The Ash Borer Effect: Does an Invasive Beetle Improve Your Golf Game?

The emerald ash borer has killed hundreds of millions of ash trees across 37+ states since arriving in Detroit in 2002. Ash trees line fairways on golf courses throughout the Midwest and East Coast. Fewer trees mean wider fairways — so does an ecological disaster actually make golfers better?

What We Built

A dual-track pipeline combining causal inference with ecological modeling:

Track A (R): Difference-in-differences on 23,444 PGA Tour scores (2009-2022) across 84 courses, with player, course, and year fixed effects. Five courses fell in counties where EAB arrived during the study window — a natural experiment.

Track B (Python): A spatial spread model trained on 861 confirmed EAB counties predicts arrival dates nationwide (CV MAE: 2.32 years). We calibrated an extinction projection using 40,959 multi-year USDA Forest Inventory records.

What We Found

The beetle helps your golf game. Courses see -0.76 strokes per tournament after EAB arrives (p=0.002). Tournaments are often decided by a single stroke.

Ash trees are in serious trouble. EAB advances ~53 km/year. Observed decline data shows 3.8% annual ash mortality post-EAB. At current rates, half of North America's 8 billion ash trees will be gone by 2035.

Why It Matters

The absurd question is a doorway into a real one. The data-calibrated extinction timeline grounds alarming "8 billion trees at risk" headlines in observed decline rates — turning a catastrophe people scroll past into something they can actually picture.

Built With

• ggplot2
• matplotlib
• numpy
• pandas
• python
• r
• scikit-learn
• streamlit
• zerve