About This Action Guide
After a hurricane or fire, forests can regenerate. But when insects and disease kill urban trees, it’s much harder – and much more expensive – to restore a community’s tree canopy.
Use this guide to help you prepare for future threats from invasive pests and diseases. If they haven’t arrived yet, they will.
Pests and disease will come from just about anywhere – from another continent, or from your neighbor down the street. Plant and tree pests and diseases easily cross international and municipal boundaries. They’re like stowaways on a ship that’s just leaving port. They have no tickets, aren’t visible and often depend on help from others to begin the journey.
As cities heat up, trees face mounting stress from rising temperatures, prolonged droughts, and erratic weather patterns. Species that once thrived in urban areas may struggle to survive, while pests and diseases—emboldened by warmer winters—spread faster and farther than ever before.
Trees cool neighborhoods, reduce energy use, trap air pollutants, and absorb carbon dioxide. However, to remain effective cities must adapt—fast. That means rethinking what we plant, where we plant it, and how we care for it.
Urban forestry must evolve from its “one tree at a time” focus and center its work on the whole urban forest. This shift in strategy will rest on the ability to anticipate what the future may look like and how changing conditions might affect your trees.
To sidestep disaster, you should know how you will respond to both abiotic and biotic threats well before they emerge.
Threats to forest health
Abiotic
- Fire
- Wind
- Severe storms
- Ice
- Sea level rise
Biotic
- Insects
- Animals
- Fungi
- Pests
- Diseases
Step 5: Strategies, Policies and Funding
Step Six: Mobilize
