Field Report 2: Forest Canopy, Ancient Hedgerow, and Ecological Corridor Conservation
Conducted across the wooded valleys and agricultural borders surrounding Saintes (Fontcouverte, Les Gonds, Chaniers, and the Vallon des Arènes), this expedition log documents how citizen volunteers and youth teams mapped 14 kilometers of ecological corridors and installed 65 avian and chiropteran refuges.
1. The Trame Verte of Saintes: Why Continuous Tree Corridors Matter
Woodland wildlife in the Saintonge basin—from red squirrels, hedgehogs, and tawny owls to xylophagous beetles such as the European Stag Beetle (Lucanus cervus)—cannot survive if oak and hornbeam groves are isolated like islands surrounded by asphalt roads or bare fields. They depend on continuous linear connections known in ecology as the Trame Verte (Green Corridor): double-story country hedgerows (haies champêtres), sunken lanes (chemins creux), and lines of ancient pollarded ash trees (frênes têtards) that connect the limestone plateaus down to the Charente River valley.
Throughout the 2025–2026 cycle, the Natural History Commission of AMICALE LAIQUE SAINTES mobilized families, high-school students, and retired forestry technicians to inventory four strategic green corridors linking the urban parks of Saintes to surrounding rural woodlands.
2. Summary of the 2026 Corridor Expedition Log & Habitat Installations
| Corridor Sector Mapped | Linear Distance Surveyed | Remarkable / Veteran Trees Cataloged | Citizen Conservation Action Taken |
|---|---|---|---|
| Corridor 1 — Vallon des Arènes to West Plateau | 3.4 km | 42 veteran pedunculate oaks & field maples | Installed 22 wooden tit & nuthatch nesting boxes crafted in our Wednesday youth workshop |
| Corridor 2 — Fontcouverte Wooded Ravine Link | 4.1 km | 58 hornbeams, wild service trees (Sorbus torminalis) & holly | Mapped 3 hedge gaps and planted 180 native hawthorn, hazel, and dogwood shrubs |
| Corridor 3 — Right Bank Charente Pollarded Ash Line | 3.8 km | 89 hollow pollarded ashes (Fraxinus excelsior) | Documented saproxylic beetle habitats & installed 18 bat roosting boxes (gîtes à chiroptères) |
| Corridor 4 — Les Boiffiers – Courbiac Rural Hedge Belt | 2.9 km | 31 old orchard pear, medlar & walnut trees | Created an educational tree-identification trail with 25 school-designed markers |
Field Operations Along the Saintonge Woodland Corridors
Dendrometric & Micro-Habitat Survey
Youth teams learned to use forestry tape measures and clinometers to calculate tree height and trunk girth, while cataloging woodpecker cavities, polypore fungi, and ivy winter shelters.
Restoring Discontinuous Hedgerows
Where 20-to-40-meter gaps broke the continuity of ancient hedges, our Saturday volunteer brigades planted multi-tiered native shrubs mulched with local straw and woodchips.
Epiphytic Lichen Air-Quality Mapping
By identifying foliose and fruticose lichens growing on oak bark along a gradient from the center of Saintes to rural woodland edges, pupils created a citizen bio-indication map of air purity.
3. Open Data Sharing With Municipal Planners and Public Schools
Every GPS coordinate, species list, and veteran-tree health sheet recorded during our 2026 corridor expeditions has been compiled into our open-access archive at 7 Rue Georges Clemenceau and shared free of charge with the urban planning and green-space departments of the City of Saintes. By documenting the exact location of hollow pollarded ashes and hedgehog passages, our citizen inventory helps ensure that future municipal pedestrian paths and maintenance schedules protect these irreplaceable biological corridors.
4. Saproxylic Entomology & Acoustic Chiropteran Monitoring Along the Ash Lines
A major scientific highlight of the 2026 expedition was our summer dusk survey of saproxylic (deadwood-dependent) beetles and insectivorous bats along Corridor 3 (the right-bank Charente pollarded ash alignment) and Corridor 1 (the Vallon des Arènes). Old pollarded ash trees (Fraxinus excelsior) and veteran oaks develop internal wood-mould cavities over decades of traditional pruning. While an untrained observer might mistake a hollow trunk for an unhealthy tree needing removal, our volunteer entomologists demonstrated to middle-school participants that these cavities act as nurseries for protected species such as the European Stag Beetle (Lucanus cervus), the Great Capricorn Beetle (Cerambyx cerdo), and the Lesser Stag Beetle (Dorcus parallelipipedus).
During four warm evenings in June and July 2026, small groups of adolescents and parents accompanied our naturalists with handheld ultrasonic bat detectors along the hedgerow edges between 21:30 and 23:00. By converting high-frequency echolocation calls (between 20 kHz and 80 kHz) into audible clicks and spectrograms, students recorded six distinct bat species hunting along continuous tree lines—including the Common Pipistrelle (Pipistrellus pipistrellus), Daubenton's Bat (Myotis daubentonii) skimming over the Charente surface, and the Barbastelle (Barbastella barbastellus) near old woodland margins. Where hedgerows had been removed across open fields, acoustic activity dropped by nearly 80%, offering young participants a striking, real-time demonstration of why dark, unlit tree corridors are essential to nocturnal biodiversity.
5. Microclimatic Buffering: Summer Thermometer Transects With Saintes Students
In addition to wildlife counts, our youth teams conducted comparative temperature and relative-humidity measurements during the July 2026 warm spell using calibrated digital thermo-hygrometers built in our Wednesday physics workshop. Measurements taken at 15:00 showed that shaded sunken lanes bordered by double-row hawthorn and hornbeam hedges remained 4.8°C cooler and retained 19% higher air humidity than adjacent unshaded asphalt roads. These findings are now used in our classroom outreach modules across Saintes to illustrate how preserving urban and peri-urban tree canopies protects both human public health and native ecosystems.