A rowan tree
Rowan tree. Photo: Lorne Gill

Rowans are resilient trees. Their fruit ripens in autumn and stays up until the winter. These plants have uses both in culinary and craftsmanship (Vedel & Lange, 1960).

Rowan walking stick
A walking stick made from a rowan tree. Photo: Mcaffee Irish store

They also have a long mythological history. In the Victorian era these plants were believed to ward-off witches and black magic (Frazier, 2009). However, there is a lot more to being rowan.

Coming from the rose family, rowans are shrubs or trees. They bloom in May with their fruit maturing in September and remaining ripe until the winter. Native throughout the Northern Hemisphere, rowans are the most diverse in the mountains of western China and the Himalaya.

Rowan tree in a semi-open woodland
Rowan tree in a semi-open woodland. Photo: Wikimedia Commons

Usually rowans are found in semi-open woodlands or forest edges. There they have enough light to flower or set fruit. Their wood is dense and used for carving tool handles and walking sticks (Vedel & Lange, 1960).

The fruit is good for jams and jellies

Rowan jam.
Rowan jam. Photo: Thea Tillberg

Their red, oval and bitter fruit is often made into jams and jellies for meat dishes. Rowan fruit are also a source of tannins for mordanting vegetable dyes (Henderson, 2000).  All that is greatly facilitated by the softness and juiciness of rowan fruit.  This trait is also helpful for their distribution.

 

 

 

 

The juicy fruit of rowans attract birds who eat and spread them

The rowan tree belongs to a group of fleshy-fruited woody plants. These are trees and shrubs that have soft, juicy fruits and woody stems. Woody plants are perennials, which means that they survive until the next season: “That makes it interesting to study them as a group”, says Matilda Arnell, a PhD student at DEEP. She studies all the wild fleshy fruited woody plants in Sweden:

“The goal for us is to study their spatial distribution and try to understand how these patterns were created. One interesting question is how the dispersers, such as the birds, affect the distribution patterns”, explains Matilda.

According to her, the purpose of the soft fruit is to disperse the plant’s seeds. Birds, like waxwings and thrushes, as well as some mammals, like foxes, eat the fruit with the seeds inside. Afterwards they distribute them through their droppings. In Sweden fleshy fruited woody plants are mostly dispersed by birds.

Bohemian waxwing eating fleshy-fruits from a hawthorn
Bohemian waxwing eating fleshy-fruits from a hawthorn (Crataegus spp.). Photo: Thomas Seippel.

The distribution of fleshy-fruited woody plants is a difficult research subject

“These plants and their dispersers have evolved like a guild, rather than in pairs. It is a, so called, diffused evolution. It’s not like one bird eats the fruit of one species. Instead, many different animals eat fruits from many different plants”, says Matilda.

Matilda’s first project was about the effect of historical land use on the distribution of fleshy fruited woody plants. The aim was to try to identify the signal of past land use in the present distribution of species:

“Our aim was to understand if there are still more species in areas that were open a 100 years ago, compared to areas that have had a more or less continuous forest cover”. We mapped all the fleshy-fruited woody plants in a part of the forests in the Stockholm archipelago and south of Stockholm. On top of that, we also digitized historical maps from around 1900”. explains Matilda.

Matilda mapping fleshy-fruited woody plants
Matilda mapping fleshy-fruited woody plants (here a bird cherry – Prunus padus) in the Stockholm archipelago. Photo: Anna Lundell.

The region in the Stockholm archipelago had more species in a formerly open land – a farmland with grazing cattle. There it was still possible to see the historical signal of past land use in the distribution of these species. Matilda believes that it is because modernization of agriculture begun later here. Understanding the legacies of historical land use can help us understand why certain species are found in one place or another. It might also aid in making future predictions about the consequences of changes in land use:

 “If the landscape changes, we might be able to better predict what will happen. For example, if open areas are left without management and forest trees start to take over, we will have a better understanding of how this will affect the distribution of fruit bearing species adapted to more open habitats”, notes Matilda.

References:

Frazier, S. (2009). The Golden Bough : A Study in Magic and Religion. Oxford University Press.

Henderson, R. , K. (2000). The Neighbourhood Forager: A Guide For The Wild Food Gourmet. Key Porter Books.

Vedel, H., Lange, J. (1960). Trees and Bushes in Wood and Hedgerow. Metheun & Co. Ltd.