To find the age of trees, we core them. Yet some trees are too small to core. Instead, we count "annual internodes."

What does that mean? Spruce seedlings produce a "whorl" of branches each year, all coming outward from the same point. Although the branches don't all survive, a small ridge-- like a scar-- remains. If you count each scar from each year of growth, you can estimate the age of the tree.


 Estimating the age of a seedling. Just because it's small doesn't mean it can't be 40 or 50 years old!

Listen to Dr. Andrea Lloyd describe how we counted seedlings. Click here for text.

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We measure the height of each seedling...

 ...and just like we do for all adult trees, we measure each seedling's basal diameter (how big around at the base).



 Trees that are too small can be damaged by coring. Because we want to keep these trees living, we get an age estimate by...

...counting the "annual internodes." During each year of growth, the seedling produces a whorl of branches out from the stem. To get an estimate of the seedling's age, we can count those whorls up the stem, and if the whorls have broken off, we can count the little scars that remain.



If the climate warms, will treeline be able to advance? If so, are there places that might be easier for treeline to advance? To help answer these questions, we want to know what each seedling is growing in. What plants are around? What type of tundra is it? (The many seedlings in the picture above are growing in "mineral soil.")

How tiny are some of the seedlings we are counting? This seedling germinated (started growing from seed) this year and was one of the tiniest ones we've seen at about 2 centimeters.
