Magento 1 - Get array of all category trees for a given product

category_trees_per_product.php

<?php

// Get all product category IDs
$categoryIds = $product->getCategoryIds();

// Get category trees, filtered by product category IDs
$helper = Mage::helper('catalog/category');
$categoryTreeCollection = $helper->getStoreCategories('path', true, false);
$categoryTreeCollection->addAttributeToFilter('entity_id', ['in' => $categoryIds]);

$categoryTrees = [];
foreach ($categoryTreeCollection as $category) {
    // Top level categories first
    if ($category->getLevel() == 2) {
        $categoryTrees[$category->getPath()][] = $category->getName();
    } else {
        // Sub level categories then
        foreach ($categoryTrees as $key => $value) {
            if (strpos($category->getPath(), $key) !== false) {
                $categoryTrees[$key][] = $category->getName();
            }
        }
    }
}

// At the end, you get an array of product trees. You can loop through it, and do whatever you need with it
Array
(
    [1/2/10] => Array
    (
        [0] => Category A level 1
    )

    [1/2/20] => Array
    (
        [0] => Category B level 1
        [1] => Category C level 2
        [2] => Category D level 3
    )

    [1/2/30] => Array
    (
        [0] => Category E level 1
        [1] => Category F level 2
        [2] => Category G level 3
    )
)