In September, as fall descends upon Alaska and the deciduous trees turn gold and then become bare, one is more keenly aware of the species of trees and shrubs found in Alaska. The majority are classified in six genus, though within each genus there may be a proliferation of species. Here’s a brief guide to the major trees and shrub groups in the state.

Alders (Alnus species)

Alders can be found in open woods and in moist areas along rivers and creeks. There are found everywhere in the state, though in the harsher northern climes they may appear as a stunted or low growing shrub. Typically alders are many branched and can form dense thickets.

Alders can be recognized by their leaves with serrated edges. Male and female flowers appear on the same plant. Male catkins are long and drooping with a somewhat cottony appearance as they shed pollen. Female catkins are green initially, but mature into woody cone-like fruits that remain on the branches all winter. This makes the alder easy to recognize after leaves have fallen.

Perhaps the most common use of alder in Alaska is for flavoring fish. Smoky fires made with fresh cut alder branches impart a delicious flavor to smoked salmon.

Birches (Betula species)

Like alders, birches range throughout the state. This genus includes the white-barked paper birch as well as the Arctic-hardy dwarf birch. Birches can be found in bogs and tundra in shrub form or in subalpine forests as 45 foot trees.

Birches are perhaps one of the most widely used trees in Alaska. As one of our few hardwoods of significant size, birch is prized as firewood. But it also has numerous other uses. The white bark of the paper birch is harvested for use in making baskets and a variety of other craft items. When the sap rises in the spring, many tap the birches in their area and hang buckets, enjoying the sweet fluid as it is or, if they’re fortunate enough to have a large grove of birch trees, boiling the sap into syrup. Unlike maple syrup, though, with it’s 30:1 sap to syrup ratio, a gallon of birch syrup requires 80 to 100 gallons of sap!

Hemlock(Tsuga species)

The hemlock is an evergreen tree of the pine family that is found in southeast Alaska. While it can be found at a wide range of elevations, you won’t find one growing wild north of the Kenai Peninsula. Two species are found in Alaska, the western hemlock and the mountain hemlock, both of which range south to the Pacific Northwest.

In mixed conifer forests, a hemlock can be recognized by its drooping tip. Hemlocks have flat needles and produce purple tinted cones that turn brown at maturity.

The hemlock is an important tree for the forest products industry and is harvested for both pulp and lumber.

Poplars (Populus species)

The poplars in Alaska include the balsam poplar or cottonwood and the aspen. This is another deciduous tree that ranges widely in Alaska, being found as far north as the Brooks Range and all through southeast Alaska. According to one source, the quaking aspen, P. tremuloides, is the most widely distributed tree species in North America. They favor river valleys and south-facing hillsides; in the fall, they weave golden threads across the landscape.

The aspen has smooth greenish-white bark marked by dark horizontal lines. The leaves, which quiver in the slightest breeze, are shiny above and have a hint of silver below, creating a shimmering effect in the right conditions. Cottonwood, on the other hand, develops deeply furrowed bark as it ages. Though typically short lived, they can be up to 400 years old and get quite large. Cottonwood trees produce either male or female flowers; an early summer breeze may release the abundant cottony seeds and create temporary “whiteout” conditions or leave a light blanket of “snow” on the ground.

Poplars have aggressive root systems. In the case of the aspen, this is the primary means of reproduction – groves of aspens are typically one plant which has cloned itself and spread. These clonal colonies are considered a single organism. As such, they can be quite large (encompassing several acres) and old, as they continually renew themselves by producing new saplings.

Spruce (Picea species)

Black spruce, white spruce, and Sitka spruce round out the state’s coniferous trees. Sitka spruce, as the name suggests, occur in coastal forests in the southeast part of the state. Black spruce are found in boggy, wet conditions typical of land underlain by permafrost; white spruce prefers well-drained soil and can be found as far north as the Brooks Range.

Black spruce and white spruce ranges overlap considerably, but they are usually quite easy to tell apart. Black spruce tend to be small, scraggly, and not very attractive, though they are tough little trees well suited to the poor conditions in which they typically grow. White spruce, in contrast, are typically tall, straight specimens. They are often used in log buildings or furniture. Spruce is also the main firewood species for Alaskans who heat their homes with wood.

Willow (Salix species)

Willow is ubiquitous in Alaska. By one count there are more than four dozen species in the state. They range throughout the state and are extremely hardy and adaptable. They sprout easily and colonize disturbed soil and fire-stricken lands quickly. Their propensity for hybridizing makes it difficult to identify species; one must often just be content to note that the plant is a willow.

Most are familiar with the fuzzy buds that appear in early spring as warmer air and longer daylight hours arrive – the “pussy willows.” These are the early flowers of the species, with male and female flowers appearing on separate plants. Willow leaves, although coming in a variety of shapes, are usually longer than they are wide and smooth underneath. The exception is the felt leafed willow, S. alaxensis, which as its name implies, has leaves with fuzzy bottoms.

Willow is an edible plant (though not all species are palatable) and packed with vitamin C. Willow also contains the compound salicin, an intermediate form of salicylic acid, one of the main ingredients of aspirin. Perhaps this is why willow is a favorite food of moose in winter. It is also a winter staple in the diet of snowshoe hares.