Recently we replaced some of the rotten and cracked true size 4 in x 6 in. posts under the house in crawlspace. The old posts were resting on concrete pads 24 in. x 24 in. and supporting a true size beam 4 in x 8 in.
The lumber we used is 4 in. x 6 in. x 8 ft. Pressure-Treated Landscape Timber , since we couldn't find any true size to match the old one. This lumber is rated as #3 grade but does not have any knots or cracks and labeled as not being used for structural purposes.
Should I be concerned about its strengths? I presume that is Douglas Fir.