diff --git a/src/woodshop/cutplan.py b/src/woodshop/cutplan.py
index b4821dd..e3b90c5 100644
--- a/src/woodshop/cutplan.py
+++ b/src/woodshop/cutplan.py
@@ -511,12 +511,13 @@ def build_cut_plan(scene, settings: ShopSettings | None = None,
 
 
 def _score(stock_pieces, s, strategy, warnings) -> dict:
-    waste_area = used_area = bought_area = 0.0
+    waste_area = bought_used = bought_area = 0.0
     reusable = 0
     bought = [sp for sp in stock_pieces if not sp.owned]
     for sp in stock_pieces:
         used = sum(p.len_in * p.wid_in for p in sp.placements)
-        used_area += used
+        if not sp.owned:
+            bought_used += used                       # yield is about BOUGHT stock only
         if sp.is_sheet:
             if not sp.owned:
                 bought_area += sp.length_in * sp.width_in
@@ -537,7 +538,7 @@ def _score(stock_pieces, s, strategy, warnings) -> dict:
         "waste_area": round(waste_area, 1),
         "reusable_offcuts": reusable,
         "reusable_in": round(reusable_in, 1),
-        "yield_pct": round(used_area / bought_area * 100, 1) if bought_area else 0.0,
+        "yield_pct": round(bought_used / bought_area * 100, 1) if bought_area else 0.0,
         "warnings": list(warnings),
     }
 
@@ -587,6 +588,7 @@ def reoptimize(scene, base_plan: CutPlan, strategy: str = "decreasing") -> CutPl
         seeds.setdefault((sp.stock, sp.material), {})[sp.id] = StockPiece(
             id=sp.id, stock=sp.stock, is_sheet=sp.is_sheet,
             length_in=sp.length_in, width_in=sp.width_in, material=sp.material,
+            owned=sp.owned, source=sp.source,
             placements=[Placement(id=p.id, item_id=p.item_id, x_in=p.x_in, y_in=p.y_in,
                                   len_in=p.len_in, wid_in=p.wid_in, rotated=p.rotated, locked=True)
                         for p in kept])
@@ -773,6 +775,8 @@ def validate_cut_plan(plan: CutPlan) -> list:
             it = items.get(p.item_id)
             if it and it.stock != sp.stock:
                 problems.append(f"{p.id} ({it.stock}) is on a {sp.stock} stock piece")
+            elif it and it.material and sp.material and it.material != sp.material:
+                problems.append(f"{p.id} ({it.material}) is on a {sp.material} stock piece")
             if p.rotated and not rot_ok:
                 problems.append(f"{p.id} is rotated but rotation isn't allowed")
         ps = sp.placements
diff --git a/src/woodshop/gui/bom_window.py b/src/woodshop/gui/bom_window.py
index 4984282..ec013aa 100644
--- a/src/woodshop/gui/bom_window.py
+++ b/src/woodshop/gui/bom_window.py
@@ -144,7 +144,7 @@ class BomWindow(QDialog):
         self._rebuild_base()
 
     def _mark_purchased(self) -> None:
-        bought = Counter(sp.stock for sp in self._plan.stock_pieces
+        bought = Counter((sp.stock, sp.material) for sp in self._plan.stock_pieces
                          if not getattr(sp, "owned", False))
         if not bought:
             QMessageBox.information(self, "Nothing to buy", "This plan needs no new stock.")
@@ -153,16 +153,19 @@ class BomWindow(QDialog):
         if not dlg.exec():
             return
         rows, save = dlg.result()
-        for stock, qty, price in rows:
-            self._ledger.purchase(stock, qty, price=price)
+        mults = prices_mod.load_material_multipliers()
+        for stock, material, qty, price in rows:
+            self._ledger.purchase(stock, qty, material=material, price=price)
             if save:
-                self._prices[stock] = price
+                # price book stores the SPF base; back out the species multiplier
+                mult = mults.get(material, 1.0) or 1.0
+                self._prices[stock] = round(price / mult, 2)
         self._ledger.save()
         if save:
             prices_mod.save_prices(self._prices)
             self._cost_te.setPlainText(self._cost_text())
         QMessageBox.information(self, "Added to inventory",
-                                f"Added {sum(q for _, q, _ in rows)} item(s) to shop inventory.")
+                                f"Added {sum(q for *_, q, _ in rows)} item(s) to shop inventory.")
 
     def _record_build(self) -> None:
         consumed, offcuts = plan_consumption(self._plan)
@@ -261,8 +264,8 @@ class BomWindow(QDialog):
                 it = plan.item(iid)
                 lines.append(f"  {it.part_id}: {_fmt_len(it.length_in)} {it.stock}")
         lines += ["", "Yield (used / bought):"]
-        for stock in sorted({sp.stock for sp in plan.stock_pieces}):
-            sps = [sp for sp in plan.stock_pieces if sp.stock == stock]
+        for stock in sorted({sp.stock for sp in bought}):    # bought only — matches score
+            sps = [sp for sp in bought if sp.stock == stock]
             sheet = sps[0].is_sheet
             used = sum(p.len_in * p.wid_in for sp in sps for p in sp.placements)
             cap = sum(sp.length_in * sp.width_in for sp in sps)
@@ -500,7 +503,8 @@ class BomWindow(QDialog):
             self._set_plan(best)
             self._status.setText("✓ optimized around locked pieces")
         else:
-            self._set_plan(best_cut_plan(self.c.scene, quantity=self._quantity))
+            self._set_plan(best_cut_plan(self.c.scene, quantity=self._quantity,
+                                         available=self._available()))
             self._status.setText("✓ optimized")
 
     def _best_of_n(self) -> None:
@@ -513,7 +517,8 @@ class BomWindow(QDialog):
             self._set_plan(best)
             self._status.setText("✓ best of 100 around locked pieces")
         else:
-            self._set_plan(best_cut_plan(self.c.scene, attempts=100, quantity=self._quantity))
+            self._set_plan(best_cut_plan(self.c.scene, attempts=100, quantity=self._quantity,
+                                         available=self._available()))
             self._status.setText("✓ best of 100 attempts")
 
     def _next_arrangement(self) -> None:
@@ -521,7 +526,8 @@ class BomWindow(QDialog):
         self._order = (self._order + 1) % len(STRATEGIES)
         st = STRATEGIES[self._order]
         plan = (reoptimize(self.c.scene, self._plan, st) if self._has_locks()
-                else build_cut_plan(self.c.scene, strategy=st, quantity=self._quantity))
+                else build_cut_plan(self.c.scene, strategy=st, quantity=self._quantity,
+                                    available=self._available()))
         self._set_plan(plan)
 
     def _draw_layout(self) -> None:
@@ -600,12 +606,20 @@ class BomWindow(QDialog):
         if target is None:
             target = sp_cur
         # Stock-type compatibility: a 2x4 can't go on a plywood sheet, etc.
-        item_stock = plan.item(p.item_id).stock
+        cut_item = plan.item(p.item_id)
+        item_stock = cut_item.stock
         if item_stock != target.stock:
             self._revert(plan, item.pid, home)
             self._status.setText(f"✗ {item_stock} can't go on {target.stock} — reverted")
             recompute(plan); self._refresh_all()
             return
+        # Species compatibility: an oak cut can't go on a spruce stick.
+        if (cut_item.material and target.material and cut_item.material != target.material):
+            self._revert(plan, item.pid, home)
+            self._status.setText(f"✗ {cut_item.material} can't go on "
+                                 f"{target.material} stock — reverted")
+            recompute(plan); self._refresh_all()
+            return
         row_y0 = self._row_of(target.id)
         x_in = max(item.pos().x() / px, 0.0)
         y_in = max((item.pos().y() - row_y0) / px, 0.0) if target.is_sheet else 0.0
@@ -803,8 +817,10 @@ class PurchaseDialog(QDialog):
 
     def __init__(self, bought, prices, parent=None):
         super().__init__(parent)
+        from ..lumber import default_material
         self.setWindowTitle("Mark purchased")
-        self.resize(360, 320)
+        self.resize(380, 320)
+        mults = prices_mod.load_material_multipliers()
         v = QVBoxLayout(self)
         v.addWidget(QLabel("Add these to your shop inventory?"))
         rows = sorted(bought.items())
@@ -812,16 +828,18 @@ class PurchaseDialog(QDialog):
         self._table.setHorizontalHeaderLabels(["Stock", "Qty", "Price $ each"])
         self._table.horizontalHeader().setSectionResizeMode(0, QHeaderView.Stretch)
         self._spins = []
-        for r, (stock, qty) in enumerate(rows):
-            name = QTableWidgetItem(stock)
+        for r, ((stock, material), qty) in enumerate(rows):
+            label = (f"{material} {stock}" if material and material != default_material(stock)
+                     else stock)
+            name = QTableWidgetItem(label)
             name.setFlags(name.flags() & ~Qt.ItemIsEditable)
             self._table.setItem(r, 0, name)
             q = QSpinBox(); q.setRange(0, 9999); q.setValue(int(qty))
             p = QDoubleSpinBox(); p.setRange(0.0, 100000.0); p.setDecimals(2)
-            p.setValue(float(prices.get(stock, 0.0)))
+            p.setValue(round(float(prices.get(stock, 0.0)) * (mults.get(material, 1.0) or 1.0), 2))
             self._table.setCellWidget(r, 1, q)
             self._table.setCellWidget(r, 2, p)
-            self._spins.append((stock, q, p))
+            self._spins.append((stock, material, q, p))
         v.addWidget(self._table)
         self._save = QCheckBox("Save these prices to my price book")
         v.addWidget(self._save)
@@ -830,8 +848,8 @@ class PurchaseDialog(QDialog):
         v.addWidget(bb)
 
     def result(self):
-        rows = [(stock, q.value(), round(p.value(), 2))
-                for stock, q, p in self._spins if q.value() > 0]
+        rows = [(stock, material, q.value(), round(p.value(), 2))
+                for stock, material, q, p in self._spins if q.value() > 0]
         return rows, self._save.isChecked()
 
 
diff --git a/src/woodshop/gui/inventory_window.py b/src/woodshop/gui/inventory_window.py
index 550efec..9b7bf8b 100644
--- a/src/woodshop/gui/inventory_window.py
+++ b/src/woodshop/gui/inventory_window.py
@@ -46,10 +46,12 @@ class InventoryWindow(QDialog):
         oh = self._ledger.on_hand()
         if not oh:
             return "ON-HAND STOCK\n\n  (empty — Mark purchased on the BOM window to add)"
+        from ..lumber import default_material
         lines = ["ON-HAND STOCK", ""]
-        for stock, qty in oh.items():
+        for (stock, material), qty in oh.items():
             unit = "sheet" if stock.startswith("ply-") else "stick"
-            lines.append(f"  {qty:>3} × {stock:<10} ({unit}s)")
+            name = f"{material} {stock}" if material and material != default_material(stock) else stock
+            lines.append(f"  {qty:>3} × {name:<14} ({unit}s)")
         return "\n".join(lines)
 
     def _offcuts_text(self) -> str:
diff --git a/src/woodshop/inventory.py b/src/woodshop/inventory.py
index b8afad1..59c991c 100644
--- a/src/woodshop/inventory.py
+++ b/src/woodshop/inventory.py
@@ -25,7 +25,8 @@ from collections import Counter
 from dataclasses import asdict, dataclass, field
 from pathlib import Path
 
-from .lumber import SHEET_LENGTH_IN, SHEET_WIDTH_IN, actual_section, is_plywood, normalize_stock
+from .lumber import (SHEET_LENGTH_IN, SHEET_WIDTH_IN, actual_section, default_material,
+                     is_plywood, normalize_stock)
 
 
 @dataclass
@@ -51,7 +52,8 @@ def _data_path() -> Path:
 def plan_consumption(plan) -> tuple[dict, list[dict]]:
     """From a CutPlan, derive (stock consumed as {stock: qty}, reusable offcuts).
     Offcuts are the reusable waste regions; ids are assigned later by the ledger."""
-    consumed = Counter(sp.stock for sp in plan.stock_pieces if not getattr(sp, "owned", False))
+    consumed = Counter((sp.stock, getattr(sp, "material", "") or default_material(sp.stock))
+                       for sp in plan.stock_pieces if not getattr(sp, "owned", False))
     offcuts = []
     for sp in plan.stock_pieces:
         for w in sp.waste:
@@ -97,16 +99,18 @@ class Ledger:
         return f"b{n}"
 
     # ----- primitives (each appends events) -----------------------------
-    def purchase(self, stock: str, qty: int, price: float | None = None,
+    def purchase(self, stock: str, qty: int, material: str = "", price: float | None = None,
                  date: str = "", is_sheet: bool | None = None) -> None:
         stock = normalize_stock(stock)
         sheet = is_plywood(stock) if is_sheet is None else is_sheet
-        self._emit("purchase", stock=stock, qty=int(qty), is_sheet=sheet,
-                   price=price, date=date)
+        self._emit("purchase", stock=stock, material=material or default_material(stock),
+                   qty=int(qty), is_sheet=sheet, price=price, date=date)
 
-    def adjust(self, stock: str, delta: int, reason: str = "", date: str = "") -> None:
-        self._emit("adjustment", stock=normalize_stock(stock), delta=int(delta),
-                   reason=reason, date=date)
+    def adjust(self, stock: str, delta: int, material: str = "", reason: str = "",
+               date: str = "") -> None:
+        stock = normalize_stock(stock)
+        self._emit("adjustment", stock=stock, material=material or default_material(stock),
+                   delta=int(delta), reason=reason, date=date)
 
     def discard_offcut(self, offcut_id: str, fate: str, date: str = "") -> None:
         self._emit("discard", offcut_id=offcut_id, fate=fate, date=date)
@@ -122,10 +126,13 @@ class Ledger:
         bin), "burned"/"trashed" (→ discard), or "ignore" (don't track). Defaults
         to keeping every offcut. Returns the build id."""
         build_id = self._next_build_id()
-        for stock, qty in consumed.items():
-            if qty:
-                self._emit("consume", stock=normalize_stock(stock), qty=int(qty),
-                           build_id=build_id)
+        for key, qty in consumed.items():
+            if not qty:
+                continue
+            stock, material = key if isinstance(key, tuple) else (key, default_material(key))
+            self._emit("consume", stock=normalize_stock(stock),
+                       material=material or default_material(stock), qty=int(qty),
+                       build_id=build_id)
         disp = dispositions if dispositions is not None else ["keep"] * len(offcuts)
         for i, oc in enumerate(offcuts):
             fate = disp[i] if i < len(disp) else "keep"
@@ -142,14 +149,19 @@ class Ledger:
 
     # ----- derived state (fold the events) ------------------------------
     def on_hand(self) -> dict:
+        """Full units on hand, keyed by (stock, material)."""
         c = Counter()
+
+        def key(e):
+            return (e["stock"], e.get("material") or default_material(e["stock"]))
+
         for e in self.events:
             if e["type"] == "purchase":
-                c[e["stock"]] += e["qty"]
+                c[key(e)] += e["qty"]
             elif e["type"] == "consume" and "stock" in e:
-                c[e["stock"]] -= e["qty"]
+                c[key(e)] -= e["qty"]
             elif e["type"] == "adjustment":
-                c[e["stock"]] += e["delta"]
+                c[key(e)] += e["delta"]
         return {k: v for k, v in sorted(c.items()) if v}
 
     def offcut_bin(self) -> list[Piece]:
@@ -172,15 +184,15 @@ class Ledger:
         """Everything the planner could consume: full on-hand units (given real
         dimensions so they pack) + offcuts."""
         pieces = list(self.offcut_bin())
-        for stock, qty in self.on_hand().items():
+        for (stock, material), qty in self.on_hand().items():
             sheet = is_plywood(stock)
             if sheet:
                 L, W = SHEET_LENGTH_IN, SHEET_WIDTH_IN
             else:
                 L, W = stick_len_in, actual_section(stock)[1]
             for i in range(qty):
-                pieces.append(Piece(id=f"{stock}#{i + 1}", stock=stock,
-                                    length_in=L, width_in=W, is_sheet=sheet))
+                pieces.append(Piece(id=f"{stock}:{material}#{i + 1}", stock=stock,
+                                    length_in=L, width_in=W, is_sheet=sheet, material=material))
         return pieces
 
     def builds(self) -> list[dict]:
diff --git a/tests/test_bom_window.py b/tests/test_bom_window.py
index 708f1ed..16b9803 100644
--- a/tests/test_bom_window.py
+++ b/tests/test_bom_window.py
@@ -156,3 +156,22 @@ def test_record_build_writes_ledger(tmp_path, monkeypatch):
     w._ledger.save()
     again = I.Ledger.load()
     assert again.builds() and again.stats()["units_built"] == 1
+
+
+def test_optimize_preserves_offcut_toggle(tmp_path, monkeypatch):
+    monkeypatch.setenv("XDG_DATA_HOME", str(tmp_path / "data"))
+    monkeypatch.setenv("XDG_CONFIG_HOME", str(tmp_path / "cfg"))
+    from woodshop import inventory as I
+    led = I.Ledger()
+    led.record_build("seed", 1, consumed={}, offcuts=[
+        {"stock": "2x4", "length_in": 96, "width_in": 3.5, "is_sheet": False}])
+    led.save()
+    c = Controller(str(tmp_path / "s.json"))
+    c.place("2x4", 30)
+    w = BomWindow(c)
+    w._offcut_chk.setChecked(True)
+    assert w._plan.score["stock_count"] == 0
+    w._optimize()                                   # Codex #1: must NOT lose the offcut
+    assert w._plan.score["stock_count"] == 0
+    w._best_of_n()
+    assert w._plan.score["stock_count"] == 0
diff --git a/tests/test_cutplan.py b/tests/test_cutplan.py
index 089e7c0..d471f11 100644
--- a/tests/test_cutplan.py
+++ b/tests/test_cutplan.py
@@ -357,3 +357,46 @@ def test_batch_estimate_per_unit():
     assert est.quantity == 4
     assert abs(est.per_unit_cost - est.total_cost / 4) < 0.01
     assert abs(est.per_unit_price - est.price / 4) < 0.01
+
+
+def test_locked_reoptimize_preserves_owned_offcut():
+    """Codex #1: a locked offcut must stay owned through reoptimize, not become bought."""
+    from woodshop.cutplan import reoptimize
+    from woodshop.inventory import Piece
+    s = Scene()
+    s.place("2x4", 30)
+    offcut = Piece(id="oc1", stock="2x4", length_in=96, width_in=3.5,
+                   is_sheet=False, is_offcut=True)
+    plan = build_cut_plan(s, available=[offcut])
+    assert plan.score["stock_count"] == 0
+    owned_piece = next(sp for sp in plan.stock_pieces if sp.owned)
+    owned_piece.placements[0].locked = True
+    re = reoptimize(s, plan, "decreasing")
+    assert re.score["stock_count"] == 0            # still bought nothing
+    assert re.score["owned_count"] == 1
+
+
+def test_validate_flags_cross_species():
+    """Codex #3: an oak cut on a spruce stick is invalid."""
+    from woodshop.cutplan import relocate
+    s = Scene()
+    s.place("1x4", 24)                              # spruce
+    s.place("1x4", 24)
+    s.set_material("p2", "oak")
+    plan = build_cut_plan(s)                        # two species → two pieces
+    spruce_sp = next(sp for sp in plan.stock_pieces if sp.material == "spruce")
+    oak_sp = next(sp for sp in plan.stock_pieces if sp.material == "oak")
+    relocate(plan, oak_sp.placements[0].id, spruce_sp.id, 40.0)
+    assert any("spruce stock piece" in p for p in validate_cut_plan(plan))
+
+
+def test_yield_excludes_owned_offcuts():
+    """Codex #4: an owned-only plan shouldn't report 0% (div by bought=0) misleadingly."""
+    from woodshop.inventory import Piece
+    s = Scene()
+    s.place("2x4", 30)
+    offcut = Piece(id="oc1", stock="2x4", length_in=96, width_in=3.5,
+                   is_sheet=False, is_offcut=True)
+    plan = build_cut_plan(s, available=[offcut])
+    assert plan.score["yield_pct"] == 0.0          # nothing bought → no bought-yield
+    assert plan.score["stock_count"] == 0
diff --git a/tests/test_inventory.py b/tests/test_inventory.py
index 0a79d26..0d3e4f8 100644
--- a/tests/test_inventory.py
+++ b/tests/test_inventory.py
@@ -8,16 +8,27 @@ def test_purchase_then_consume_on_hand():
     led = Ledger()
     led.purchase("2x4", 5)
     led.purchase("ply-3/4", 2)
-    assert led.on_hand() == {"2x4": 5, "ply-3/4": 2}
+    assert led.on_hand() == {("2x4", "spruce"): 5, ("ply-3/4", "spruce-ply"): 2}
     led.record_build("table", 1, consumed={"2x4": 2}, offcuts=[])
-    assert led.on_hand()["2x4"] == 3
+    assert led.on_hand()[("2x4", "spruce")] == 3
 
 
 def test_adjustment_corrects_count():
     led = Ledger()
     led.purchase("2x4", 5)
     led.adjust("2x4", -1, reason="broke one")
-    assert led.on_hand()["2x4"] == 4
+    assert led.on_hand()[("2x4", "spruce")] == 4
+
+
+def test_inventory_is_species_aware():
+    led = Ledger()
+    led.purchase("1x4", 3, material="oak")
+    led.purchase("1x4", 2, material="spruce")
+    oh = led.on_hand()
+    assert oh[("1x4", "oak")] == 3 and oh[("1x4", "spruce")] == 2
+    # consuming oak doesn't touch spruce
+    led.record_build("x", 1, consumed={("1x4", "oak"): 1}, offcuts=[])
+    assert led.on_hand()[("1x4", "oak")] == 2 and led.on_hand()[("1x4", "spruce")] == 2
 
 
 def test_record_build_keeps_and_discards_offcuts():
@@ -46,7 +57,7 @@ def test_plan_consumption_from_cutplan():
     s.place("2x4", 60)            # leaves a reusable ~35" offcut on a 96" stick
     plan = build_cut_plan(s)
     consumed, offcuts = plan_consumption(plan)
-    assert consumed.get("2x4") == 1
+    assert consumed.get(("2x4", "spruce")) == 1
     assert offcuts and offcuts[0]["stock"] == "2x4" and offcuts[0]["length_in"] > 12
 
 
@@ -66,7 +77,7 @@ def test_ledger_save_load_roundtrip(tmp_path, monkeypatch):
     led.purchase("2x4", 3, price=3.98)
     led.save()
     again = Ledger.load()
-    assert again.on_hand()["2x4"] == 3
+    assert again.on_hand()[("2x4", "spruce")] == 3
     assert again.stats()["spent"] == round(3 * 3.98, 2)
 
 
@@ -91,3 +102,15 @@ def test_planner_consumes_offcuts_before_buying():
     assert plan.score["owned_count"] == 1
     owned = [sp for sp in plan.stock_pieces if sp.owned]
     assert owned and owned[0].placements                # the 30" sits in the offcut
+
+
+def test_oak_project_not_satisfied_by_spruce_onhand():
+    """Codex #2: a generic spruce 1x4 on-hand must NOT satisfy an oak 1x4 cut."""
+    led = Ledger()
+    led.purchase("1x4", 5, material="spruce")
+    s = Scene()
+    s.place("1x4", 30)
+    s.set_material("p1", "oak")
+    plan = build_cut_plan(s, available=led.available_stock())
+    assert plan.score["stock_count"] == 1          # must buy oak
+    assert plan.score["owned_count"] == 0