--- title: what a kelp forest actually is canonical_url: https://ensurance.app/guide/what-a-kelp-forest-actually-is markdown_url: https://ensurance.app/guide/what-a-kelp-forest-actually-is.md subtitle: a living canopy in the nearshore — not a postcard and not a grant category: ecosystem-services --- # what a kelp forest actually is *a living canopy in the nearshore — not a postcard and not a grant* A photograph of the canopy is not a kelp forest. A **kelp forest** is the living stand on the rock: canopy kelp at the surface, understory algae beneath it, holdfasts on the reef, dense enough to shade the reef under it. From the bluff the two are easy to confuse. Both look like a brown mat on the Pacific. A harbor district, a state agency, and a coastwide partnership can write the same two words into a plan and mean a picture, a bare reef, a line of twine, or the stand. The line item does not say which one it is buying. :::johnson **you don't have an empty reef. you have a missing kelp forest.** The rock can still look like a coast. The forest is the canopy that has to be standing in the water. [the reef with the forest gone →](/guide/you-dont-have-an-empty-reef-you-have-a-missing-forest?from=guide) ::: ## what a kelp forest actually is Kelp are large brown algae, not plants. [NOAA's Office of National Marine Sanctuaries](https://sanctuaries.noaa.gov/visit/ecosystems/kelpdesc.html) states that directly, and counts about 30 species worldwide. They grow in cool, nutrient-rich water, anchored to rocky seafloors. The parts have plain names. A **holdfast** grips the rock. NOAA calls it root-like. It is an anchor, not a root feeding from soil. A **stipe** is the stalk. **Blades** do the photosynthesis. **Pneumatocysts**, gas-filled bladders, hold blades toward the light so a canopy can form at the surface. A single blade washed up on the sand is not the forest. The forest is the stand: enough kelp, living together, that the canopy shades the reef and the rock underneath is habitat rather than bare rock. Along the Pacific coast of North America the canopy is one of two kelps, and they are not the same forest. **Bull kelp** (*Nereocystis luetkeana*) is the canopy on the Oregon coast and on California's North Coast. **Giant kelp** (*Macrocystis pyrifera*) is the canopy farther south. NOAA's sanctuary program calls bull kelp the most abundant kelp in Oregon, Washington, British Columbia, and Alaska, and says giant kelp dominates to the south. It does not name a county where the canopy switches. That difference is [bull kelp and giant kelp are not the same forest](/guide/bull-kelp-and-giant-kelp-are-not-the-same-forest?from=guide). ## a postcard, a barren, twine, and the forest Four objects get called a kelp forest. The order matters, because the first three are easier to point at than the fourth. | object | what it is | what you are holding | | --- | --- | --- | | postcard coast | The shore as scenery: a bluff photo, a brochure, a brown mat seen from the cliff | A picture. It can outlast the canopy by years | | urchin barren | The rocky reef left when the canopy is gone | A reef. The forest is the missing part | | seeded twine | A line of kelp started from spores or a lab and set out on the reef | A tool. It can start plants | | living kelp forest | Bull kelp or giant kelp on rock, canopy at the surface, understory beneath, alive this year | The forest | The first three can be photographed, permitted, or paid for as kelp work. The fourth is the kelp. An urchin barren is the reef with the forest gone, and that is a different question: [you don't have an empty reef. you have a missing forest](/guide/you-dont-have-an-empty-reef-you-have-a-missing-forest?from=guide). A line of seeded twine can be the right tool on a cove that just lost its canopy. The line is still not the stand: [a line of twine is not a kelp forest](/guide/a-line-of-twine-is-not-a-kelp-forest?from=guide). A grant can pay for a season of that work. The divers in the water, and the alliances that organize that work, are doing restoration. The grant is not the canopy that has to be there next year. ## two coasts, two receipts Two surveys measured a missing canopy. They are two receipts, not one map, and neither is a price on the forest. The Oregon receipt is the Oregon Kelp Alliance's [2024 status report](https://www.oregonkelp.com/wp-content/uploads/2024/11/ORKA_StatusReport_2024-Digital-150dpi.pdf). From 2010 to 2022, the alliance summarizes the decline in kelp canopy cover as 67–73%. Aerial surveys from Cape Arago south to Brookings show a 66.4% decrease. A satellite estimate for the whole Oregon coastline shows 73.5%. The same summary estimates that more than two-thirds of the state's kelp forest habitat no longer supports substantial kelp. About 892 acres of bull kelp forest have disappeared since 2010 in that accounting, and the acre figure is aerial loss in southern Oregon, from Brookings to Cape Arago. The alliance treats the percentages as a snapshot. The canopy moves from year to year. California's North Coast is a different survey. A [California Sea Grant](https://caseagrant.ucsd.edu/our-work/research-projects/accelerating-bull-kelp-ecosystem-recovery-recently-deforested-location) project page on bull kelp recovery states that over 96% of bull kelp canopy has been lost on California's North Coast. That percent is Northern California. It is not Oregon's two-thirds. Averaging the two would invent a coast that neither survey measured. ## the forest is already in the water Bull kelp and giant kelp already grow in the Pacific nearshore. The fish, the abalone, and the sea otters that use them exist whether or not anyone buys a certificate. An **urchin barren** is the reef with the forest gone. A line of seeded twine is a tool, not the forest. Ensurance funds the living forest. It is not the forest. A **certificate** is funding tied to a named stock. The stock is the canopy. The certificate is not the kelp. Coastal work already has an agent at [coastal-resilience.syndicate](/coastal-resilience.syndicate?from=guide). The agent can carry funding for a coast. It is not the canopy in the cove. The [marine-systems.ensurance](/marine-systems.ensurance?from=guide) coin funds marine systems as a stock, and it is not this kelp forest. A coral reef is an animal city of limestone, and [what coral reefs actually are](/guide/what-coral-reefs-actually-are?from=guide) is that other stock. Kelp is not an estuary, a salt marsh, a mangrove, or a seagrass meadow, and the place where a river meets the sea is [what estuaries actually are](/guide/what-estuaries-actually-are?from=guide). [Coastal systems](/coastal-systems.ensurance?from=guide) is the coin for that tidal edge. It is not this canopy. ## frequently asked questions ### what is a kelp forest? A kelp forest is a living stand of large brown algae on a rocky nearshore reef, dense enough to form a canopy. A holdfast anchors the kelp to rock, and gas bladders lift the blades toward the surface. On this coast the canopy is bull kelp or giant kelp. A photograph, an urchin barren, and seeded twine are not that stand. ### is kelp a plant? No. Kelp are large brown algae, not plants. NOAA's Office of National Marine Sanctuaries states that, and counts about 30 species worldwide. A holdfast anchors the alga to rock. It is not a root pulling nutrients from soil. A stipe is not a trunk. A blade photosynthesizes and is not a leaf. The forest is a stand of algae. ### what lives in a kelp forest? The canopy, the water under it, and the rock are three layers of the same stand. At the surface, blades shelter fish, invertebrates, and marine mammals. Sea otters, where they are present, often wrap themselves in kelp to rest. Among the stipes, fish including rockfish hold in the midwater. On the rock, holdfasts sit with crabs, snails, sea urchins, sea stars, and abalone. The Oregon Kelp Alliance's status report also lists gray whales and groundfish among the species these forests provide habitat for. ## sources [Oregon Kelp Alliance, Oregon Kelp Forest Status Report (2024)](https://www.oregonkelp.com/wp-content/uploads/2024/11/ORKA_StatusReport_2024-Digital-150dpi.pdf) — canopy cover from 2010 to 2022 summarized as a 67–73% decline (66.4% in aerial surveys from Cape Arago south to Brookings; 73.5% in a satellite estimate for Oregon's coastline); more than two-thirds of the state's kelp forest habitat no longer supports substantial kelp; about 892 acres of bull kelp forest disappeared since 2010, the aerial loss in southern Oregon from Brookings to Cape Arago [California Sea Grant, accelerating bull kelp ecosystem recovery](https://caseagrant.ucsd.edu/our-work/research-projects/accelerating-bull-kelp-ecosystem-recovery-recently-deforested-location) — over 96% of bull kelp canopy lost on California's North Coast; Northern California, not Oregon [NOAA Office of National Marine Sanctuaries, kelp forest](https://sanctuaries.noaa.gov/visit/ecosystems/kelpdesc.html) — kelp are large brown algae, not plants; about 30 species; holdfast, stipe, blade, pneumatocyst; canopy, midwater, and seafloor, including sea otters resting in kelp [NOAA Office of National Marine Sanctuaries, bull kelp and giant kelp](https://sanctuaries.noaa.gov/earthisblue/wk210-bull-kelp-vs-giant-kelp.html) — bull kelp is the most abundant kelp in Oregon, Washington, British Columbia, and Alaska; giant kelp dominates to the south ## the series Five posts. The forest first, then the barren, the two kelps, the twine, and who already keeps the canopy in the water. 1. [what a kelp forest actually is](/guide/what-a-kelp-forest-actually-is?from=guide) — you are here 2. [you don't have an empty reef. you have a missing forest](/guide/you-dont-have-an-empty-reef-you-have-a-missing-forest?from=guide) 3. [bull kelp and giant kelp are not the same forest](/guide/bull-kelp-and-giant-kelp-are-not-the-same-forest?from=guide) 4. [a line of twine is not a kelp forest](/guide/a-line-of-twine-is-not-a-kelp-forest?from=guide) 5. [who already keeps the forest in the water](/guide/who-already-keeps-the-forest-in-the-water?from=guide)