Western Redcedar Tree Breeding Program

The western redcedar (Thuja plicata) breeding program is the youngest of British Columbia's conifer breeding programs. Western redcedar is an important commercial species in B.C., prized for its naturally durable heartwood which is in demand for outdoor building material.

A genetic improvement program has been established for the Maritime (0–700 metres) seed planning unit (SPU) with the objective of developing a population that is resilient to multiple pests, as well as maintaining adaptability and growth. The goal of the western redcedar breeding program is to produce genetically improved and diverse seed for reforestation in the Maritime SPU.

Climate Change

As the climate changes and pests become more abundant, breeding strategies need to adapt to better accommodate shifts in environmental stresses to ensure current and future forest health. Challenges for western redcedar include:

  • Volume & adaptability
  • Foliage pathogens
  • Ungulate damage
  • Heartwood rots

Current Progress

Significant gains have been realized since the western redcedar program’s inception in 1998. Current breeding efforts include establishing cloned first-generation families from multiple populations. The goal is to develop a second-generation population that has resistance to a broad spectrum of health traits, as well as maintain growth and adaptability.

Gains from four provincial orchards (one government and three industry orchards) currently include increased volume and resistance to cedar leaf blight that is 20 percent greater than a wild stand.

  • Gesell A, Blaukopf M,  Madilao L, Yuen MS, Withers, SG, Mattsson J, Russell JH, Bohlmann J (2015). The gymnosperm-specific cytochrome P450 CYP750B1 catalyzes stereospecific monoterpene hydroxylation of (+)-sabinene in thujone biosynthesis in Thuja plicata. Plant Physiol. 168(1):94-106.
  • Gray L, Russell JH, Yanchuk AD, Hawkins,BJ (2013) Predicting the risk of cedar leaf blight (Didymascella thujina) in British Columbia under uncertain future climate change. Agr. For. Meter. 180:152-163.
  • Foster AJ, Hall DE, Mortimer L, Abercromby S, Gries R,Gries G, Bohlmann J,Russell J, Mattsson J. (2013) Identification of Genes in Thuja plicata Foliar Terpenoid Defenses. Plant Physiol. 161: 1993-2004.
  • Foster A, Hall D, Abercromby S, Gries R, Gries G, Bohlmann J, Russell J, Mattsson JA. (2012) Genomics approach to gene discovery related to biosynthesis of thujone in western red cedar (Thuja plicata). Pharm. Biol. 50: 668-668
  • Kimball BA, Russell JH, Ott P (2012) Phytochemical variation within a single plant species influences foraging behavior of deer. Oikos. 5(121):743-751.
  • Russell JH, Yanchuck, ADY (2012) Breeding for growth improvement and resistance to multiple pests in Thuja plicata  under a changing climate. Proceedings of the Fourth International Workshop on the Genetics of Host-Parasite Interactions in Forestry: Disease and Insect Resistance in Forest Trees. GTR-PSW 240:40-44.
  • Kimball BA,  Pfund F, Gourley M, Griffin DL Russell, JH (2011) Silvicultural attempts to induce browse resistance in conifer seedlings. Int. J. For. Res. Article ID 108529.