While wooden cultural spheres in India lie mainly along the Himalayas in the north, most of the Indian Subcontinent belongs to the stone cultural spheres of an arid subtropical climate with meager timber. However, it is not well known that there is also a wooden cultural region in southernmost India.

‘South India’ usually indicates four states where people speak Dravidian languages. In its northern area, there are two states of Andra Pradesh and Karnataka, while in the southernmost area of the Subcontinent, the Western Ghats mountain range separates Tamil Nadu in the east and Kerala in the west.

A rock edict inscribed in the 3rd century B.C.E. by the Emperor Ashoka mentions that there were two kingdoms of Chola and Keralaputra in southernmost India, the former of which roughly corresponds to current Tamil Nadu and the latter to Kerala. Although Buddhism and Jainism spread in Kerala in ancient times while the Chera Dynasty thrived, hardly any vestige remains today.
Christianity and Islam were brought here from an early period through maritime trade, counting nowadays 20% of the population for the followers of each religion, and the remaining 60% are Hindus.

The neighboring state on the east, Tamil Nadu, is a vast extent of arid land, where the ‘Southern Style’ stone temples developed most splendidly and when one comes to say the ‘Dravidian Style,’ it largely indicates Hindu temples in this state.

On the other hand, since the state of Kerala is a narrow strip of land situated between the Arabian Sea and the Western Ghats mountain range of an altitude of 1,000 to 1,500m, the wind blowing from the sea strikes the mountains, shedding a lot of rain, supporting forests, and making this state a wooden cultural area completely different from Tamil Nadu.

As the two states are separated by the mountain range, mutual exchange was done along the seashore at the southernmost part, the further south one goes in Kerala the more the Tamil elements increase.
The contrast of the architecture of both states is most clearly seen in Gopuras (temple gates). While Gopras in the Tamil region are typically in the Dravidian style made of stone, Gopras in the pluvial Kerala region are crowned with wooden hipped roofs.

 
Gopuras of temples in Tamil Nadu and Kerala

As timber is abunadnt in Kerala, houses are usually built of wood with a gabled roof covered with tile. Though temples resembling such houses must have been erected throughout this region in ancient and medieval times, those old temples have almost disappeared like in the Himalayas, and the extant temples are mostly from early-modern and modern times. Regarding the species of timber, teak has been mainly used and jack fruit, rosewood, and ebony were added to it.

In accordance with the enlargement of temples in scale, main pillars and walls came to be made of firmer materials and crowned with wooden framed roofs. Cave temples and stone columns and the foundations of temples were largely of granite, but walls were usually made of laterite, which is amply produced at the foot of the Western Ghats Mountains. Laterite is a reddish tropical soil, which is soft when first extracted from the ground and hardens like stone during exposure to the air, used as low priced construction material. However, as it is porous, containing lots of bubbles, its surface is often plastered, painted, or sculpted.

Nalambalam of the Kudalmanikkam Temple, Irinjalakuda

A temple’s square precinct is usually surrounded with cloister-like walls called ‘Nalambalam.’ It is sometimes made of laterite, but often made of wood with latticed walls, through which the other side is seen, giving an impression like delicate Japanese architecture.

Because of the seeming resemblance of such timber Hindu temples in Kerala with wooden architecture in Nepal, it has been surmised that there was some influential relationship between the architectures of the two regions. However, there cannot have been direct relations between lands as far remote as 2,000 km from each other. Both areas have developed wooden architecture respectively in different ways.
What displays it most clearly is the emphasis of gables in Kerala temples. In Nepal, there are not so many gabled roofs; in addition, they are not treated so decoratively as in Kerala.

Mahadeva Temple at Ettumanur

As Hindu temples in Kerala are exhaustively guarded in terms of religion, even H. Sarkar, working with the Archaeological Survey of India, wrote in his report that it was difficult to survey Kerala temples. Even looking inside can be refused, let alone taking photographs of the interiors. Still more for me as a non-Hindu foreigner, it was occasionally not possible to enter an inner precinct, even though wearing a Dhoti (wrapping cloth around the lower half of the body) and being stripped to the waist like Hindus. I will report below the outline of wooden temples in Kerala, based on books I was able to obtain and photos I could take.

Round (Oval)-type ____________Square-type _____________Apsidal-type
(Shiva Temple Vaikom)___(Shiva Tem. Peruvanam)___(Subrahmanya Tem. Payanur)
Plans of the 3 types of Kerala Temples
(From H. Sarkar: An Architectural Survey of Temples of Kerala, 1978, A.S.I.)

To begin with, there are three plan-types of Shrikovil (main shrine) in traditional Hindu temples in the state of Kerala; that is the Round-type, Square-type, and Apsidal-type. It is a distinctive feature of Kerala that there are lots of Round-type temples, which are not found in other states.
This type is often transformed into an oval plan, and the Shiva Temple at Vaikom is an example with a grand oval cone roof covered with copper. In contrast to this simple overall form, paintings in full color, covering the entire wall space, give this temple a splendid external appearance, along with ornamentation around the windows and wood carvings on the brackets.

Wall of Shiva Temple at Vaikom

At Polonnaruwa in Sri Lanka, there are the remains of a circular Buddhist shrine called Vatadage from the 12th century. It enshrines a small stupa, which is surrounded with two concentric rows of stone columns and a circular brick wall and furthermore an outer row of stone pillars. Though the upper part of the building has been utterly lost, it is supposed that it had been covered with a wooden conical roof.

If so, the architectural form of the Vatadage is quite similar to that of the circular temples in Kerala, in spite of the difference in their religions: Buddhism and Hinduism. Also considering that the number of circular temples is greater in southern and middle Kerala (viz. nearer to Sri Lanka) than in the north, it can be presumed that the form of circular shrine in Kerala had an influential relationship with Sri Lankan architecture.
According to H. Sarkar, the form of Buddhist circular shrines in ancient India had probably been brought to Sri Lanka, and later it might behave been reimported to India by Ilavar people, who emigrated from Sri Lanka to the Kerala region.

 
Vadakkunnatha Temple in Thrissur (Trichur)

In the famous Vadakkunnatha Temple in Thrissur (former Trichur), there stand three shrines in line, two of the Circular-type and one of the Square-type. The Square-type shrine, in common with many others of its type, has a ‘Mukha-Mandapa’ (entrance porch) with a gabled roof. Furthermore, in front of the shrines, again in common with other types, there stands an independent building called a ‘Namaskara-Mandapa,’ which is an open Mandapa with stone columns supporting a wooden pyramidal roof.

The square type shrine is the most popular and often has dormer windows on its pyramidal roof, but they are not actual windows but decoration. The Shiva Temple at Peruvanam presents a unique figure, crowned with an ornate octagonal roof over a Square-type plan.
In northern India a stone tower of a temple is referred to as a ‘Shikhara,’ while in the Kerala region the word Shikhara refers to such a roof on the top of a Multi-tiered Tower-type temple.

It is assumed that the Apsidal plan originated from ancient Buddhist temples; the Chaitya caves among the cave temples of Ajanta and Ellora took this plan. It was gradually diffused to the south and eventually may have been brought to Kerala by way of the Karnataka region, as can be seen in the Hindu temples of Aihole for instance.
Although at ancient cave temples, a front gable was an actual window called a 'Chaitya Window,’ here in Kerala, it lost its function as a window, being transformed into a stage for ornamental wooden carvings.

Mahashiva Temple at Viliappary

A temple with an ambulatory around the sanctuary is referred to as ‘Sandhara’ and one without as ‘Nirandhara,’ and a grand scale temple might have a double ambulatory. A pilgrim circumambulates it clockwise as an act of worship.

As can be seen on the plan, the formation of a Circular-type temple can be comprehended like this: an initial Dravidian stone sanctuary is surrounded with one or two rows of stone columns to prepare an ambulatory around it and then enclosed with a circular wall, over which a wooden roof is constructed to protect the whole.
However, at a Square-type temple, the ambulatory is not demarcated by columns but only by a thick wall made of laterite, even at a temple with a double ambulatory. Those two types of temple-form must have derived from different origins.
Regarding the Apsidal-type, since it is an intermediate form of the former two types, there are cases of temples with and without a colonnade around the sanctuary.

Even if the upper part of a temple has been altered or reconstructed many times, the stone Adhisthana (basal part) is likely to preserve the original structure, on which there is often left an inscription that tells the history of the temple in some degree. The wall above the Adhisthana is often decorated with wooden sacred sculptures. One is generally prohibited from taking photographs in the inner precinct, so it is regrettable not to be able to show those fine sculptures here.

At later temples in Kerala, a magnificent Entrance Mandapa came to be built in front of the Nalambalam. The Mahadeva Temple at Kaviyur has meticulous wooden carvings, made up of miniature sculptures, on the coffered ceiling of its Entrance Mandapa. Those sculptures of gods and warriors remind us of the highly stylized dancers of Kathakali, which is the most famous traditional performing art in Kerala similar to Kabuki in Japan.

Nataraja, a wall painting in the Mahadeva Temple

As for wall paintings in Kerala, those at the Mattancherry Palace in Kochi (Cochin), the Mahadeva Temple at , and the Royal Palace in Padmanabhapuram are renowned, showing the unique Kerala style, painted in the 16th century and after.
Compared with abundant sculptures, murals are quite scarce in India. The above-mentioned murals might have originated from the intermittent tradition of Indian painting from the cave temples in Ajanta.