Changelog

Version: 1.16.28
Date: 2026-06-14
  Bugfixes:
    - Queued tree seeds whose marker was deleted without raising a mined event (e.g. removed by a
      blueprint mod through a script destroy) are no longer grown into phantom trees. Previously
      the waiting-seed growth queue was only cleaned when a marker was hand-mined or
      bot-deconstructed; a script-based deletion left the queue entry behind, so the seed kept
      growing even though it had been removed. (Actively-growing trees were already dropped when
      their growth-stage entity was destroyed; this gap was specific to parked/waiting seeds.)
      Two checks now cover it: try_dequeue_tree verifies the waiting marker still exists before
      growing a queued seed and discards the entry if it is gone, and a per-surface prune at dusk
      clears any parked waiting-seed entries whose marker has disappeared (useful when the
      active-tree cap is full so the stale entries are never otherwise drawn).

Version: 1.16.27
Date: 2026-06-14
  Changes:
    - The seed-ghost collision sweep now runs on every surface, not just the first one, so tree
      seeds placed with the seeder tool on other surfaces are also protected. Each surface is
      tracked independently and sweeps at its own day->night transition (dusk), so surfaces with
      different day lengths each fire once per cycle. Space platforms are skipped. Note: surfaces
      with no real day/night cycle (e.g. always-day surfaces) never reach dusk and so are not
      swept; mention it if you want a fixed-interval fallback added for those.

Version: 1.16.26
Date: 2026-06-14
  Bugfixes:
    - Colored Nitrate Pellets can now be removed by construction robots. The entity had no
      minable result (no paired item), which makes bot deconstruction unreliable in the engine.
      It now returns a regular white Nitrate Pellet (soil-crystal) when mined or deconstructed.
      Hand-mining while trample mode is on still yields nothing, as before.
    - Fixed colored pellets never actually running their Nitrate Catalyst behavior. They were
      enqueued through a stale three-argument call that left the internal "colored" flag false,
      so the catalyst path (extra tile upgrades, adjacent-tile upgrades, chain trigger, and
      pollution-neutrality) never executed and colored pellets were wrongly eligible for the
      Enduring Nitrates re-queue. They are now correctly flagged colored.
  Changes:
    - A Nitrate Catalyst now only chain-triggers nearby WHITE pellets; it no longer counts other
      colored pellets as chain targets. When no white pellet is in reach, the catalyst simply
      performs its own tile upgrade and is consumed, as before.
  Features:
    - Added a once-per-day/night seed-ghost collision sweep (runs at dusk). If another mod has
      placed a tree on the tile a tree-seed-site ghost is waiting on, construction robots can
      never fulfil that ghost and keep retrying. The sweep cancels any tree-seed ghost that has
      become unfulfillable because a foreign tree/plant now blocks the tile (the planting is
      lost). A ghost is only cancelled when a tree/plant overlaps its tile AND the seed-site can
      no longer be placed there, so still-buildable ghosts and ghosts blocked by non-tree causes
      are left untouched.

Version: 1.16.25
Date: 2026-06-13
  Optimizations:
    - process_crystals no longer walks the whole nitrate queue when nothing is due. A lower
      bound on every queued pellet's fire time is tracked as pellets are enqueued, so the nightly
      pass returns immediately while a freshly-placed backlog is still waiting out its delay,
      instead of scanning tens of thousands of not-yet-due entries every cycle.
    - The Nitrate Catalyst chain trigger no longer rescans the entire queue for every catalyst
      that fires. It now looks up nearby pellets through the engine's spatial index and maps them
      back to queue entries via a per-call index built once and shared by all catalysts firing
      that tick, so the cost scales with the number of nearby pellets rather than queue size.

Version: 1.16.24
Date: 2026-06-13
  Changes:
    - Nitrate Catalyst Reactions now scales the chain reach as well as the trigger count. Each
      level extends both together: radius 1 / 1 pellet with no levels, up to radius 4 / 4 pellets
      at level 3 (previously the radius was a fixed 8 tiles and only the count scaled). The
      neighbour search is now inclusive of the radius, so radius 1 reaches orthogonally-adjacent
      pellets.
  Bugfixes:
    - Fixed the Nitrate Catalyst Reactions research description showing a missing-locale-key error
      in-game: the description was keyed 'soil-crystal-reactions' but the technology resolves to
      'soil-crystal-catalyst-reactions' (Factorio strips the trailing level number).

Version: 1.16.23
Date: 2026-06-12
  Optimizations:
    - try_dequeue_tree now uses a swap-remove instead of table.remove at a random index when
      pulling a waiting seed into the active growth set. table.remove shifts every element after
      the removed index (O(n)); swap-remove moves the last element into the freed slot and drops
      the tail (O(1)). Order is irrelevant because the draw is random, so behaviour is unchanged.
      Removes the backlog-size cost previously paid on every tree completion.

Version: 1.16.22
Date: 2026-06-12
  Optimizations:
    - process_crystals now returns early when 'Pellets work at night only' is on and it is
      currently daytime, instead of scanning the whole pellet queue every 60 ticks only to skip
      every entry. Eliminates the daytime queue walk for night-only configurations.

Version: 1.16.21
Date: 2026-06-12
  Optimizations:
    - Pellet pollution is now emitted on its own coarser cadence (every 600 ticks instead of
      every 60), so the pellet queue is walked one tenth as often for pollution. The per-pellet
      amount scales with the new interval, so total pollution per minute is unchanged. This was
      the main cost when a large queue had built up after a rainstorm.
  Features:
    - Added pellet overflow draining. When the queue exceeds the new 'Pellet overflow threshold'
      setting (default 2000), the processor drains a percentage of the queue per night (new
      'Pellet overflow drain' setting, default 40%) instead of the fixed batch size, so large
      backlogs clear in a few nights rather than dozens. The drain tapers automatically as the
      queue shrinks, and the fixed batch size is always honoured as a floor. Set the threshold to
      0 to disable. Both settings are runtime-global and can be changed mid-game.

Version: 1.16.20
Date: 2026-06-12
  Bugfixes:
    - Extended the 1.16.19 ghost-deletion fix to the three other placement paths that build a
      real entity after a ghost check: seed-site maturation (handle_site), the growth-queue
      processor, and Cloud Seeding (plant_seed_at). All three used a centre-based position+radius
      ghost check that could miss a multi-tile building ghost covering the target tile but centred
      more than half a tile away; the real tree/plant was then built over that ghost and the engine
      deleted it. Each now checks the full tile footprint (an area search) instead. The Crystal
      Placer area tool was reviewed and intentionally left unchanged: it places a ghost (not a real
      entity), so it cannot delete an overlapping ghost.

Version: 1.16.19
Date: 2026-06-12
  Bugfixes:
    - Restorative Rains no longer deletes player ghosts when placing nitrate pellets. The
      placement guard detected ghosts with a centre-based position+radius search, which only
      matches ghosts whose centre lies within the radius. A multi-tile building ghost covering
      the target tile but centred elsewhere slipped through, the pellet was then built directly
      on top of it, and the engine deletes any ghost a real entity is built over. The ghost
      check now uses the pellet's full tile footprint (an area search), so any ghost overlapping
      the tile is detected and the pellet is placed elsewhere instead.

Version: 1.16.18
Date: 2026-06-10
  Changes:
    - Atmospheric Arbory and Restorative Rains: Space Exploration compatibility. When SE is
      installed, both techs now require the se-rocket-science-pack technology as a prerequisite
      and as a research ingredient, gating them behind SE's rocket milestone. When SE is not
      installed, vanilla space-science-pack is required as both a technology prerequisite and a
      research ingredient. Restorative Rains previously had no space-tier gate; it now matches
      Atmospheric Arbory in all configurations.

Version: 1.16.16
Date: 2026-06-06
  Bugfixes:
    - Fixed nitrate placer tool placing pellet ghosts on top of existing entity ghosts. The
      placer tool now explicitly checks for any ghost before placing, matching the guard already
      present in the Restorative Rains and seed-planting paths.
  Changes:
    - Arboreal Aromatics renamed to "Atmospheric Arbory".
    - Atmospheric Arbory: reworked how the rocket-science gate is expressed for Krastorio 2
      compatibility. Now uses space-science-pack as a *technology prerequisite* (not a research
      ingredient). In vanilla this naturally gates behind rocket-silo (since the space-science-pack
      technology requires it); in Krastorio 2 the space-science-pack technology is the equivalent
      late-game milestone. Removed space-science-pack from the ingredient list to avoid Krastorio's
      tier-separation enforcer stripping the lower-tier packs.
    - Atmospheric Arbory now requires Rocket Science: rocket-silo as a technology prerequisite
      and space-science-pack as a research ingredient (in addition to existing packs).
    - Thunderstorms now place twice as many nitrate pellets per cleaned chunk (credits doubled
      from 1 to 2 per on_rain_pollution_cleaned event).
    - Cloud Seeding technology description shortened.

Version: 1.16.13
Date: 2026-06-03
  Changes:
    - Cloud Seeding now also increases rain seeds per cleaned chunk (requires Arboreal Aromatics).
      Formula: floor(cloud_seeding_levels / 2) + 1 seeds per chunk.
      CS 0-1 → 1 seed, CS 2-3 → 2, CS 4-5 → 3, CS 6 → 4.
    - Arboreal Aromatics now controls rain seed scatter (1 seed per rain-cleaned chunk) instead
      of Cloud Seeding. Cloud Seeding levels now exclusively boost the simultaneous tree growth
      cap, decoupling the two systems.

Version: 1.16.12
Date: 2026-06-03
  Features:
    - Added "Primitive Nitrates" technology (automation + logistic science). Unlocks a slow,
      low-yield nitrate pellet recipe (10 wood + 3 stone + 200 water → 1 pellet, 120 s) in
      assembler-2 (crafting-with-fluid). The main Nitrate Pellets technology (chemical plant
      recipe) now requires Primitive Nitrates as a prerequisite, enforcing natural progression.
    - Added "Arboreal Aromatics" technology (Dynamic Rain only). Uses the Restorative Rains
      art and cost (150 auto + logistic + chemical packs, 60 s). Gates Cloud Seeding 1 so
      players explore the rain-soil feedback loop before pursuing atmospheric seeding.
    - Cloud Seeding 1 now requires Arboreal Aromatics in addition to Sapling Growth 1.

Version: 1.16.11
Date: 2026-06-02
  Bugfixes:
    - Waiting seed markers (treez-seed-waiting) can now be selected by the
      deconstruction planner. The "player-creation" flag was re-added; Factorio
      requires this flag for the deconstruction planner to pick up an entity.
      The "not-blueprintable" flag already prevents blueprint capture, and the
      on_player_setup_blueprint handler in control.lua rewrites any stray entries
      as a belt-and-suspenders guard. The force-build (shift+click) concern that
      prompted removing the flag in 1.16.10 is minimal in practice: the waiting
      marker has a very small collision box (0.05 tiles) and rarely blocks builds.

Version: 1.16.10
Date: 2026-05-31
  Bugfixes:
    - Force-building (shift+click) over a waiting seed marker (treez-seed-waiting)
      no longer shows "entity in the way". The "player-creation" flag was removed
      from that entity; selectability and minability are preserved via
      selectable_in_game=true and the minable field respectively. The entity is
      now explicitly flagged "not-blueprintable" since it is a transient queue
      marker, not something the player should capture in a blueprint.
    - Force-building (shift+click) over a planted seed site (tree-seed-site) now
      correctly marks it for deconstruction instead of blocking. tree-seed-site
      must keep "player-creation" to remain blueprintable (robots need it to plant
      seeds from blueprints), so the fix is scripted: the on_pre_build handler now
      calls order_deconstruction on any seed-site at the target position when
      event.shift_build is true, letting the force-build proceed normally.

Version: 1.16.9
Date: 2026-05-31
  Bugfixes:
    - Cloud seeding (plant_seed_at) no longer plants trees on top of fully-built
      buildings. The root cause was that placement was checked using SITE_NAME
      (tree-seed-site) as a proxy, whose collision box is intentionally tiny
      (0.2x0.2 tiles) so seeds can be placed near trees. A large building whose
      footprint covers a tile but whose centre lies elsewhere would pass that
      check. Fixed by adding an explicit find_entities_filtered scan for built
      entities at the target position before the can_place_entity call. The other
      two planting paths (handle_site, try_dequeue_tree) were not affected because
      they check placement against the full tree/growth-stage collision box.

Version: 1.16.8
Date: 2026-05-31
  Changes:
    - Tree seed fuel fields (fuel_category, fuel_value) are now also set on the
      base-game fallback item definition in data.lua in addition to the existing
      patch in data-final-fixes.lua. The data-final-fixes.lua patch is kept so
      Space Age's tree-seed definition (which lacks fuel fields) also gains them.
      Values are identical in both places: chemical, 200 kJ.

Version: 1.16.7
Date: 2026-05-31
  Features:
    - Tree seeds can now be used as fuel (fuel_category: chemical, 200 kJ — one
      tenth the fuel value of wood at 2 MJ). Useful as a last-resort fuel source
      or to dispose of excess seeds. Applied in data-final-fixes so it works
      whether the tree-seed item comes from the base-game fallback or Space Age.

Version: 1.16.6
Date: 2026-05-31
  Balancing:
    - Increased the base concurrent-tree cap for both tracks. Sapling Growth now
      uses 2^(levels+2) instead of 2^(levels+1), so the floor with no research
      is 4 (was 2) and the max at level 6 is 256 (was 128). Cloud Seeding now
      uses 2^(levels+1) instead of 2^(levels-1), so level 1 contributes 4 (was
      1) and level 6 contributes 128 (was 32). With no research at all the
      combined cap is therefore 4+0=4 (sapling only) or 4+4=8 (with any Cloud
      Seeding level 1 researched), up from 2 and 3 respectively.

Version: 1.16.5
Date: 2026-05-31
  Bugfixes:
    - Seeds (both directly planted and queued) no longer overwrite pre-placed
      entity ghosts. Previously, handle_site() had no ghost check, so planting a
      seed directly on a blueprint ghost would silently clobber it. Additionally,
      try_dequeue_tree() had no ghost check, so a seed queued before a ghost was
      placed would overwrite the ghost when it later tried to grow. Both functions
      now detect any entity-ghost at the target position and abort/requeue
      respectively. The cloud-seeding path (plant_seed_at) already had this check.

Version: 1.16.4
Date: 2026-05-30
  Bugfixes:
    - Tree Seeder shortcut now correctly appears greyed-out (unavailable) until
      the Tree Seeder technology is researched. Previously technology_to_unlock
      locked it on new games but existing saves or mid-session loads would show
      it as active. A new sync_seeder_shortcut() helper now fires on on_init,
      on_configuration_changed, and on_research_finished to keep the shortcut
      state in sync with actual research, matching the behaviour of the Pellet
      Placer shortcut introduced in 1.16.1.

Version: 1.16.3
Date: 2026-05-30
  Bugfixes:
    - Blueprint seed ghosts can no longer be placed on natural resource patches.
      Previously the resource check only fired when a robot fulfilled a ghost, so
      the ghost itself would appear over ore and sit waiting for a robot. Now the
      ghost is immediately destroyed and the seed refunded when placed over any
      resource entity, preventing robots from ever attempting fulfillment there.

Version: 1.16.2
Date: 2026-05-30
  Bugfixes:
    - Tree seeds and tree-seed sites can no longer be placed on natural resource
      patches (coal, iron ore, copper ore, stone, oil, uranium, etc.). Attempting
      to place on a resource entity now cancels placement, refunds the seed to the
      player or robot, and shows a "Can't place on natural resources" flying text.
      Robot placements are silently refunded. The same guard applies to all three
      placement paths: player, robot, and script-revived entities.

Version: 1.16.1
Date: 2026-05-30
  Bugfixes:
    - Pellet Placer shortcut now correctly locks until the Nitrate Pellets (soil-crystal)
      technology is researched. technology_to_unlock handles new games; a new
      sync_placer_shortcut() helper also fires on on_research_finished, on_init,
      and on_configuration_changed so existing saves and mid-session research
      completion both show the shortcut at the right time.

Version: 1.16.0
Date: 2026-05-30
  Changes:
    - Mod description updated: reflects Nitrate Pellets (not Soil Crystals), and
      lists all major features including Dynamic Rain integration, Sapling Soil
      Enrichment, Restorative Rains, Enduring Nitrates, and compatibility mods.
    - Removed colored pellet absorption mechanic (treez-crystal-colored-absorption-rate
      setting, crystal_colored_absorption_rate local, and its settings change handler).
      Colored pellets are pollution-neutral — neither emitting nor absorbing. The
      setting was hidden and the absorb_amount variable was computed but never applied.
    - rain-cloud-source.png moved from graphics/icons/ to source-art/ so it is
      retained as a reference image without being shipped as a mod asset.
    - Removed orphaned rain-started-tracking locale key (polling path was removed
      in 1.15.90; the key was never cleaned up).
    - Removed storage.dr_polluted_chunks (legacy polling storage, unused since
      1.15.90 when the event-driven path replaced polling entirely).
    - Updated stale comment above emit_crystal_pollution to reflect that colored
      pellets are pollution-neutral and rare pellets no longer exist.

Version: 1.15.x
Date: 2026-05-09 through 2026-05-30
  Features:
    - Tree seeds grow through animated growth stages (200 steps, fast/smooth speed options).
      Active growth cap starts at 2 and doubles with each Sapling Growth research level (max 128).
      Queued seeds show an acorn marker and start growing automatically as slots open.
    - Seeds and growing trees respect biome: Alien Biomes species are matched by sampling
      nearby trees. Cleared land falls back to the tile's native species list.
    - Tree growth delayed by pollution: chunks with more pollution cause longer delays between
      growth stages. Trees in growth also have a chance to upgrade the tile beneath them.
    - Sapling Soil Enrichment (6 levels): each growth stage has a cumulative chance to upgrade
      the tile under the sapling, using distance-weighted random selection to produce organic halos.
    - Nitrate Pellets (formerly Soil Crystals): craftable items that upgrade degraded terrain one
      step per firing, active at night after a configurable delay. Work on vanilla and Alien Biomes
      tiles. Cannot be placed on hard surfaces or rails.
    - Colored pellet variant: fires as a chain catalyst, advancing nearby normal pellets.
      Catalyst research chain unlocks probability, abundance, and reaction strength upgrades.
    - Pellet Placer and Tree Seeder area tools: drag a selection to queue robot ghost placement
      at a chosen density. Robots fulfill from the logistic network automatically.
    - Enduring Nitrates (3 levels): cumulative 10%/20%/30% chance a normal pellet survives
      firing and re-queues for the next night.
    - Cloud Seeding (6 levels, requires Dynamic Rain): seeds are automatically scattered in
      any chunk where rain removes all pollution. One seed per level per cleaned chunk.
    - Restorative Rains (requires Dynamic Rain): while it rains, nitrate pellets accumulate
      in pollution-cleaned chunks and fire the coming night. Toggle in mod settings post-research.
    - Dynamic Rain: trees grow faster in rain (halved stage delay). Both features gate off
      Cloud Seeding / Restorative Rains research respectively.
    - Winter Is Coming compatibility: tile changes raise set_tiles events so WIC updates its
      warm-tile snapshot correctly.
    - Blueprint Shotgun / script-placement compatibility: script_raised_revive and
      script_raised_built are handled identically to player and robot placement.
    - Space Exploration compatibility: seeds and pellets blocked on scaffold/asteroid surfaces.
    - Pellet trample: players walking over pellets destroy them (configurable radius). Biters
      attacking a pellet destroy it instantly. Robots unaffected.
    - Randomise upgrade paths (off by default): pellets pick a random destination tile from
      the same colour/base-type group rather than following a strict linear chain.
    - Pellet pollution emission: placed pellets emit a small, configurable amount of pollution
      while queued. Colored pellets are pollution-neutral.
    - Research gates: Seeds tech auto-completes after cutting 10 trees; Tree Seeder requires
      Seeds; Forest Management auto-completes after planting 1000 seeds.
  Bugfixes:
    - Rare nitrate crystal mechanic removed entirely (simplified to colored/normal only).
    - Seeds and pellets can no longer overlap each other at placement.
    - Seeds blocked on ore patches (resource entities) in rain/cloud seeding paths.
    - Acorn markers correctly cleaned up in all edge cases via spatial search at placement.
    - Growth stage sprites use a square-root curve with a 5% floor so saplings are visible.
    - Various crash fixes for Space Age icon validation, load-order issues, and stale
      storage values across mod updates and save migrations.