The beloved aspen. Their long and lean trunks are easily recognizable, and their yellow hues this time of year remind us our season is changing. Most forest ecologists consider it a pioneer species, meaning that when aspen is present in the forest, and when the forest is heavily disturbed by fire, wind, or clear cutting, then aspen fills an ecological niche. They sprout by the thousands. According to the Wisconsin DNRʼs Silviculture and Forest Aesthetics Handbook, after an aspen stand is disturbed, root suckers generally sprout 10,000 to 30,000 per acre. And that is not brush, itʼs healthy, young trees. Shortly after these areas burn from forest fires or shortly after clear cutting an area, we typically find aspen sprouts numbering over 20,000 saplings per acre.
But our aspen ecotype is now being threatened in the state of Wisconsin. And itʼs not from logging! In-fact, forest ecologists attribute the declining acreage of aspen forests due to better fire suppression and a reluctance of our society to simulate fire disturbance by clear cutting. Clear cutting has become taboo, a four letter word of sorts. It is ingrained in many peoplesʼ minds as a bad thing, and nothing good comes from it. But, as we see less clear cutting, the trade-off is that the aspen ecotype is being depleted. As aspen now have the time to mature and die, more shade tolerant hardwoods are taking over the forest.
There are several bird species whose life cycles are dependent upon young aspen stands. The woodcock and gold-winged warbler are two species whose recent population declines are a direct result of suppressing fires, an aging aspen forest and minimal disturbance harvesting in aspen stands. The birds need the dense, young stands of recently disturbed aspen to raise their broods.
At Kretz Lumber Company, we get very little of our raw material from aspen clear cuts. But as a forester, the aspen life cycle is the most dramatic and illustrates the dynamic nature of our ecosystems. We should not forget that forests naturally grow back after harvest and the forests we see today will change over time.
You may disagree with clear cutting as a practice. And certainly, there are certain timber types that generally should not be clear cut for a host of economic and ecological reasons. But in the case of aspen, itʼs decline is resulting in less ideal habitat for birds and a changing of the Wisconsin landscape. And we must remember, because we are entering unprecedented territory, the impact this decline will have on our ecosystem in the future is still unknown.