Explore the Benefits of River Woodlands
Water Temperature
The shade provided by trees helps regulate water temperature, which is crucial for the survival of many aquatic species, like Atlantic Salmon, and aids in the reduction of phenomena like excessive algae. Reducing water temperatures at river headwaters is crucial for salmon, who migrate there to spawn in search of cooler environments and lower risks of predation and parasites. This is particularly important as both salmon eggs and juvenile salmon are highly vulnerable to water temperatures above 23°C.
Habitat Connectivity
River woodlands are crucial for providing habitats to both water and land species, such as the protected freshwater pearl mussel and the Atlantic salmon, and act as green corridors that connect different woodland areas. This connectivity allows plants and animals to migrate along the river, aiding in gene flow and seed dispersal. Additionally, these woodlands serve as vital refuges and pathways for various species to move throughout the river catchment area.
Clean Water
River woodlands, acting as natural buffers, play a crucial role in filtering out diffuse pollution and trapping suspended sediment from agricultural run-off and forestry land, thereby helping to maintain freshwater quality. Additionally, river woodlands contribute to reducing soil erosion, with their roots stabilizing riverbanks.
Carbon Sequestration
River woodlands can contribute significantly to achieving Scotland’s goal of net zero carbon by 2045. River woodlands help contribute to climate resilience by absorbing carbon dioxide as they grow and storing that carbon in the trees themselves, in the fallen wood, in the soil and across floodplains, contributing to the overall reduction of atmospheric carbon.
Flood Mitigation
River woodlands play a crucial role in reducing flood risk. On the surface, the roots and trunks of trees increase what’s called “hydraulic roughness”, bumpy features on the surface of the land that create pockets, helping to spread the water over a larger area, like a natural floodplain. This allows more water to be temporarily held in the woodland area, reducing immediate runoff into the river and reducing flood risk downstream. Underground, the soil in wooded areas is more porous and effective at absorbing and retaining water and the roots of trees create pathways allowing water to easily drain into underground aquifers. This allows for increased ground water storage during times of heavy rainfall minimizing the water flow directly into the rivers. Riparian vegetation also plays a role in trapping sediment, maintaining natural river channels, and preventing the build-up of materials that can lead to flooding.
Wildlife Protection and Provision
Large woody material from river woodlands diversifies the river’s flow, forming pools that offer slow-moving water as refuges for fish, protecting them from high flows and predators, and creating gravel deposits essential for fish spawning and rearing.
Water Shortage and Drought Adaptation
As water shortage or water scarcity becomes a more frequent issue in Scotland, healthy river woodlands can serve as a key nature-based solution in the right place. The cooling effect of trees, largely due to shading and water evaporating from leaves, reduces air temperatures. Shading by leaves reduces drying at the soil surface and retains moisture coming from the river in the air under the canopy. Some roots of river woodland trees can aid the transfer of water from lower wet layers to upper drier layers of soil. Furthermore, river woodlands, with their healthy, well-structured soils, are capable of storing more water and can act like a reservoir, which is particularly beneficial during prolonged dry spells that lead to water scarcity.
Soil Loss and Quality
Planting river woodland trees is vital in improving soil health and reducing soil loss. As trees grow, they add organic material to the soil through fallen leaves, branches, and even the trees’ own roots. This organic matter is a key ingredient for a healthy soil environment. Under trees, the soil is less disturbed protecting important root and fungal systems and even creatures like earthworms who create tiny holes in the soil that allow moisture and nutrients to infiltrate. The rich biodiverse life in healthy soil plays a crucial role in decomposing organic matter, cycling nutrients, breaking down pollutants, controlling pests, and supporting the overall health of the ecosystem. Furthermore, river woodlands help reduce soil loss and soil erosion from riverbanks and hillsides. The trees stabilizing the soil with their roots and reducing raindrop impact with their canopy, keeping the healthy soil from being washed away into rivers.
Health and Wellbeing
River woodlands, with their smaller trees, are perfectly suited for urban spaces and play a crucial role in enhancing air quality by filtering out pollutants from nearby vehicle emissions. River woodlands offer a range of benefits for our mental and physical health. They provide a natural escape from noise and air pollution, help reduce stress, strengthen our immune system, and offer a more comfortable and inviting climate for outdoor activities and recreation, especially on hot days. Tree canopies cool the air and provide shading from harmful ultraviolet radiation.
Food Production
River woodlands can provide multiple benefits to arable and livestock farms. Trees and shrubs provide livestock with shelter, which improves animal welfare and productivity. With the correct trees and management, river woodlands can also encourage pollinator abundance and diversity, leading to increased crop yields.
Nutrient Cycling and Food Webs
The leaves that fall into rivers and streams from trees on the banks are more than just autumn scenery—they’re a crucial food source for tiny water creatures, invertebrates. Over 3,800 invertebrate species in the UK spend at least part of their lifecycle in freshwater. These include well known freshwater invertebrates like dragonflies, mayflies, pond skaters and crayfish to lesser known worms and mites. But not all leaves are equal in the eyes of these critters. The kind of nutrients these leaves pack depends a lot on the soil and types of trees they come from. One key nutrient for these water bugs is nitrogen, a kind of natural plant food that’s especially rich in leaves from broadleaf trees like the Alder, much more so than in needles from pine trees. Having a variety of native mixed broadleaf trees along the riverbank is like offering a buffet with different nutritional options for the stream’s tiny inhabitants. Each type of leaf breaks down at its own pace—Alder leaves break down quickly, providing a fast food option, while Oak leaves are more of a slow-release meal. This variety is important for keeping the stream’s ecosystem balanced and healthy, making sure there’s something for every tiny critter to munch on throughout the year. Invertebrates are not just beneficiaries of this system; they are also key players in maintaining water quality. Through their activities of breaking down and filtering organic matter, they contribute significantly to the cleanliness of the water. Furthermore, they are an essential link in the food chain, serving as prey for fish, birds, and mammals, enhancing biodiversity. The presence of a rich variety of invertebrates is a hallmark of a thriving ecosystem.