Replanting ash in Italian farmland after the disruption caused by Hymenoscyphus fraxineus requires decisions that were largely unnecessary before the disease arrived: which species to plant, from what provenance, at what density, and whether to replant ash at all or to substitute with species less vulnerable to the same pathogen. These questions have no single answer across Italian conditions, which range from the clay plains of the Po Valley to limestone hillsides in Umbria and upland riparian margins in Trentino.
The Case for Retaining Ash in the Species Mix
There are practical reasons to continue including Fraxinus species in Italian farmland plantings despite the disease risk. Ash occupies an ecological and functional niche — fast early growth, nutrient-rich leaf litter, tolerance of winter flooding in valley-bottom settings, and a wood with mechanical properties (high toughness, good elasticity) that few common hedgerow species match. Field maple (Acer campestre) is often cited as the closest functional substitute in Italian hedgerows, and it has been widely used in recent agri-environment plantings, but it does not provide equivalent timber rod characteristics for traditional agricultural uses.
The counterargument — that planting ash into dieback-affected landscapes simply creates future mortality — is addressed partly by the selection of tolerant provenance material. Research from northern European screening programmes has demonstrated that tolerance to H. fraxineus is heritable at a useful level. If planting stock is derived from tolerant parents, the expected survival rate in heavily affected areas is meaningfully higher than with unscreened standard nursery stock. Whether Italian-provenance tolerant material is commercially available in sufficient quantity is a practical constraint that varies by region.
Species Options for Different Site Types
For northern Italian valley-bottom and riparian planting, Fraxinus excelsior remains the default ash species, but its vulnerability to dieback means it is now typically used at lower proportions in mixed planting schemes — between 10 and 20 percent of the total planting mix rather than the 30–40 percent typical of older rural landscape restoration specifications from the 1990s. The balance is made up with field maple, black alder (Alnus glutinosa), crack willow (Salix fragilis), and wild cherry, depending on soil conditions.
On calcareous soils in central Italy — the Apennine foothills of Umbria, Marche, and parts of Lazio — Fraxinus ornus is native and notably less susceptible to ash dieback. It represents a pragmatic choice for mixed farmland planting in these zones. Its timber is slightly harder than F. excelsior and less valued for traditional tool handle use, but for general hedgerow structure and biodiversity function it performs comparably. Its tolerance of dry, shallow limestone soils gives it a clear advantage over F. excelsior in those conditions.
In Trentino-Alto Adige and the eastern Alps, Fraxinus excelsior is native at relatively high altitudes — up to around 1200m in sheltered valley sites. Replanting in these areas has been complicated by the simultaneous pressure from dieback and by the complex ownership structure of mountain farmland, where small parcels change management frequently. Regional forestry services have prioritised natural regeneration monitoring to identify naturally occurring tolerant seedlings from surviving parent trees, with the intention of using these as propagation sources.
Provenance and Nursery Stock Considerations
EU phytosanitary requirements under Regulation 2016/2031 require that ash planting stock be certified free of detectable H. fraxineus infection. In practice, most Italian nurseries supplying certified ash stock draw on domestic seed lots, but provenance documentation is inconsistent across the sector. For large-scale replanting under agri-environment schemes, regional forestry agencies have increasingly specified that seed provenance must match the ecological region of the planting site — a requirement codified in the Italian Seed Decree (D.Lgs. 386/2003 and subsequent amendments) for the forestry seed sector.
Tolerant-provenance ash is commercially available in Italy on a limited basis. Nurseries in Friuli-Venezia Giulia with connections to Slovenian and Austrian forestry research institutions have offered small quantities of screened stock, and at least two Lombard nurseries were trialling expanded production of tolerant ash as of 2024. For plantings of any significant scale, procurement typically requires advance planning of 2–3 years to align with nursery growing cycles.
Planting Density and Spacing
In Italian agri-environment schemes, hedgerow planting specifications typically follow standard regional guidelines. For mixed-species hedgerow restoration, spacing of 1.0–1.5 metres between plants in a single line is common, with two or three staggered lines at 0.8-metre row spacing where a dense boundary structure is the goal. Where ash is included in an agroforestry alley cropping system — trees planted in rows across arable fields to provide wind protection and timber — spacing of 8–12 metres between rows and 4–6 metres within rows allows mechanical crop management between the tree lines while maintaining productive tree density.
Post-planting management in the first five years is critical. Ash competes poorly with vigorous grass sward in its early establishment phase; weed control through mulching or mechanical cutting within a 60–80cm radius of the planting spot significantly improves first-year growth rates. Italian agri-environment payment schemes that include hedgerow planting have historically required five-year aftercare plans as a condition of grant eligibility.
Ecological Interdependencies to Restore
Ash in Italian farmland supports a suite of associated species whose presence depends on the structural and chemical characteristics of Fraxinus rather than just tree cover in general. Several lichen species associated specifically with ash bark — including members of the genus Lobaria in upland settings — have declined with the loss of mature ash trees. Replanting does not immediately restore this association; colonisation of bark by specialist lichens typically takes decades on new tree surfaces. However, the presence of replanted ash provides the future substrate without which recovery is impossible.
Ash keys (the winged seeds) are a winter food resource for bullfinches (Pyrrhula pyrrhula) and other finches. Observations from Italian ornithological monitoring data (particularly from LIPU — Lega Italiana Protezione Uccelli) indicate that bullfinch winter densities correlate with ash seed production in hedgerow-rich landscapes. A reduction in ash key production across the range will reduce this winter food resource, though the magnitude of the effect relative to other food availability changes is not yet quantified.
Current Support Mechanisms
Ash replanting on Italian farms is eligible for support through the CAP Strategic Plan (Piano Strategico Nazionale 2023–2027) under interventions related to non-productive investments in agricultural land and eco-schemes promoting agroforestry. Farmers in designated Natura 2000 areas or landscape protection zones may access supplementary payments for planting and maintaining hedgerow trees. The exact payment rates and technical conditions vary by region, as Italian regions are responsible for implementing rural development interventions within their territories.
Further reference: CREA Foreste e Legno — technical guidelines for agroforestry in Italy; MIPAAF Piano Strategico Nazionale 2023–2027; D.Lgs. 386/2003 on forestry reproductive material; European Forest Institute Fraxinus dieback monitoring portal.