The western larch (Larix occidentalis) is one of three species from the genus Larix that occurs in North America. The western larch’s range is in the basin of the Upper Columbia River, with the tree found in parts of British Columbia, Montana, Washington, Idaho and Oregon. The western larch is a deciduous conifer, dropping old needles in the fall and developing new needles the next spring.
Size and Form
The western larch grows to heights ranging between 100 and 180 feet, with the United States Department of Agriculture noting some can grow to be over 200 feet tall. The width of the trunk, at the level that matches the chest height of a human being, will be from 1.5 to 3 feet wide on a mature specimen. The western larch can live to ages of around 700 years old under the right circumstances. The mature western larch often lacks branches for the first 60 to 100 feet of its trunk, with the upper part of the tree taking on a pyramidal shape.
The needles of western larch feature sharp points and they grow in clusters, although on occasion some will emerge by themselves on the twigs. The needles will be an inch to 1.5 inches in length and a cross-section view of one of them will show they have three sides. The needles are stiff after they develop in May or June. They are a light shade of green, which changes to yellow before they tumble from the branches in October or November.
The cones that grow on a western larch are oblong to round in shape and from an inch to 1.5 inches long. The cones will grow on top of the limbs in an upright position, with each cone having a very short stalk to which it attaches to the branch. The cones have pointy bracts protecting their woody scales, giving the entire cone the appearance of being spiny.
You will typically find the western larch growing in stands of similar sized trees, since this species cannot tolerate the shade. Those that do wind up in the shade of larger trees will have a crown of branches that deteriorates, reports the National Forest Service. Most grow on the slopes of mountains or in moist but well-draining valleys within the range of the species.
The bark of western larch is thick--so thick that it makes the tree more resistant to the effects of fire than any other tree in the northern portion of the Rocky Mountains. The tree has a deep and large root system, so very few larches fall victim to high winds. Although the areas where larches grow can receive significant snowfalls, very little snow accumulates on this coniferous species because it does shed its needles.