Puu Kukui is a mountain peak in Hawaii

Hawaii

Hawaii is the newest of the 50 U.S. states , and is the only U.S. state made up entirely of islands. It is the northernmost island group in Polynesia, occupying most of an archipelago in the central Pacific Ocean, southwest of the continental United States, southeast of Japan, and northeast of...

. It is the highest peak of Mauna Kahalawai (the West Maui Mountains

West Maui Mountains

The West Maui Mountains or West Maui Volcano, known to the Hawaiians as Maui Komohana and to geologists as Mauna Kahalawai, forms a much eroded shield volcano that constitutes the western one-quarter of the Hawaiian Island of Maui....

). The 1764 metres (5,787.4 ft) summit rises above the Puu Kukui Watershed Management Area, an 8661 acres (35 km²) private nature preserve maintained by the Maui Land & Pineapple Company

Maui Land & Pineapple Company

Maui Land & Pineapple Company, Inc. is a land holding and operating company founded in 1909 and based in Maui, Hawaii, United States. It owns approximately on the island of Maui. It develops, sells, and manages residential, resort, commercial and industrial real estate; and operates retail, golf...

. The peak was formed by a volcano

Volcano

2. Bedrock3. Conduit 4. Base5. Sill6. Dike7. Layers of ash emitted by the volcano8. Flank| 9. Layers of lava emitted by the volcano10. Throat11. Parasitic cone12. Lava flow13. Vent14. Crater15...

 whose caldera

Caldera

A caldera is a cauldron-like volcanic feature usually formed by the collapse of land following a volcanic eruption, such as the one at Yellowstone National Park in the US. They are sometimes confused with volcanic craters...

 eroded

Erosion

Erosion is when materials are removed from the surface and changed into something else. It only works by hydraulic actions and transport of solids in the natural environment, and leads to the deposition of these materials elsewhere...

 into what is now Īao Valley.

Puu Kukui is one of the wettest spots on Earth and the second wettest in the state after Mount Waialeale

Mount Waialeale

Mount Waialeale at an elevation of , is a shield volcano and the second highest point on the island of Kauai in the Hawaiian Islands. Averaging more than of rain a year since 1912, with a record in 1982, its summit is one of the rainiest spots on earth....

, receiving an average of 386.5 inches (9,817.1 mm) of rain a year. Rainwater unable to drain away flows into a bog. The soil

Soil

Soil is a natural body consisting of layers of mineral constituents of variable thicknesses, which differ from the parent materials in their morphological, physical, chemical, and mineralogical characteristics...

 is dense, deep, and acidic

Soil pH

The soil pH is a measure of the acidity or basicity in soils. pH is defined as the negative logarithm of the activity of hydrogen ions in solution. It ranges from 0 to 14, with 7 being neutral. A pH below 7 is acidic and above 7 is basic. Soil pH is considered a master variable in soils as it...

.

Puu Kukui is home to many endemic plant

Plant

Plants are living organisms belonging to the kingdom Plantae. Precise definitions of the kingdom vary, but as the term is used here, plants include familiar organisms such as trees, flowers, herbs, bushes, grasses, vines, ferns, mosses, and green algae. The group is also called green plants or...

s, insect

Insect

Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...

s, and bird

Bird

Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...

s, including the greensword (Argyroxiphium

Argyroxiphium

Argyroxiphium is a small genus of five species in the sunflower family, Asteraceae. Its members are known by the common name of silversword or greensword due to their long, narrow leaves and the silvery hairs on some species. It belongs to a larger radiation of over 50 species, including the...

 grayanum

Argyroxiphium grayanum

Argyroxiphium grayanum, commonly known as the greensword, is a species of flowering plant in the sunflower family, Asteraceae, and a member of the silversword alliance, a group of over 50 species which are diverse in morphology and habitat but are genetically closely related.The silversword...

), a distinctive bog variety of ōhia lehua (Metrosideros polymorpha var. pseudorugosa

Metrosideros polymorpha

The ōhia lehua is a species of flowering evergreen tree in the myrtle family, Myrtaceae, that is endemic to the six largest islands of Hawaii. It is a highly variable tree, being tall in favorable situations, and much smaller when growing in boggy soils or on basalt...

) and many lobelioid

Hawaiian lobelioids

The Hawaiian lobelioids are a group of flowering plants in the bellflower family, Campanulaceae, all of which are endemic to the Hawaiian Islands. This is the largest plant radiation in the Hawaiian Islands, and indeed the largest on any island archipelago, with over 125 species...

species. Due to the mountain peak's extreme climate and peat

Peat

Peat is an accumulation of partially decayed vegetation matter or histosol. Peat forms in wetland bogs, moors, muskegs, pocosins, mires, and peat swamp forests. Peat is harvested as an important source of fuel in certain parts of the world...

soil, many species, such as the ōhia, are represented as dwarfs. Access to the area is restricted to researchers and conservationists.