1. Class “A” western larch seed and interim seed deployment zones Barry Jaquish and Susan Zedel Tree Improvement Branch October 3, 2015 0

2. Forest Seed classification in B.C. In B.C., tree seed must be registered with Tree Improvement Branch to be deployed legally on public lands. Class “B” – collected in natural stands; no genetic improvement. Class “B+” – collected in natural stands that have demonstrated superior growth performance in genetic tests; modest level of genetic improvement in growth and/or pest resistance traits. Class “A” - produced in one of the many provincial seed orchards (private or public); - some level of genetic improvement in value traits (eg. tree volume or pest resistance) assigned to each seedlot. - level of genetic improvement is determined through an extensive network of genetic tests on field or nursery sites (varies between 10- 35% tree volume at rotation). 1

3. Background Reasons for realized gain testing: 1.Establish allowable cuts 2.Altering forest management regimes to best utilize the growth behavior of improved stock 3.Establishing value of the genetic improvement program 4.Refining selection criteria on the basis of real or predicted final yields 5.Compare yields estimated from progeny tests with area-based tests 2

4. Western Larch Realized Gain Genetic Tests Established spring 2004 Design: – 12 x 12 tree square plots – 3 spacings (1.5m, 2.5m, 3.5m) – 4 seedlots Control (5 wild seedlots) Seed orchard low GW (6%) Seed orchard high GW (12%) Elite – composite 5 full-sib families – 2 replications per site 3

5. Western Larch Realized Gain Genetic Tests SiteBEC zoneElev (m)MAT (C) MAP (mm) Bear CkICHdw18226.0785 Burton CkICHmw28994.4861 Taurus CkMSdm112424.0579 4

6. Western Larch Realized Gain Genetic Tests 5 Elite seedlotControl Burton realized gain test: 4-years-old

7. Results 6

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10. Conclusions Site and seedlot had a significant effect on height at age 6; spacing had little effect; Elite and seed orchard seedlots demonstrated 21 % and 10 % greater growth than wild-stand control seedlots, respectively; Seedlot growth trends were similar across sites, but differences were more pronounced on productive sites; and, Survival similar for all effects. 9