The topography of Bhutan is truly
amazing, ranging in elevation from 150 m to 7,000 m. The
summer monsoon from the Bay of Bengal plays a critical
role in the weather pattern in this mountainous land,
bringing up to seven meters of rain per year. On top of
this, temperatures range from minus 7 degrees Celsius to
30 degrees Celsius in areas that are less than 100 km
apart. These climactic extremes influence vegetation
profoundly, allowing for a incredible diversity of
In low elevations of 350 to 2,000
m, plants can grow actively all year.
A huge variety of trees are found
there, including Bombax, oak, banyan, and pipal. Rufous-necked
hornbills use Ficus trees for nesting. Leopards move
during the day, to avoid the tigers prowling at night.
Spotted deer are preyed on by dholes - a kind of wild
dog. Wild boar eat roots, tubers, snakes, and insects.
Gaur can weigh over 1,000kg, and are active at night in
the hill forest of the Siwaliks. Rhinoceros eat short
grasses and shrubs, and are able to cool off by wading
in the water.
The plants and animals in Bhutan's
temperate forests are adapted to the year-long moisture
from rain, snow, and mist. Bamboo grows alongside
conifer trees. Orchids grow on old trees, rocks, or even
on the ground. They coexist with a fungus that absorbs
nutrients. In the spring, the flowers of the orchids
attract birds and insects. Coniferous trees also depend
on fungi on their roots to absorb minerals. We humans
rarely see these fungi until they reproduce via fruiting
bodies that we call mushrooms.
Barking deer live by eating fruit
and bamboo. Himalayan black bears primarily eat leaves
and fruits, but also supplement their diet with meat
when they can obtain it. Goral have long, narrow hooves
that have soft soles for climbing steep, rocky terrain.
They prefer grassy slopes near cliffs where they are
mostly safe from predators.
Fir forests grow on the protected,
north-facing slopes of mountains, or on the highest
ridges where low clouds bring moisture. The slant of the
branches on these trees allows them to survive the
winter without collecting heavy snow. Musk deer survive
by living in the dense undergrowth and eating lichens
off of the trees. These lichens, Usnea, grow on branches
above the snowline.
At the treeline, the winds and
cold light prevent trees from growing. Here, many
animals change to adapt to the changing seasons. The
Himalayan weasel, for example, turns gray-brown in the
summer for camouflage, but becomes white in the winter
when it preys on voles. Takin migrate from high
elevations in the summer to low in the winter. The
needles of larch trees stop producing chlorophyll and
drop off every autumn in order to conserve moisture. As
soon as the snow melts every spring, anemones bloom to
maximize their sunlight exposure in the short summer
The Alpine Tundra
At the highest elevations, winter
lasts for eight months of the year. The bowl-shaped
flowers of poppies and anemones focus the light from the
sun for warmth, and red pigmentation in other plants
serve as protection from the direct light of high
elevations. Many alpine plants have thick or waxy leaves
to avoid desiccation by the wind. Other plants, like the
dwarf rhododendron and juniper shrubs, crowd into the
few moist ridges and gullies. Here, animals have adapted
to survive freezing temperatures and a severe shortage
of food. Springtails, for example, feed on wind-blown
pollen. Pika survive by gathering plants into their
burrows during the summers in order to have a source of
food for the long winters. Marmots, on the other hand,
go into hibernation, surviving only off their body fat.
Blue sheep manage to live out in the open all year,
protected by their thick winter coats and eating frozen
grasses. Snow leopards survive by eating these blue
Tree Rings and the Wheel of
In ten years, a tree in the
southern forest of Manas will grow twice the size of a
tree near Thimphu at mid level elevations. And it will
be four times greater than a tree growing in Laya in the
subalpine forest. The short growing season and frigid
temperatures at higher elevations stunts or prevents the
growth of trees.
Much can be learned from looking
at the rings of trees. Black rings tell us when fires
swept through the forests. Wide rings mean long, warm
summers, while thin rings are formed by slowed growth in
the cold seasons. Trees are absolutely critical for
future conservation. It is natural forests that support
the biodiversity that allows nature to regenerate.