Hedgerows

- human component is crucial [5]

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1. multiplication of edge effects - network of interconnected biomes that enhance or disrupt fluxes between them [1]

2. provide 'wild' habitat and nectar sources for native species [7] such as bees [10]

3. greater abundance of predator insects and parasitoids in hedgerows, with benefits extending 100m into adjacent crops [12]

4. reduction in wind, especially in bocage landscapes [1][2] due to surface roughness and its effect on air mass fluxes. The shelter effect is strongly tied to average tree and brush height in the hedgerows, though even a height of 2m is enough for substantial reduction in wind [19]. Effect extends 8-10x the hedgerow height [22] and peaks at 4-5x hedgerow height [23]

5. barrier to dispersal of micropropagules (spores, dust, seeds, etc) [1] [8] and herb/pest/fungicides [11]

6. hedgerows and accompanying ditches used for irrigation in summer months and drainage in winter [1] - can be broken into apparent functional subunits: hedgerows and ditches perpendicular to the slope that trap water accumulating gin superficial soil layers, hedges/ditches that run parallel to slop and carry water to main streams, and hedges/ditches that line flood plains and contain flood events [3]

7. hedgerows provide biomass that aids in denitrification of waterways [1] [4], though they have less effect on hillslope and catchment scales due to NO3 contamination of groundwater aquifers by past fertilizer applications [20]

8. otherwise help screen water for pathogens and chemicals [8]

9. hedgerow soils are less compacted, more fertile (in both nitrogen and phosphorus) and more permeable to rainwater

10. provide corridors for animal and plant dispersal [1]

11. greater heterogeneity in the landscape reduces flux of pests and diseases between adjacent plots [1]

12. psychological enclosure leads to a sense of safety among humans [5] [6]

13. source of wood, fodder, fruits, medicinal plants, vegetables, materials for tools (eg. ash, baskets) [5]

14. linear shape of shelterbelt/hedgerow maximizes solar insolation (higher light availability than forest [16]) to understory and thus improves production of a 'food forest' planting [9]

15. anecdotal "light funnel effect" when hedgerows are oriented such that they reflect light back onto adjacent crop fields [17]. Conversely, it has been found that intercropping maize between hedgerows in a tropical climate significantly decreases yields nearest to the hedgerows due to competition for light [18]

16. hedgerows store considerably more carbon in the soil than grass strips [13]. This is due to direct effect of treefall as well as reduction in erosion on the hillslope scale [14]

17. reduce pollution when planted as medians in urban street canyons [15]

18. deep roots increase percolation of groundwater into aquifer [23][21]

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farmers tend to see a more open landscape more favorably as a better place to work, hedgerows on farm limits. People visiting tend to prefer unbroken hedgerows as important parts of the landscape. People that live there get the impression of being locked in by unbroken hedges and prefer at least some open sight lines to "see outside." [22]