plantation Development Notice before work commences. The Shire Planning Officer will provide a list of requirements for the proposed area and can advise whether a site inspection is necessary. If there is any proposed clearing of native vegetation, then a vegetation clearance permit is also required from the Shire. The Department of Sustainability and Environment can clarify whether approvals will be required.
It is also a good idea to check with your local Private Forestry Development Committee (PFDC) since they are often a good source of information. In our region, we are covered by Plantations North East.
The overarching "bible" for all things to do with plantations in Victoria (including farm forestry) is the Code of Practice for Timber Production from DSE. Whilst it is not a short document, it is well worth a read, just to ensure that you are not doing something totally illegal or stupid (or both!).
