On Rakaia River bank, infected with fungus?
The hillsides along the route towards Banks Peninsula holds smaller details than just the impressive hills. Alongside some of the ridges, one can observe layers of volcanic ash embedded in the rock which designate past volcanic eruptions. Volcanic ash can be formed of rock fragments, volcanic glass, and also minerals that are a key ingredient to making soil with volcanic ash extremely fertile.
The minerals trapped inside the ash is usually dissolved through rainfall. The nutrient enriched water mixes with the soil underneath and creates a layer called Andisol. This is the layer accessed by flora and used to create the lush plant life usually found in areas where current or past volcanic activity was present.
New Zealand has a unique geological system in which the Australian and Pacific tectonic plates meet on a boundary that runs directly under both islands. When a plate subducts under another, the mantle of the subducting plate heats up due to being exposed to the magma underneath. This newly melted crust is pushed upwards and can result in volcanic activity.
Banks Peninsula, where this photo was taken, is made from the remains of the two shield volcanoes Akaroa and Lyttleton as well as the Mt. Herbert Volcanic group. This peninsula is the only relic of volcanic activity on the South Island.
The Ōtepatotu Scenic Reserve, where we hiked, had a few very dense portions of trees and brush. Unfortunately, this is not the case for most of the Peninsula. The area used to be heavily forested, and was cut down due to the colonization of Akaroa at the center of one of the craters by the French. Additionally, much of the forested portion is also non-endemic, and had crops of non-native trees planted by hand in the area that took advantage of the soil. The identification on this post is one of them – Scot’s Broom. Our class has also seen signs of Scot’s Broom in Wanaka (1.17.17).
During the drive towards the hike we saw several examples of the volcanic ash embedded in the rocks running along the road. I hadn’t thought to really look at the details in the rock faces until our bus driver, Alan, mentioned that lines of ash were sometimes visible. Sure enough, after a few more minutes I too was able to spot the difference between layers of rock and snapped a few pictures.
Besenginster (Cytisus scoparius) im Almet bei Sankt Arnual
Cytisus scoparius, the common broom or Scotch broom, syn. Sarothamnus scoparius, is a perennial leguminous shrub native to western and central Europe. In Britain and Ireland, the standard name is broom, but this name is also used generically for other related species (see broom), and the term common broom is sometimes used for clarification. In other English-speaking countries, the most prevalent common name is Scotch broom (or Scot's broom); English broom is also occasionally used.