Detection of Fungal Degradation at Low Weight Loss by Differential Scanning Calorimetry


  • Robert C. Baldwin
  • Robert C. Streisel


Incipient decay, thermal analysis, differential scanning calorimetry (DSC), hybrid poplar, <i>Populus maximowiczii</i> x <i>trichocarpa</i>, <i>Lenzites trabea</i>


A thermo-analytical method to detect incipient fungal degradation was investigated. Hybrid poplar (Populus maximowiczii x trichocarpa) specimens were degraded by the brown-rot fungus Lenzites trabea and analyzed at five sequential, 3-day intervals to a weight loss of 5%. To measure the extent of decay, cold water, hot water, and sodium hydroxide solubilities, ethanol-benzene extractive content as well as lignin, holocellulose, and alpha-cellulose were determined. Viscometric analysis was conducted to determine changes in the weight average degree of polymerization (DPw), and thermal analysis by differential scanning calorimetry (DSC) was performed to determine endothermic transitions in the whole decayed wood, extractive-free wood, and holo- and alpha-cellulose. Chemical analyses provided results consistent with those expected in wood decayed by a brown-rot fungus. DPw changes of both holo- and alpha-cellulose were significant with regard to decay interval. Analysis of DSC data revealed that this methodology was a reliable means of evaluating fungal degradation in extractive-free wood and holo- and alpha-cellulose preparations from the decayed wood but not the whole wood.


American Society for Testing Materials. 1972. Preparation of extractive free wood. ASTM D 1105-56, Philadelphia, PA.nAmerican Society for Testing Materials. 1976. Standard method for testing wood preservatives by soil block cultures. ASTM D 1413-76.nAmerican Society for Testing Materials. 1977. Lignin in wood. ASTM D 1106-56.nAmerican Society for Testing Materials. 1977. Alpha-cellulose in wood. ASTM D 1103-60.nAmerican Society for Testing Materials. 1977. Water solubility of wood. ASTM D 1110-56.nAmerican Society for Testing Materials. 1978. One percent caustic soda solubility of wood. ASTM D 1109-56.nAmerican Society for Testing Materials. 1978. Standard method of accelerated laboratory test of natural decay resistance of woods. ASTM D 2017-71.nBeall, F. C. 1972. Introduction to thermal analysis in the combustion of wood. Wood Sci.5(2): 102-108.nBeall, F. C., and H. W. Eickner. 1970. Thermal degradation of wood components: A review of the literature. USDA, USFS Forest Products Laboratory, Research Paper, FPL-130, Madison, WI. 26 pp.nBeall, F. C., W. Merrill, R. C. Baldwin, and J-H Wang. 1976. Thermogravimetric evaluation of fungal degradation of wood. Wood Fiber8(3):159-167.nBlankenhorn, P. R., R. C. Baldwin, W. Merrill, Jr., and S. Ottone. 1980. Calorimetric analysis of fungal degraded wood. Wood Sci.13(1):26-31.nConrad, C. M., V. W. Tripp, and T. Mares. 1951. Intrinsic viscosities of cellulose as affected by rate of shear. J. Phys. Colloid. Chem.55:1474-1491.nCowling, E. B. 1961. Comparative biochemistry of the decay of sweetgum sapwood by white-rot and brown-rot decay. USDA, USFS Forest Products Laboratory. Technical Bulletin No. 1258. Madison, WI. 79 pp.nCowling, E. B., and W. Brown. 1969. Structural features of cellulosic materials in relation to enzymatic hydrolysis. In G. J. Hajny and E. T. Reese, eds., Celluloses and their applications. Adv. Chem Serv.95:152-187.nErickson, H. D. 1962. Some aspects of methods in determining cellulose in wood. Tappi45(9):710-719.nFengel, D. 1967. On the changes of wood and its components within the temperature range up to 200°C. Part IV. The behavior of cellulose in spruce wood under thermal treatment. Holz Roh- Werkst.25:102-111.nHartley, C. 1958. Evaluation of wood decay in experimental work. USDA, USFS Forest Products Laboratory. Mimeo. No. 2119. Madison, WI. 57 pp.nKennedy, R. W. 1958. Strength retention in wood decayed to small weight losses. For. Prod. J.8(10):308-314.nKirk, T. K. 1973. The chemistry and biochemistry of decay. In D. Nicholas, ed., Wood deterioration and its prevention by preservative treatments, vol. I. Syracuse Univ. Press. Pp. 149-181.nKirk, T. K., and T. L. Highley. 1973. Quantitative changes in structural components of conifer woods during decay by white- and brown-rot fungi. Phytopathology63:1338-1342.nKrahmer, R. L., R. C. DeGroot, and E. C. Lowell. 1982. Detecting incipient brown rot with fluorescence microscopy. Wood Sci.15(2):78-80.nKubler, H. 1982. Heat release in thermally disintegrating wood. Wood Fiber14(3):166-177.nMerrill, W., and D. W. French. 1964. Particle size alters cellulose yield in wood decayed by Lenzites trabea. For. Prod. J.14(5):228.nSafo-Sampah, S., and R. D. Graham. 1976. Rapid agar-stick breaking radius test to determine the ability of fungi to degrade wood. Wood Sci.9(2):65-69.nSchaffer, E. L. 1966. Review of information related to the charring of wood. USDA, USFS Forest Products Laboratory, Research Note FPL-0145, Madison, WI. 55 pp.nSchaeffer, T. C. 1973. Microbiological degradation and the causal organisms. In D. Nicholas, ed., Wood deterioration and its prevention by preservative treatments, vol. I. Syracuse Univ. Press. Pp. 47-50.nTechnical Association of the Pulk and Paper Industry Standard T230 os-76 Viscosity of Pulp (Capillary Viscometer Method). Atlanta, GA.nWendlandt, W. W. 1974. Thermal methods of analysis, 2nd ed. Wiley-Interscience Publications, NY.nWilcox, W. W. 1978. Review of literature on the effects of early stages of decay on wood strength. Wood Fiber9(4):252-257.nWilcox, W. W. 1983. Sensitivity of the "pick test" for field detection of early wood decay. For. Prod. J.33(2):29-30.n






Research Contributions