Emergency Conservation Program Improvement Act of 2023 This bill revises the Emergency Conservation Program and the Emergency Forest Restoration Program to provide agricultural producers and owners of nonindustrial private forest land impacted by natural disasters the option to receive an advance on cost-sharing payments before carrying out emergency measures. The bill also expands eligibility for payments under the programs to include emergency measures to address damages caused by (1) a wildfire that is not caused naturally if the damage is caused by the spread of the wildfire due to natural causes, and (2) a wildfire that is caused by the federal government.