GRÖTHMÅ

The First Grothulthir. The Sky-Banyan. The Rooted Star.

“It does not rise from the land. The land gathers itself around it.”
— Old Negzölir saying

THE VERTICAL BIOMES OF GRÖTHMÅ

A Living World Column
Gröthmå is divided by Sölmiri scholars into strata, not heights. Elevation alone isn’t enough — light, pressure, oxygen, wind, and biology shift too fast.

STRATUM I — THE ROOTED DARK

(Below ground to +0 m)
Also called: Neggroth — “The Under-Holding”
This is where Gröthmå truly begins.

Environment

• Permanent darkness except for fungal bioluminescence
  

• Warm, mineral-rich air
  

• Extremely high microbial and fungal density
  

• Oxygen-poor but nutrient-saturated
  

Life

• Colossal mycelial networks (older than Sölmiri history)
  

• Root-leeches the size of boats
  

• Blind amphibians and crustacean analogues
  

• Resin pools containing extinct spores and pollen
  

Significance

• All Grothulthir fungal symbioses originate here
  

• Roots are fused with bedrock — removal is impossible
  

• Earthquakes dampen or reroute around this stratum
  

Humans do not enter the Rooted Dark.
Not because it’s forbidden — because the air alone will kill you.

STRATUM II — THE TRUNK WILDS

(0–300 m)
Also called: Grothfold
This is the realm of bark, moss, resin, and shadow.

Environment

• Twilight lighting
  

• Humidity near 100%
  

• Constant resin seepage
  

• Air dense, oxygen-rich, slightly intoxicating
  

Life

• Bark-forests growing on the trunk
  

• Mosswolves (rare, larger subspecies)
  

• Varkhúl sightings are documented but disputed
  

• Giant beetles, gliders, and resin-feeders
  

Human Interaction

• Temporary research camps only
  

Long exposure causes:

• altered circadian rhythms
  

• vivid dreams
  

• mild euphoria followed by fatigue
  

STRATUM III — THE BANYAN DESCENT

(300–700 m)
Also called: The Hanging World
Here the banyan nature asserts itself.

Environment

• Massive descending trunks form bridges
  

• Natural platforms kilometers across
  

• Constant mist and drizzle
  

• Stable temperatures year-round
  

Life

• Entire soil systems suspended mid-air
  

• Grazing megafauna adapted to vertical migration
  

• Canopy predators that never touch ground
  

• Rare medicinal grothfruits
  

Notes
This stratum could support Grothavír cities.
It never has.

Most Sölmiri cultures consider it “too close to the breath of the First Tree.”

STRATUM IV — THE LOWER CLOUD BELT

(700–1,200 m)
Also called: Zölvael — “Shadow-Air”

Environment

• Permanent cloud cover
  

• Sudden wind shears
  

• Lightning without storms
  

• Reduced visibility to tens of meters
  

Life

• Photosynthetic mosses adapted to diffuse light
  

• Aerial plankton analogues
  

• Floating seed-mats
  

• The first exclusive dragon nests
  

Human Experience

• Disorientation
  

• Altitude sickness amplified by oxygen spikes
  

• Sound behaves… incorrectly
  

This is where expeditions historically stop.

STRATUM V — THE CROWN SEA

(1,200–1,800+ m)
Also called: Mojtgroth — “The High Branch”

Environment

• Thin, hyper-oxygenated air
  

• Violent updrafts
  

• Electrical storms generated by the canopy itself
  

• Sunlight filtered through kilometers of leaves
  

Life

• Entire ecosystems floating on limb networks
  

• Species unknown elsewhere on Aerda
  

1. Apex aerial megafauna
   

• True dragons in their oldest, largest forms
  

Nothing here evolved for the ground. Everything either flies, glides, or falls and dies

STRATUM VI — THE UNMEASURED CROWN

(Above ~1,800 m)
Also called: The Quiet Height
No confirmed measurements. No confirmed returns.

Observations (from afar)

• Shadows moving above cloud tops
  

• Thunder with no lightning
  

• Wing silhouettes larger than valleys
  

Some scholars argue this stratum is less biological and more atmospheric-organic, where the tree and sky blur. Others refuse to speculate.

GRÖTHMÅ — INTERNAL STRUCTURE (CROSS-SECTION)

A Colossal Banyan-Type Grothulthir
Think of Gröthmå not as a single trunk, but as a biological megastructure: part tree, part reef, part mountain.

I. OUTERMOST LAYER — THE WORLD-SKIN (Mantlebark)

Thickness: 5–15 meters (varies by age zone)

What it looks like:

• Vast, plated bark segments like tectonic slabs
  

• Cracked, overlapping, basalt-dark with bronze-green lichen
  

• Deep grooves large enough to hold rainwater, moss forests, and entire animal niches
  

Function:

• Armor against wind shear at 2 km height
  

• Fire-resistant, self-sealing after damage
  

• Primary attachment point for epiphytes, moss, fungi, insects, birds, and smaller trees
  

This bark is less “wood” and more bio-ceramic composite — packed with silica, calcium carbonate, and iron microfilaments.

Think: living rebar wrapped in cork.

II. THE FLEX LAYER — THE LAMINAR BAST ZONE

Thickness: 20–60 meters

Structure:

• Dense bundles of bast fibers arranged in spirals and counter-spirals
  

• Fibers run vertically and helically
  

• Interwoven like the world’s strongest rope
  

Purpose:

• Absorbs wind oscillation
  

• Prevents catastrophic snapping
  

• Allows the tree to bend kilometers at the crown without tearing
  

This is why Gröthmå doesn’t topple in storms that flatten forests.
It sways like a continent, not like a tree.

III. THE LOAD-BEARING CORE — FERRO-LIGNIN MEGABANDS

Thickness: 200–400 meters (multiple concentric bands)
This is the real skeleton.

Composition:

• Mineralized lignin infused with iron, silica, magnesium, and trace metals
  

• Density ranges from 1,100–1,400 kg/m³ (heavier than water, close to stone)
  

• Grown in seasonal rings thicker than city blocks
  

Function:

Handles compressive load of:

• Its own trunk
  

• The canopy (which weighs millions of tons)
  

• Epiphytic ecosystems
  

• Dragons. Yes. Dragons.
  

This zone behaves more like engineered laminated stone than wood.

It’s why ancient Sölmiri say:
“The tree does not grow upward. The world grows around it.”

IV. THE VASCULAR VOID — THE SPONGIA MEGACORE

Diameter: 300–600 meters
This is the most alien part.

Appearance:

• Honeycombed caverns
  

• Vast vertical channels
  

• Pillared walls like a living cathedral
  

Purpose:

• Nutrient transport
  

• Weight distribution
  

• Buoyancy and shock absorption
  

• Thermal regulation
  

The internal structure spreads stress across thousands of micro-columns. Think bone marrow meets gothic architecture.
This core is why internal collapse doesn’t propagate — damage is localized, not structural.

V. INNER ROOT CONDUITS — THE UNDERWEB

Descending from the core are root-trunks, each hundreds of meters wide, plunging 4–7 km into bedrock.

They:

• Anchor tectonic plates
  

• Stabilize mountains
  

• Redirect groundwater
  

• Interlace with continental mycelium networks
  

Geologically speaking, Gröthmå isn’t sitting on Sölmir.
Sölmir is sitting on Gröthmå.

HOW MUCH DOES GRÖTHMÅ WEIGH?

Let’s be conservative (which is funny, given the scale).

Rough dimensions:

• Height: ~2,000 m
  

• Effective trunk + aerial root diameter (average): ~1,200 m
  

• Banyan spread massively increases mass
  

Estimated volume:

• ≈ 1.2–1.8 cubic kilometers of biomass
  

Average density (composite):

• ≈ 900–1,100 kg/m³
  

Estimated total mass:

• 1.1–2.0 × 10¹² metric tons
  

That’s one to two trillion tons.

For comparison:

• Mount Everest ≈ 8–10 trillion tons
  

• Large asteroids ≈ trillions of tons
  

Gröthmå is mountain-class mass.