Daylight analysis, species viability mapping, and planting recommendations for an indoor 照葉樹林 (shining-leaf forest) within a commercial office atrium.
Planting zone overlay on annual average illuminance map — generated with AI visualization
From Latin lucidus (shiny) + Greek phyllon (leaf) — a warm-temperate evergreen broadleaf forest defined by thick, glossy, wax-coated leaves.
Literally “shining-leaf tree forest.” These forests are the climax vegetation of lowland and foothill southwestern Japan, extending from Kyushu through Shikoku to the southern Kantō plain. Dominated by evergreen oaks (Quercus), chinquapins (Castanopsis), and laurels (Machilus, Cinnamomum), they form a densely layered canopy that transmits only 2.5–5% of sunlight to the forest floor. The flora comprises approximately 1,008 species including ferns, forest-floor herbs, and epiphytes.
The atrium design uses “engawa” — the traditional Japanese covered veranda that serves as a liminal space between inside and outside. In the original architecture, one sits at the edge and contemplates the garden. Here, the engawa zone transitions from office floor to forest core: light levels, materiality, and planting density all shift gradually, echoing the traditional house–garden relationship.
Canopy • Sub-canopy • Understory • Ferns • Ground cover
From the Japanese lucidophyllous forest species reference
Of full sunlight reaches the forest floor — DLI 1–4 mol/m²/d
No large-scale indoor lucidophyllous forest installation exists globally
Daily Cumulative Illuminance (klxh) measured at 0.76m above floor. Glazing VLT 0.60, skylight VLT 0.45. Climate data: Tokyo Chofu TMYx 2009–2023.
Center: 100–200+ klxh (DLI 6.7–13+). Engawa: 40–100 klxh (DLI 2.7–6.7). Edges: 18–40 klxh. Red/orange hotspots directly under skylights.
Center: 40–75 klxh (DLI 2.7–5.0). Engawa: 18–40 klxh (DLI 1.2–2.7). Green-yellow patches under skylights, blue-cyan spreading.
Center: 40–75 klxh (DLI 2.7–5.0). Inner: 18–40 klxh (DLI 1.2–2.7). Edges: <18 klxh (<1.2 DLI). This is the baseline for planting decisions.
Near-zero everywhere. The entire atrium drops below survival thresholds for all species. Supplemental lighting is not optional — it is the entire light budget for 3 months.
Derived from annual average illuminance. Winter light is near-zero everywhere — supplemental lighting targets are based on bridging the winter gap entirely.
| Zone | Location | Annual Avg (klxh) | Annual DLI | Supplemental Target | Required PPFD (15h) |
|---|---|---|---|---|---|
| A — Skylight Core | Directly under central skylights | 40–75 | 2.7–5.0 mol/m²/d | DLI 3–5 (winter) | 56–93 µmol/m²/s |
| B — Inner Engawa | Engawa corridor, semi-open meeting edges | 18–40 | 1.2–2.7 mol/m²/d | DLI 2–3 (winter) | 37–56 µmol/m²/s |
| C — Periphery | Edges near project rooms | <18 | <1.2 mol/m²/d | DLI 1–2 (winter) | 19–37 µmol/m²/s |
Cross-referencing each species’ DLI minimum against annual average conditions per zone. All zones require supplemental lighting in winter.
| Species | Layer | DLI Min | Zone A | Zone B | Zone C | Action |
|---|---|---|---|---|---|---|
| Daphniphyllum macropodum | Sub-canopy | 2.0 | ✓ | ✓ | +light | Keep |
| Distylium racemosum | Sub-canopy | 2.0 | ✓ | ✓ | +light | Keep |
| Neolitsea sericea | Sub-canopy | 3.0 | ∼ | +light | × | Keep (Zone A) |
| Ilex rotunda | Sub-canopy | 3.0 | ∼ | +light | × | Keep (Zone A) |
| Ilex integra | Sub-canopy | 3.0 | ∼ | +light | × | Keep (Zone A) |
| Fatsia japonica | Understory | 2.0 | ✓ | ✓ | +light | Keep |
| Aucuba japonica | Understory | 2.0 | ✓ | ✓ | +light | Keep |
| Sarcandra glabra | Understory | 2.0 | ✓ | ✓ | +light | Keep |
| Ardisia sieboldii | Understory | 3.0 | ∼ | +light | × | Keep (Zone A–B) |
| Cyrtomium falcatum | Ferns | 1.0 | ✓ | ✓ | ✓ | Keep |
| Dryopteris erythrosora | Ferns | 2.0 | ✓ | ✓ | +light | Keep |
| Polystichum polyblepharum | Ferns | 2.0 | ✓ | ✓ | +light | Keep |
| Coniogramme japonica | Ferns | 2.0 | ✓ | ✓ | +light | Keep |
| Aspidistra elatior | Ground | 0.5 | ✓ | ✓ | ✓ | Keep |
| Hedera rhombea | Ground | 0.5 | ✓ | ✓ | ✓ | Keep |
| Carex morrowii | Ground | 1.5 | ✓ | ✓ | +light | Keep |
| Ophiopogon japonicus | Ground | 1.5 | ✓ | ✓ | +light | Keep |
| Ardisia japonica | Ground | 2.0 | ✓ | ✓ | +light | Keep |
| Liriope muscari | Ground | 2.0 | ✓ | ∼ | +light | Keep (monitor) |
✓ Viable on natural light • ∼ Marginal • +light Needs supplemental • × Not viable
Species with verified indoor performance that complement the core palette. These provide additional structural height, seasonal color, and ground cover options for the atrium design. All DLI values assume a 15-hour supplemental photoperiod.
Supplemental lighting is survival-critical from November through February. The system must provide the entire plant light budget during winter while remaining invisible as “grow lights” to office occupants.
Full-spectrum warm-white LED. High CRI for natural appearance. Optional deep-red 660nm channel for winter compensation in canopy zones.
Total installed electrical load for ~800 m² planting zone at full output. Equivalent to 20–30 office workstations.
With seasonal dimming strategy. Full output Nov–Feb, 30–70% Mar–Apr/Oct–Nov, 0–30% May–Sep.
PAR sensors at representative canopy and understory positions. Supplemental DLI = Target DLI − Measured Daylight DLI.
Three-layer system: concealed high-output bars above canopy, narrow-beam accent spots for tree crowns, understory bars in planter edges.
Dedicated horticulturists for ongoing maintenance. Plant rotation contract recommended (Amazon Spheres model).
No large-scale indoor lucidophyllous forest installation exists globally. These are the closest references — each contributing different lessons.
5,400 m² terraced green roof with temperate Japanese species. Self-enriched from 76 to 120 species over 30 years through bird-dispersed seeds. The most relevant species palette precedent.
~40,000 plants, 400+ species in glass domes. Custom LED system with 150+ photocell-controlled lights. Team of 6 horticulturists. Plant rotation with off-site greenhouses.
Native Japanese plants emphasizing seasonal change. Trees to second floor, shorter plants higher. ~7,800 m² total green area. Closest Tokyo precedent for atrium + Japanese planting integration.
Indoor trees define breakout spaces on each level. Greenery travels to top of building around spiraling atrium. Digital Phyllotaxy art installation mimics tree canopy.
22,000 m² Forest Valley, 900+ trees, ~60,000 shrubs. Massive daylight via glass toroidal dome. ~30 gardeners for weekly maintenance. teamLab responsive forest lights.
~24,000 m² green space, ~320 plant species. Demonstrates Tokyo market appetite for large-scale integrated green infrastructure in premium commercial developments.