Some Tips for Landscaping Slopes:

Transcription

1 Some Tips for Landscaping Slopes: Tip 1 - Preserve trees in your community Use protective fencing to screen construction works from areas of existing vegetation 12 Use tree rings to retain existing trees where a hard surface is required (Professional advice should be sought as necessary) Protect existing tree trunks with wooden pallets and/ or hessian wrapping during construction works Locate soil nails and other engineering features away from tree trunks and roots Use toe walls to retain existing trees where the slope surface has to be re-graded

2 Examples of tree preservation on slopes and retaining walls Tree rings are provided to protect existing trees 13 Rings formed in the slope surface around tree trunks and roots allow retention of existing woodland trees

3 14 Existing trees are retained after upgrading works using soil nails Use of soil nails to stabilise an existing masonry wall allows attractive wall trees to remain undisturbed Soil nail heads concealed behind blocks in the wall face

4 Tip 2 - Crea eate planting opportunities 15 Slope Angle θ 35 o 35 o < θ 45 o 45 o < θ 60 o 60 o < θ 90 o Possible Planting on Slope Face grass hydroseeding with pit planting of trees and shrubs grass hydroseeding with erosion control matting and pit planting of trees and shrubs grass mix with erosion control matting with wire mesh reinforcement and pit planting of groundcovers, climbing plants and ferns use of new method including proprietary systems

5 Examples of vegeta etation tion on slopes and retaining walls Ornamental shrubs and groundcover at the toe of a retaining wall 16 Climbers on a retaining wall Self-clinging climbers on a steep rock slope Erosion control mat supporting a grass surface

6 Toe wall planter supporting colourful flowering shrubs 17 Combination of trees and shrubs on a slope Trees on a slope Grass surface on a slope

7 Species Commonly Planted in Hong Kong Trees 18 Casuarina equisetifolia (Horsetail Tree) Melaleuca leucadendron (Paperbark Tree) Groundco oundcover er and Cree eeper pers Eucalyptus citriodora (Lemon-scented Gum) Wedelia trilobata (Wedelia) Ficus pumila (Creeping Fig)

8 Shrubs Calliandra haematocephala (Red Powderpuff) 19 Ligustrum sinense (Chinese Privet) Hibiscus rosa-sinensis (Chinese Hibiscus) Rhododendron spp. (Azalea)

9 Tip 3 - Provide Ornamental planting Ornamental low shrubs on a slope 20 Clipped shrubs used in combination with flowering shrubs and mature trees to provide an attractive appearance to a slope

10 Are e Landscape pe Wor orks s Costly? The typical unit cost for a rang ange of products in 2001 are as below: Groundcovers Hydroseeding Shrubs Climbing Plants Tree: light standard Planter Hole Toe Planter (HK$10-15 each) (HK$10-20 per sq m) (HK$15-30 each) (HK$25-40 each) (HK$ each) (HK$200 each) (HK$ per linear m) Rates given are indicative only and may vary according to scale and site conditions. 21 Are Landscape Wor orks Difficult icult to Maintain? Typical maintenance wor orks for soft landscape wor orks: Regular inspections of plants to check their healthy growth Replacement planting where necessary Control of pests Trimming of vegetation as necessary Watering of ornamental planting Inspection of hard landscape works in relation to planting Clearance of drainage channels Typical maintenance wor orks for hard landscape wor orks: Check for damage of surface finishes and make necessary repairs

11 Seven en Things to Remember 22

12 Assistance More guidance can be found in GEO Publication No.. 1/2000 "Tec echnical Guidelines on Landscape Trea eatment and Bio-engineering for Man-made Slopes and Retaining Walls", which h is availa ailable le from : Government Publications Centre, Ground Floor loor,, Low Block, k, Queensway y Government Offices ices, 66 Queensway,, Hong Kong ong. "Layman's Guide to Slope Maintanence", and other leaflets and booklets on slope safety can be obtained from om District Offices ices.. For or more e informa ormation on slope related matters, please contact: Community Advisory Unit, Geotechnical Engineering Office ice, Civil Engineering Department Tel. No.: or browse the following web-sites: Civil Engineering Department Hong Kong Slope Safety Hong Kong Institute of Landscape Architects 23

13 Selected Publica lications Rela elated to Slopes 24