If you’ve been to the Leopold Center here in Baraboo, you might have heard a tour guide say, “the Leopold family started growing our building eighty years ago!” But what many don’t know is that at first there was some resistance to cutting the trees that would ultimately allow the Leopold Center to be so unique.
In 2003, about sixty-three years after the first successful pine plantings of the Leopold family along the southern bank of the Wisconsin River, the four living Leopold children entertained a proposal from the Aldo Leopold Foundation staff: How would you feel about us cutting down around 500 of those trees?
Once all the “kids” had picked their jaws up off the table, a lengthy discussion ensued. Following weeks of back-n-forth, it was agreed that the overall health of this woodland, created by the Leopold’s shovels and sweat, needed an intervention or it faced chronic weaknesses caused by tree overcrowding.
Long story short, a careful harvest ensued in 2005-6, the Leopold forest health improved, and the harvested material allowed for a piece like this to be written from within the knotty pine walls of one of the world’s greenest (and lovliest) buildings, The Aldo Leopold Foundation Legacy Center in Baraboo, Wisconsin.
Fast-forward to 2021, eighty-three years after the trees first took root, and questions surrounding Leopold pines health have come up for answers once again. While the 2005-6 harvest catalyzed improvements in the stability of this famous woods, it’s time to go back in for a robust check-up to assure ongoing forest health.
“Harvesting 500 trees sounds like a lot, however, the thinning was light to protect the remaining trees from damaging high winds because their small crowns lacked wind-resistance,” stated Arik Duhr, Site Manager for the foundation. “The canopies of neighboring trees are once again overlapping and it is time for a check-up.”
So, on April 23, forester Dan Pubanz who performed the original timber cruise while working for Clark Forestry and now as principle of Wolf River Forestry, LLC, returned for his second timber cruise of the Leopold Pines. Pubanz’s familiarity with this particular woodland’s harvest history, combined with his standing as a well-respected mind in forest management specializing in pines, made him the perfect cruiser this second time around.
“Timber cruise” is industry jargon for a precise woodland survey to determine tree health and value within a specific wooded plot—a term that burbled out of the early days of the forestry industry. Back then, determining value was the leading motivation; now, we are most interested in using the data to maintain the health of this woodland. Therefore, If Pubanz were to see no health/vigor concerns as reason to harvest trees, he would not recommend thinning.
Leopold Foundation land stewardship coordinator Mitchell Groenhof, site manager Arik Duhr, and I walked along with Pubanz as he inspected the Leopold pines and a few other nearby foundation wood lots. As we walked and talked, it became clear that some trees would have to be thinned as before, especially several stressed red pines (who’s health was a concern during the 2003 cruise as well), to allow the more stable, larger white pines the best conditions to thrive through the second half of their expected life span of 150 years.
In June, Pubanz submitted his technical report on the pine stands surveyed, including the following summary:
Generally, white pine is in good physiological condition with full deep crowns and most should readily live to 150+ years of age with continued light thinnings.
Red pine in all areas is still struggling due to their small crown mass. Radial growth rates show no improvement from the past thinning and are exceptionally low for trees of this age. These findings are consistent with the small crown mass in red pine that resulted from the delayed start of a thinning regime. These trees are likely unable to vigorously respond to crown release and will likely have a shortened biological lifespan as a result.
Crown closure is high in all areas, even where tree stem stocking is not excessive. Generally, this is due to the large span of the white pine crowns. This indicates that some light thinning could be done over the next 1-2 years. Only retain red pines that have the healthiest, densest crowns and focus thinning around those if it is desired to maintain a red pine component in these stands. The harvest volume will be quite low and likely non-commercial. Some trees may be girdled and left standing to provide wildlife habitat elements.
Invasive plants are common in all stands and control is warranted.
Creating cleared gaps in hardwood patches in, and adjacent to, Stands 1 and 2 should encourage white pine regeneration and the development of multiple age classes. While the stands are only middle-aged, creating multiple age classes over time would enhance structural diversity.
The Leopold Foundation Stewardship Team along with the Leadership Team is now developing a plan to implement Pubanz’s recommendations. Unlike the more intensive and widespread thinning of 2005-6, which was of a commercial scale and therefore required the contracting of a commercial timber harvester, minimal thinning over the next few years will be executed by the foundation’s staff and fellows.
“Although the scale of our work won’t be huge, the weight of those actions couldn’t be heavier for a land manager. It’s an awesome responsibility to care for a piece of living history,” stated Mitchell Groenhof. “We have a couple of very small areas identified to get started.”
For those who experienced the harvest that built the Legacy Center, the future appears bright. “The foundation, with strong input from the four Leopold children made an important and affirmative decision in the early 2000’s to prioritize the longevity of these special trees,” stated Buddy Huffaker, Executive Director. “It is so exciting to think that we are still seeking outside expertise, willing to make tough decisions to care for the past by looking to the future, and that we have a professional staff that can properly care for this very special place. Success as a result of intentional decisions is so powerful—right now our staff are reassessing and prioritizing projects within this very special National Historic Landmark.”
So, the next time you’re out visiting the Leopold Shack and farm, you might see a Leopold lumberjack or two doing their utmost to perpetuate the health and vigor of the Leopold pine stands. And it all started with a timber cruise to lay out this iteration of a plan to nurture the next 80+ years of these treasured trees, planted with love by the Leopolds themselves.