Tuesday 18 June
Knothole moss (Zygodon forsteri)
Knothole moss fact file
- Find out more
- Print factsheet
Knothole moss description
Knothole moss is a small moss, and forms dark green cushions on tree trunks or exposed roots. It resembles other Zygodon species and the best identification for the non-expert eye is the dark, shiny, almost blackish-green colouring.
- Height: 5 mm
Knothole moss biology
This moss tends to be found in association with older trees that have cavities in exposed roots, or where branches have broken away. These can catch rainwater and fill up with dead leaves. The water trickling out of these reservoirs forms a seepage track which can persist for years. In wet autumns, the moss can form large colonies, but in a dry summer, these can, apparently, disappear rapidly. The trees favoured by the moss are usually ancient beech pollards growing in a well-lit woodland. The practice of pollarding has become less common since the turn of the twentieth century, but has enjoyed a recent revival as the conservation benefits of this form of management have been realised.Top
Knothole moss range
This species is widespread but rare across most of Europe. In Britain it is now restricted to three locations, the New Forest, Burnham Beeches in Buckinghamshire, and Epping Forest in Essex. Of these colonies, the one at Burnham Beeches is the largest, with much smaller populations at the other sites where it is restricted to a handful of trees.Top
Knothole moss habitat
Knothole moss has very precise habitat requirements. It grows only in the raintracks on beech trees growing on acid soils in open, well-lit sites. Very occasionally it has been recorded on other species of tree. The raintracks are not fed with water from the canopy of the tree, but from pools of water held in a cavity in the exposed roots or truck of the tree. Colonies typically, grow around wound tissue such as knotholes giving the moss its common English name.Top
Knothole moss status
Classified as Endangered in the UK, fully protected under the Wildlife and Countryside Act Schedule 8. Classified as Vulnerable in Europe.Top
Knothole moss threats
Whilst never common, this moss is threatened by the felling of its host trees, possibly through safety considerations. The famous 'hurricane' of October 1987 that tore through southern England, also felled several host trees in Epping Forest. Another long-term issue is creating replacement pollarded trees for the future. A continuity of suitable trees is essential for the moss to survive at any one particular locality. Another, rather ironic factor, is the increase in competing species of moss which have benefited from the reduction of acid rainfall. These other mosses are suspected of crowding out the knothole moss. Moss collecting is another possible threat as a small colony of knothole moss could be removed completely by an irresponsible collector.Top
Knothole moss conservation
Knothole moss is listed in the UK Biodiversity Action Plans and also included in English Nature's Species Recovery Programme. As it is rare it is vitally important to conserve the remaining colonies of the moss and, where possible, increase the populations.The sites where the moss is known to grow are now all within Sites of Special Scientific Importance (SSSIs). A management plan exists for conserving the species and is available to all managers of these sites. Surveys are also taking place to establish the true extent of this species and whether colonies can be grown in culture for potential re-introduction programmes.Top
Information supplied by English Nature.
- The process of 'beheading' a tree at around 2 m above the ground. This creates many small poles that can be used in many ways, including fencing. The regrowth occurs out of the reach of deer and other browsers.
MyARKive offers the scrapbook feature to signed-up members, allowing you to organize your favourite ARKive images and videos and share them with friends.
Terms and Conditions of Use of Materials
Copyright in this website and materials contained on this website (Material) belongs to Wildscreen or its licensors.
Visitors to this website (End Users) are entitled to:
- view the contents of, and Material on, the website;
- download and retain copies of the Material on their personal systems in digital form in low resolution for their own personal use;
- teachers, lecturers and students may incorporate the Material in their educational material (including, but not limited to, their lesson plans, presentations, worksheets and projects) in hard copy and digital format for use within a registered educational establishment, provided that the integrity of the Material is maintained and that copyright ownership and authorship is appropriately acknowledged by the End User.
End Users shall not copy or otherwise extract, alter or manipulate Material other than as permitted in these Terms and Conditions of Use of Materials.
Additional use of flagged material
Green flagged material
Certain Material on this website (Licence 4 Material) displays a green flag next to the Material and is available for not-for-profit conservation or educational use. This material may be used by End Users, who are individuals or organisations that are in our opinion not-for-profit, for their not-for-profit conservation or not-for-profit educational purposes. Low resolution, watermarked images may be copied from this website by such End Users for such purposes. If you require high resolution or non-watermarked versions of the Material, please contact Wildscreen with details of your proposed use.
Creative commons material
Certain Material on this website has been licensed to Wildscreen under a Creative Commons Licence. These images are clearly marked with the Creative Commons buttons and may be used by End Users only in the way allowed by the specific Creative Commons Licence under which they have been submitted. Please see http://creativecommons.org for details.
Any other use
Please contact the copyright owners directly (copyright and contact details are shown for each media item) to negotiate terms and conditions for any use of Material other than those expressly permitted above. Please note that many of the contributors to ARKive are commercial operators and may request a fee for such use.
Save as permitted above, no person or organisation is permitted to incorporate any copyright material from this website into any other work or publication in any format (this includes but is not limited to: websites, Apps, CDs, DVDs, intranets, extranets, signage, digital communications or on printed materials for external or other distribution). Use of the Material for promotional, administrative or for-profit purposes is not permitted.