If you’ve ever ordered your own seed or bought overruns you’ll have heard about seed transfer guidelines.
Trees grow best in the spot they’ve evolved to grow in. I don’t know if you’ve noticed, but trees don’t move around much, or at least not until they are cut down. Then they go on a road trip. When they are alive, growth rate and vigour are based on the resources their roots can access. They can’t travel south when it gets cold, or find a shady spot when the temperature skyrockets. In order to survive, trees are incredibly diverse and families have traits that help them survive elevation, temperature, and length of season as well as different forest pathogens.
Let’s start with some definitions. Seedlot: A seedlot is a quantity of seed with similar characteristics. Depending on if they are from a natural stand or seed orchard, there are different requirements on what would be considered a seedlot. For natural stands, seed must be collected from at least 10 individuals. Seed orchard seed is given a Genetic Worth (GW) value, which is an index to identify breeding improvements in growth and yield as compared to natural seed. Seedlot characteristics also guide what area the seedlings will grow best.
Where to plant the seed is incredibly important as, in our original assumptions above, we’ve determined that live trees cannot move. Over the years the B.C. government has developed different algorithms to determine what areas seed can be planted. It all began with seed collected off of ‘natural’ trees which could be transferred based on latitude, longitude and elevation. Then we got fancy and started breeding trees in seed orchards. This ‘orchard’ seed was given a name to go along with that premium price you pay: Class A. Cones that are harvested from natural stands are Class B and are, of course, cheaper.
You are legally required to buy the best seed available for the area you are planting. This means you must buy Class A if it is available, even if Class B is available and considerably cheaper. Class A seed has Genetic Worth (GW), but perhaps just as importantly, some seedlots have better resistance to some forest pathogens. If your woodlot has a high degree of rust, GW may not be as important as resistance to rusts. Just as choosing the right bull for the cattle you have in the back pasture, choosing your seedlot family characteristics is just as important of an investment.
Class A seedlots used to be assigned a Seed Planning Zone (SPZ) based on where the seedlot family originated and what environment the family will grow well within. This is called the geographic based seed transfer guidelines (GBST). Seedlots could have one or multiple SPZ’s and the seedlings could be planted anywhere within those SPZ. Planting a tree outside their SPZ is considered ‘off site.’
About a decade ago, this little thing called climate change became all the rage and the B.C. government started to model how Biogeoclimatic Zones will move as the climate changes. From that they developed a new seed transfer process which is based on BEC (Biogeoclimatic Ecosystem Classification) zones. The balancing act with all of this is again based on trees not being able to move.
We need to plant trees somewhere they will survive today while still being able to thrive in 100 years. Every tree we plant is a very long-term investment! This new seed transfer guideline is called Climate Based Seed Transfer (CBST).
As of May 2022, seed can only be ordered for BEC zones identified in the Climate Based Seed Transfer (CBST) area of use. To determine what seedlings fit for your woodlot, you need to know the BEC zone, subzone and variant of the block you are planting (e.g. SBSmc2). Your nursery or forester can take it from there. Or if you’ve got access to the Seed Planning and Registry Application (lovingly known as SPAR), you can find the information in the CBST tab in seedlot details. You can get access to SPAR as a woodlot licensee and review all the seedlots available for purchase. Admittedly, this is not as interesting as perusing a West Coast Seeds catalog, but there is information on each seedlot such as germination rate, disease resistance and genetic worth.
There are a number of reasons to make sure you choose the right seed for your woodlot:
- The first is of course, compliance. Only a small amount of your seed can be ‘offsite.’
- Second, and more importantly, seed transferred correctly gives you the best chance of having high survival rates and high growth rates. Seeds planted in areas they aren’t suited to grow in will not flourish.
- Third, the viability of your plantations directly impacts your AAC. Healthy, vigorous trees increase your AAC. Remember those Class A seeds you pay a premium for? When you do your next inventory calculations, make sure to add Genetic Worth in your future reforestation projections.
So, make sure you are using the new Climate Based Seed Transfer (CBST) Guidelines when you buy your overruns this year or when you sow this fall. This will not only keep you in compliance, but also makes the best investment possible on your woodlot. B.C. has been breeding seed for a number of decades and by choosing parents for certain traits and testing the offspring we have some very robust seed on the market. Now we have a new seed transfer protocol to make sure that seed is given the best BEC Zone to grow on based on family characteristics.