Urban forests are being threatened by rapid urbanization, biodiversity crises, and climate variability. In response, governments are increasingly collaborating with the public for solutions to these mounting challenges. Non-governmental organizations (NGOs) are dominant players in these collaborations because of their ability to deliver on communities' environmental issues. Despite their growing visibility in forest management, there is a lack of attention directed to the forms of NGO relationships and their range of collaborative activities. This study focuses on addressing these gaps and examining collaborations between local governments and NGOs in urban forest programming by characterizing their components including mandates, relationship ties, accountability, resource exchange, and power dynamics. We collected data using semi-structured interviews with three groups: leaders of NGOs, municipal government o cials in an urban forest or public works departments, and urban-forest experts who have observed their interactions. The participants represent 32 individuals in nine Canadian cities. Our results indicate that NGO-government collaborations have relational ties and accountability processes that are both formal and informal in nature; however, formality in collaborations is associated with the amount of funding, proximity to government, or size of the NGO. Additionally, our ndings suggest that NGOs present an opportunity to local governments to supplement their resources and capacity. While the strength and formality of collaborations may be a product of NGO size and budgets, public servants should hesitate to engage smaller, grassroots NGOs to realize their public service mandates.Characterizing the components of these governance processes provides a benchmark for practitioners participating in similar public-civic interactions and arms them with the knowledge to navigate collaborative decision-making.