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A comprehensive study to determine the effects of initial espacement and subsequent thinning on the growth and yield of lodgepole pine plantations
(EP 962)



EP 962 at age 15

(click to enlarge)
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  1600 sph
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  400 sph
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  3200 sph,
thinned to 800 sph
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  1600 sph,
thinned to 800 sp

Thinning is characterized by a number of different elements: type, weight, cycle, level of growing stock, and intensity.  Few existing studies have distinguished between these various thinning elements, and fewer yet have held the remaining elements constant while testing the effect of one element.  Using rigidly controlled initial espacements and neutral-type thinnings, the present study tests several quantitatively-defined weights, cycles and intensities of thinning, and levels of growing stock. 


To determine the effects of initial espacement (i.e., planting density) and subsequent thinning on the growth and development of lodgepole pine.


Four initial espacements (400, 800, 1600, and 3200 trees per hectare) are tested in this study.  Except for the 400-tph density, all espacements are scheduled for thinning at 15-year intervals to age 45 years after planting, on either a single- or multiple-entry regime.  The study involves 18 single-, 12 double- and one triple-entry thinnings.  The study contains two replicates of 35 treatment combinations, arranged in a completely randomized block design.  A second replicate of the 400-tph espacement (no thinning) is included in each block, bringing the total number of plots to 72.  All treatment plots are 0.25 ha (50m x 50m) in size.

This installation is re-measured at 5-year intervals.  The 1st scheduled thinning was completed in the fall of 2001.


Installation Details

Inst District Spp BEC Year Establ. Lats Longs Map
1 Prince George Pl SBSmh 1987 53-46' 122-44' 93G.077


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Last Modified: 2007 APR 20. Ministry contact: Frank van Thienen