Annual growth is reflected by patterns seen in the branches of conifer trees. Robert Knudson, a local biologist, points this out in a terrific YouTube video about our Northern Minnesota conifers. Pictures in this post illustrate two of the patterns featured in his presentation.
Annual growth of Balsam Fir
The pictures above show buds of a Balsam Fir that are the starting points for next year’s new growth. Note that the buds are in groups of three.
Zooming out, the picture above shows how last year’s group of three buds at a tip of a branch (at the red dot) have grown out to produce three new branches. Each new branch has its own set of three buds at its tip.
Zooming out again, the picture above shows the pattern of annual growth in this Balsam Fir branch. The picture is annotated with alternating red and blue lines to indicate five years growth of this branch.
Annual Growth of Red Pines
Stands of Red Pine are shown in the pictures above. Note that branches are seen at fairly regular intervals along the trunks of the trees. Each interval between levels with branches reflects one year of the tree’s growth. The age of a Red Pine can be roughly estimated by counting the levels with branches along the trunk of the tree.
White and Jack Pines have the same growth pattern, but not as pronounced or regular as seen in Red Pines.
I noticed that this growth pattern is also evident in knotty pine tongue-in-groove panelling. As shown in the photos below knots in the wood are at regular spacings, reflecting yearly growth of the pine trees.