There are a plethora of stocktypes and common language used in the world of forestry and Christmas tree stock. You will hear and see the same thing said in very different ways and with different numbers and letters all over the place. This is a very brief description of the most common terms used to help understand the basics of seedling stocktypes. Here is a great resource that goes into more detail on the subject.
P+0 (commonly P0), P+1, 1+1 are the three main descriptions you will see when people talk about what size tree it is. The first letter or number refers to where the seed was started. P stands for a plug which is sown in a greenhouse. 1 stands for the first year sown in a bareroot field for the first year usually at high densities. The second number refers to where the tree was grown for the second year. A P0 is a 1-year- old plug that was shipped after its first year to the customer and was never transplanted. A P/1+1 means it was grown the first year in the greenhouse or field then lifted and transplanted at a lower density in a field for the second year.
- 1+1 – is the dominant stocktype for Douglas-fir in the industry and is a large robust seedling.
- P+1 – is the dominant stocktype for minor species like western hemlock and western red cedar. It is also used for more southern Oregon coastal Douglas-fir which is more susceptible to frost in first year fields.
- P0 – is the dominant stocktype for Noble fir, western larch, ponderosa pine and other minor species as well as 1-year- old Douglas-fir plugs. P0’s range is size depending on the species, geographic location, and site variable from 6 inches 3 to 20 inches 3 . The most common format you will see for plug size is an “S” in front of the number which refers to a styroblock(add link https://www.stuewe.com/products/beaver.php) (most common growing container) and then the volume of the cell in cubic inches.
All stocktypes when ordered are designated as a winter lift (December-March) and ship seedlings unless you specify in the comments that you would like to plant them in the fall.