Nursery Seedlings

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BVRC/PICS summer intern Andrew Sheriff with whitebark germinants at Woodmere Nursery, May 2012

A goal of the Bulkley Valley Research Centre’s Whitebark Pine Restoration Project is to successfully produce 2500 – 7500 nursery-grown seedlings over 5 years.  Because whitebark pine has complicated seed germination requirements and grows slowly, it takes 2-3 years to produce a seedling ready for outplanting. 

In 2011/12 and 2014/15 we stratified 26,000 seeds from 44 seedlots using procedures adapted from Don Pigott (Yellowpoint Propagation), Linda Tackaberry (UNBC), Vicky Berger and Dave Kolotelo (FLNRO Tree Improvement Branch and Tree Seed Centre).  This is a very fussy, labour-intensive process.

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Seed Stratification

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Seed Stratification Winter 2012 H202 Soak

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Woodmere Nursery May 2012 Poor emergence Jonas Creek seed

The seeds received 1 month warm stratification followed by 12 - 20 weeks cold stratification and were rinsed and/or soaked in H202 at 1-2 week intervals to prevent moulding.  After stratification, the tip of each seed was nicked with a razor blade to improve germination – this laborious procedure also allows decayed seeds to be identified and discarded.  In April, 2012 and Feb., 2015, the seeds were sown in styroblock containers at Woodmere Nursery. The seedlings remain at Woodmere Nursery for 2 years until they are large enough for outplanting.

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Woodmere Nursery May 2012 Good emergence Kidprice seed

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Woodmere Nursery May 2012

Germination rates of good quality seeds from stands located south of Houston (Kidprice Lake, Smoke Mountain, Sibolas) have consistently exceeded 50% whereas germination rates of small, poor quality seeds from the Smithers area (Hudson Bay Mtn, Telkwa Mtns, Babine Mtns) have been much lower.  Germination rates from our 2013 seed collection exceeded those from seeds collected in 2011.  This was due partly to more favorable weather conditions for cone maturation in 2013, and partly to 20 weeks rather than 12 weeks of cold stratification.  New results from Alberta suggest that northern whitebark pine seedlots will also greatly benefit from an extended period of warm stratification that allows underdeveloped embryos to mature. 

From 6900 seeds stratified in 2011/12, we successfully grew 817 seedlings that were out-planted in 2014.  In 2014/15 we stratified 19,000 seeds and currently have some ~7000 seedlings growing at Woodmere Nursery for out-planting in 2017.

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Flat of nursery seedlings from high quality Kidprice Lake seeds April 2013

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Lessons to date indicate that collecting small, immature cones and seeds from the northern limits of whitebark pine’s range will result in low success rates in the nursery.  For gene conservation purposes of this endangered tree species, we do, however, need to collect seedlots from a range of locations and elevations, and will need to accept poorer results than for commercial tree species.  Fortunately, new research at provincial tree seed centres in BC and Alberta are helping to refine the techniques originally developed further south to improve seed handling and nursery growing regimes for our northern seedlots.

Many thanks to Joe Wong and the staff at Woodmere Nursery for generously growing these seedlings for us.