diff --git a/loko/assets/models/nature.py b/loko/assets/models/nature.py
index 668d11c..f37440c 100644
--- a/loko/assets/models/nature.py
+++ b/loko/assets/models/nature.py
@@ -281,6 +281,11 @@ class NatureTree(AbstractGeoAsset):
         verbose_name = _("Arbre")
         verbose_name_plural = _("Arbres")
     
+    def save(self, *args, **kwargs):
+        from assets.utils.tree_ecoservices import compute_tree_ecoservices
+        compute_tree_ecoservices(self, overwrite_existing=False)
+        super().save(*args, **kwargs)
+
     def get_absolute_url(self):
         return reverse('assets:nature_assets_detail', kwargs={'asset_model': 'naturetree', 'asset_id':self.id})
 
diff --git a/loko/assets/tests.py b/loko/assets/tests.py
index 2520abe..265354f 100644
--- a/loko/assets/tests.py
+++ b/loko/assets/tests.py
@@ -5708,3 +5708,52 @@ class NatureLocationDetailViewTest(TestCase):
         self.assertContains(response, 'id="asset-map"')
 
 
+
+
+class NatureTreeEcoServicesTest(TestCase):
+    def test_tree_ecoservices_automatic_calculation_on_save(self):
+        from assets.models import NatureTree
+        tree = NatureTree.objects.create(
+            code="TR-ECO-TEST-1",
+            name_fr="Chêne test",
+            scientific_name="Quercus robur",
+            height=10.0,
+            circumference=70.0,
+            crown_diameter=5.0,
+            vitality="normal",
+        )
+        self.assertIsNotNone(tree.amenity_value)
+        self.assertGreater(tree.amenity_value, 500)
+        self.assertIsNotNone(tree.carbon_stock)
+        self.assertGreater(tree.carbon_stock, 5.0)
+        self.assertIsNotNone(tree.cooling_energy_indicator)
+        self.assertEqual(tree.cooling_energy_indicator, 7408.93)
+        self.assertEqual(tree.cooling_indicator, 12.75)
+        self.assertEqual(tree.biodiversity_index, 0.92)
+
+    def test_tree_missing_dimensions_deduction(self):
+        from assets.models import NatureTree
+        tree = NatureTree.objects.create(
+            code="TR-ECO-TEST-2",
+            name_fr="Platane sans circonférence",
+            scientific_name="Platanus x acerifolia",
+            height=20.0,
+        )
+        self.assertEqual(tree.circumference, 150.0)
+        self.assertEqual(tree.crown_diameter, 9.0)
+        self.assertIsNotNone(tree.amenity_value)
+        self.assertIsNotNone(tree.carbon_stock)
+        self.assertEqual(tree.biodiversity_index, 0.85)
+
+    def test_dead_tree_has_zero_amenity_and_cooling(self):
+        from assets.models import NatureTree
+        tree = NatureTree.objects.create(
+            code="TR-ECO-DEAD",
+            name_fr="Arbre mort",
+            height=8.0,
+            circumference=60.0,
+            is_dead=True,
+        )
+        self.assertEqual(tree.amenity_value, 0.0)
+        self.assertEqual(tree.cooling_energy_indicator, 0.0)
+        self.assertEqual(tree.cooling_indicator, 0.0)
diff --git a/loko/assets/utils/tree_ecoservices.py b/loko/assets/utils/tree_ecoservices.py
new file mode 100644
index 0000000..be84785
--- /dev/null
+++ b/loko/assets/utils/tree_ecoservices.py
@@ -0,0 +1,190 @@
+import math
+from typing import Optional
+
+
+# Coefficients allométriques carbone par genre botanique (t CO2 / (cm_circ * m_hauteur))
+# Dérivés des tables de biomasse et densités ligneuses (i-Tree / Chave / Grality)
+GENUS_CARBON_K = {
+    "aesculus": 0.02471,    # Marronnier
+    "carpinus": 0.02370,    # Charme
+    "quercus": 0.01952,     # Chêne
+    "betula": 0.01952,      # Bouleau
+    "fagus": 0.01882,       # Hêtre
+    "prunus": 0.01813,      # Cerisier / Prunier
+    "fraxinus": 0.01743,    # Frêne
+    "acer": 0.01673,        # Érable
+    "platanus": 0.01673,    # Platane
+    "castanea": 0.01900,    # Châtaignier
+    "robinia": 0.01850,     # Robinier
+    "ulmus": 0.01750,       # Orme
+    "cedrus": 0.01600,      # Cèdre
+    "salix": 0.01550,       # Saule
+    "populus": 0.01500,     # Peuplier
+    "pinus": 0.01450,       # Pin
+    "tilia": 0.01366,       # Tilleul
+    "malus": 0.01800,       # Pommier
+    "pyrus": 0.01800,       # Poirier
+}
+
+# Indices écologiques de biodiversité par genre / essence
+GENUS_BIODIVERSITY = {
+    "quercus": 0.92,        # Chêne (très forte valeur d'accueil)
+    "fagus": 0.88,          # Hêtre
+    "platanus": 0.85,       # Platane
+    "fraxinus": 0.78,       # Frêne
+    "tilia": 0.78,          # Tilleul
+    "carpinus": 0.76,       # Charme
+    "salix": 0.75,          # Saule
+    "acer": 0.68,           # Érable
+    "aesculus": 0.62,       # Marronnier
+    "pinus": 0.62,          # Pin
+    "populus": 0.60,        # Peuplier
+    "ulmus": 0.60,          # Orme
+    "malus": 0.53,          # Pommier
+    "betula": 0.47,         # Bouleau
+    "prunus": 0.44,         # Cerisier / Prunus ornemental
+}
+
+# Constante d'énergie de refroidissement par an (kWh / m^2 de canopée projetée)
+# Dérivée de l'évapotranspiration urbaine Grality : 296.357 * D^2
+COOLING_ENERGY_PER_D2 = 296.357
+
+# Valeur de base au cm² de section de tronc (Barème de l'Arbre / Plante & Cité)
+BASE_AMENITY_VALUE_PER_CM2 = 3.20
+
+
+def get_genus_carbon_k(botanical_str: Optional[str]) -> float:
+    """Retourne le coefficient allométrique de carbone pour l'essence ou genre spécifié."""
+    if not botanical_str:
+        return 0.0180
+    b_lower = botanical_str.lower()
+    for genus, k in GENUS_CARBON_K.items():
+        if genus in b_lower:
+            return k
+    return 0.0180
+
+
+def get_genus_biodiversity_index(botanical_str: Optional[str]) -> float:
+    """Retourne l'indice de biodiversité pour l'essence ou genre spécifié."""
+    if not botanical_str:
+        return 0.60
+    b_lower = botanical_str.lower()
+    for genus, b in GENUS_BIODIVERSITY.items():
+        if genus in b_lower:
+            return b
+    return 0.60
+
+
+def compute_tree_ecoservices(tree, overwrite_existing: bool = False) -> bool:
+    """
+    Calcule et met à jour automatiquement les indicateurs écosystémiques et patrimoniaux
+    d'un arbre (NatureTree) :
+    1. Dimensions déduites si manquantes (circonférence et diamètre de houppier).
+    2. Valeur d'aménité (€) selon le Barème de l'Arbre (section du tronc et coefficients).
+    3. Stock de carbone (t CO2) selon l'allométrie dendrométrique et l'essence.
+    4. Énergie de refroidissement (kWh) et Indice de fraîcheur selon la canopée.
+    5. Indice de biodiversité selon l'essence.
+
+    Si overwrite_existing=False (par défaut), ne remplace pas les valeurs déjà renseignées
+    (ex: valeurs officielles Grality déjà enregistrées).
+    Retourne True si au moins un champ a été calculé/mis à jour.
+    """
+    changed = False
+
+    # 1. Estimation / déduction des dimensions manquantes à partir de la hauteur ou circonférence
+    h = getattr(tree, 'height', None)
+    c = getattr(tree, 'circumference', None)
+    crown_d = getattr(tree, 'crown_diameter', None)
+
+    if (not c or c <= 0) and h and h > 0:
+        c = round(h * 7.5, 1)
+        tree.circumference = c
+        changed = True
+
+    if (not crown_d or crown_d <= 0):
+        if h and h > 0:
+            crown_d = round(max(2.0, min(18.0, h * 0.45)), 1)
+            tree.crown_diameter = crown_d
+            changed = True
+        elif c and c > 0:
+            estimated_h = c / 7.5
+            crown_d = round(max(2.0, min(18.0, estimated_h * 0.45)), 1)
+            tree.crown_diameter = crown_d
+            changed = True
+
+    if (not h or h <= 0) and c and c > 0:
+        h = round(c / 7.5, 1)
+        tree.height = h
+        changed = True
+
+    # 2. Coefficients de situation et plantation par défaut si absents
+    sit = getattr(tree, 'situation_coefficient', None)
+    if sit is None or overwrite_existing:
+        ctx = getattr(tree, 'implantation_context', 'street')
+        sit = 5.0 if ctx in ('park', 'square', 'isolated') else 4.0
+        tree.situation_coefficient = sit
+        changed = True
+
+    plant = getattr(tree, 'plantation_coefficient', None)
+    if plant is None or overwrite_existing:
+        plant = 5.0
+        tree.plantation_coefficient = plant
+        changed = True
+
+    # Statut sanitaire / vitalité
+    is_dead = bool(getattr(tree, 'is_dead', False))
+    vitality = getattr(tree, 'vitality', 'normal') or 'normal'
+
+    if is_dead or vitality == 'dead':
+        sa_coeff = 0.0
+    elif vitality == 'declining':
+        sa_coeff = 0.3
+    elif vitality == 'weak':
+        sa_coeff = 0.6
+    else:
+        sa_coeff = 1.0
+
+    # 3. Valeur d'aménité (€) — Barème de l'Arbre
+    if getattr(tree, 'amenity_value', None) is None or overwrite_existing:
+        if sa_coeff == 0.0:
+            tree.amenity_value = 0.0
+            changed = True
+        elif c and c > 0:
+            section_cm2 = (c ** 2) / (4.0 * math.pi)
+            tree.amenity_value = round(
+                section_cm2 * BASE_AMENITY_VALUE_PER_CM2 * (sit / 5.0) * (plant / 5.0) * sa_coeff,
+                2
+            )
+            changed = True
+
+    # 4. Énergie de refroidissement (kWh) et Indice de fraîcheur
+    if getattr(tree, 'cooling_energy_indicator', None) is None or overwrite_existing:
+        if is_dead or vitality == 'dead':
+            tree.cooling_energy_indicator = 0.0
+            changed = True
+        elif crown_d and crown_d > 0:
+            tree.cooling_energy_indicator = round(COOLING_ENERGY_PER_D2 * (crown_d ** 2), 2)
+            changed = True
+
+    if getattr(tree, 'cooling_indicator', None) is None or overwrite_existing:
+        if is_dead or vitality == 'dead':
+            tree.cooling_indicator = 0.0
+            changed = True
+        elif tree.cooling_energy_indicator is not None and tree.cooling_energy_indicator > 0:
+            tree.cooling_indicator = round(math.sqrt(tree.cooling_energy_indicator) / 6.75, 2)
+            changed = True
+
+    # 5. Stock de carbone (t CO2)
+    botanical = getattr(tree, 'scientific_name', '') or getattr(tree, 'genus', '') or getattr(tree, 'name_fr', '')
+    if getattr(tree, 'carbon_stock', None) is None or overwrite_existing:
+        if c and h and c > 0 and h > 0:
+            k = get_genus_carbon_k(botanical)
+            tree.carbon_stock = round(k * c * h, 3)
+            changed = True
+
+    # 6. Indice de biodiversité
+    if getattr(tree, 'biodiversity_index', None) is None or overwrite_existing:
+        tree.biodiversity_index = get_genus_biodiversity_index(botanical)
+        changed = True
+
+    return changed