Assessing the Effectiveness of Deep Embeddings for Tree Species Classification in the Dutch Forest Inventory

TL;DR

This study demonstrates that using deep pre-trained remote sensing embeddings with Random Forest significantly improves tree species classification accuracy in the Dutch Forest Inventory, especially with limited annotated data.

Contribution

It shows that fine-tuning pre-trained remote sensing models enhances NFI classification accuracy over traditional hand-crafted features.

Findings

Deep embeddings outperform traditional features in classification accuracy.

Fine-tuning pre-trained models yields 2-9% performance improvements.

Deep embeddings are effective for data-limited forest inventory applications.

Abstract

National Forest Inventory serves as the primary source of forest information, however, maintaining these inventories requires labor-intensive on-site campaigns by forestry experts to identify and document tree species. Embeddings from deep pre-trained remote sensing models offer new opportunities to update NFIs more frequently and at larger scales. While training new deep learning models on few data points remains challenging, we show that using pre-computed embeddings can proven effective for distinguishing tree species through seasonal canopy reflectance patternsin combination with Random Forest. This work systematically investigates how deep embeddings improve tree species classification accuracy in the Netherlands with few annotated data. We evaluate this question on three embedding models: Presto, Alpha Earth, and Tessera, using three tree species datasets of varying difficulty. Data-wise, we compare the available embeddings from Alpha Earth and Tessera with dynamically calculated embeddings from a pre-trained Presto model. Our results demonstrate that fine-tuning a publicly available remote sensing time series pre-trained model outperforms the current state-of-the-art in NFI classification in the Netherlands, yielding performance gains of approximately 2-9 percentage points across datasets and evaluation metrics. This indicates that classic hand-defined features are too simple for this task and highlights the potential of using deep embeddings for data-limited applications such as NFI classification. By leveraging openly available satellite data and deep embeddings from pre-trained models, this approach significantly improves classification accuracy compared to traditional methods and can effectively complement existing forest inventory processes.