About Alnus jorullensis Kunth
Alnus jorullensis Kunth is a medium-sized tree that reaches 20–25 m in height. Its leaves are obovate to elliptic, 5–12 cm long, with a somewhat leathery texture, serrated margins, and glandular tissue on the underside. It produces wind-pollinated catkin flowers in early spring. This species grows in high-elevation forests across the Sierra Madre Occidental, Sierra Madre Oriental, and Sierra Madre del Sur of Mexico, as well as in the highlands of Honduras, at elevations between 2,800 and 3,800 meters. It is the most common alder found in Mexico’s mountains, and grows at higher elevations than other Mexican alders. Populations in Guatemala that have been identified as A. jorullensis may actually be A. acuminata, so the species’ confirmed presence in Guatemala is uncertain. It grows most often on moist soils, including stream and river banks, wetlands, and moist slopes, where it forms dense stands. It can also be found in open oak-pine and fir woodlands. It acts as an early successional species in areas disturbed by either natural processes such as landslides or fires, or human activities such as logging or forest clearance to create pasture. In southern Mexico, it occurs in high-elevation tropical montane forests that have cool temperatures and abundant rainfall. It is cultivated and used for ornamental planting in warm temperate regions, such as southern California.
