Western hemlock tree breeding program

Hemlock is harvested on the British Columbia coast more than any other species, though planting has declined drastically in favour of slower natural regeneration, largely due to costs of re-planting. As a result, new studies have been curtailed, though established trials continue to be monitored and measured.


Tree breeding efforts in coastal western hemlock began over 60 years ago and still continue. Selecting healthy vigorous hemlock trees in the wild started in the late 1950s. These were put into seed orchards to supply seed for re-planting harvested stands and into clone banks for gene conservation. As time progressed, some trees were tested to ascertain their value in terms of growth rate, wood quality, form and disease resistance.

In the 1990s a breeding co-operative was formed with the forest industry, BC Forest Service, government agencies and First Nations from Washington and Oregon. This provided B.C. with faster growing seedlings and seed sources that were better adapted to the conditions likely to be experienced under climate change.

  • Cappa, E.P.,  A. D. Yanchuk and C.V. Cartwright. 2012. Bayesian Inference for multi-environment spatial individual-tree models with additive and full-sib family genetic effects for large forest genetic trials. Annals of Forest science 69: 627-640.
  • Cappa, E.P., A. D. Yanchuk and C.V. Cartwright. 2014. Estimation of genetic parameters for height using spatial analysis in Tsuga heterophylla full-sibling family trials in British Columbia. Silvae Genetica 64, 1-2, 59-73.