Castanopsis fissa

This species is a large evergreen tree that can reach up to 20 meters in height. Its bark is greyish-brown and becomes coarse with age, while the branchlets are red-purple with conspicuous ribs. The leaves are alternate, thick, and papery, highly variable in size and shape, ranging from oblong to obovate-elliptic, with a cuneate base and rounded, undulate, and crenate teeth on the lower half. Lateral veins are numerous, typically 15-20 pairs, raised on the underside; the upper surface is glabrous, while the lower surface is initially yellowish-brown puberulent but becomes glabrescent. Flowers are arranged in erect spikes forming panicles that resemble fireworks; they are unisexual, monoecious, and many-flowered, with white, clustered stamens. The fruit consists of an ovoid to ellipsoid cupule, slightly dark reddish-brown and tomentose, which fully encloses the nut when immature and splits into 2-3 irregular segments at maturity. Each cupule contains a single globose to elliptic nut that is reddish-brown in color.^[4]

The species flowers from April to June, and fruits from October to November.^[3]

While the species occurs in Southeast China, Hong Kong,^[3] Laos, Thailand and Vietnam, it extend its range closer to the south China coast.^[5] And, it grows primarily in the wet tropical lowland.^[1]

The seed dispersal of C. fissa is strongly constrained by both biological and landscape factors. Its cupules are extremely hard and are primarily consumed by rodents and other scatter-hoarding animals, while otherwise relying largely on gravity for dispersal.^[3] As a result, seeds typically fall and establish close to the parent tree, usually within about five meters in forest environments.^[3] This limited dispersal capacity makes natural migration of Castanopsis species unlikely, especially in areas with low forest connectivity.^[5] Expansion into new habitats depends on continuous forest cover, particularly near the northern edge of their historical range.^[5] However, primary forests in these regions were cleared centuries ago, and existing forested landscapes now mainly consist of plantations or regenerating secondary forests with reduced species diversity, further limits their migration.^[5]