• Energy Research

Abstract Context Current production from natural forests will not satisfy future world demand for timber and fuel wood, and new land management options are required. Aims We explore an innovative production system that combines the production of short rotation coppice in wide alleys with the production of high-value trees on narrow strips of land; it is an alternative form of alley cropping which we propose to call ‘alley coppice’. The aim is to describe this alley coppice system and to illustrate its potential for producing two diverse products, namely high-value timber and energy wood on the same land unit. Methods Based on a comprehensive literature review, we compare the advantages and disadvantages of the alley coppice system and contrast the features with well-known existing or past systems of biomass and wood production. Results We describe and discuss the basic aspects of alley coppice, its design and dynamics, the processes of competition and facilitation, issues of ecology, and areas that are open for future research. Conclusion Based on existing knowledge, a solid foundation for the implementation of alley coppice on suitable land is presented, and the high potential of this system could be shown.

tEnsuring increased and sustainable biomass production is critical for European countries. Short-rotationcoppice (SRC) plantations on agricultural lands have a great potential to increase biomass supply for bio-fuels, bioenergy, and bioproducts. In Italy, SRC is based on the use of fast growing species, high plantingdensity, and short harvesting cycles. In this study, the performance of new genotypes to be used in SRCplantations for biomass production was evaluated after three biennial rotations. At the trial plantationin Mira (Northern Italy), six different poplar (Populus) genotypes, belonging to different interspecifichybrids were studied. This plantation provided the opportunity to study the relationships between sur-vival, biomass production and other growth parameters over multiple rotations and for a wide genotypicrange. Biomass production differed significantly among rotations starting from 16 Mg ha-1year-1in thefirst, peaking at 20 Mg ha-1year-1in the second, and decreasing to 17 Mg ha-1year-1in the third rota-tion. At the end of each rotation, significant differences among genotypes were observed in number ofshoots per stool and per ha, stem diameter, tree height, and biomass production. Mean survival ratesbecame significantly different from the other rotations only in the third rotation during which survivalrate ranged from 95% for (P. × generosa) × P. nigra 'Monviso' to 75% for (P. × generosa) × P. nigra 'AF6',but non-significant difference was observed among genotypes. Skewness and inequality of shoot sizedistributions were genotype-dependent and increased with rotations. Highest biomass production wasfound for genotypes P. × canadensis '83.148.041', 'Monviso' and (P. × generosa) × P. trichocarpa 'AF8' withmean annual dry mass production of 21.7, 19.5 and 19.3 Mg ha-1year-1, respectively. Genotype × rotationinteractions were significant on shoot size, diameter and number, but not on survival and biomass pro-duction highlighting that genotypes behaved differently over rotations. Moisture and ash content, woodspecific gravity, and higher heating value were determined at the end of the third biennial rotation, andsignificant differences among genotypes were found. This study is critical for investigating the behav-ior of novel poplar genotypes with potential for commercial biomass production over multiple coppicerotations.

La pioppicoltura in Italia è un comparto di eccellenza per la produzione di legno ad uso industriale ed energetico. Questo contributo intende analizzare lo stato della filiera produttiva del pioppo in Italia, illustrando le principali prospettive per la crescita della produttività e della sostenibilità del settore, in coerenza con una prospettiva di intensificazione sostenibile. Oltre all'aspetto produttivo, la pioppicoltura ha anche una elevata valenza ambientale. Lo sviluppo e la diffusione di cloni a maggiore sostenibilità ambientale, i nuovi moduli colturali, le prospettive offerte dalla meccanizzazione e dalla selvicoltura di precisione, i prodotti della bioeconomia e della bioraffineria, e i benefici ambientali in termini di sequestro della CO2 e contrasto all'inquinamento dell'aria e dei suoli rendono la pioppicoltura una tessera importantedella filiera forestale italiana. Poplar cultivation in Italy is a sector of excellence for the production of wood for industrial and energy use. This contribution intends to analyze the state of the poplar production chain in Italy, illustrating the main prospects for increased productivity and sustainability of the sector, in line with a perspective of sustainable intensification.In addition to the productive aspect, poplar cultivation also has a high environmental value. The development and use of clones with greater environmental sustainability, the new cultivation modules, the perspectives offered by high mechanization and precision forestry, the products of the bioeconomy and biorefinery, and the environmentalbenefits in terms of CO2 sequestration and remediation to air and soil pollution make poplar cultivation an important sector of the Italian forestry chain.

Two perennial exotic grasses, Virginia Mallow (or Sida -Sida hermaphrodita (L.) Rusby) and Cup plant (Silphium perfoliatum L.), were tested in the frame of SidaTim project (FACCE-SURPLUS) in two sites in Italy, in continental North West and in Mediterranean areas. In this work, we reported the results of the possible utilization of the two species to feed an automated boiler system (200 kW) mixed with poplar chip. The economic analysis emphasizes the sustainability of chip-fed system for the production of thermal energy. The lignocellulosic chips represents the main cost, while other costs correspond to the electric energy for pumping water in the pipe and for other minor auxiliary equipment of the boiler. We have also assesses sustainability of these two crops/species investigating the productivity and water use efficiency (WUE, intrinsic and agronomic ones) in comparison to common energy crops (poplars Short Rotation Coppice and maize and sorghum for biogas). Additionally, the environmental impact was assessed comparing the competiveness of Sida in comparison to endemic vegetation (crops, forage species and seeds bank) in controlled experiments. During the establishment year, Sida showed a lower WUE in comparison to maize, although preliminary data of the second growing season estimate much better WUE. Sida competiveness depends of crop/forage species, requiring an implementation of this issue with field experiments.

Il Volume, in cui il Capitolo fa parte, è stato prodotto e pubblicato con il supporto dell'Accademia dei Georgofili di Firenze e del MiPAAF (Ministero Politiche Agricole, Alimentari e Forestali).

Poplar is a fast-growing tree with high industrial demand for its timber which can be allocated to different uses such as plywood, sawwood, particle board, bioenergy, etc. Poplar adequacy as component of silvoarable practices is based on the reduced amount of light it intercepts when compared with other tree species, the great knowledge about its silviculture and decades of genetic improvement, its integration in the agricultural landscape and its shorter rotation. Agroforestry practices with poplar in Europe include alley cropping to produce biomass as renewable energy and silvoarable practices. The use of poplar as part of an agricultural plot increases productivity but also promotes environment protection and carbon sequestration while enhancing social benefits. This paper aims at reviewing the main poplar plantation areas in Spain, Italy and France and the potential of combining it with crops and also identifies the main drawbacks to implement agroforestry with poplar from a policy point of view.