201. Behaviour of sawn timber in seasoning in relation to the physical properties of wood
- Author
-
Vilnis Balodis
- Subjects
High rate ,Forester ,Relation (database) ,Thinning ,Agroforestry ,media_common.quotation_subject ,Production (economics) ,Quality (business) ,Forestry ,Business ,Pruning ,Rate of growth ,media_common - Abstract
GENERAL INTRODUCTIONTo keep pace with the increasing demand for sawn timber and toncompensate for the depletion of naturally regenerated forests, it hasnbeen estimated (Grenning, 1962) that within twenty years approximatelynhalf of the total timber supply for Queensland will have to be obtainednfrom plantations. This situation was recognized over forty years agonand steps have been taken to establish the necessary plantations.nAccording to the latest available records (Director of Forests, 1964)nsome 105,000 acres of native and exotic conifers have been establishednin Queensland and these are being continuously extended at the rate ofnca. 5,000 acres per annum (Director of Forests, 1957).However, the production of a mere quantity of timber does notnnecessarily ensure an adequate supply of high quality sawn material.nThis aspect has also been recognized for a considerable time and annintensive research programme has been followed on the Various aspects ofnplantation management, improvement and utilization. In the early 1950'snthe research programme on utilization was extended and a series ofnexperiments were started with the aim of assessing the quality ofnplantation grown material. The most important results and conclusionsnfrom these early experiments are summarized by Jennings (1957) togethernwith an outline of future policy of integrated Forest Products and ForestnResearch.nTo give a brief introduction of this policy, hereunder is anshort quote from the paper:qIf the rate of growth is not a significant factorin wood quality then there are very definite economicadvantages to be gained from either a shorter rotationor larger size in the same rotation. If the growing ofconifers is to be rationalised then the costs of growingand conversion must be on the soundest possible economicbasis. This, in effect, means a policy of the largestpossible size of tree of suitable quality in the minimumpossible time No forester can be sure of the ultimate end use ofthe forest crop, and there are many special attributesdesirable for particular purposes. A compromise isinevitable but in all uses, however, there are certainequirements always in demand:1. Freedom from defect; innfreedom from knots.nconifers primarily2. Durability.3. Satisfactory mechanical and physical propertiesnand in particular n n stability or freedom fromndistortion.qThe aspects of high rate of growth or vigour and freedom from knotsnare basically problems of Forest Research and these are attacked both bynspecialized silvicultural treatments (e.g.. intensity of thinning ofnplantations and pruning of stems) and by the selection of suitable parentntrees and cross breeding (McWilliam and Florence* 1955). Durability maynbe partly controlled by the selection of species with early heartwoodnformation, but it is doubtful that this procedure will provide anpractical solution because the excess resin in the heartwood of Pinus spp.nis disadvantageous if the material is to be utilized for the productionnof pulp. n n n n
- Published
- 2020