Effects of Compression on Parenchyma Cell Viability, Initial Heating, and Microflora of Aspen Fuel Chips


  • Ya-Lih Lin
  • Elmer L. Schmidt


Wood chips, bigtooth aspen, compression, parenchyma viability, heating, microflora


In order to study fundamental factors influencing storage of compression-dewatered wood chip bales, compressed bigtooth aspen chips were compared to noncompressed chips to note differences in parenchyma cell viability, initial heating, and early microflora types. Immediately after pressing (28 MPa for 5 min), surface area of chips stained as a result of parenchyma cell dehydrogenase activity on triphenyltetrazolium chloride was reduced from 83% (noncompressed) to 23% (compressed). Half-life of remaining viable parenchyma cells was reduced by 14 days at ambient temperatures. Temperatures in insulated chip bales were 30% higher for compressed chips after 24 h than in noncompressed chips. After 10 days of ambient storage, bacteria were abundant in the compressed chips, while Phycomycetes and Fungi imperfecti were more frequently isolated from the noncompressed chips. Such differences in compressed chips may influence the fuel potential of baled chips stored for extended periods by changing the pattern and parameters of organism activity.


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