Genetic improvement of western larch: Series 2 progeny tests for East Kootenay seed planning zone

Last updated on August 31, 2023

Project number: EP 1020.02.03

District: Rocky Mountain Forest District


  • To evaluate the growth and adaptability of local and non-local (including Inland Empire) western larch families in the East Kootenay seed planning zone
  • To estimate breeding values of parents included in first-generation seed orchards in order to remove genetically inferior parents
  • To estimate components of genetic variance/covariance, heritabilities and genetic gain for traits relating to tree growth, form, adaptability and wood properties

Experimental design

Genetic entries included in test (160 in total)
Zone Number of wind-pollinated families
East Kootenay 124
West Kootenay 6
North Idaho 20 superior families from the Inland Empire Tree Improvement Cooperative
Controls 10 local operational EK seedlots


  • Randomized complete-block design with eight replicate blocks
  • The 160 genetic entries were randomly subdivided into 4 sets of 40 entries; sets were randomly assigned to positions in blocks
  • Genetic entries were randomly assigned to four-tree row plots within sets
  • Sampling units are individual trees spaced at 2 x 2 m. White stakes identify set corners


  • 1994 sites were mechanically site prepared
  • 1995 sites were planted
  • 1997 manual brushing, third-year heights and condition recorded, data analysis in progress
  • 2000 sixth-year height and condition assessment


Jaquish, B., G. Howe, L. Fins and M. Rust. 1995. Western larch tree improvement programs in the Inland Empire and British Columbia. In Ecology and management of Larix forests: a look ahead. Proc. of an international symposium; 1992 October 5-9; Whitefish, MT, U.S. Schmidt, W.C. and K.J. McDonald (comps). Gen. Tech. Rep. INT-GTR-319. Ogden, UT: U.S.D.A., Forest Service, Intermountain Research Station. pp. 452-460.


In 1996, we established a small planting of subalpine x western larch hybrids at the Lamb Creek site. The objective is to compare the survival and early growth of artificially created hybrids with local western larch seedlots.

The planting has eight entries including three artificially created hybrids from Dr Clint Carlson, USDA Forest Service, Missoula MT,. and five local western larch seedlots; design has four replicate blocks with the eight entries randomly planted in ten-tree row plots within replications.