Tree Nursery Practices in the Mountain Communities of Trentino

Trentino’s nursery sector is small by national standards but disproportionately significant for the production of provenance-certified native planting stock. The province’s combination of forest cover (roughly 62% of the provincial territory), active reforestation programmes, and a tradition of community forest management (Magnifica Comunità di Fiemme, Regole di Spinale e Manez) has supported a cluster of specialist nurseries in the Adige valley and its tributaries that has no obvious parallel elsewhere in Italy.

Scale and structure of the sector

As of 2023, the Provincia Autonoma di Trento listed 34 registered forest nurseries, of which 18 produced and sold native broadleaf species alongside the more commercially dominant conifers. The typical operation is a family-run business of 1–5 hectares of propagation beds, with a small permanent staff supplemented by seasonal workers during lifting and packing periods. Annual production volumes range from 20,000 to 250,000 units per nursery, depending on species mix and market focus.

The main customers are the provincial forestry service (Servizio Foreste e Fauna), private landowners undertaking reforestation under EU rural development schemes, and a smaller number of landscape architects and ecological restoration contractors. Export to other Italian regions is limited by the cost of transport and the availability of competing nurseries in Veneto and Lombardy.

Propagation methods for native broadleaf stock

For Acer campestre and Acer pseudoplatanus, the standard production path begins with seed collection in October–November from designated seed stands (soprassuoli portaseme) registered with the national gene resource register. Seeds are stratified cold for 90–120 days before spring sowing in outdoor seedbeds. First-year transplants (1+0 stock) are typically 15–30 cm; most buyers specify 1+1 or 2+1 stock for planting, requiring one or two additional growing seasons in lined-out beds.

Carpinus betulus presents particular propagation challenges at altitude: germination is erratic without thorough double stratification (warm followed by cold), and seedling growth in the first year is slow. Several Trentino nurseries have experimented with early autumn sowing to extend the cold period naturally, with variable results. Where seed supply is reliable, yields from seedbed sowing are adequate; in years of poor mast, grafting from collected scion material onto containerised rootstocks is used to maintain production.

Container production (cells of 0.15–0.5 litre volume) is used primarily for small orders and for species that transplant poorly bare-root, including Sorbus torminalis and Ulmus glabra. Bare-root production remains the norm for bulk orders of the main broadleaf species, as the cost per unit is substantially lower and field establishment rates are comparable when planting is carried out correctly.

Certification and provenance requirements

Since Italy transposed Directive 1999/105/EC on the marketing of forest reproductive material, nurseries supplying material for forestry use must hold certification for each seed lot and be able to provide a master certificate (certificato principale) with each consignment. The Trentino provincial forestry service maintains a regional gene resource register that extends beyond the national minimum requirements, with a particular emphasis on provenance tracing for Picea abies and Pinus sylvestris seed lots from high-altitude stands.

For broadleaf species, provenance tracing is less systematically enforced in commercial practice. The distinction between “identified source” (fonte identificata) and “selected” (selezionato) material is understood within the sector but is rarely communicated downstream to private landowners, who typically specify species and size class without reference to provenance category.

Supply constraints

The recurring constraint on broadleaf native stock production in Trentino is seed supply. Mast years for Acer campestre and Carpinus betulus are irregular, and the logistics of collecting, processing, and storing seed from designated stands require coordination across multiple private landowners and community forest bodies. In poor mast years, nurseries reduce sowing programmes and carry forward orders to the following season, which compresses delivery timelines for restoration projects with fixed planting windows.

A secondary constraint is the training and retention of skilled propagation staff. Seed stratification, seedbed management, and grading of bare-root stock require experience that is not easily transferred and that cannot be adequately captured in operational manuals. Several nursery operators interviewed in the course of preparing this article noted that finding skilled workers for nursery operations was more difficult in 2023–2024 than at any previous point in their experience.

Relationship with community forest bodies

Trentino’s Magnifica Comunità di Fiemme and similar community forest bodies hold large areas of certified forest and have historically maintained their own in-house nursery capacity for replanting after wind damage, fire, or harvesting operations. The relationship between these in-house nurseries and the commercial nursery sector is cooperative rather than competitive: community bodies frequently purchase specialist broadleaf stock from commercial nurseries while supplying conifer stock to smaller private operators who lack propagation facilities.

This informal division of labour reflects the comparative advantages of each type of operation: community nurseries have access to local seed lots from their own certified stands; commercial nurseries have the propagation infrastructure and market flexibility to respond to variable demand for minority species.

Sources and further reading

1. Provincia Autonoma di Trento — Servizio Foreste e Fauna (2023). Registro regionale del materiale di base. provincia.tn.it
2. European Commission (1999). Council Directive 1999/105/EC on the marketing of forest reproductive material. EUR-Lex. eur-lex.europa.eu
3. Magnifica Comunità di Fiemme (2022). Piano di Assestamento Forestale 2022–2031. Cavalese.
4. Morgante, M. & Vendramin, G.G. (2009). “Forest genetic resources of conifers and broadleaves in Italy.” In: Genetic resources of forest trees in Europe. Bioversity International, Rome.