Studies on Lenzites abietina FR. and some of its Allied Species (Ⅱ) : Decay of coniferous trees caused by Lenzites abietina FR., L. subferruginea BERK. And L. trabea (PERS.) FR.

1. This present paper deals with the results of writers investigation on the decay of coniferous woods affected by Lenzites abietina F_R., L. subferruginea B_ERK. and L. trabea (P_ERS) F_R.. 2. It was clearly observed that the decay in the heart-wood was more advanced than in the sap-wood. The decayed portion was cleatly distinguished from the normal portion and changed to a brown in colour and became crumbly in the most advanced stage. The rotten wood crushed very easily to a brown powder when pressed between the fingers. By such macroscopical symptoms, the writer considered that the type of rot caused by these three fungi belongs to the brown cubical rot. 3. Microscopical studies on the penetration of these three fungi in the hot tissue were made by means of the staining methods recommended by H_UBERT and C_ARTWRIGHT. It was proved that the hyphae of these three fungi are capable not only of passing through the natural openings on the cell walls but also of penetrating them through the bore holls. Microchemical tests indicated also that these three fungi are to be classified as belonging to the group of cellulose-dissolving fungi. 4. Durability-tests were made on the heart-woods of five coniferous trees such as Pinus densiflora S. et Z., Larix Kaempfer S_ARG., Cryptomeria japonica D. D_ON, Chamaecyparis obtusa E_NDL,. and C. pisifera E_NDL to these three fungi under the controlled laboratory conditions. In these tests Lenzites trabea (P_ERS.) F_R. showed the strongest virulence, especially upon Larix Kaempfer S_ARG. and Pinus densiflora S. et Z. and L. abietina F_R. had the weakest. The test-blocks of Chamaecyparis obtusa E_NDL. and C. pisifera E_NDL. showed the most resistance to decay and those of Larix Kaempfer S_ARG. showed in serious decays. 5. In order to observe the effect of decay on the chemical compositions of Pinus densiflora S. et Z. and Cryptomeria japonica D. D_ON, the chemical experiments were carried out. The writer found a marked decrease in cellulose and peutosan and an increase in lignin and 1% NaOH extract. Judging from the results of this experiment the writer came to the conclusion that these three fungi are to be classified as belonging to the cellulose-dissolving fungi.Article信州大学農学部学術報告 3: 9-14(1954)departmental bulletin pape