Lowland Conifers
Lowland conifer stands in Wisconsin contain a variety of species and provide
a variety of values. Balsam fir, black spruce, tamarack, and northern
white cedar are the most common dominant species in lowland conifer stands.
Common associated species include hemlock, black ash, red maple, and balsam
poplar. While several of the dominant and associated species can be found
growing on upland sites, lowland conifer stands are found on wet sites
including wet mineral soils as well as mucky peat soils. For more details
on the growth characteristics of lowland conifers, see the USDA
Manual of Silvics.
Lowland conifer stands will rarely be as productive for timber as upland stands with similar species. However, conifers tend to be more productive on lowlands than broadleaf species. Cedar has the potential to produce sawlogs under certain conditions, but most other lowland conifer species usually only produce pulp products.
In addition to timber product values, lowland conifer forests have great value for both wildlife and water quality. Lowland conifer stands provide critical wildlife cover in the winter. In particular, whitetail deer tend to yard and feed in cedar stands, and where deer populations are particularly high, browse pressure can prevent successful cedar regeneration. Additionally, lowland conifer forests provide significant benefits to both surface and ground water quality. Lowlands are typically groundwater recharge zones, and forested lowlands protect those recharge zones. Forest vegetation also stabilizes soil and protects surface water.
Tom and Mary DeWitt have some lowland conifers on their property in Rusk County, and the DeWitts have chosen the hands-off approach to managing these stands. Their primary objective is aesthetics as these stands are directly along the Ice Age Trail in this area. The DeWitts are also concerned about protecting the wet soils in these stands, and the very low timber value of these stands on the DeWitt’s property doesn’t warrant the risks of harvesting.
Other landowners may choose to manage their lowland conifer stands for timber products and the exact silvicultural system used may depend in part on the species composition of the particular stand. Timber production in lowland conifer stands typically follows an even-aged management strategy with strip clearcutting being the most common prescription. Strip cutting involves clearcutting strips 120-to-180 feet wide. Strips should be oriented perpendicular to the prevailing wind direction. Begin with cutting the most leeward strip and cut every third strip. Once strips are fully stocked with new regeneration, proceed with cutting the second set of strips. In stands dominated by cedar, a shelterwood system may work somewhat better than a strip cut system, but any type of regeneration of cedar is essentially impossible in areas with dense deer browse and winter yarding. In stands dominated by black spruce, full clearcuts may be possible when followed by direct seeding. Without disturbance, cedar and tamarack stands will eventually convert to a more shade tolerant species composition. In all harvests intended to regenerate new tree seedlings, the seedbed should be disturbed and slash should be spread lightly throughout the stand. Intermittent thinning harvests (the removal of some of the trees to promote the growth of the remaining trees) in swamp conifer stands during stand development typically do not pay unless there are a significant number of cedar crop trees whose crowns can be released.
Silvicultural prescriptions for the successful regeneration of lowland conifers are somewhat less consistently reliable than for upland stands, so working with an experienced forester is highly recommended. For more details on managing lowland conifer stands, see the DNR Silviculture and Forest Aesthetics Handbook.
Whenever heavy equipment is used in lowland timber stands, it is critical to take great care to protect soil resources. Wet soils are particularly prone to damage and rutting from the operation of heavy equipment, so heavy equipment should be restricted to the season when ground conditions are fully frozen.