As LTER enters into its 35th year as a network, the opportunity for long-term data to address critical questions that advance general ecological theory and understanding has never been more informed. In accordance with this meeting’s theme “From Long-term Data to Understanding: Toward a Predictive Ecology”, this proposed working group will build on current, network-level syntheses that integrate long-term data to inform LTER’s core research areas (primary production, population studies, movement of organic matter, movement of inorganic matter, and disturbance patterns). Our objective is to identify important, general ecological questions that a) derive from key theories, b) are motivated by the analysis of long-term data, and c) require additional, long-term data collection to be answered. We will 1) review current developing syntheses of long-term primary productivity and inorganic nutrient data, 2) discuss the merit for continuation of long-term data at LTER sites for enhancing forecasts of future ecological patterns, 3) discuss the essential components of a successful integrated framework for LTER long-term core datasets with NEON core datasets that enable regional data and forecasts to be downscaled and related to observed changes at LTER sites, and 4) outline important general ecological questions and theories that are only tenable through continued long-term data collection and analysis of both LTER and NEON core data.