Urban forestry plays a critical role in mitigating micro-climate variations and enhancing environmental sustainability in developing regions. However, high deployment costs and reliance on continuous cloud connectivity often limit the feasibility of real-time environmental monitoring systems. This paper presents a low-cost, offline-first embedded system designed for urban forestry auditing and micro-climate impact analysis. Built using resource-constrained microcontrollers, integrated environmental sensors, and local non-volatile data storage, the system continuously logs localized temperature, humidity, and canopy metrics without requiring active internet connectivity. Unlike existing solutions that necessitate expensive gateways, this architecture utilizes a decentralized edge-computing approach to ensure data integrity in areas with intermittent connectivity. Field evaluations conducted in urban environments demonstrate reliable edge-data collection, resilient data synchronization upon reconnection, and the ability to derive actionable insights into local urban heat island effects. By significantly reducing hardware costs and eliminating the need for constant network uptime, this system offers a scalable, sustainable solution for forestry management and micro-climate assessment in resource-limited settings.