diff --git a/tests/NestedSetsBehaviorTest.php b/tests/NestedSetsBehaviorTest.php
index 42fa5a2..a675ae5 100644
--- a/tests/NestedSetsBehaviorTest.php
+++ b/tests/NestedSetsBehaviorTest.php
@@ -10,7 +10,13 @@
 use yii\db\{ActiveRecord, Exception, StaleObjectException};
 use yii\helpers\ArrayHelper;
 use yii2\extensions\nestedsets\NestedSetsBehavior;
-use yii2\extensions\nestedsets\tests\support\model\{MultipleTree, Tree, TreeWithStrictValidation};
+use yii2\extensions\nestedsets\tests\support\model\{
+    ExtendableMultipleTree,
+    MultipleTree,
+    Tree,
+    TreeWithStrictValidation,
+};
+use yii2\extensions\nestedsets\tests\support\stub\ExtendableNestedSetsBehavior;
 
 use function get_class;
 use function sprintf;
@@ -2045,4 +2051,38 @@ public function testPrependToWithRunValidationParameterUsingStrictValidation():
             'Node name should remain unchanged after \'prependTo()\' with \'runValidation=false\'.',
         );
     }
+
+    public function testProtectedApplyTreeAttributeConditionRemainAccessibleToSubclasses(): void
+    {
+        $this->createDatabase();
+
+        $testNode = new ExtendableMultipleTree(
+            [
+                'name' => 'Extensibility Test Node',
+                'tree' => 1,
+            ],
+        );
+
+        $extendableBehavior = $testNode->getBehavior('nestedSetsBehavior');
+
+        self::assertInstanceOf(
+            ExtendableNestedSetsBehavior::class,
+            $extendableBehavior,
+            '\'ExtendableMultipleTree\' should use \'ExtendableNestedSetsBehavior\'.',
+        );
+
+        $condition = ['name' => 'test'];
+
+        $extendableBehavior->exposedApplyTreeAttributeCondition($condition);
+
+        self::assertTrue(
+            $extendableBehavior->wasMethodCalled('applyTreeAttributeCondition'),
+            '\'applyTreeAttributeCondition\' method should remain protected to allow subclass access.',
+        );
+        self::assertEquals(
+            ['and', ['name' => 'test'], ['tree' => 1]],
+            $condition,
+            '\'Tree\' attribute condition should be applied correctly when \'treeAttribute\' is enabled.',
+        );
+    }
 }
diff --git a/tests/phpstan-config.php b/tests/phpstan-config.php
index d25d0c1..1b93c30 100644
--- a/tests/phpstan-config.php
+++ b/tests/phpstan-config.php
@@ -5,6 +5,7 @@
 use yii\db\{ActiveQuery, ActiveRecord};
 use yii2\extensions\nestedsets\{NestedSetsBehavior, NestedSetsQueryBehavior};
 use yii2\extensions\nestedsets\tests\support\model\{
+    ExtendableMultipleTree,
     MultipleTree,
     MultipleTreeQuery,
     Tree,
@@ -20,6 +21,9 @@
         ActiveQuery::class => [
             NestedSetsQueryBehavior::class,
         ],
+        ExtendableMultipleTree::class => [
+            NestedSetsBehavior::class,
+        ],
         MultipleTree::class => [
             NestedSetsBehavior::class,
         ],
diff --git a/tests/support/model/ExtendableMultipleTree.php b/tests/support/model/ExtendableMultipleTree.php
new file mode 100644
index 0000000..c7e3335
--- /dev/null
+++ b/tests/support/model/ExtendableMultipleTree.php
@@ -0,0 +1,59 @@
+<?php
+
+declare(strict_types=1);
+
+namespace yii2\extensions\nestedsets\tests\support\model;
+
+use yii\db\ActiveRecord;
+use yii2\extensions\nestedsets\tests\support\stub\ExtendableNestedSetsBehavior;
+
+/**
+ * @property int $id
+ * @property int $depth
+ * @property int $lft
+ * @property int $rgt
+ * @property int $tree
+ * @property string $name
+ */
+class ExtendableMultipleTree extends ActiveRecord
+{
+    public static function tableName(): string
+    {
+        return '{{%multiple_tree}}';
+    }
+
+    public function behaviors(): array
+    {
+        return [
+            'nestedSetsBehavior' => [
+                'class' => ExtendableNestedSetsBehavior::class,
+                'treeAttribute' => 'tree',
+            ],
+        ];
+    }
+
+    public function rules(): array
+    {
+        return [
+            ['name', 'required'],
+        ];
+    }
+
+    /**
+     * @phpstan-return array<string, int>
+     */
+    public function transactions(): array
+    {
+        return [
+            self::SCENARIO_DEFAULT => self::OP_ALL,
+        ];
+    }
+
+    /**
+     * @phpstan-return ExtendableMultipleTreeQuery<static>
+     */
+    public static function find(): ExtendableMultipleTreeQuery
+    {
+        return new ExtendableMultipleTreeQuery(static::class);
+    }
+}
diff --git a/tests/support/model/ExtendableMultipleTreeQuery.php b/tests/support/model/ExtendableMultipleTreeQuery.php
new file mode 100644
index 0000000..adb17d9
--- /dev/null
+++ b/tests/support/model/ExtendableMultipleTreeQuery.php
@@ -0,0 +1,32 @@
+<?php
+
+declare(strict_types=1);
+
+namespace yii2\extensions\nestedsets\tests\support\model;
+
+use yii\db\ActiveQuery;
+use yii2\extensions\nestedsets\NestedSetsQueryBehavior;
+
+/**
+ * @template T of ExtendableMultipleTree
+ *
+ * @extends ActiveQuery<T>
+ */
+final class ExtendableMultipleTreeQuery extends ActiveQuery
+{
+    /**
+     * @phpstan-param class-string<T> $modelClass
+     * @phpstan-param array<string, mixed> $config
+     */
+    public function __construct(string $modelClass, array $config = [])
+    {
+        parent::__construct($modelClass, $config);
+    }
+
+    public function behaviors(): array
+    {
+        return [
+            'nestedSetsQueryBehavior' => NestedSetsQueryBehavior::class,
+        ];
+    }
+}
diff --git a/tests/support/stub/ExtendableNestedSetsBehavior.php b/tests/support/stub/ExtendableNestedSetsBehavior.php
new file mode 100644
index 0000000..9f56be0
--- /dev/null
+++ b/tests/support/stub/ExtendableNestedSetsBehavior.php
@@ -0,0 +1,91 @@
+<?php
+
+declare(strict_types=1);
+
+namespace yii2\extensions\nestedsets\tests\support\stub;
+
+use yii\db\ActiveRecord;
+use yii2\extensions\nestedsets\NestedSetsBehavior;
+
+/**
+ * @phpstan-template T of ActiveRecord
+ *
+ * @phpstan-extends NestedSetsBehavior<T>
+ */
+final class ExtendableNestedSetsBehavior extends NestedSetsBehavior
+{
+    /**
+     * @phpstan-var array<string, bool>
+     */
+    public array $calledMethods = [];
+
+    /**
+     * @phpstan-param array<int|string, mixed> $condition
+     */
+    public function exposedApplyTreeAttributeCondition(array &$condition): void
+    {
+        $this->calledMethods['applyTreeAttributeCondition'] = true;
+
+        $this->applyTreeAttributeCondition($condition);
+    }
+
+    public function exposedBeforeInsertNode(int|null $value, int $depth): void
+    {
+        $this->calledMethods['beforeInsertNode'] = true;
+
+        $this->beforeInsertNode($value, $depth);
+    }
+
+    public function exposedBeforeInsertRootNode(): void
+    {
+        $this->calledMethods['beforeInsertRootNode'] = true;
+
+        $this->beforeInsertRootNode();
+    }
+
+    public function exposedDeleteWithChildrenInternal(): bool|int
+    {
+        $this->calledMethods['deleteWithChildrenInternal'] = true;
+
+        return $this->deleteWithChildrenInternal();
+    }
+
+    public function exposedMoveNode(ActiveRecord $node, int $value, int $depth): void
+    {
+        $this->calledMethods['moveNode'] = true;
+
+        $this->moveNode($node, $value, $depth);
+    }
+
+    public function exposedMoveNodeAsRoot(): void
+    {
+        $this->calledMethods['moveNodeAsRoot'] = true;
+
+        $this->moveNodeAsRoot();
+    }
+
+    public function exposedShiftLeftRightAttribute(int $value, int $delta): void
+    {
+        $this->calledMethods['shiftLeftRightAttribute'] = true;
+
+        $this->shiftLeftRightAttribute($value, $delta);
+    }
+
+    public function resetMethodCallTracking(): void
+    {
+        $this->calledMethods = [];
+    }
+
+    public function wasMethodCalled(string $methodName): bool
+    {
+        return $this->calledMethods[$methodName] ?? false;
+    }
+
+    /**
+     * @phpstan-return array<string, bool>
+     */
+    public function getCalledMethods(): array
+    {
+        return $this->calledMethods;
+    }
+}