Eucalyptus Grandis - Silviculture and Management

Silviculture and Management:

Seedlings should be from good genetic stock; provenance trials with some eucalypts, including Eucalyptus grandis, have shown that generally the local provenances of seed taken from well-shaped and vigorous trees will be among the best. Planting should be timed to coincide with natural rainfall. In southern latitudes this is predominantly determined by the severity of frost and minimum temperatures experienced. Seedlings can be hand-planted or machine-planted.

For machinery to be used, allow a spacing of 3–5 m between rows. Mounding may be required on wetter sites and deep ripping should take place in rocky, stony or compacted ground. Eucalyptus grandis has been found to respond well to complete cultivation than spot cultivation, and to chemical weed control and early fertiliser application.

Spacings and planting designs vary, but suitable initial spacings for woodlots are 3 m x 3 m (1111 trees/ha) and 4 m x 2.5 m (1000 trees/ha).These spacings encourage rapid canopy closure,reduce weed problems, promote good form and allow ample selection for a final stocking of 200–300 trees/ha. In forest situations Eucalyptus grandis has the ability to self-prune, however small plantations will require pruning for sawlogs. Decay often occurs at branch stubs because the wood is not durable,so branch diameter should be kept small by high stocking rates or early pruning.

To produce high quality paper from plantation trees requires rotations of 7–10 yrs with no thinning or pruning and generally a minimum require area of 20,000 ha with an expected productivity of 30–40 m3 /ha/year. To produce veneers, plywood etc. requires a rotation length of 15 years with pruning and selected fertiliser applications; planting stock is generally clonal or control-pollinated seed orchard material, often growing greater than 25 m3 /ha/year.

For high value cabinet timber, use selected seedlings; a rotation of 40 years or more, with pruning and selected fertiliser applications required; expected productivity 12–18 m3 /ha/year. (Lambert & Turner 2000).

Eucalyptus grandis is probably the most widely planted plantations or woodlots because of its ease of care, excellent form, rapid growth and variety of end uses. It should be considered for short-rotations light construction material and pulpwood. It is planted extensively in South Australia as a fast growing hardwood and returns are expected after 15 years, but usually 20–30 years for good sawlogs. Prices received are variable and dependent on local market conditions.

Tolerance Information:

Qualifying Tolerance Information:

Frost sensitive when young but will withstand low temperatures if hardened; can tolerate moderate frost up to 20 times per year.

Tolerates short-term flooding but is intolerant of swampy conditions; intolerant of severe drought.

Water use and growth are slower under low humidity, even when adequate soil water is present.

Moderately tolerant of soil acidity down to pH 5.5, although best growth is obtained with a soil pH closer to 7.