We use some essential cookies to make this website work.
We’d like to set additional cookies to understand how you use forestresearch.gov.uk, remember your settings and improve our services.
Planting trees along stream banks could play an important part in protecting sensitive fish such as salmon and trout from rising temperatures as the climate warms. Results from an ongoing study in the lowland streams of the New Forest suggest that riparian shade can prevent summer water temperatures exceeding dangerous limits.
Water temperture in shaded and unshaded reaches of three stream across the New Forest was monitored at 15 min intervals.
The riparian shade at each site was characterised using hemi-spherical photographs, aerial photographs and GIS software.
The site shade parameters were used to investigate the influence of riparian shade on the spatial and temporal variation of thermal regime.
Water temperature fluctuates through the day in small, rain-fed streams such as those of the New Forest. The study found that riparian woodland had a marked effect on the water temperatures, with daily peaks in water temperature typically 5 degrees cooler in shadeed reaches than open water. This was enough to significantly reduce the number of days on which stream water temperature exceeded critical thresholds for trout.
Critically, the study indicates that riparian shade of about 20% canopy cover for at least 500 m in small, rain-fed streams could be effective in preventing current summer maximum water temperatures from exceeding potentially life threatening levels for native cold-water fish. However, higher proportions of riparian woodland are likely to be needed to address future climate warming.
The results illustrate how the riparian shade can be managed to provide essential cool-water refugia in the streams for the benefit of fish such as salmon and trout.
Cookies are files saved on your phone, tablet or computer when you visit a website.
We use 3 types of cookie. You can choose which cookies you're happy for us to use.
These essential cookies do things like remember your progress through a form. They always need to be on.
We use Google Analytics to measure how you use the website so we can improve it based on user needs. Google Analytics sets cookies that store anonymised information about: how you got to the site the pages you visit on forestresearch.gov.uk and how long you spend on each page what you click on while you're visiting the site
Some forestresearch.gov.uk pages may contain content from other sites, like YouTube or Flickr, which may set their own cookies. These sites are sometimes called ‘third party’ services. This tells us how many people are seeing the content and whether it’s useful.