Estimating air drying times of small-diameter ponderosa pine and Douglas-fir logs.

      Because dense stands of softwood trees are causing forest health problems in the western United States, new ways to use this material need to be found. One option is to use this material as logs rather than sawing it into lumber. For many applications, logs require some degree of drying. Even though these logs may be considered small diameter, they are large compared with the thickness of typical lumber, and they may require uneconomically long kiln drying times. Air drying is a logical alternative to kiln drying, but the variables involved make estimating air drying times difficult. In this study, we developed experimental air drying time data for 4- to 8-in.- (102- to 203-mm-) diameter ponderosa pine and Douglas-fir debarked logs stacked at four different times of the year. These data were used to develop multiple linear and nonlinear regression models that relate daily moisture content loss to moisture content at the start of the day, average daily temperature and relative humidity, and log diameter. The models provide a way to calculate estimated air drying times for logs stacked at any time of the year and at any location where historic weather data is available. It also provides a way to estimate the benefit of simple, low-cost dryers in reducing drying time. 2003

This article is in PDF format (file size: 2787 kb). To download this article, right click on the link immediately below and choose "save target as". To view the article, left click the link immediately below.
(Download the latest Acrobat Reader if required.)

Estimating air drying times of small-diameter ponderosa pine and Douglas-fir logs.   (2003)

Because dense stands of softwood trees are causing forest health problems in the western United States, new ways to use this material need to be found. One option is to use this material as logs rather than sawing it into lumber. For many applications, logs require some degree of drying. Even though these logs may be considered small diameter, they are large compared with the thickness of typical lumber, and they may require uneconomically long kiln drying times. Air drying is a logical alternative to kiln drying, but the variables involved make estimating air drying times difficult. In this study, we developed experimental air drying time data for 4- to 8-in.- (102- to 203-mm-) diameter ponderosa pine and Douglas-fir debarked logs stacked at four different times of the year. These data were used to develop multiple linear and nonlinear regression models that relate daily moisture content loss to moisture content at the start of the day, average daily temperature and relative humidity, and log diameter. The models provide a way to calculate estimated air drying times for logs stacked at any time of the year and at any location where historic weather data is available. It also provides a way to estimate the benefit of simple, low-cost dryers in reducing drying time.

Author: Simpson, William T.; Wang, Xiping.

Source: Res. Pap. FPL-613. Madison, WI : U.S. Dept. of Agriculture, Forest Service, Forest Products Laboratory, 2003. 14 pages.

Citation: Simpson, William T.; Wang, Xiping.  2003.  Estimating air drying times of small-diameter ponderosa pine and Douglas-fir logs.  Res. Pap. FPL-613. Madison, WI : U.S. Dept. of Agriculture, Forest Service, Forest Products Laboratory, 2003. 14 pages..

Would you like to add information to this article?
Interested in writing or submitting an article?
Have a question about this article?


Have you reviewed the related Knowledge Base areas below?
  • KnowledgeBase: FPL (Forest Products Laboratory)

  • KnowledgeBase: Forestry

  • KnowledgeBase: FPL (Forest Products Laboratory)


    Would you like to add information to this article? ... Click Here

    If you have a question regarding a Knowledge Base article, your best chance at uncovering an answer is to search the entire Knowledge Base for related articles or to post your question at the appropriate WOODWEB Forum. Before posting your message, be sure to
    review our Forum Guidelines.

    Questions entered in the Knowledge Base Article comment form will not generate responses! A list of WOODWEB Forums can be found at WOODWEB's Site Map.

    When you post your question at the Forum, be sure to include references to the Knowledge Base article that inspired your question. The more information you provide with your question, the better your chances are of receiving responses.

    Return to beginning of article.



    Refer a Friend || Read This Important Information || Site Map || Privacy Policy || Site User Agreement

    Letters, questions or comments? E-Mail us and let us know what you think. Be sure to review our Frequently Asked Questions page.

    Contact us to discuss advertising or to report problems with this site.

    To report a problem, send an e-mail to our Webmaster

    Copyright © 1996-2014 - WOODWEB ® Inc.
    All rights reserved. No part of this publication may be reproduced in any manner without permission of the Editor.
    Review WOODWEB's Copyright Policy.

    The editors, writers, and staff at WOODWEB try to promote safe practices. What is safe for one woodworker under certain conditions may not be safe for others in different circumstances. Readers should undertake the use of materials and methods discussed at WOODWEB after considerate evaluation, and at their own risk.

    WOODWEB, Inc.
    335 Bedell Road
    Montrose, PA 18801

    Contact WOODWEB











  • WOODWEB - the leading resource for professional woodworkers


      Home » Knowledge Base » Knowledge Base Article