Forest-Chat: Adapting Vision-Language Agents for Interactive Forest Change Analysis

TL;DR

Forest-Chat is an innovative LLM-driven system that enables natural language interaction for detailed forest change analysis using satellite imagery, integrating change detection, captioning, and reasoning to improve interpretability and accessibility.

Contribution

The paper introduces Forest-Chat, a novel vision-language agent tailored for forest change analysis, combining multi-level change interpretation with zero-shot capabilities and a new forest-specific dataset.

Findings

Achieves 67.10% mIoU and 40.17 BLEU-4 on Forest-Change dataset.

Demonstrates effective zero-shot change detection with 60.15% accuracy.

Shows caption refinement enhances geographic domain knowledge injection.

Abstract

The increasing availability of high-resolution satellite imagery, together with advances in deep learning, creates new opportunities for forest monitoring workflows. Two central challenges in this domain are pixel-level change detection and semantic change interpretation, particularly for complex forest dynamics. While large language models (LLMs) are increasingly adopted for data exploration, their integration with vision-language models (VLMs) for remote sensing image change interpretation (RSICI) remains underexplored, especially beyond urban environments. This paper introduces Forest-Chat, an LLM-driven agent for forest change analysis, enabling natural language querying across multiple RSICI tasks, including change detection and captioning, object counting, deforestation characterisation, and change reasoning. Forest-Chat builds upon a multi-level change interpretation (MCI) vision-language backbone with LLM-based orchestration, incorporating zero-shot change detection via AnyChange and multimodal LLM-based zero-shot change captioning and refinement. To support adaptation and evaluation in forest environments, we introduce the Forest-Change dataset, comprising bi-temporal satellite imagery, pixel-level change masks, and semantic change captions via human annotation and rule-based methods. Forest-Chat achieves mIoU and BLEU-4 scores of 67.10% and 40.17% on Forest-Change, and 88.13% and 34.41% on LEVIR-MCI-Trees, a tree-focused subset of LEVIR-MCI. In a zero-shot capacity, it achieves 60.15% and 34.00% on Forest-Change, and 47.32% and 18.23% on LEVIR-MCI-Trees. Further experiments demonstrate the value of caption refinement for injecting geographic domain knowledge into supervised captions, and the system's limited label domain transfer onto JL1-CD-Trees. These findings demonstrate that interactive, LLM-driven systems can support accessible and interpretable forest change analysis.