The biotic adversities of poplar in Italy: a reasoned analysis of factors determining the current state and future perspectives

Poplar cultivation in Italy since its early stages has been conditioned and orientated by biotic and abiotic adversities. Spontaneous hybrids between European black poplar (Populus nigra L.) and Eastern cottonwood (Populous deltoides W. Bartram (Marshall)) were empirically introduced into cultivation for their suitable characters of branchiness, rooting and tolerance to root rots; nevertheless, the first true scientific programme of genetic improvement began after leaf and shoot blight epidemics from Venturia populina during the second and third decades  of the twentieth century. The resulting selection of resistant ‘I-214’ clone fostered poplar cultivation in Italy, but at the same time «crystallised» it in a condition of delay with respect to other European countries. With the arrival of leaf spot disease from Marssonina brunnea in the Sixties, phytoiatric treatments were introduced rather than diversifying with more resistant genotypes. Similarly, the increased virulence of leaf rusts from Melampsora spp. starting from about twenty years later, did not succeed in undermining the near monopolisation of ‘I-214’. At present, Marssonina leaf spot and leaf rusts are the most incident diseases: fungicide treatments are carried out mainly on the plantation against the former and mainly in the nursery against the latter. The woolly aphid (Phloeomyzus passerinii) is the most constant and incident pest in plantations. Besides, persisting problems are associated with new pests mainly of exotic origin, especially with the brown marmorated stink bug (Halyomorpha halys).Experiences in other important European poplar cultivation systems highlight the suitability of genetic control, together with a diversification of planted material and efficient agronomic practices. It is advisable to undertake research programmes for vertical and horizontal or quantitative (QTL) resistances, recurring to molecular markers, associated with studies on epigenetics and on microbial communities of various tissues through the new approach offered by metagenomics. The complexity of poplar agrosystems should be increased promoting a homeostatic control of pathogens and pests through antibiotic or competitive features triggered by other microbiota components

Evaluation of the expression level of the endogenous marker poUBI gene for studies on transgene stability in bar and StSy GM poplars

Abstract This work reports on the isolation and molecular characterization of the poUBI cDNA encoding polyu-biquitin from white poplar (Populus alba L. cv 'Villafranca'). Expression analysis was performed on different poplar organs and tissues, at different developmental stages and in relation to the growth/dormancy cycle. Information concerning the steady-state level of poUBI transcripts in planta are required to better evaluate the possible use of this gene as endogenous marker for studies on long-term transgene stability in genetically modified white poplars

Evaluation of the expression level of the endogenous marker poUBI

Abstract This work reports on the isolation and molecular characterization of the poUBI cDNA encoding polyu-biquitin from white poplar (Populus alba L. cv 'Villafranca'). Expression analysis was performed on different poplar organs and tissues, at different developmental stages and in relation to the growth/dormancy cycle. Information concerning the steady-state level of poUBI transcripts in planta are required to better evaluate the possible use of this gene as endogenous marker for studies on long-term transgene stability in genetically modified white poplars

Dataset of tree inventory and canopy structure in poplar plantations in Northern Italy

The dataset reports data collected in 38 square (50 x 50m) 0.25 ha plots representative of poplar plantations in Lombardy Region (Northern Italy), which were used to calibrate optical information derived from unmanned aerial vehicle (UAV) and satellite (Sentinel-2) sensors.In each plot, the diameter at breast height was measured using a caliper; height, stem and crown volume of each tree were then derived from diameter using allometric equations developed in an independent study. Additional canopy attributes (foliage and crown cover, crown porosity, leaf area index) were derived in each plot from 12-20 optical images collected using digital cover photography (DCP).The collected data allows characterizing the assessment of structure of these plantations, along with their variation over the rotation time. Canopy and crown data also enable the evaluation of optimal rotation and tree spacing, as well as the relationship between stand and canopy structure.The raw datasets consist of 2,591 records (trees) associated with inventory measurements and 616 records (images) associated with optical canopy measurements. An R code was also provided to calculate plot-level attributes from raw data.Dataset and associated metadata are freely available at http://dx.doi.org/10.17632/ycr7w5pvkt.1

The GIS database of WOODnat project for the inventory and monitoring of walnut plantations in Italy and Spain

Within the activity of the H2020 ‘WOODnat’ project (“Second generation of planted hardwood forests in the European Union”) the growth parameters, yield and sanitary conditions of the most important walnut (Juglans spp.) plantations, established in Italy in the 1990s and in Spain starting from 1996, were recorded. One of the objectives of the project was to evaluate tree growth and stem quality to derive insight on the main environmental factors affecting the production of this valuable specie. An inventory of walnut plantations in the area of interest was necessary due to the relevance of this tree species in the EU timber market. In this paper the final dataset is presented and available with DOI: 10.5281/zenodo.3769940. The database is finalized to narrow the knowledge gap between growers and processing industry with the aim to relaunching the market for this valuable species. Data were collected in the spring 2017 and winter 2017-2018 on 27 stands established in Northern Italy (Piemonte and Lombardia), on 51 stands in Central Italy (Toscana and Marche) and on 17 stands in Spain for a total of 95 plantations. In each plantation, general information was collected such as the planting layout, spacing, age, environment conditions as well as tree-level dendrometric data and phytosanitary information. The sampled stands have been georeferenced in WGS84 reference system (EPSG 4326). These data can be exploited to assess potential wood volume obtainable and quality of raw material, and to identify the weaknesses and errors, strengths and opportunities of the experiences conducted to plan future plantings with greater awareness

The walnut plantations (Juglans spp.) in Italy and Spain: main factors affecting growth

Walnut tree species (Juglans spp.) are commonly used for high-quality wood production in plantation forestry. In this paper, the most relevant walnut plantations in Italy and Spain have been reviewed and analysed under a geographic and technician management point of view. Between 2016 and 2019 a total of 96 plantations (15 - 25 years old) were visited distributed in the North-western part of the Mediterranean basin. A statistical analysis (linear model no interaction and PCA) was then performed to evaluate the relative importance of some environmental and management variables for walnut trees in analysed plantations. Results highlighted a variable situation with many different adopted planting schemes across the regions as well as a not standardised spatial layout and management type (thinning). Lower densities and smaller trees were adopted in Italy with about 200 trees ha-1 versus 330 trees ha-1 in Spain. In addition to the age of the plantation as one of the most influencing parameters also the plantation density and the average crown diameter were highly statistically significant. Overall, the interesting potentiality of walnut for timber production with active management in suitable areas was detected as the focal point for a successful timber production from walnut trees

Evaluation of the expression level of the endogenous marker poUBI gene for studies on transgene stability in bar and StSy GM poplars

This work reports on the isolation and molecular characterization of the poUBI cDNA encoding polyubiquitin from white poplar (Populus alba L. cv ‘Villafranca’). Expression analysis was performed on different poplar organs and tissues, at different developmental stages and in relation to the growth/dormancy cycle. Information concerning the steady-state level of poUBI transcripts in planta are required to better evaluate the possible use of this gene as endogenous marker for studies on long-term transgene stability in genetically modified white poplars

The Environmental Impact of Poplar Stand Management: A Life Cycle Assessment Study of Different Scenarios

The circular economy will play an important role in the reduction of carbon emissions and poplar might be one of the winning choices according to sustainable development. As for agricultural crops, high-quality production is strictly related to genetic variability and best management practice. The main objective of this study was to analyze different stand management options to quantify differences on carbon emission and environmental impacts. Moreover, the study was focused on the assessment of differences between standard poplar management for veneer and poplar management according to sustainable production (such as the PEFC certification scheme). The system boundaries embraced fertilization (inorganic or organic), agricultural operations, machinery, and field emissions associated with poplar cultivation. The environmental impacts were quantified by a life cycle assessment (LCA) calculation using SIMAPRO software v8.0 with different databases. The primary data of poplar stands were collected during a decades-long Italian experience. A reduction of carbon emissions was observed in the stand managed with MSA clones (Case “Mezzi PEFC”), and negative emissions were observed due to organic fertilization (scenarios 7m-29 t CO2-eq ha−1 and 26M-129 t CO2-eq ha−1). In all cultivation scenarios, the environmental impacts were lower than conventional crops in the study area, such as corn. A higher impact was observed in the 26M scenario with oversized machinery for stand management. These data can also contribute to poplar stand modeling and represent a basis for future research developments in this field

Nondestructive tree stem and crown volume allometry in hybrid poplar plantations derived from terrestrial laser scanning

Accurate and frequently updated tree volume estimates are required for poplar plantations, which are characterized by fast growth rate and short rotation. In this study, we tested the potential of terrestrial laser scanning (TLS) as a reliable method for developing nondestructive tree volume allometries in poplar plantations. The trial was conducted in Italy, where 4- to 10-year-old hybrid plantations were sampled to develop tree crown volume allometry in leaf-on conditions, tree stem volume, and height-diameter allometries in leaf-off conditions. We tested one-entry models based on diameter and two-entry models based on both diameter and height. Model performance was assessed by residual analysis. Results indicate that TLS can provide accurate models of tree stem and crown volume, with percentage of root-mean-square error of about 20 percent and 15 percent, respectively. The inclusion of height does not bring relevant improvement in the models, so that only diameter can be used to predict tree stem and crown volume. The TLS-measured stem volume estimates agreed with an available formula derived from harvesting. We concluded that TLS is a reliable method for developing nondestructive volume allometries in poplar plantations and holds great potential to enhance conventional tree inventory and monitoring