IL SB1589

Changes the Illinois Finance Authority's emerald ash borer revolving loan program from mandatory ("shall") to discretionary ("may") administration.

Expands the loan program to include treatment of standing ash trees in addition to replanting, with "treatment" defined as administering environmentally sensitive products and materials proven by academic research to protect trees from emerald ash borer damage.

Maintains loan limits of $5,000,000 per unit of local government with a 20-year maximum repayment period and minimum annual repayment of 5% of principal or remaining balance.

Authorizes municipalities to treat or remove ash trees infected with emerald ash borer (in addition to elm trees with Dutch elm disease) from private property after owner notice and refusal, with costs collected as a lien on the property.

Defines "treatment" in the Illinois Municipal Code as administration of environmentally sensitive processes and materials proven by academic research to protect elm and ash trees from invasive disease.