Research: wolf trees & post-agricultural forest biodiversity

Research: wolf trees & post-agricultural forest biodiversity

From Marion Holmes

I'm raising money to travel to Athens County, OH to continue research on the ecology of post-agricultural forests. Money is requested to contribute to travel, supplies, lodging, and food during field work.

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You're going for a walk in the woods and encounter a large tree. It stands out from others nearby not only for its unusual size, but for its spreading branches and open crown. You've encountered a pasture tree! Also called wolf trees, they grew in open areas and developed a distinctive branching structure characteristic of full-sun environments. The forest surrounding them is younger, and likely regenerated following abandonment from agriculture.

Wolf trees can tell us a lot about the history of forests, but what about the ecology of how forests regenerate on former agricultural land? Wolf trees influence plant community development by providing shady habitats for forest species to establish and increase arrival of fleshy-fruited species by providing habitat for seed-dispersing wildlife. Most research on pasture trees comes from tropical regions and earlier in succession (<20 years after abandonment). Less is known about how they influence forest community composition over the long term-decades to centuries after canopy closure. In a previous study (Holmes 2020, Journal of Vegetation Science), I demonstrated that pasture trees shape the diversity and distributions of forest plant species within post-agricultural  forest sites even 50 years or more after canopy closure. But what about differences between forests? Do plant communities in post-agricultural forests that included pasture trees develop differently than in sites without them? If so, why? I hypothesize that, because of their value as wildlife habitat, forests that regenerate on sites with wolf trees will be more diverse in terms of number of species, number and abundance of fleshy-fruited and nut-bearing species, and have a richer herbaceous layer than forests without them.

Why it matters outside academic ecology

Understanding how forests develop is important for conservation and management. Suppose you're part of a land trust looking to prioritize land acquisition with the highest conservation value. A site with wolf trees might prove to be a better investment for protecting biodiversity than another site without them. There is also evidence from tropical regions that single trees facilitate reforestation on abandoned pastureland, and could therefore be valuable for afforestation in eastern North America. Most modern eastern forests have regenerated following conversion to agriculture, and are therefore lacking in species diversity. Any factor, such as the presence of a wolf tree, that can increase that diversity within a site should be considered to have high value. I aim to demonstrate the importance of these trees to temperate deciduous forest succession to improve evidence-based ecological decision making.

Why I'm crowdfunding

Doing research when you're unemployed or an adjunct takes some creativity. In the past, I've funded research with bake sales (See Holmes 2020 paper on pasture trees in Journal of Vegetation Science for the result) and put a lot of my own money into my projects. Luckily I've been a postdoc at Pitt since May 2019 and had access to all the equipment and money I could possibly want! That position will soon be coming to an end (November 14th), but the adventures in ecology aren't over.

Fortunately, I have some teaching work and won't be totally unemployed. The bad news is that, while I teach at two institutions, these are adjunct positions. Adjuncting means that you're on short-term contracts to teach courses without benefits or access to institutional research funding. There are also limits on external funding that can be obtained because many agencies do not pay out to individuals without a full-time position at a university, museum, or other research institution. I have applied for small society grants but not been selected for any so far.

I'll likely be self-funding parts of this project but would like to offset as much of the cost as possible. Any contribution helps!

Project methodology

I've selected 30-32 formerly pastured forest sites in Athens County, Ohio. Half of them have wolf trees, half of them don't. I've already sampled the tree community in about half of the 30 sites and the results look promising! I'm looking for funding to complete tree sampling (November 2021) and also sample the herbaceous community (May and August 2022).


November 2021: Tree community sampling and final site selection

Winter 2021-2022: Tree community data analysis

May 2022: Herb community sampling and soil collection

June-July 2022: Soil analysis, data management

August 2022: Herb community sampling, data management

Fall 2022: Herb community data analysis

Winter and Spring 2023: Manuscript preparation

Spring 2023: Present results to contributors


1-2 peer-reviewed journal articles

Conference presentations (eg Ohio Natural History Conference, Botany, Ecological Society of America)

Special seminar of results for contributors (remote delivery and recording)

Costs I'm aiming to cover in whole or in part:

1. Three round trips from North Braddock to Athens, $712.32 (212 miles x 56 cents per mile = $237.44 per trip)

2. pH tester for soil analysis, ~$50

3. DBH tape, $38.25

4. Field supplies including metersticks, flagging tape, plot markers (~$20)

5. Other miscellaneous costs: food and lodging while in Athens (TBD)

Thanks for reading and sharing!

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