CONCLUSIONS 



These studies show that for both western white pine and lodgepole pine the mois- 

 ture content of lumber made from dead trees is about half the moisture content of 

 lumber cut from green trees. The average moisture meter reading obtained from four 

 packages of western white pine dimension lumber was 23.7 percent, and the average 

 moisture content obtained from a subsample of this material by the ovendry method was 

 28.8 percent. The average moisture meter reading for the lodgepole pine studs was 

 16.5 percent, and the weighted average moisture content based on ovendried test sec- 

 tions was 22.7 percent. The difference in the moisture meter readings and ovendry 

 test results can be attributed to (1) the reduced reliability of moisture meter read- 

 ings above 25 percent; (2) the fact that the meter readings were not always adjusted 

 for temperature or species; and (3) the number of readings that exceeded the scale 

 maximum in the lodgepole pine study but were recorded as the scale maximum. 



The moisture distribution specimens showed there was only a slight moisture 

 gradient in the dead tree lumber. The average difference between the shell and the 

 core was less than 2 percent moisture content for both species. Also, neither the 

 dead white pine nor the dead lodgepole pine lumber had any significant amount of drying 

 stress. Out of 93 white pine test sections, 61 remained straight, 26 showed some case- 

 hardening, and 6 showed some reverse casehardening . Of the 22 lodgepole pine test 

 sections, 19 remained straight, and 3 showed a small amount of casehardening. 



As a result of the relatively low moisture content, absence of drying stresses, 

 and low moisture gradient, the drying schedule used to dry lumber from dead trees 

 should be about half the time required to dry green tree lumber. These schedules could 

 use higher initial drying temperatures. Avoiding excessive drying will reduce energy 

 costs as well as prevent degrading of material by overdrying . 



RECOMMENDATIONS 



It is impossible to make hard and fast rules for drying lumber from dead trees 

 because of the variability in trees from different areas and in milling equipment and 

 procedures. Furthermore, if only an occasional dead log is milled, the present prac- 

 tice of mixing the dead with green lumber and using the green lumber drying schedule 

 is satisfactory. But if a sufficient quantity of dead lumber is produced to justify 

 the sorting and use of a special drying schedule, greater efficiency will result. For 

 the mill that does produce a quantity of dead lumber, some experimentation will prob- 

 ably be necessary to determine the optimum drying conditions. The study results re- 

 ported in this paper indicate that the drying time could and should be reduced by at 

 least 50 percent (based on the moisture content of the dead lumber) . 



9 



