What is a Quality Seedling?

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

ArborGen is unique in the nursery business as the only company having a Seedling Quality Assessment (SQA) program that includes seedling quality measurements we take at each nursery as well as quality measurements taken by the Auburn University Southern Forest Nursery Management Cooperative.  Seedling quality is critical because 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 follow the bareroot specifications detailed in this graphic from Auburn University Southern Forest Nursery Management Cooperative. We produce seedlings with 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 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 size of the container, and container seedlings have a slightly smaller target RCD of 4 mm.

The significant resources we put into our SQA program show that 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 ensure 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 and calculate 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 sound 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 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.

Whether you are buying our advanced genetic seedlings such as MCP^® or Open Pollinated (OP) seedlings, you can rest assured that ArborGen is committed to providing you with the best quality seedlings available.

Sawmill Expansion Continues

With housing starts expected to stay at high levels over the coming years with generational household formation, sawmill construction and expansion is growing hugely.

FEA, RISI, Forisk and other industry experts point out that any lumber production growth in the US will take place in the US South. Log shortages in Canada and log demand outstripping supply in the US West coupled with large timber inventories make the South the place to expand.

The future does look brighter and there are already pockets of hot log markets in SC, GA, and MS. Now IS The Time for planting the best genetics available (such as MCP®) for higher yields and for better log quality to position you for sawlog demand in the future. Even if log prices stay flat, landowners who have the most productive, high-quality timber will be the most successful.

Customer Success Story

MCP^® Seedling Update

MCP Piedmont and MCP Coastal are still available, but going fast.
Get in touch soon to secure your order.

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