The Driftless Oaks: A new network of tree-ring chronologies to improve regional perspectives of drought in the Upper Midwest, USA

New and updated multi-century tree-ring chronologies from living oak trees, remnants, and archeological beams from across the Driftless Area of southwest Wisconsin and northeast Iowa, USA, were developed to fill a spatial gap in the network of available tree-ring chronologies. We produced a robust 303-year summer drought reconstruction (June–August Palmer’s Modified Drought Index (PMDI): r 2 = 0.45) that identified clusters of extreme droughts and pluvials (PMDI ≤ –4.0 or ≥ 4.0) in the early 1700s and more even distributions of drought conditions, with the exception of the post 1930s period when drought became relatively infrequent. Compared to the Living Blended Drought Atlas (LBDA) and the North American Drought Atlas (NADA), our reconstruction more accurately represented moderate moisture conditions across the Driftless Area, the NADA and LBDA more closely represented extreme pluvials, and our reconstruction and the LBDA better represented extreme drought years. The three reconstructions largely captured the same high-frequency variability in drought conditions and differed most at low frequencies. Significant correlations were identified between our reconstruction and corn ( r = 0.30, n = 91, p = 0.002) and soybean ( r = 0.25, n = 81, p = 0.012) yields, with the strength of the correlations increasing over recent decades suggesting a tighter coupling of interannual climate variability and crop productivity in the region. Superposed epoch analyses indicated significantly wetter conditions in the Driftless Area two years after major volcanic eruptions. In the context of long-term climatic variability, the Driftless Oaks drought reconstruction demonstrated that drought and pluvial conditions more extreme than those experienced during the instrumental record have occurred in the past.

Promoting Reforestation to Landowners: The Role of Advice-Giving through Information, Efficacy, Narratives, and Identification in Storytelling

AbstractCommunicating reforestation efforts is a challenge for foresters. There are many types of advice to offer, and it is unclear which type of advice is better suited to promote tree-planting behaviors. This study explored the effectiveness of three different types of advice (narrative, informational, and efficacy) for different groups of landowners. We recruited landowners (N = 317) from the Driftless Area of Wisconsin and segmented them into two groups based on their self-reported stage of behavior. They were randomly assigned to view one type of advice message in the form of an online video. Landowners in the early stage of tree-planting behaviors had higher intentions to take the advice with a narrative message. Those in the later stage of behavior were more influenced by informational and efficacy advice messages. We also found that with narrative messages, identification with the narrator was important for increasing intention to use advice. Study Implications: Reforestation is a key component to preserving woodlands and maintaining ecosystems. Professional foresters are tasked with speaking to private woodland owners about this issue and encouraging tree-planting behaviors on their properties. However, not all advice is created equal, and the best type of advice may differ depending on the landowner. The results of this study show that it is important to (1) segment landowners into groups based on previous behaviors and (2) determine the best type of advice for each group. Our analyses found that landowners in Wisconsin’s Driftless Area could be segmented by differences in their current stages of behavior, and different groups responded more strongly to certain types of advice than others. This emphasizes the need for foresters to gain a better understanding of their intended audience rather than considering them as a homogeneous sample. Additionally, foresters can be more effective in advice-giving by creating individualized messages that target specific groups. This approach to advice-giving can be used by foresters to develop better communication strategies for their unique situation with woodland owners.