With 36% of its area covered by forest, Tokyo has extensive growths of cryptomeria and Japanese cypress, especially in the mountainous western communities of Akiruno, Ōme, Okutama, Hachiōji, Hinode, and Hinohara. Decreases in the price of timber, increases in the cost of production, and advancing old age among the forestry population have resulted in a decline in Tokyo's output. In addition, pollen, especially from cryptomeria, is a major allergen for the nearby population centers. Tokyo Bay was once a major source of fish. Most of Tokyo's fish production comes from the outer islands, such as Izu Ōshima and Hachijō-Jima. Skipjack tuna, nori, and ''aji'' are among the ocean products.