Pinus pinaster

The maritime pine is a tall tree.

It has very long green needles. The tree has orange-red bark.

It grows big cones. These cones can open after a forest fire. This heat helps the seeds come out. The seeds have wings.

The wind carries the seeds to new spots. This helps the tree grow in many places. It is a very fast growing tree.

The maritime pine is a large tree.

It grows in parts of Europe. It also grows in North Africa. This tree has very long needles. These needles are bluish-green or yellowish-green. The bark is thick and orange-red.

It makes large, cone-shaped parts. We call these cones. They are green at first. They turn red-brown after 24 months.

The cones open slowly. They can also open after a forest fire. This heat lets out the seeds. The seeds have wings. This helps the wind carry them to new places. This is called wind dispersal.

In South Africa, this tree is an invasive species. This means it spreads too much. It can take over land where other plants live. It can also use a lot of water. In some areas, streamflow dropped by 82 percent. This happened after the trees grew for 20 years. Some streams even dried up completely. When people thin out the trees, the water comes back. This helps the local plants and animals stay healthy.

The maritime pine is a sturdy tree with a very interesting life.

It is a fast-growing pine found in southern Atlantic Europe and the western Mediterranean. These trees can grow quite tall and have very thick, orange-red bark. The bark is deeply cracked at the bottom of the trunk. One of its most special features is its needles. These needles are long, stout, and bluish-green or yellowish-green.

In fact, they are the longest and strongest needles of any pine in Europe.

This tree has a clever way of spreading its seeds. It grows large, cone-shaped parts called cones.

These cones start out green and turn a glossy red-brown after 24 months. They open slowly over a few years to let seeds out. Sometimes, the heat from a forest fire helps the cones open even faster. The seeds are shiny black on top and grey-brown on the bottom. Each seed has a large wing attached to it. This wing allows the wind to carry the seeds to new places.

People have moved these trees to different parts of the world. In South Africa, the maritime pine was brought in between 1685 and 1693. By 1772, it was already spreading through the Cape Peninsula. Later, in the early 1800s, people planted them for wood and timber. Now, they are known as an invasive species in South Africa. This means they spread so much that they cause problems for the local environment. They often grow in areas called fynbos, which are shrublands that catch fire often.

Because they grow so fast, these pines can change the land. They use a lot of water compared to local grasses and shrubs. In some places, like the Drakensberg, streamflow dropped by 82 percent after 20 years. In the Mpumalanga Province, six streams even dried up completely after 12 years.

However, thinning out the trees can help. When people removed some pines in the Western Cape, streamflow increased by 44 percent. This helps the water return to the native plants and animals.

It is helpful to think of the pine as a very strong competitor. It uses special oils called resins to protect itself from hungry insects. These resins act like a shield that only comes out when the tree is attacked. This way, the tree does not waste energy when it is safe. In South Africa, the pine also wins because it loves fire. While other plants might struggle after a fire, the pine uses the heat to release its seeds. This allows it to take over new spaces very quickly.

The maritime pine, known scientifically as *Pinus pinaster*, is a fast-growing, hardy tree species. It is native to the southern Atlantic Europe region and parts of the western Mediterranean. This tree is a significant part of its native ecosystem, but it has also become a famous example in invasion ecology.

Because it grows so quickly and spreads so easily, it can change entire landscapes. Understanding this tree helps scientists learn how plants compete for resources like water, light, and space.

The physical structure of *Pinus pinaster* is built for durability and growth. It is a medium-sized tree that can reach exceptional heights. The trunk can grow to a diameter of up to 1.11 meters in some cases. Its bark is a thick, orange-red color that is deeply fissured at the base of the trunk. In the upper crown, the bark becomes somewhat thinner. The tree is famous for its foliage, which consists of long, stout needles. These needles grow in pairs and can appear bluish-green or yellowish-green.

In fact, these are the longest and most robust needles of all European pine species.

Reproduction in the maritime pine involves a specific sequence of biological steps. The tree produces conic cones that are long and broad at the base when closed. These cones start as green structures. They take approximately 24 months to ripen into a glossy red-brown color. The cones then open slowly over several years to release seeds. However, the heat from a forest fire can also cause them to open.

Once open, the seeds are released. Each seed is long and shiny black on top with a matt grey-brown underside. Every seed has a large wing, which allows for wind dispersal to new locations.

Taxonomically, *Pinus pinaster* is closely related to the Turkish pine, the Canary Island pine, and the Aleppo pine. While it is generally a non-variable species with constant morphology, scientists recognize three distinct subspecies. These include *Pinus pinaster* subsp. *pinaster* in Atlantic Europe, *Pinus pinaster* subsp. *escarena* in Mediterranean Europe, and *Pinus pinaster* subsp. *renoui* in Northwest Africa. The tree thrives in a Mediterranean climate, which features cool, rainy winters and hot, dry summers. It prefers acidic soils but is hardy enough to grow in basic, sandy, or poor soils.

History shows how this tree moved from its native home to new continents. It was imported to South Africa during the late 17th century, specifically between 1685 and 1693. By 1772, the species had already spread into the Cape Peninsula. In the early 19th century, around 1825 to 1830, it was planted commercially for the forestry industry and timber resources.

Today, it is considered a highly successful invasive species in South Africa, particularly in the fire-prone fynbos shrublands.

The impact of this invasion is measured by significant changes in biodiversity and water availability. In the Cape Peninsula, invasive species can decrease native plant diversity by 50% to 86%. Because *Pinus pinaster* is an evergreen tree, it consumes much more water year-round than local grasses or shrubs. This leads to a massive reduction in streamflow in certain areas. For example, in the Western Cape, streamflow decreased by 55% twenty-three years after planting. In the KwaZulu-Natal Drakensberg, streamflow dropped by 82% after 20 years. In Mpumalanga, six streams dried up completely just 12 years after the pines replaced grasslands.

Despite these challenges, humans can manage the pine's impact through thinning. When dense areas of pine are thinned, water levels often recover. In the Western Cape, streamflow increased by 44% after thinning. In Mpumalanga, it increased by 120%. Thinning also helps livestock by allowing understory vegetation and grasses to grow back. This demonstrates how managing invasive species can restore the balance of a local ecosystem.