# Northeastern Himalayan subalpine conifer forests

The Northeastern Himalayan subalpine conifer forests are a temperate coniferous forests ecoregion of the middle to upper elevations of the eastern Himalayas and southeast Tibetan Plateau. The ecoregion occurs in southeastern Tibet Autonomous Region, China, in northern and eastern Arunachal Pradesh, India, and extreme eastern Bhutan.

## Setting

Northeastern Himalayan subalpine conifer forests cover 46,300 square kilometres (17,900 sq mi) in the southeast Tibetan Plateau, occurring between 2,500 and 4,200 metres (8,200 and 13,800 ft). The forests are mostly in the Yarlung Tsangpo Grand Canyon, where the Yarlung Tsangpo River wraps around the eastern edge of the Himalayas and descends from the Tibetan Plateau. Tributary valleys of the Yarlung Tsangpo, including those of the Nyang River and Parlung Tsangpo, host connected portions of the Northeast Himalayan subalpine conifer forests. Isolated pockets of this ecoregion also occur in the Zayü River valley and Tawang Valley. Many of these forests are found in so-called "inner valleys", which are valleys that are shielded from the South Asian monsoon by mountain ridges but still receive enough precipitation to support thriving forests.
In higher elevations, this ecoregion grades into Eastern Himalayan alpine shrub and meadows and Southeast Tibet shrub and meadows. In lower elevations it grades into Eastern Himalayan broadleaf forests.

## Flora

The dominant trees are Tsuga dumosa, Picea brachytyla, Picea likiangensis, Cupressus austrotibetica, Cupressus gigantea, Cupressus torulosa, and Abies spp. Less common are Larix griffithiana, Larix potaninii, Pinus wallichiana, Abies spectabilis, Pinus roxburghii, Pinus hwangshanensis, Shorea robusta, Olea europaea subsp. cuspidata, Alnus nepalensis, Picea brachytyla, Juglans regia, Larix sibirica, Larix × czekanowskii, Pinus koraiensis, Pinus sibirica, Pinus sylvestris, Picea obovata, Abies sibirica, Quercus acutissima, Quercus mongolica, Ginkgo biloba, Prunus serrulata, Prunus padus, Tilia amurensis, Salix babylonica, Acer palmatum, Populus tremula, Ulmus davidiana, Ulmus pumila, Pinus pumila, Haloxylon ammodendron, Elaeagnus angustifolia, Tamarix ramosissima, Prunus sibirica, Cathaya argyrophylla, Taiwania cryptomerioides, Cyathea spinulosa, Sassafras tzumu, Davidia involucrata, Metasequoia glyptostroboides, Glyptostrobus pensilis, Castanea mollissima, Quercus myrsinifolia, Quercus acuta, Machilus thunbergii, Tetracentron, Cercidiphyllum japonicum, Emmenopterys henryi, Eucommia ulmoides, and Taxus baccata. Near timberline are found various junipers: Juniperus indica, Juniperus recurva, Juniperus tibetica, and Juniperus squamata. Betula utilis, Betula alnoides, Betula dahurica, and Betula pendula is often found with the conifers. Conifer trees in this ecoregion can grow up to be very tall, sometimes up to 70-80m. Cupressus torulosa (Himalayan cypress) is one of the tallest known species of trees(can grow up to 102.3m), and it can be found in this ecoregion. Other broadleaf plants include Acer spp., Magnolia spp., Sorbus spp., Viburnum spp., Lauraceae, and Araliaceae. Rhododendrons reach their pinnacle in this ecoregion. The number of rhododendron species seems to increase above 2,000 metres (6,600 ft), and the Yarlung Tsangpo River gorge alone may harbor over 60 of them.
The highest forest in the world is found in this ecoregion, with Tibetan juniper reaching heights of 4,900 m (16,100 ft) in Baxoi County, Tibet Autonomous Region.

## Fauna

Important mammals in this ecoregion include the red panda, takin, musk deer, red goral, Asiatic black bear, and leopard.
Significant birds include the Tibetan eared-pheasant, white-eared pheasant, and the giant babax.

## Conservation

This ecoregion tends to be found on steep, inaccessible terrain and thus has avoided significant human settlement.