Hoh Rainforest: Olympic's Moss-Draped Temperate Jungle

The Hoh Rainforest in Washington State's Olympic National Park is one of the finest examples of temperate rainforest in the Western Hemisphere. Receiving over 3,500 millimeters (140 inches) of rain annually, the Hoh is a cathedral of towering Sitka spruce and western hemlock draped in thick curtains of club moss, fern, and lichen.

Introduction

Unlike tropical rainforests, the Hoh is cool and quiet, with temperatures rarely exceeding 27°C even in summer. The forest floor is a spongy carpet of decomposing logs, ferns, and seedlings growing on fallen "nurse logs." The silence of the Hoh is so profound that it has been designated one of the quietest places in the United States.

Geography & Setting

• Location: Olympic Peninsula, Washington State, USA
• Area: ~100 km² (Hoh River valley)
• Elevation: 160-1,000 m above sea level
• Annual Rainfall: 3,500-4,500 mm (140-180 inches)

The Hoh Rainforest occupies the valley of the Hoh River, which flows westward from the glaciers of Mount Olympus (2,432 m) to the Pacific Ocean. The rainforest extends roughly 50 kilometers along the river valley, bounded by steep mountain slopes on either side. The valley's orientation directly faces the moisture-laden storms that blow in from the Pacific.

The Hoh is part of a series of temperate rainforest valleys on the western Olympic Peninsula, including the Queets, Quinault, and Bogachiel. Together, these valleys form the largest block of temperate rainforest in the contiguous United States. The Olympic Mountains create a dramatic rain shadow, so while the western valleys receive over 3,500 mm of rain, the town of Sequim on the eastern side receives only 400 mm.

Forest Structure & Ecology

• Canopy Height: 60-75 m (Sitka spruce)
• Dominant Trees: Sitka spruce, western hemlock, western red cedar, bigleaf maple
• Moss Biomass: Over 25 kg per tree in some cases
• Nurse Logs: Fallen logs that support new tree growth

The Hoh's forest structure is defined by its immense trees and its mosses. Sitka spruce can reach 75 meters in height and 5 meters in trunk diameter, making them among the largest trees in the world. Western hemlock, western red cedar, and Douglas fir are the other dominant conifers. Bigleaf maples are so heavily draped in club moss, licorice fern, and selaginella that individual trees can support over 25 kilograms of epiphytic growth.

Nurse logs are a defining feature of the Hoh. When a large tree falls, it becomes a raised platform for the germination and growth of new trees. Seedlings that establish on nurse logs gain an advantage in the competition for light and avoid the perpetually waterlogged forest floor. Rows of mature trees growing along the line of a long-decomposed nurse log, their roots straddling the empty space where the log once lay, are called "colonnades."

Wildlife

• Key Species: Roosevelt elk, black bear, cougar, northern spotted owl, marbled murrelet
• Roosevelt Elk Herd: ~500-1,000 individuals in the Hoh valley
• Salmon Species: 5 (Chinook, coho, chum, pink, steelhead)
• Bird Species: ~200

The Hoh Rainforest is home to one of the largest herds of Roosevelt elk on the Olympic Peninsula, with 500 to 1,000 animals frequenting the river valley. These elk play a crucial ecological role: their grazing maintains open meadows and river terraces within the forest, creating habitat diversity. Bull elk can weigh up to 500 kilograms and grow antlers spanning over a meter.

The Hoh River supports all five species of Pacific salmon, which spawn in the river's gravel beds. Salmon carcasses carried into the forest by bears and floods provide marine-derived nutrients — nitrogen and phosphorus from the ocean — that fertilize the forest soil. Studies have traced ocean nitrogen from salmon carcasses into the wood of Sitka spruce trees growing near spawning streams.

Climate & Acoustics

• Summer Temperature: 15-27°C
• Winter Temperature: 2-10°C
• Fog Days: ~100 per year
• Sound Level: As low as 20 decibels (One Square Inch of Silence)

The Hoh Rainforest has a mild, maritime climate moderated by the Pacific Ocean. Winters are cool and extremely wet, with nearly constant rain from November to March. Summers are drier but fog frequently rolls up the valley from the coast, contributing additional moisture. The forest canopy intercepts this fog, dripping water onto the understory even during dry spells.

In 2005, acoustic ecologist Gordon Hempton designated a location in the Hoh Rainforest as "One Square Inch of Silence," arguing it was one of the quietest places remaining in the United States. Ambient noise levels in the Hoh can drop below 20 decibels — quieter than a whisper. The National Park Service has since incorporated soundscape protection into park management, limiting overflights and mechanical noise sources.

Access & Visitor Information

• Visitor Center: Hoh Rain Forest Visitor Center (open year-round)
• Key Trails: Hall of Mosses (1.3 km), Spruce Nature Trail (2 km), Hoh River Trail (28 km)
• Best Season: Year-round (rainiest November-March; driest July-August)
• Park Fee: $30 per vehicle (Olympic National Park)

The Hall of Mosses Trail is the Hoh's most popular walk, a 1.3-kilometer loop through a grove of bigleaf maples so heavily draped in moss that the trees resemble green ghosts. The Spruce Nature Trail follows the milky-blue Hoh River through old-growth Sitka spruce forest. For backcountry hikers, the Hoh River Trail extends 28 kilometers into the heart of the Olympic wilderness to the base of the Blue Glacier on Mount Olympus.

The Hoh receives approximately 300,000 visitors annually, making it the most visited area in Olympic National Park. The National Park Service has implemented a timed entry system during peak summer months to manage impacts. Visitors should expect rain at any time of year — the Hoh averages over 200 rainy days annually — and should bring waterproof layers even in summer.

Key Facts

• The Hoh Rainforest receives over 3,500 mm (140 inches) of rain annually.
• Sitka spruce in the Hoh can reach 75 meters tall and 5 meters in trunk diameter.
• Roosevelt elk herds of 500-1,000 animals maintain meadow habitats within the forest.
• All five species of Pacific salmon spawn in the Hoh River.
• The Hoh has been designated one of the quietest places in the United States with ambient noise below 20 decibels.

Fun Facts

• Nitrogen from ocean salmon carcasses has been traced into the wood of Sitka spruce trees growing near the Hoh River.
• A single bigleaf maple in the Hoh can support over 25 kilograms of moss and fern growing on its branches.
• The Olympic Mountains create such an extreme rain shadow that the west side receives 3,500 mm of rain while the east side gets only 400 mm.
• Rows of trees growing on "nurse logs" form stilted colonnades when the underlying log finally decomposes.

Final Thoughts

The Hoh Rainforest is a living demonstration of what happens when abundant rain meets ancient forest. Its moss-draped trees, salmon-fed soils, and profound silence create an ecosystem that feels like a remnant of an older, wilder world. As one of the most accessible temperate rainforests on Earth, the Hoh offers visitors a chance to experience a cathedral of green that rivals any tropical jungle in its beauty and ecological complexity.