Journal of Natural Environment

Journal of Natural Environment

Mapping the distribution of remaining stands of Hyrcanian boxwood using Sentinel-2 Imagery for conservation prioritization)

Document Type : Research Paper

Authors
Seyedeh Kosar Hamidi
Hamed Aghajani
Zeinab Khalili
Hamid Jalilvand
Department of Forest Sciences and Engineering, Sari Agricultural Sciences and Natural Resources University, Sari, Iran.
10.22059/jne.2026.412040.2899
Abstract
Hyrcanian boxwood (Buxus hyrcana Pojark.) is a valuable relict species from the Tertiary period in the Hyrcanian forests, playing an important role in the stability of this ecosystem. Over the past two decades, widespread decline of boxwood stands, particularly due to the box tree moth and blight disease caused by the fungus Calonectria pseudonaviculata, has become a serious crisis. Despite the importance of the issue, no comprehensive study has been conducted to map the distribution and conservation prioritization of the remaining stands. The present study was designed to map the distribution of remaining B. hyrcana stands using Sentinel-2 imagery and to prioritize conservation in three key habitats (Cheshmeh-Bolbol, Sisangan, and Shafaroud). Field sampling was conducted in summer 2025, and fungal isolates were purified on MEA culture medium. Pathogenicity was confirmed through greenhouse tests, and the fungal species was identified using ITS region sequencing. Distribution maps of the stands were prepared using supervised classification of Sentinel-2 images with Support Vector Machine (SVM) algorithm and NDVI calculation. The results showed all isolates were identified as Calonectria pseudonaviculata with 99–100% similarity. The area of restorable stands was estimated at 78 ha (mean NDVI= 0.55) in Cheshmeh-Bolbol, 105 ha (mean NDVI= 0.38) in Shafaroud, and 4.2 ha (mean NDVI= 0.23) in Sisangan. Conservation priorities were assigned to Cheshmeh-Bolbol, Shafaroud, and Sisangan, respectively. Overall classification accuracy ranged from 86.5% to 91.6%. This study presents, for the first time, the distribution map of remaining B. hyrcana stands and determines conservation priorities. The proposed methodology can be generalized to other habitats and provides a basis for restoration planning and in situ conservation of this valuable species.
Keywords
">Boxwood blight, ">Calonectria pseudonaviculata, Conservation prioritization, Hyrcanian boxwood, ">NDVI, Sentinel-2, ">SVM classification.
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Journal of Natural Environment
Volume 79, Issue 2
Summer 2026
Pages 251-266