Long-term responses of <I>Eucalyptus obliqua</I> to pre-commercial thinning
Research Projects
About WARRA Biophysical Features Research Projects Publications Contact Us Links WARRA

Obtaining a Grant

Project Search
Project SearchLong Term Ecological Research
Project name: Long-term responses of Eucalyptus obliqua to pre-commercial thinning
Year started: 1998
Project number: WRA036
Primary investigator: Ann LaSala
Other investigator(s):
Enquiries: warra.enquiries@forestrytas.com.au
Organisation(s): Forestry Tasmania
Project type: Professional
Project status: Active

Ann LaSala (right) describing the thinning treatment applied in the surrounding study area to a group of foresters.

Ann LaSala (right) describing the thinning treatment applied in the surrounding study area to a group of foresters.

Image: Jo Dingle

Project summary:

The study area consists of 1983 Eucalyptus obliqua regeneration, with an open understorey consisting primarily of wet sclerophyll and rainforest species. The 1982 logging was the first harvest on this site.

The site has well-drained, reddish-brown soils derived from dolerite parent material. There is evidence of high levels of past soil disturbance associated with the logging. The site index is 41m (predicted height of dominants at age 50).

Assessment surveys prior to trial establishment indicated a mean basal area of 30 m2 ha-1 over the coupe, and of 33 m2 ha-1 over the trial area, with a stocking of c. 2500 stems 2cm dbhob. The study site located in Warra, WR03G, includes the first of three experiments in Pre-Commercial Thinning (PCT) and Fertilisation in young E. obliqua to be established under the Intensive Forest Management (IFM) program. The objectives of Pre-Commercial Thinning (PCT) are to enhance growth on retained trees and to prepare the stand for subsequent commercial thinning. Anticipated future benefits include a shortened rotation, an increase in pulpwood yield at the time of commercial thinning, and increased size of retained crop trees. The 50 ha coupe is being treated to an average density of 600 SPH. A 6 ha part of the coupe has been delineated for the PCT and Fertilisation Trial. PCT was done using stem injection of glyphosate, on November 23-25, 1998.

Spacing was done to zero (control), 50% (operational standard), and 75% removal of total pre-thinning stand basal area (BA; m2 ha-1). At the trial, these basal area reductions correspond to 450 and 200 SPH, respectively. Each of these two spacing treatments and unthinned control plots have been trialed with and without added fertiliser, at rates of 300 kg ha-1 elemental N plus 75 kg ha-1 elemental P. Fertiliser addition was done on December 1, 1998. The trial is replicated three times.

Methodology:

Assessment surveys prior to establishment of pre-commercial thinning at 0, 50 and 75% removal of trees.

Datasets:

None available.

Publications:

None available.

top