What is a Quality Seedling?

Good seedling quality is one of the key components of a successful forest regeneration project.

A high-quality seedling will survive prolonged periods of environmental stress and grow well following out-planting. While there have been many definitions of seedling quality over the years, at ArborGen, we tend to follow the bareroot specifications detailed in this graphic from Auburn University Southern Forest Nursery Management Cooperative. We produce seedlings that have a woody stem and secondary needles (needles in fascicles) and a 10 to 12 inch top. We also specify a 6 inch tap root with preferably eight or more primary lateral roots, an average root collar diameter (RCD) of 5mm or more, and a seedling that is free from incidence of insects and disease. These seedlings specifications produce seedlings that work well for either hand or machine planting operations. Our container seedlings have similar specifications with the key differences from bareroot being that the root length is limited to the length of the container, and container seedlings have a slightly smaller target RCD of 4 mm.

Our Process For Assessing Seedling Quality and Health

Seedling quality is a high priority at every ArborGen nursery. The nursery teams routinely monitor seedling health and growth along with soil moisture and fertility to ensure that we produce a quality seedling. In addition, the ArborGen Product Development Seedling Quality Team provides an independent, second set of eyes looking at the quality of seedlings at every nursery. We track seedling growth throughout the growing season, comparing the current season’s growth with previous seasons. We also compare our results with those of the nursery teams to make sure that seedlings are growing at the rates they should be to achieve the proper shoot and root dimensions at lifting. Then in December, our Product Development Team will lift and measure seedling height, diameter, and root length and count root numbers to determine the percentage of trees that meet our specifications. We also ship seedlings to Auburn University for a third independent assessment of seedling quality. Auburn will measure many of the same traits that we do, along with calculating the root weight ratio.

Why do we emphasize seedling root collar diameter in our assessments?
A good root system is key to seedling survival. It is like the foundation of a house. It is the support for everything that is going on above ground. A good root system at the time of planting will generate new roots quickly. These new roots are necessary when spring arrives, and the seedling starts new top growth. Without a good root system, there is not enough water and nutrient uptake to support the new top growth, and the seedling is prone to a slow start or may even suffer top dieback. Root collar diameter (RCD) is highly correlated with root mass. So by monitoring our seedling RCD, we are indirectly monitoring root system development. Several research studies over the years have shown the positive link between seedling caliper and bareroot seedling survival like the chart below from David South (1990). Factors such as the quality of site preparation, planting date, planting quality and weather also affect survival beyond RCD.

David South’s Quality Pine Tree Seedling Survival Chart from 1990, which showcases the survival rate of seedlings based on Root Collar Diameter at the time of planting (in millimeters)

Whether you are buying our advanced genetic seedlings such as MCP or open pollinated seedlings, you can rest assured that ArborGen is committed to providing you with the best quality seedlings available.

Seedling Delivery:
Where You Want Them, When You Want Them

On time delivery of seedlings to you is a critical step in providing fresh, healthy seedlings for planting at your site. ArborGen will partner with you for delivery of your seedlings using the optimum mode of delivery, packaging, and scheduling. The final method of shipping and cost to deliver will be based on our efforts to achieve the lowest cost solution while meeting your service requirements for delivery. All orders shipping from ArborGen locations or coolers is shipped F.O.B. nursery of origin. You always have the option to pick your seedlings up at the nursery.

To ensure the lowest cost and best service, we request 5 business day notification for pine and 10 business day notification for hardwoods, whether you are having them shipped or you are picking them up.

An additional service available to you for medium to large volume orders is refrigerated van rental for the purpose of dropping the van at your site for as many days as required to complete planting.

Seedlings lifted before January 1st typically have limited storage time. Please contact the nursery providing your seedlings to see how much storage time can be used for the seedlings. This could impact the number of seedlings being delivered in a single shipment recognizing the time required to plant the seedlings once delivered.

Please contact your Reforestation Advisor or your local ArborGen nursery for more information.

Limited Number of Hardwood Seedlings Available!

Contact ArborGen, your hardwood seedling source

Protecting Your Seedlings During Transit

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