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The Next Generation of Heritage Oaks

The Next Generation of Heritage Oaks

On the afternoon of August 20, 2022, the car was loaded up with wagons, empty garbage cans, tarps, 5-gallon buckets, and most importantly the Bag-A-Nut machine. We headed out to the Yahara Hills Golf Course, where a golf cart was waiting, ready to assist us with our acorn collection.

My 4-year-old son and I had been searching for Heritage Oak trees for the previous several months, always looking for trees, sometimes with binoculars, that would have a bumper crop of acorns in the fall – only to be disappointed time and time again. In fact, we were barely able to find any oak trees with acorns in Dane County.

But at last, we found our first Heritage bur oak grove with a remarkable acorn crop. In just one trip we were able to collect 50 gallons of Heritage acorns from several trees. These acorns will eventually make their way to a nursery and then on to new permanent homes, where they will enhance the tree canopy and continue their native tree lineage, all as part of the larger Dane County Heritage Oak Project.

“From the finest and bestoaks wise persons will secure acorns for planting.”

– Walter Scott

In 2022, the Dane County Heritage Oak Project set out to inventory the roughly 250 remaining Heritage Oaks originally catalogued in 1976 by Walter Scott.[1] The trees identified in the original inventory were later re-inventoried by Bruce Allison in 2001, this time with GPS coordinates. In 2022, the Dane County Heritage Oak Project continued this unique inventory that began nearly 50 years ago.

The initial purpose of the current inventory was to document how many of these living artifacts, trees present on the landscape prior to our country’s founding, were still standing today, continuously providing shade, ecosystem services and inspiration to generations of humans. While a noble endeavor in and of itself, the project has since produced some interesting offshoots.

One of those side projects grew out of conversations with DNR Urban Forestry staff regarding the need to collect seed from trees of natural origin for the state’s reforestation program. “Natural origin” refers to wild seed not originating from landscaping trees or trees from private nurseries. It quickly became apparent that trees identified through the Dane County Heritage Oak Project were exactly the type of seed source that DNR nurseries were seeking.

Collecting seed from the identified Heritage Trees proved to be more difficult than one may assume. While we anticipated a race to collect acorns before the hungry squirrels, chipmunks, raccoons, and crows consumed them, the real challenge turned out to be locating trees with a significant acorn mast. Depending on the species of oak, a significant mast occurs on a cyclical basis every 2-6 years. Additional factors impacting mast years include weather conditions, drought conditions, and other related stressors.

For species in the red oak family (red oak, black oak, northern pin oak), acorns take two years for development, as opposed to species of oak in the white oak family (bur oak, white oak, swamp white oak) that develop in one year. This development difference further compounds factors that affect the likelihood of a successful mast crop for red oak family members.    

In fall 2022, Yahara Hills Golf Course was the only location in all of Dane County where we were able to identify a significant acorn mast from Heritage bur oaks.[2] A second significant mast was found from a heritage red oak grove at Hudson Park (red oaks drop their acorns typically 2-4 weeks after the bur oaks). The City of Madison Parks Division allowed and assisted with acorn collection at these public locations. Between the end of August and middle of September, we collected over 100 gallons of acorns at these two sites from just six trees.

The Dane Country Tree Board is currently growing about 200 of these trees, with plans to expand collection efforts and growing capacity in 2023-24. However, the Dane County Tree Board’s growing operation success is dwarfed by that of the experienced experts at the DNR’s Wilson State Nursery in Boscobel, where the majority of the Heritage acorns were sent. Currently there are over 10,000 Heritage bur and 10,000 Heritage red oak heritage seedlings successfully growing in state nursery fields.

Significant potential white oak masts have been identified for collection this fall; we are still looking for Heritage swamp white oak and red oak masts for collection. Conversations and plans are currently ongoing on how to most impactfully use these trees for reforestation efforts and educational opportunities, all while preserving time tested, resilient, native tree genetics.

Those interested in following the Dane County Heritage Oak Project updates are invited to sign up for our Heritage Oak email listing. To learn more about collecting seed for the DNR, contact your nearest state nursery. To add Heritage trees to the inventory, contact Matt Noone at mattn@capitalarearpc.org

[1] For more information on the original inventory, see Our Oldest Oaks – A Living Heritage.

[2] Bur oak acorns differ in size based on their location and latitude; acorns produced in northern locations are much smaller than acorns produced from southern populations. Interestingly, the acorns collected from the bur oaks at Yahara Hills Golf Course were very small and resembled acorns from much more northern populations rather than what is typical for our latitude.