2013 Scientist Lecture Series

Make New Discoveries with Holden's Research Scientists

Join us this year to learn all about Holden's current research endeavors and important topics that impact our lives. All lectures are free, but registration is required. Register online or call call 440.602.3833.

Eligible for ISA CEU credit.

Mushrooms, Trees and Microbes: How do our Forests Respond to Decades of Acid Rain?

David Burke, PhD

Hardwood forests of the Northeastern United States are often subject to high levels of acid deposition that can appreciably lower soil pH, affecting forest plants and soil organisms. But can soil fungi and bacteria help plants cope with nutrient limitations that accompany acid rain? In 2009, Holden scientists and collaborators at Ohio University applied 60,000 pounds of agricultural limestone to 36 forest plots in northern and southern Ohio to answer that question. Burke, Holden scientist and Research Department chair, will present the findings from the first three years of soil and plant sampling and discuss how trees, mushrooms, and microbes may interact to overcome human alterations to forest ecosystems.

Getting By With a Little Help From a Friend: How Symbiotic Root Fungi Help Maple Trees Overcome Phosphorus Limitations

Sarah Kyker, PhD

Phosphorus is an essential plant nutrient, needed for plant growth, development and reproduction.  However, phosphorus is often limited in forest soils.  Plants can partly overcome phosphorous limitation by forming associations with mycorrhizal fungi, which live on the roots of the plants and act as an extension of their root system to mine the soil for this essential nutrient. Thanks to funds from the R. Henry Norweb Jr. Fellowship for Scientific Research in Horticulture, Holden scientists have been investigating how mycorrhizal fungi associated with maple trees are helping the plants acquire phosphorus in nutrient poor conditions. 

Kyker is a post-doctoral research associate in Holden’s Research Department. She holds a doctorate from Case Western Reserve University. She will be presenting her work on phosphate transporters.  These proteins transfer phosphorus from the soil into the plant root and are currently Kyker’s favorite molecule!

Burn Baby Burn? The Use of Fire in Management of Midwestern Forests and Savannas

Sheryl Petersen, PhD

We hear about the catastrophic effects of wildfires in the headlines. But fires and other disturbances are also natural processes that have shaped the evolution of plants and maintain plant communities – even those close to home. In fact, fire has played a critical role in the development of prairies, savannas, and forests of the midwestern and eastern United States, including Ohio. And in many of these ecosystems, it is the lack of fire that is driving dramatic, perhaps catastrophic, changes in plant communities. For example, fire suppression may be contributing to the loss of oaks as a canopy dominant in oak forests. Can we use fire to bring them back, or are we, as some have suggested, running out of time? In this talk, we will explore the history and effects of fire in Midwestern ecosystems, the consequences of changing fire regimes on plant communities, and the science behind the use of fire as a restoration and management tool.

Petersen is a postdoctoral research associate at The Holden Arboretum. She holds a doctorate from Case Western Reserve University. Her research focuses on the role disturbance (e.g., fire, herbivory, and wind-throw) plays in shaping vegetation patterns.

Rhododendrons – Enough Already?

Steve Krebs, PhD

Thousands of rhododendrons have been hybridized since the mid-19th century. Is there really a need for more? The short answer is yes.  As long as there are rhododendron diseases there will be a need for more hybrids.  Root rot disease caused by Phytophthora cinnamomi, an invasive soil fungus, is the primary cause of mortality in rhododendrons and many other ornamental plants. Climate change, particularly warmer and wetter conditions, is expected to increase disease pressure from P. cinnamomi.  Krebs, director of Holden’s David G. Leach Research Station, is conducting a breeding program to develop root rot resistant rhododendrons that can be more successfully and sustainably grown by producers and consumers. This presentation describes the nuts and bolts of that work – how to identify resistance, where to find it, and how to transfer it into a broader ornamental array of plants. Although the focus is on product development, the project has yielded insights on the genetics of resistance and the relationship between abiotic stresses (flooding, high temperatures) and resistance.