Implementing the 3Ps of Oak Regeneration
By Dan Shaver
Planning, Persistence and Patience sounds more like the catch phrase for a self-help seminar than forest management, but if you want to grow oak trees in the Central Hardwoods Region commit the 3P’s to memory and then put them into practice. Oak trees are the backbone and bread and butter of the region. There are 18 native species of oak trees found in Indiana. Oak is a phenomenal tree if you love wildlife with over 96 animal species using if for food, well over 250 species of insects feeding, foraging or living on oak trees and many more animal species using oaks for cover or shelter. Our oak resources have been a mainstay in the timber industry for as long as there has been forestry in Indiana.
Unfortunately we are experiencing what ecologists refer to as the “oak bottleneck.” We have a lot of mature oak trees in Indiana. We also have a lot of young oak seedlings in Indiana. However, forest inventory and research shows that we don’t have a lot of oak saplings or pole sized oak trees. The bottleneck, or missing saplings and pole size oak is a result of 8 decades of fire suppression, too many deer, and forest management that favors shade tolerant species. If we want to ensure oak trees for future generations, we need to begin implementing the 3Ps of oak regeneration on private and public lands in Indiana.
The Nature Conservancy in Indiana has been working to implement the 3Ps on Nature Preserves and our private Forest Bank land across southern Indiana. Success is not easy or guaranteed, but we are making progress.
For example, in 2005 we purchased 80 acres of land from a neighbor in Brown County. The 80 acres had just been harvested. It was a marked sale that targeted mature oak, cherry and maple, but still left 20-22 inch DBH mature oak in the stand. It was a good harvest, but was not aimed at regenerating the understory. Once TNC purchased the property, we made the decision that, like most oak stands in Indiana, there was not enough oak in the understory or mid-story to replace this stand in the event the canopy was removed from natural disturbances like an ice storm or tornado, or a man-made disturbance like a harvest. We developed a PLAN to create Oak Advanced Regeneration (OAR). Based on research and a forest inventory we began thinning the mid-story and understory on what we felt were the best oak sites on the property. We deadened all trees less than 12” DBH in the mid-story that were not oak or hickory. We did leave some native small trees and shrubs like dogwood, service berry, and leatherwood. Fortunately we had some good acorn crops in 2005-2007. PATIENCE, two years after the understory thinning we had a really good crop of oak seedlings, but no Oak Advanced Regeneration (OAR). By this time we were getting some competition from muscle wood and ironwood in the understory. We made the decision to conduct a prescribed burn, PERSISTANCE. The disturbance favored the oaks. The next year we had less competition from other trees and the oak seedlings re-sprouted just like they are supposed to according to the research (big sigh of relief). PATIENCE, we waited again. The oaks were doing well, but not advancing like we had hoped – too many deer. We have hunters on the property and they are encouraged to harvest female deer, but we still felt the browse pressure was too high. We then built concrete reinforcing wire cages, 6 feet in diameter, and placed them over oak seedlings in the center of canopy gaps, PERSISTANCE. We could not protect all the oak seedlings, but we wanted to ensure that where canopy gaps existed, an oak was going to eventually take its place in the canopy. The oaks have been growing for a couple of years, PATIENCE. Inside and outside of the cages we were starting to get a significant number of Oak Advanced Regeneration (OAR). In the spring of 2012, we PLANNED and conducted another burn on part of the property where the oak was being out competed. The burn reduced competition from woody species and we hope the oaks will re-sprout and move quickly into an advanced position, PERSISTANCE. If things go as PLANNED, in two years, PATIENCE, we should be able to remove the overstory with a harvest and have a very good chance of having this wonderful oak woodland replaced with a young oak woodland. Nine years in the making, but to regenerate the 5 species of oak found on this property, wildlife food and habitat for migratory songbirds and many other animals and potentially hundreds of insects, the PLANNING, PERSISTNCE, and PATIENCE have been worth it. An added benefit is that the grasses, sedges and wildflowers in the understory are making an impressive show and the dead snags from the midstory thinning are a boon for woodpeckers, bats, insects and cavity nesting birds.
PLANNING/PATIENCE, this example is from a Nature Preserve. By our own choice, we will not be removing the overstory through a timber harvest, but we will maintain the oak in the understory, with periodic fire and thinning, until such time as the overstory naturally collapses or is suddenly removed from wind or ice. Regardless of the final outcome of the mature timber, the goal is to ensure the presence of oak woodlands in Indiana forests for generations to come.
Dan Shaver is a Forester and the Acting Operations Manager for The Nature Conservancy’s Forest Bank Program and the Brown County Hills Project Director for The Nature Conservancy in south-central Indiana.