The science of forestry is known as silviculture. Silviculture is applied in management of State forests to sustain or enhance ecological outcomes, continually improving productivity, vitality and diversity of forest ecosystems.
Native forest silviculture
Native forests are naturally occurring treed areas that are managed for sustainable timber production. In NSW, native State forests have been harvested and regenerated many times over the past 100 years or more and careful planning and management ensures they will continue to produce a sustainable supply of timber well into the future. The video below explains the harvesting and regeneration process.
Before harvesting, foresters carefully select a silvicultural technique that will create ideal conditions for regeneration, provide habitat for wildlife and maintain a diverse forest ecosystem. For example, in some forests, only a few individual trees will be harvested while in other areas blocks of trees will be removed to open up the canopy for the light-hungry seedlings to regrow.
Native forests are part of a broader landscape that contains forested land that is set aside for conservation and land that is actively managed. State forests are only a part of the landscape and the area harvested for timber each year is only a tiny fraction of the State forest estate each year. Forests are dynamic and contain a mix of wildlife and flora, some that respond well to disturbance and thrive in young regenerating forest and others that do not respond well to disturbance. The science of silviculture looks at the best way to maintain biodiversity across the whole landscape in a productive forest. More detail is included in the native forest silviculture manual.
Silviculture in pine plantations
Pine plantations are essentially a slow-growing agricultural crop, needing roughly 35 years to mature between planting and final harvest. In NSW, plantations are grown on previously cleared land in an ongoing cycle, with new seedlings replanted on the same site once the mature trees have been harvested.
Every year, Forestry Corporation selects seeds from specialist tree breeders and sows them in its custom-built nursery at Tumut, where they are nurtured for around seven months.
Each winter, the nursery dispatches millions of seedlings to be planted in harvested pine plantations across NSW. Pine seedlings are planted during winter because they are dormant during the cooler months, which means they can be transported more easily and planted in the ground in time for their spring growth period.
During the life of a pine plantation, smaller and weaker trees are removed or ‘thinned’ to allow the remaining trees more space, light and water to grow. The smaller, younger trees usually produce pulpwood, which is processed to make items such as paper products and particleboard. As the trees mature, each tree can produce a range of different products. For example, the strong solid bottom half of the trunk is usually ideal for house frames and furniture while the narrower sections towards the top are generally used to create products like particleboard and paper products.
The remaining trees are harvested after 30–35 years and these trees will mainly produce timber used for house construction and furniture. The typical radiata pine tree may grow up to 33 metres tall and half a metre across at chest height when harvested at about age 35. The video below explains the process.