High mountain scrub
High mountain scrub is a shrubby formation characterized by a great variety of Rhododendron species from large trees to dwarf undershrubs (comprising 75% of the vegetation), intermixed with other shrubby genera (e.g. Salix, Berberis, Euonymus) and stands of dwarf bamboo. According to Kingdon-Ward (1948) this is a Rhododendron climax formation with more species growing in this zone (20+) than any other of equal depth. There are c.130 species recorded from Myanmar – mostly from the far north with c. 30% being endemic (UNESCO, 2014).
This zone marks the transition between silver fir forest and alpine areas. From just within and extending beyond the silver fir forest, 3-5 m tall tree-like rhododendrons (R. beesianum, often mixed with R. uvariifolium) predominate, giving way to stands of R. praestans and R. selense, a small tree or large bushy shrub growing gregariously, which dominates the scene (Kingdon-Ward, 1944).
No data suitable for assessing the majority of the criteria were found during the assessment process. However, our map data indicates this ecosystem is highly restricted to high mountain regions of northern Myanmar. Despite its restricted distribution, threats to the ecosystem appear relatively benign, and therefore the ecosystem did not meet subcriteria for Criterion B. We recommend further work to fill knowledge gaps on biotic and environmental degradation, particularly in relation to climate change, as well as work to estimate historical distributions required to assess Criterion A. The ecosystem is assessed as Least Concern under Criterion B.