TMP FROM DOUGLAS-FIR - RESULTS OF PILOT-P LANT TESTS

For the first time ever in Germany Douglas fir wood was pilot tested i n industrial TMP production. The objective was to follow up comprehens ive laboratory investigations by testing the suitability of Douglas fi r wood for large-scale pulp production. A total of approx. 550 m(3) (a bout 118 t oven dry weight) Douglas iir from thinnings were converted into TMP. The quality of the resultant Douglas iir TMP was tested by a pproved chemical, technological and optical methods and compared with results for TMP manufactured from spruce. Special emphasis was placed on the characterization of the test material, tree age as well as annu al ring width, increment, sapwood and heartwood portions. A direct com parison of the two tree species as regards TMP qualities and the inter pretation of results was difficult due to overlapping effects based on the use of waste sawnwood on the one hand and roundwood from thinning s on the other. One disadvantage, apart from the deliberately high hea rtwood portion, was the concomitant great portion of juvenile wood whe n roundwood was used. The above pilot tests, however, clearly show tha t the addition of defined amounts of Douglas fir to spruce for TMP chi ps lead to satisfactory results.