Seed Source Matters!

Melissa Spearing Ontario's Natural Selection, Seed Collector, Stock Production, Uncategorized

Since the early 1990’s the Forest Gene Conservation Association (FGCA) has worked to conserve the native genetic diversity of our urban and rural forests. This is an increasing challenge in the face of development, agricultural land use, invasive species and climate change, especially in Southern Ontario. Where forest conservation fails, restoration becomes the next and increasingly necessary challenge, and the importance of seed source cannot be overstated in any tree planting effort. Recognizing this is the first step to ensuring that we leave a renewable resource for generations to come. We are also working to help make it easier for consumers, government and practitioners to do the right thing with the most current science. As several large Ontario growers have shown, source-identified native stock can also be an economically viable endeavour.

The FGCA’s Seed Source Program is helping to increase the supply of high quality, source-identified seed and helping to educate and strategically move seed via these current initiatives:

  • Seed Collector Training and Mentoring
    • New Field Manual – Seeds of Ontario Trees and Shrubs (2014); going online in 2017. Click here for information on purchasing the manual.
    • Certified Seed Collector training and mentoring workshops – recently updated; part of our Ontario’s Natural Selections Seed Source Certification Program, in partnership with Forests Ontario and the Ontario Ministry of Natural Resources and Forestry’s Ontario Tree Seed Plant. Click here for information on upcoming workshops with Forests Ontario, or be put on a waiting list for when we hold one in your area.
  • Seed Collection Area Network (SCAN) – to date includes over 1,000 high quality native species seed collection areas in southcentral Ontario (including 8 grafted white pine seed orchards).
  • Seed movement analysis – to acquire (procure) and move (deploy) seed using MNRF’s Tree Seed Zones* and Natural Resources Canada’s (NRCan) SeedWhere climate-matching GIS tool. The FGCA can help suppliers acquire and market see, and buyers/consumers obtain adapted stock. SeedWhere specifically allows us to make decisions with climate change effects in mind. *(see attached MNRF letter re seed zone support at the bottom)
  • Developing USA seed contacts to facilitate strategic assisted migration for Southern Ontario; following up on our five assisted migration trials currently with Conservation Authorities

We look forward to answering any questions you have about any of these programs. And we are always looking for partners in these endeavours. Please contact us here.

Why Seed Source Matters, Especially in a Changing Climate

The FGCA initiated a voluntary seed source program, Ontario’s Natural Selections in the early 1990s to help all involved in tree planting better understand the importance of seed source – both location and seed quality. It is a matter of tracking a woody plant’s origin from seed collection through all stages of shipping, processing, growing and planting. With custody information intact, the consumer at each stage can then decide how appropriate it is for their site and their objectives. With climate change effects here and increasing, knowledge about seed source can help us relate planting performance back to the seed source, to repeat successes and avoid failures. Ultimately, we hope this program will help Ontario plantings survive and thrive, one tree or 10,000 at a time, to provide the many benefits we expect from our rural and urban forests.

The following FGCA information has been around in various formats for over 25 years; but this is nothing compared to the volume of seed and genetic science that began in Europe in the 1750s and has continued into modern genomics today. We hope you will work with us to remove ‘maladapted seed source’ from the many challenges of tree planting.

Seasonal Growth Diagram of a Conifer Seedling

Annual growth processes under genetic control (adapted from Fig 8.1: Regenerating the Canadian Forest, OMNR 2001)


Studies of many woody plant species done over the last few hundred years have shown that the timing and pattern of growth are under genetic control though the degree of control varies by species. They show that natural selection over thousands of years has created local populations in tune with local climate conditions. Species with large ranges (i.e. white spruce, trembling aspen) have many unique populations in terms of adaptive variation. This means that moving plants to a different climate, and especially different growing season lengths, is an experiment that could have negative consequences. Moving plants without any knowledge of their origin is especially risky.

Map of growing season length in 5-day classes in Southern Ontario.

Growing Season Length map (Ontario Forest Research Institute, 1996).


Ontario’s climate and geology is diverse. This figure shows the variation in growing season length (from the Ontario Forest Research Institute, based on CFS Ontario Climate Model 1996). The effect of the Great Lakes and elevation differences create a great range in climate. March is (usually) early spring in Windsor and winter in Algonquin. Other variables such as minimum winter temperatures, maximum summer temperatures, and seasonal precipitation also have an effect on growth potential and reproduction. Local climate change effects are hard to predict, but recognizing what won’t change, i.e. lakes and elevation, as well as the evolved climate parameters inherent in a seed source can help us be strategic.

Maximizing growth and minimizing risks are universal objectives in any homeowner or landowner’s planting project. Using locally adapted seed sources is a first step in achieving these. Bringing material in from dissimilar areas often results in low survival from heat stress or winterkill, frost damage, reduced growth rates, and increased insect and disease problems. Red oak, for example, grows over a wide range of climate and is frequently planted in horticulture and forestry. The Algonquin Park red oak (shortest seedling, right) has evolved over many, many generations to thrive in a minimum mean winter temperature of -21.5 degrees Celsius and a growing season length of only 185 days on average. The Niagara population (tallest seedling, left) is adapted to a warmer winter and a longer growing season of 230 days on average. Same species; genetically distinct populations. Algonquin red oak on a Niagara planting site would result in early growth cessation; Niagara red oak in Algonquin Park would suffer frost damage and winter kill. In both cases, the trees would be growing out of sync with the climate, be less vigourous than they should be and more susceptible to insect and disease damage. And we know nothing about future seed production.

Niagara to Algonquin red oak seed source trial 1996.

1-yr old red oak grown from various Ontario seed sources under the same greenhouse conditions; from an OMNR seed source study (unpublished, OMNR 1996).

Seed Source + Genetic Diversity + Seed Quality

Experts are increasingly aware of the importance of high quality plant material to the long-term economic and ecological success of planting efforts. Where some aspects such as species and stock quality (size and health) are easy to assess, seed quality even if from a known source, cannot be observed. It is a combination of physiological quality (and resulting effect on seed storage/germination rate or seedling size/health) and the breadth and quality of genetic diversity in a seedlot (e.g. outcrossed vs. inbred seed).

We encourage Certified Seed Collectors (CSCs) to collect in good seed years when they can get a lot of seed from many healthy trees in a localized area. This is not only efficient in labor but has large biological implications. The resulting large seedlot has a broad genetic base (with important buffering capacity for the many pressures over the plantings’ lifespan), greater germination vigor and if the seed is orthodox (can be dried below 10% moisture content), can be stored in a seed bank for a longer period of time. When sown immediately, growers can manage large seed lots more efficiently and economically than small ones. Buyers intererested in greater strategic deployment options should request greater detail from collectors, especially when dealing with edge-of-zone seedlots or planting sites, or in climate change assisted migration plans.

Again, high quality, source-identified seed is just the first step in successful tree planting. Consumers must still match the species and seed source to their planting site. We are working with partners such as Forests Ontario,, to educate people about local species diversity (, about matching species and stock type to their objectives, soils, site and labour resources, and about how to protect seedlings from competition, drought and browsing in the first few years.

Forests Ontario and the OMNRF’s Ontario Tree Seed Plant and the 50 Million Tree Program are key supporting partners. We are working together to ensure that homeowners and landowners understand what’s at stake. And to date several southern Ontario nurseries buy source-identified seed from certified collectors. We hope more will follow their lead.

Making a Seed Source Decision

We want to work with, not against, the genetic adaptation that has evolved over many generations, to ensure the long-term success of tree planting efforts; remember that the most expensive planting is a failed planting.

The red oak trial above shows local genetic adaptation is different than a species’ entire genetic diversity. If the plant material is adapted to conditions that substantially differ from those of the planting site, no amount of additional genetic diversity will improve the project’s success; no amount of tending, fertilizing, irrigation or pest control will help it grow as vigorously as a plant from a properly matched source.

You can consult the widely available Canada Plant Hardiness Zone Maps. Remember the Canadian and USDA maps of describing plant hardiness differ dramatically in how they are calculated (7 variables versus avg annual winter temp respectively). Also, a species described as being “hardy from Zones 2 to 6” only describes that species’ range, not the genetic adaptation of an individual or local population.

The OMNRF delineated the Tree Seed Zones (OMNR 1996), based on detailed information on Ontario’s climate (NRCAN 1996) and seed source study results that to date are limited to black spruce, jack pine, red oak, white spruce and white pine. Seed from within a seed zone is generally expected to be adapted to the climate anywhere within the same zone. However, seed zones do not compensate for mismatched soil, site or light preferences, e.g. silver maple preferring low, moist sites but red oak better for upland sites. As we learn more about native species’ needs, genetic diversity amongst populations and climate change, from both scientific studies and local observations, it is intended that these zones can be amended or empirical transfer values defined. Note that movement outside of seed zones boundaries is allowed only when the seed source is well documented and suitables sites can be matched.

SeedWhere software was developed by the Canadian Forest Service/NRCAN (Sault Ste Marie, 1996), to support decisions on moving plants across environmental gradients. SeedWhere addresses 3 basic questions:

  • Where can a particular seed lot be used, i.e. how similar are climatic conditions of a seed collection site to potential planting sites?
  • What seed sources are best suited to a particular planting site, i.e. how similar are climatic conditions of a planting site to potential seed collection sites?
  • With today’s best climate change models, where is the predicted matching climate in the future, i.e. where is the similar procurement or deployment sites for 2011-2040, 2041-2070, or 2071-2100 establishment?

The FGCA offers this service to consumers, seed collectors and growers (see example here). It helps us make the best use of available supplies of source-identified seed and trees. Please note it is difficult to make accurate SeedWhere maps when only the Seed Zone number is used; it depends on knowing an exact point from which to compare similar climates.

Who is the FGCA?

We are a non-profit corporation of organizations and individuals, including Forests Ontario, Conservation Ontario and Conservation Authorities, the Society for Ecological Restoration Ontario Chapter (SERO), Sustainable Forest License Holders, as well as landowners, forest managers, conservationists, planting agencies, seed collectors and growers. We promote the maintenance and restoration of the genetic diversity of Southern Ontario’s native woody plants. our main goal is to ensure the use of genetically adapted seed sources in planting programs. Whether they be urban, rural, commercial or private, it’s all one forest; it’s our foundation.

Click here for OMNRF Letter of Support for FGCA and Tree Seed Zones.

OMNRF Letter of Support for FGCA and Seed Zones

OMNRF Letter of Support for FGCA and Seed Zones, November 21, 2016.


References for geographic variation, seed source and transfers and demand for source-identified stock:

  1. Becker, C.E. The Chain of Demand. Landscape Architecture Magazine, May 2015. American Society of Landscape Architects.
  2. Cherry, M. 2001. Options for allocation afforestation stock in Ontario with anticipated climate change. Ontario Forest Research Institute, Information Paper No 148. Ontario Ministry of Natural Resources. 29 p.
  3. Eskelin, N., Parker, W.C., Colombo, S.J., and Lu, P. 2011. Assessing assisted migration as a climate change adaptation strategy for Ontario’s forests: Project Overview and Bibliography. Ontario Forest Research Institute Climate Change Research Report 19. Queen’s Printer for Ontario, Toronto, ON. 55 p.
  4. Kitzmiller, J.H. Genetic Considerations in Propagating Diverse Tree Species. Presented at the Western Forest Nursery Association meeting, Fallen Leaf Lake, CA, September 14-18,1992.
  5. Morgenstern, E.K. 1996. Geographic variation in forest trees. UBC Press, Vancouver. 209 p.
  6. White, T.L, Adams, W, T. and Neale, D.B. 2007. Forest Genetics.Chapter 8: Geographic Variation – Races, Clines and Ecotypes. CABI Publishing. Oxfordshire, UK. 704 p.
  7. Tree Seed Working Group News Bulletin, Canadian Tree Improvement Association. No 35, 2002. Legislation, policies and procedures review.
  8. Tree Seed Working Group News Bulletin, Canadian Tree Improvement Association. No 46, 2002. Seed Transfer.
  9. Yeatman, C.W. 1976. Seed origin – first, last and always. Environment Canada, Petawawa Forest Experiment Station, Information Report PS-X-64. 12 p.