Subtropical Pine Forests in the Himalayas

The Himalayan subtropical pine forests ecoregion is the most extensive subtropical pine forest in the Indo-Pacific region. It is dominated by a single pine species — Chir pine. From Pakistan to Bhutan, the ecoregion covers over 3,000 kilometers along the lower altitudes of the Himalayan mountain range, spanning numerous Himalayan states. The world’s deepest canyon divides this ecoregion in Nepal between drier western conifer forests and wetter eastern conifer forests. It’s cut into the Himalayas by the Kali Gandaki River, which originates north of the high Himalayas in the trans-Himalayan area.

About 50 million years ago, the Himalayan Mountain Range was created when the northward-drifting Deccan Plateau met with the Eurasian continent, thrusting the Himalayas higher via major geological upheavals. The Himalayas are geologically young in comparison to other significant mountain ranges.

The southwestern monsoon, which arrives from the Bay of Bengal and lasts from May to September, is responsible for most of the rainfall in this area. Because the monsoon winds are intercepted first in the eastern Himalayas, closer to the Bay of Bengal, rain is heavier and early in the season. The west receives less rainfall than the east, creating a climate gradient. The ecoregion is significantly more prominent in the west because subtropical pine forests are better suited to drier climatic conditions.

Flora and Fauna

Chir pine is the most common tree species. The understory is sparse with a few bayberries and Bengal currant bushes, brambly shrubs of barberry, blackberry, Himalayan raspberry, and tiny wild strawberry. Climate change and human disturbance of nearby broadleaf forests, according to some botanists, are making circumstances more conducive for Chir pine, letting it increase and fill these woods. This pine forest ecoregion does not have exceptionally high levels of species richness or endemism from a biological standpoint. Consequently, although this ecoregion should be recognized as a unique component of the region’s biodiversity, a continuous incursion into the more biologically rich temperate broadleaf forests may result in biodiversity degrading in the Himalayas.

Except for a few gorals (a goat-like mammal) and little barking deer, the ecoregion does not sustain many grazing or browsing herbivores due to a lack of vegetation and browse. The ecoregion does not sustain stable populations of big predators since natural prey is scarce. Smaller animals, such as the yellow-throated marten (pictured above), are the local predators. The avian fauna is more diverse, with over 480 species. However, it is shared with neighboring ecoregions.