Mechanical properties of lodgepole pine: 6- and 9-inch diameter stems

A large study entitled ?Gross characteristics of lodgepole pine trees in North America? (10), and a study entitled ?Mechanical properties of lodgepole pine: 3-inch diameter stems? (13) have been completed previously. The objective of the current research study reported herein was to evaluate the mechanical properties of the 6-inch (152 mm) and 9-inch (228 mm) diameter stems of lodgepole gathered for the original study by Koch and to determine the variation (if any) associated with location and elevation across the major range of the species. The tree-stem sections made available for the evaluation of mechanical properties consisted of eighty-one 6-inch and eighty-one 9-inch diameter at breast height (DBH) stems of latifolia and twelve 6-inch and twelve 9-inch DBH stems of murrayana. Each section was taken from 10 to 20 percent of tree height from stump top to apical tip. Analysis of tabulated results yielded the following conclusions: 1) properties of test specimens cut 3.5 inches from the pith were significantly greater than those from specimens cut 2 inches from the pith; 2) the bending properties, modulus of rupture and modulus of elasticity, were significantly larger for the latifolia than for the murrayana; 3) in most instances, properties of stems obtained from lower elevations were greater than those from the higher elevations; 4) where elevation zone (high, medium, low) showed significant differences, the stems from the high zone yielded properties lower than the stems from medium and low zones; 5) in general, stems from the higher latitudes possessed higher properties than stems from the lower latitudes, which corresponds to the correlation with elevation (latitude span of the study was from 37.5? to 60?); 6) in general, latifolia stems from longitudes 120? and 125? had higher properties than those of stems from other longitudes spanned by the study (total span was from 102.5? through 132.5?).

You must be logged in to download any documents. Please login (login accounts are free) or learn how to Become a Member