Northland Nature: Oaks grow new leaves, catkins

Those of us who regularly walk in northland forests find that going out now, in late May, we are surrounded by happenings. Each day while walking, I note sights or sounds and think, “that wasn’t here yesterday.” This is a great time to see that there is a new story here every day. And I’m sure that there will be more tomorrow. The green leafing of trees is reaching its end. Soon the woods will have reached a complete green canopy, reminding us of last summer.

Below, on the forest floor, early spring wildflowers that thrived in sunlight are waning and giving way to the next batch of wildflowers — the shade-tolerant ones. During recent weeks, these plants have been growing thick under the trees, soon to bloom. But when I came here recently, I discovered a few that already had begun to flower. The seven-petaled white blossoms of starflower are blooming, and nearby, the tall baneberry, 2 feet tall, holds its cluster of small white flowers. Soon, others of this unique group will join as we exit the month: wild lily-of-the-valley, sarsaparilla, blue-bead lily and bunchberry.

Trees have been producing more than new leaves. We also see their blossoms. This arboreal flora show began with wild plum, but was quickly followed by Juneberry, pin cherry, elderberry, crab apple and chokecherry. Later, in June, viburnums and dogwoods also bloom.

But as we now look among tree branches, it is often that we try to see others also present. This is still the time of bird migration. Each day, each walk, will reveal newcomers to the woods. Warblers may be the most varied and abundant new arrivals. They present a challenge to see and discern. Fortunately, they wear breeding plumages and often sing. Warbler watching is best done with binoculars and patience. But these active little birds are not alone. Other migrants here include orioles, grosbeaks, tanagers, thrushes, sparrows, vireos and hummingbirds. All make use of trees to pause, feed and sing. We look into the newly foliated trees a lot now.

One of the last trees to become fully foliated are the oaks. In our region, northern red oak is most common. Burr oak, pin oak and white oak may be in the outlying areas, west or south of us. These large and powerful trees that make up much of the local deciduous forests are slow to get new leaves. But now, in late May, they join the forest foliation. Leaves are lobed and at first appear a bit reddish. And as we look among their branches, we are likely to see another growth of spring besides leaves — the catkins.

Catkins on several other common trees have been with us for the past couple months. We saw long “hot dog” growths on alders, willows, aspen and hazel in April. In May, birch had their long, descending catkins as well. Now is the time for oak catkins. These grow as a cluster near the end of the twigs. Not as colorful as blossoms, they are the flowers of oaks. Oak catkins hanging down several inches are male (staminate) flowers. The female (pistillate) are small and form at the base of the catkins. It is weeks from now, but the fertilization of these will lead to a new crop of acorns. Like other flora of spring, they will not last long. We’ll soon see them falling onto the ground, driveway and deck after they mature. But for now, oak catkins show us another example of the new growth here every day.