Managing Riverbank Trees

Transcription

1 Managing Riverbank Trees Mike Kelly River Valleys Officer

2 The Importance of Riparian Woodlands The meeting point of two major systems land and freshwater Riparian Woodlands fundamentally influence the health and productivity the river Valuable in terms of: Wildlife- Alder is the dominant life form - 80% of riverbank trees Home to riverbank invertebrates providing up to 90% of the salmon/trout diet. Leaf litter provides up to 90% of a streams energy budget Roots to provide shelter and protect fish from predators Structure - Important Wildlife corridors for small mammals and bugs Shade to limit temperature fluctuations Bank stabilisation Buffer Strip intercepts runoff (Sediment, fertilisers, pesticides) Amenity & Landscape Economic: Firewood Angling Tourism

3 Key issues at the riverbank 1. Over-maturity and undermanagement of riverbank trees 2. Alder monoculture/suppressed natural regeneration 3. Alder Disease since 1990 s and now Ash dieback

4 1 Over-mature alders Large trees = high mechanical stress Large canopy prone to wind throw Increased risk due to undercutting Short lived tree unless coppiced Susceptible to age related diseases

5 2 Alder Monoculture With no other tree species whole site is susceptible to dieback Often little or no understory Limited field layer Grasses, wildflowers Therefore site is structurally simple/ lacks diversity Ineffective as a buffer strip Regeneration can be encouraged by restricting stock access

6 3 Alder Dieback Phytophthora - Greek for Plant Destroyer Disease with important implications for the health of UK rivers FC first identified in the UK Local reports suggest longer Water/soil borne fungus Long lived spores - Free-swimming Dispersed on dead plant material, soil, animals and vehicles Tree has no defence and dies rapidly once crown symptoms observed Not possible to eradicate alder disease management is only option Significant % of trees on lower Clun are diseased

7 Identifying Alder Dieback Brown tarry marks near the base of tree Leaves abnormally small, yellow and sparse Premature leaf loss Heavy masting Root and branch dieback Over a few years the tree will lose structure and die If alder is showing signs of dieback the likely cause is alder Phytophthora

8 Collar Rot Alder Thomas Jung,,

9 Tree Management Striking a Balance Balance required between the need to manage woodland and the need to protect sensitive wildlife Too much light may negatively impact upon white-clawed crayfish, freshwater pearl mussel Very heavily shaded may benefit from coppicing to introduce some light Think about nonintervention areas wet woodlands Coppice little and often! Recently managed site

10 Riparian Management 1 Managed alder and willow can live for hundreds of years Rejuvenated alders create beneficial low fringing shade Target diseased, leaning or undercut trees Pollard/re-pollard crack willows before they become a problem phase work if possible Important to ensure that enough light penetrates to support regrowth Keep stool clear of competing vegetation May need to coppice neighbouring trees Technique Do not cut into branch collar Do not cut too low or too high Cut should be clean with no separation of bark Slope cuts away from the centre of the stool

11 Riparian Management 2 Stems should not felled into the river Use chain and winch to direct fall Consider singling multi-stemmed alder to favour single stem Site burns sites carefully, away from trees that may host bats. Use old burn sites, tracks etc. Be aware of ground conditions use low impact machinery Retain standing deadwood Retain large canopy trees e.g. ash, sycamore Retain young trees and understory Resist temptation to over-tidy e.g. collapsed willows have great wildlife value There should never be a case for whole tree removal Avoid clear-fell - Try to retain at least 60% of canopy

12 Low impact forwarder

13 Newly Coppiced Site

14 Same Site Six Months Later

15 Planning and Consultation Site Planning Will the work affect sensitive habitats/species E.g. white clawed crayfish, freshwater pearl mussel, bats, otters etc. - A NE licence may be required For information consult with landowner EA, NE, Wildlife Trust, National Biodiversity Network (NBN). Avoid working in any sensitive areas Undertake works when trees are dormant Be aware of fish spawning and fry hatch season Sept - Early May and vulnerable times for other species However best ground conditions between June and September Does the site have any statutory designations? Consent required if any of the following Special Area of Conservation (SAC) Site of Special Scientific Interest (SSSI) Scheduled Monument Other Permissions Obtain felling licence if felling >5m3 in any quarter Main River - EA consent may be required: Ordinary watercourse Local Authority Consent Work in a Village or Town Conservation Area will require consent from Local Authority

16 How we can help Funding and Advice Part of a Capital Funding Programme working along with other funders Capital funding available for holdings: Not in any scheme/agreement In ELS, UELS, ESA (scheme not benefiting from a capital works element) Capital Projects Coppicing and Pollarding Fencing Livestock watering Tree planting Track Improvements Water/sediment capture and storage Ponds, Sediment Traps, wetland creation etc. We can help with the paperwork and project management : Surveys Getting consents Minimal Paperwork to be involved

17 Tree Management

18 Fencing

19 Livestock Watering

20 Watergates

21 Tree Planting