Managing Temperate Forests For Nut Oil Production

Commodities

Practices

The broad problem we are all facing is how to live on this planet without destroying it and ourselves along with it. This can be more narrowly applied to my specific situation: how can I manage wooded ecosystems in Southeast Iowa to produce food without compromising their ecological integrity? This question led me to my interest in hickory oil. By harvesting the nuts from this common tree, it is possible to produce a substantial amount of high quality culinary oil. However, some management may be important to increasing both oil yield and ecosystem health. This brings us to the final and most specific question: what are the best woodland management practices that promote both production and ecosystem health while remaining feasible and replicable? 

Objectives: This demonstration and education project will focus on managing local woodlands using best known practices, and sharing reflections on the process with a unique emphasis on hickory oil production. While timber stand improvement is a common practice, it has not in modern times been done with a specific focus on promoting Carya cordiformis nut production. Managing land typically is done with either an agricultural lens or a conservation lens; this project is designed to show that both can happen simultaneously with mutual benefit. In addition to a written report for this grant, I will focus on disseminating information through exiting networks, specifically through presentations at the Savannah Institute's perennial farm gathering in October 2026, the Northern Nut Growers Association annual meeting in July 2026, and for the Johnson County Food Policy council (a neighboring county to mine). I will also include information on my website.

Solution: The first management strategy I will pursue is thinning. Historically, the presence of fire would have kept stem counts lower, especially in oak or oak-hickory savannas, which once covered 15% of Iowa. I will manually eliminate trees to achieve about 30-70% canopy cover over time, depending on the site. I will focus on preserving oaks, hickories, and some black walnuts, while reducing the amount of hackberries, mulberries, and non-native species. I will do this with advice from my state forester, Bailey Yotter. We have already had the opportunity to meet and walk through one woodlot to discuss appropriate management. Thinning is also important for nut production. In chestnut farming, it is important to maintain the trees with as broad a canopy as possible. My observations with hickories are similar. Open-grown trees consistently yield higher than trees in dense forests. In time, thinning forests should increase nut production. 

The next management focus will be on invasive brush. The majority of my sites are overgrown with multiflora rose and honeysuckle, and the increased light that comes with thinning will only encourage their growth. There are four main tools I have used to address this issue: digging, mowing, livestock, and burning. Each strategy has advantages and drawbacks, which I will explore and reflect on in my results. This brush management is also important for nut harvest, which requires minimal ground cover in October and November.

The third management focus will be on carbon, though the conversion of thinned trees to biochar. Carbon sequestration is an important part of climate change prevention and mitigation. When a tree decomposes, most of the carbon it contains is respirated back into the atmosphere. In contrast, biochar is a durable form of carbon that can last a thousand years. To turn the thinned trees into biochar, I will cut and pile the smaller diameter branches to be burned the following year. The trunks and larger limbs I will let lay on the forest floor- these parts are insect habitat and provide other ecosystem functions. When it is time to burn the piles, I will try a few established methods (cone pit, trench, kiln), which I will reflect on in my results. Increased carbon in the soil also improves water holding capacity and promotes microbial activity, likely benefitting the trees.

The final management focus will be on fertility. Some forests have micronutrient deficiencies which can negatively impact the health and productivity of the trees. For example, most soils in Iowa have poor Boron, which is important for chestnut production. Some of my sites have been historically overgrazed, which may have hurt the soils. I will do soil testing at each of my sites, and then apply nutrients as needed.