Pit and pit aperture dimensions in plantation-grown Douglas fir as affected by local growth conditions and height in stem

What is it about?

This study concerns pit sizes in stems of Douglas fir trees. Pits are the connections between the elongated cells that conduct water and nutrients from the roots towards the needles. Pit and pit aperture diameters were measured in plantation grown Douglas fir trees from two different sites in Denmark. One site was fertile, the other more poor. Results showed that pit diameter varied between 17 and 24 μm and decreased with increasing height above ground. Representing the position in the tree as a power function of distance from the top of the tree (L0.2) rather than the height above ground improved the model fit for pit diameter. However, the pit diameter relationship was found to be affected by site, suggesting that anatomic dimensions relate not only to tree size, but also to growth conditions, contrary to an existing hypothesis suggesting that the size of anatomical features are linked solely to tree height. That is: According to the current study, two trees with the same height and growing at two different sites will not necessarily have the same pit sizes if they do not also have the same age.

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