Description

Douglas firs are coniferous trees that tend to be pyramidal, or classic Christmas tree-shaped. They have a strong resinous odor (classic Christmas again!) that many conifers with a similar appearance lack.

Stewardship Considerations

Douglas fir trees are very flammable due to their leaf shape and resinous quality. Although Douglas firs are native to Mendocino County, fire suppression has caused encroachment of Douglas fir into oak woodlands.

Many inland Douglas firs may also be dead, dying and/or drought- and disease-stressed. When possible, take out Douglas fir trees that encroach into oak woodlands. Douglas firs growing in areas with coastal influences tend to be healthier and can be thinned, spaced and/or limbed-up if they are not crowding out native oaks.

Douglas fir does not stump-sprout, although some stumps may form a cap and continue to grow in girth.

If it is impractical or undesirable to remove a tree, limb-up branches using correct pruning techniques. Conifers often have naturally occurring dead and dying lower branches, because lower branches get shaded out. No more than 1/3 of the crown, or 15% of living tissue, should be removed.

Douglas firs might tolerate relatively drastic pruning, but removing too much top growth (lion-tailing) decreases tree stability. Removal of branches greater than ½ of the trunk’s diameter creates a portal for disease. Removal of too many lower branches at once may also stress the tree, thereby increasing future fire risk.

Bottom left: Douglas fir encroachment into oak woodland.

Bottom right: Douglas fir cone. Identifying cones on the tree or on the ground below a tree is the easiest way to differentiate Douglas fir from other conifers. Doug firs have 3-pointed bracts with the appearance of the tails and back legs of mice diving into the scales of the cone. The needle-like leaves usually radiate out from the stem in all directions, and tend to be soft to the touch.

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Learn more about Douglas fir trees from the California Native Plant Society