Recovery and Value in Cypress Pine

March 2005 RIRDC Publication No 04/184 RIRDC Project No PN 99.2005
Executive Summary
This project investigated aspects of white cypress pine forest management and utilisation in order to promote retention and management of white cypress pine forests for high value timber production.
 Three principal areas were addressed, viz:
  o A review of available information on the ecology, distribution and marketing of white cypress1
o A sawing study to quantify links between forest management, green-off-saw (GOS) and dried graded timber recovery, and
o An investigation and review of the insect pests and decay fungi of white cypress relating to timber production.
                                                                                                                                                                                                                                              Never Treated Cypress Ecology, distribution and management
White cypress (Callitris glaucophylla) is a native conifer principally occurring in the sub-humid zone in a band stretching from southern New South Wales (NSW) into approximately central Queensland.
 It grows as a small to medium tree and occurs naturally in a range of vegetation associations, either as a pure stand or as a subdominant in mixed forests. It is fire sensitive, however, once established, litter loads are much reduced and with the exception of severe wildfire, fires are generally very mild and do not carry into the crowns or in the understorey.
 The species is known to regenerate prolifically when good seed years coincide with optimal seasonal conditions. When this occurs, very dense stands or ‘wheatfield’ regeneration can establish.
 Regeneration in New South Wales tends to rely more on this method than in Queensland where small amounts of regeneration occur on a more regular basis. The resultant stand types are also different with more ‘uneven-aged’ stand structures occurring in Queensland although some of this is influenced by management. In the absence of silvicultural intervention, the dense regeneration tends to develop into a stand condition termed ‘lock-up’ and become moribund where trees are in a stage of intense competition with very low or nil growth and low rates of mortality.
  Silvicultural regimes have been developed in both states to manage white cypress pine for timber production. In New South Wales, a ‘shelterwood’ system has been developed where harvesting is carried out in two stages to promote regeneration. Under this regime much of the volume is removed in a single harvest leaving seed trees and there is a relatively long growth interval between harvests.
                                                                                                                            Treated Cypress Stand  Stands tend towards a more ‘even-aged’ or ‘two tier’ structure.

In Queensland, a ‘single tree selection’ or ‘selective harvesting’ approach has been taken favouring an ‘uneven-aged’ structure where harvesting intervals are relatively short and a range of diameter classes are always present in the stand. These two management regimes have developed in response to regeneration patterns in each state. In both cases, management of cypress pine results in relatively high productivity, up to or in some cases exceeding 1 m3 / ha / yr in high quality stands, in comparison with unmanaged stands where negligible growth is often recorded.                                                                                                                                                                        Twice logged Cypress Stand Inventory information for State forest and some leasehold areas is

comprehensive and this provides state agencies with accurate estimates of overall productivity from which to manage harvest levels.
  Distribution of white cypress outside of State forest and some leasehold land has been mapped by remote sensing and is therefore an estimate only. There is no qualifying information from this mapping in terms of either forest condition or stand composition. Of a total area of approximately 4.1 M ha of forest containing or dominated by cypress pine in both States, approximately 1.3 M ha is on freehold land (870,000 ha in Queensland and 430,000 ha in New South Wales). While much of this is likely to be relatively unproductive, the potential freehold resource is quite significant.
Pests and disease
Major pests of cypress pine include jewel beetles, Durabilla white grub, cypress bark weevil and termites. The major insect pests of white cypress are listed and their distribution, damage type and life cycles described in this report. Implications for forest management and timber processing are also discussed. In general, pests and disease of white cypress did not have a major influence on sawn recovery in this study. Some insects, in particular beetles, have an influence on both aesthetics and sawn recoveries, and thus influence utilisation and marketing of white cypress.
                                                                                                                               Large Sawn Cypress Branch Sawing study:  To test and quantify the relationship between forest

management and timber recovery, both greenoff- saw and graded, a sawing study was conducted where logs from three different management intensities, viz, managed, partially managed and unmanaged, from each of three geographically different localities, were harvested and processed.
Two localities were selected in Queensland and one in New South Wales. From the processor’s perspective, larger, defect free logs are desirable due to the higher recovery overall and in particular the higher volume of large piece sizes produced.
 Large Smaller logs generally equate to lower recoveries and a higher proportion of narrow boards (75mm or 3 inch) for which there is currently limited market opportunity.
A total of 270 trees were harvested, consisting of 30 representative trees from nine sites in three localities, to produce a total sawlog volume of 67 m3. These logs were sawn by a commercial operation in southern Queensland to produce green sawn, 25mm thick boards in 75mm, 100mm, 125mm and 150mm widths.
 Boards 100mm and wider (nominally 4-inch, 5-inch and 6-inch) were kiln-dried, dressed to standard tongue and groove flooring profiles and graded to export specifications (i.e. moisture content 6-9%, North American flooring grade). The 75mm wide material (nominal 3-inch) was green-dressed to a pencil-round profile and graded to specifications for southern Australian markets, principally Victoria.
                                                                                                                                    Knots in Cypress Pine Harvested volumes from each site ranged from 4.33 m3 to 15.19 m3.

Green-off-saw recoveries ranged from 33.8% to 42.1%, depending on original source. The recovery study showed that the relationships between tree size and sawn recoveries (green-off-saw and dried graded) were influenced by past silvicultural management on some sites more than others.
  In general, past intensive management produced an increase in both green-off-saw and dried graded recoveries over nil or partial forest management. Some aberrations were apparent and not all variation was due to past management effects. It is suggested that site factors may also influence sawn recoveries.
                                                                                                               Large Knot Defect in Cypress   

A report for the RIRDC/Land & WaterAustralia/FWPRDC/MDBC Joint Venture Agroforestry Program,
with the assistance of the Myer Foundation.
 by D.Taylor, J. King, S. Swift, G. Hopewell, V. Debuse, S. Roberts and D. Cotter