Storage of Pine timber under Sprinklers during the Summer

1990

33 S.

11 Abb., 8 Tab., 11 Lit. Ang.

Bandaufführung

2044

34027

There are several reasons for the large need for research into storage of timber. Among other things, forms of silviculture, felling methods, transport systems, storage conditions and drying methods have changed since the strage investigations were made upon which current knowledge is based. In general, we may observe that far too little is known about relationships between wood permeability, chemical composition and microbial resistance, as well as how these relationships are influenced by felling time and the subsequent handling of timber, such as storage and drying. The aim of the project is to attempt to reveal the different changes in properties that occur in pine timber during storage. More long-terms aims are to: Obtain better knowledge upon which general advice on storage periods can be based, particularly under sprinklers; To obtain more used-adapted sorting regulations. The aims of the pilot study have been: To test different investigations methods for providing data on planning the main investigation; To obtain results that enable accurate planning and design of the main experiment. The parameters studied on the sawed and dried pine saw timber after storage for different periods under sprinklers have been: Quality according tothe "Green Book"; Permeability; Chemical composition, establishment of extractives (Dept. of Chemistry); Resistance to injurious fungi (mycological experts). The results of the survey of extractives and the resistance to injurious fungi are reported separately. The sample logs were colleced from a felling area close to Jaervsoe and were stored in Borlaenge. The sprinkling of the timber was started immediately upon arrival to the depot and continued totally for about 10 weeks. Samples for analysis were taken: Immediately after sprinkling had started; After two weeks of sprinkling; After six weeks of sprinkling; after ten weeks of sprinkling. The results show that quality determined according to the procedures in the "Green Book" was not particularly influenced after a wet storage period of about 10 weeks. Laboratory tests with decalin show that the permeability for middle and top logs increased by 50-85% after a wet storage period of weeks. After 10 weeks the relative increase is 65-100% for the above-mentioned types of logs in comparison with newly felled material. For butt logs the permeability increase is not as large. The staining results also show that the permeability changes become fully visible after a sprinkling period of 6 weeks. The damages cause increased uptake of stain and are visible as streaks or stripes on the sawing yield. More than 200 side cuts were stained and assessed visually in three classes according to the grouping below: I. No influence. II. Uneven uptake causing patchiness and suggestion of darker stripes. III. Clear stripes or streaks with darker staining.