Long-term precommercial thinning effects on Larix occidentalis (western larch) tree and stand characteristics

Michael S. Schaedel, Andrew J. Larson, David L.R. Affleck, R. Travis Belote, John M. Goodburn, David K. Wright, Elaine Kennedy Sutherland

Research output: Contribution to journalArticlepeer-review

8 Scopus citations


Precommercial thinning (PCT) is used to increase tree size and shorten harvest rotation time. Short-term results from PCT studies often show a trade-off between individual-tree growth and net stand yield, while longer-term effects of PCT on tree growth and stand yield are less well documented. We used a 54-year-old PCT study to test long-term effects of forest density and thinning schedules on stand yield and tree-level characteristics in even-aged western larch (Larix occidentalis Nutt.) stands. The study has three target densities (494, 890, and 1680 trees.ha-1) crossed with three thinning schedules (target density achieved through one, two, or four entries). Analysis of variance (ANOVA) and linear contrasts were used to test the effects of density and number of entries on tree- and stand-level attributes. Thinning before stand age 10 years leads to long-term constant yield (219.0-269.5 m3.ha-1; P > 0.05) across the tested densities. We also found constant volume growth across stand densities during the most recent measurement interval (5.42-6.41 m3.ha-1.year-1; P > 0.05). Number of entries did not affect any tree- or stand-level attribute. The primary effect of early PCT is to control whether wood volume and growth are concentrated on few large, stable trees or spread over many small, unstable trees.

Original languageEnglish
Pages (from-to)861-874
Number of pages14
JournalCanadian Journal of Forest Research
Issue number7
StatePublished - 2017


We thank Wyman Schmidt and Jack Schmidt for years of diligent work on the Western Larch Density Management Study. This work was supported in part by Weyerhaeuser Company (formerly Plum Creek Timber Company). We thank field crew members C.J. Weisbrod, E.E. Schneider, L. Glasgow, and W. George for help with data collection.

FundersFunder number
Weyerhaeuser Company


    • Competition
    • Density management
    • Growth and yield
    • Stand density
    • Stand dynamics


    Dive into the research topics of 'Long-term precommercial thinning effects on Larix occidentalis (western larch) tree and stand characteristics'. Together they form a unique fingerprint.

    Cite this