Visual Evidence Library

BGS GeoIndex Onshore — Carwynnen sheet

British Geological Survey GeoIndex Onshore viewer centred on the Carwynnen / Higher Bodrivial area, with mass-movement deposits and site investigation report layers enabled. The red pin marks the reference location used in the report.

What this does and does not show: A black cross-marked line runs north-west to south-east across this extract. It is a mapped linear geological feature — a reported weak fracture / structural lineament corridor. It is now shown as an optional layer on the environmental map. Its position on this website is traced from the screen capture and is indicative only.

Source: BGS GeoIndex screen capture, reproduced in the BGS geology & hydrogeology report

Local subsurface reference points (OSGB grid)

Plot of BGS and local subsurface reference points around Holmans–Carwynnen on the OSGB national grid, including the X-area tree-failure coordinate 50.1850998, -5.2902908 and the Holmans Test Mine reference point.

Source: BGS geology & hydrogeology report, figure

Principal Carnmenellis granite joint trends

Rose diagram of the principal joint sets recorded in the Carnmenellis granite: approximately 340°, 242°, 012° and an east–west set.

What this does and does not show: Jointing controls where granite can transmit water and where energy can travel. These orientations are the reason the investigation asks whether effects are aligned with structure rather than randomly distributed.

Source: BGS Falmouth memoir, summarised in the geology & hydrogeology report

Operator facility description sheet

Operator facility sheet for Holmans Test Mine describing underground tunnels, a 3D trials suite, environmental chamber, vibration chamber and firing range, lecture rooms and workshops, an open-cast quarry and fully alarmed HSE-licensed explosive storage.

Source: Operator-published material reproduced in the master dossier

Underground tunnel, granite host rock

Photograph of an underground excavation in granite with a graded floor and a side chamber opening. The operator states excavations are predominantly in igneous intrusive granite with some minor mineral veins.

Source: Operator-published material reproduced in the master dossier

Community-defined investigation outline

Satellite mapping of Carwynnen with a hand-drawn outline around the woodland block west of the facility. This is the community-defined investigation area and is not a surveyed or legal boundary.

Source: Community-supplied annotated mapping, reproduced in the master dossier

Reported X1–X3 corridor annotation

Mapping annotated by hand with points marked X1, X2 and X3 forming a corridor between the Carwynnen woodland and the facility area.

What this does and does not show: The X1–X3 marks are a reported corridor of interest, not measured sampling stations. Their purpose is to tell surveyors where to look first, not to assert that anything has been found.

Source: Community-supplied annotated mapping, reproduced in the master dossier

Overturned mature tree with exposed root plate

A mature broadleaf overturned at the root plate, with soil, root mass and stone lifted clear of the ground surface, adjacent to a woodland path.

Source: X-area tree-failure photographic schedule (Appendix B)

Root plate with entrained stone

Exposed root plate showing shallow rooting and substantial angular stone held within the root mass.

What this does and does not show: Shallow rooting over stony or rock-near-surface ground is a recognised ordinary vulnerability. Whether that vulnerability is natural, or has been changed by ground disturbance or altered water levels, is a question for an arboriculturist and an engineering geologist together.

Source: X-area tree-failure photographic schedule (Appendix B)

Multiple stems down in one area

Several fallen and leaning stems within one part of the woodland, with lichen-covered bark and standing trees around them.

Source: X-area tree-failure photographic schedule (Appendix B)

Fallen stems across the slope

Fallen stems lying across a sloping section of woodland with dense fern and bramble regrowth beneath.

Source: X-area tree-failure photographic schedule (Appendix B)

Failure cluster with standing survivors

A group of failures with apparently unaffected mature trees immediately adjacent.

What this does and does not show: Clustering with unaffected neighbours is the observation the investigation is built around. Storm loading alone would not be expected to produce a tight cluster; nor does a cluster by itself establish any particular cause.

Source: X-area tree-failure photographic schedule (Appendix B)

Root plate and depression, second location

Upturned root plate with a hollow behind it. An environmental geologist is reported to consider part of this ground sunken or depressed; this has not been surveyed.

Source: X-area tree-failure photographic schedule (Appendix B)

Woodland floor debris field

Accumulated fallen timber and broken branch material on the woodland floor within the reported failure zone.

Source: X-area tree-failure photographic schedule (Appendix B)

Leaning stem, root plate partially lifted

A stem leaning with the root plate partially lifted on one side — a condition that may progress to full failure.

Source: X-area tree-failure photographic schedule (Appendix B)

Root plate detail, third location

Close view of a root plate with soil, stone and fine roots exposed, and a cavity behind the plate.

Source: X-area tree-failure photographic schedule (Appendix B)

Cut sections at a failure site

Cut timber sections beside a failure site, indicating clearance work after the event.

What this does and does not show: Where failed stems are cut and removed, physical evidence is lost. Recording condition before clearance is one of the highest priorities for this investigation.

Source: X-area tree-failure photographic schedule (Appendix B)

Field survey — multiple down stems (20 Aug 2026)

Lichen-covered stems down across the slope with browned foliage still attached on some limbs, and green standing canopy behind.

Source: Community field photograph, X-area, 20 August 2026

Field survey — canopy dieback with fallen stems (20 Aug 2026)

Fallen lichen-covered stems in the foreground with visible brown, thinning crowns in the standing trees above.

What this does and does not show: Crown dieback alongside physical failure is the pattern that a combined arboricultural and root-zone assessment is being asked to explain. Drought, disease, root damage and altered water table are all live candidate explanations.

Source: Community field photograph, X-area, 20 August 2026

Field survey — root plate and hollow (20 Aug 2026)

Large upturned root plate holding soil and stone, with an open hollow behind it and further failures visible in the background.

Source: Community field photograph, X-area, 20 August 2026

Local ecological context plot

Schematic coordinate plot showing the relative positions of Pendarves Wood (Cornwall Wildlife Trust reserve), Troon village and Holmans Test Mine.

Source: Wildlife & ecology impact report, figure

Cornwall Wildlife Trust reserve material

Published Cornwall Wildlife Trust reserve material used to establish the protected and managed nature-conservation context of the wider area.

Source: Cornwall Wildlife Trust published visitor material