Container Seedling Inspection

Inspection of container seedlings is similar to that of bareroot seedlings. As with the bareroot inspection, regions have different assessment forms to fill out during the inspection process. The Northern Region (R1), for example, uses the Stock Quality Assessment Form, R1-FS-2470-21, to document assessment of the delivered stock. Use one form for each lot of trees received. The form is designed so that once the standard is understood, the quality of the trees can be indicated by a mere checking of yes or no boxes. A narrative section is provided to explain why the trees are not acceptable. The seed lot number, pack number, and pack date at the top of the form is required for lot identification and may be taken right from the end of the tree boxes. Tree quality items to check when inspecting container stock are:

General Tree Vigor

Abnormal tree color, dry or damaged roots, needles falling off, and similar maladies suggest problems. Always check the condition of the root and stem cambium, along with the buds.

Root and stem cambium-To check the cambial tissue, peel back the exterior bark of the roots and stems. The cambium underneath should be glistening white or a creamy color. If the cambium is brown, yellow, or creamy brown, the trees have been damaged by freezing, poor storage, or fungal attack. This may also indicate damage before packing.

Buds-Slicing the buds vertically should reveal green, healthy internal tissue. Brown, black, or yellowish tissue in the bud is a sign that the bud has been damaged. If just the terminal bud has been damaged, the trees can still be planted. If the other buds are damaged as well, the stock should be thrown out.

Needles-Dry or wilted foliage is a sign of stress or damage. Spruce and Douglas-fir needles that fall off when they are brushed are dead. Pine needles that easily break when bent are also dead (unless the needles are still frozen). (top)

Adequate Root Mass

The root mass should be developed to the point where the plug can be extracted from the container and still retain its original form. Excessive root development, or pot binding, is not acceptable. To check, shake the plug until the media pulls away from the roots. Most of the roots should be pointing down, with the exception of small, lateral horizontal roots. Larger roots should not be circling or spiraling the plug. If large horizontal roots are spiraling the plug, or if the plug stays in a thick net (the shape of the original plug), the tree is suffering from pot binding. Pot-bound trees often will not develop into a normal tree. (top)

Moist Root Media

Generally, the roots and plug should be moist when seedlings arrive. Plugs of dormant stock can be relatively dry. Dry roots are not uncommon for container stock delivered during the spring. (top)

Live Roots

Check whether roots are alive by stripping the outer layers of bark with a pocketknife or fingernail to expose the roots' cambial tissue. This tissue will be a white to cream color in healthy roots and brown to yellow tan in dead roots. Tree boxes can be checked by taking a tree from the top, center, and bottom of a box. Do not be alarmed to find that some roots are dead a quarter of an inch or less from the cut ends. This is normal. Also, in some species (especially Douglas-fir) a portion of the fine root system may die with no apparent adverse effect to the tree. However, if more than 15 to 25 percent of the roots are dead more than half an inch from the tip, there is reason for concern. Seek advice on the quality of the stock. (top)

Caliper and Height

Nursery cull standards for both top height and stem caliper should meet nursery standards. Unless agreed to otherwise, at least 95 percent of the stock packed should meet this standard. Contact the Nursery Manager for the top caliper and height requirements.