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An investigation into the suitability of Paulownia as an agroforestry species for UK & NW European farming systems

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The combined impacts of climate change, soil erosion, deforestation, pollution, population growth and resource depletion require urgent attention in instituting regenerative agricultural practices worldwide. This is particularly the case in NW Europe where the current farming paradigm is becoming obsolete due to pressures from many fronts. A new way forward has become necessary using agroecology wherein agroforestry is a key component. Paulownia species are indigenous to China and have been used as an agroforestry tree for over 2600 years due to their many positive attributes and multifaceted uses. Over the last four decades, the use of Paulownia intercropping systems have been established on up to three million hectares on the North China Plain and the species has been introduced as a plantation crop on all inhabited continents being one of fastest growing hardwood species in the world with up to six meters growth per year possible under optimal conditions. Paulownia, in particular P. tomentosa has been planted as an ornamental tree in NW Europe since the early 1800s but has not been considered as a possible commercial species in the region until the last few years. This study set out to explore whether Paulownia species could be suitable as an agroforestry species in intercropping systems on a field scale in NW Europe using methods consisting of literature review, secondary data analysis, and interviews with experts and growers. Furthermore, two case studies were carried out from existing commercial operations growing Paulownia in the focus area. Specific areas covered to assess suitability included a review of species and cultivars, ecological requirements, planting and growing techniques, invasiveness risk and market research into the timber product based on data from EU and abroad. In addition to the species assessment, a review was carried out identifying the main barriers to the adoption of agroforestry in NW Europe as part of a broader overview and analysing how Paulownia species could possibly have added advantages in overcoming some of these barriers. The results indicated that Paulownia species and hybrids could grow successfully as a commercial agroforestry crop in NW Europe based on data gathered from existing sites in the focus area established since 2009 where high survival rates and growth rates greater than 1 m per year were reported. No particular species or hybrid was identified as most suitable for agroforestry in the focus area but differences were confirmed depending on country of origin and propagation method. It was confirmed that species/hybrid selection, propagation method, site establishment, management practices in maintenance and pruning are critical factors to take into account in order to achieve timber of high quality. Invasiveness risk in NW Europe is assessed to be very low due to low summer temperatures and the use of sterile hybrid clones in agroforestry rather than P. tomentosa. Research showed that there is presently no established market in NW Europe for the timber but that interest in the unique properties of the wood is increasing in EU and the potential exists for profitable niche market in the future in particular for slow grown wood to be sold either in Europe or overseas. The study concludes that Paulownia species’ actual performance under local field conditions, adaptability and its diverse products and services fulfil most of the attributes of an ideal agroforestry tree and has the potential to be used more widely in NW European farming systems with the recommendation that further field trials be carried out into finding the most suitable species/hybrids in addition to increased dissemination of knowledge to farmers about the species.
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... The most commonly cultivated species are P. tomentosa, P. elongata, P. fortunei, P. taiwaniana, P. fargesii, P. galbrata and P. catalpifolia [15,37]. In the early introduction of paulownias worldwide, pure botanical species were used. ...
... Some of the best-known hybrids are the clones in vitro 112 [10,19,46], Cotevisa 2, Sundsu 11 [47] and Shan Tong [48,49]. Examples of less well-known hybrids include Arctic [37] and the selected genotypes PWCOT-2, PW-105, PWL-1, PWST-33 and PWST-11 [50]. There are also naturally occurring hybrids, such as P. taiwaniana from a cross between P. kawakamii and P. fortunei [51,52]. ...
Article
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This review aimed to determine the current state of research on the growth conditions and use pertaining to paulownia wood, mainly in European countries where paulownia has been introduced only relatively recently. Several studies carried out on Paulownia hybrids have shown significant differences in the growth dynamics of individual clones in their response to local environmental and climatic conditions. For example, dry biomass production yields in the second year of cultivation range from 1.5 t ha−1 to as much as 14 t ha−1. This diversity has manifested itself not only in growth characteristics but also in the properties of the wood and the possibilities for its use. Despite having clear similarities to the genus Paulownia, the cultivation of species and hybrids under different conditions has produced varying results. The best growing conditions for this wood (that make economic sense) are in the Middle East and Southern Europe. These regions have accumulated the most experience because of the earlier establishment of the crop. Today, paulownia cultivation is dominated by hybrids with selected traits that are propagated mainly in vitro. The most commonly planted hybrids include the clones in vitro 112, Cotevisa 2 and Shan Tong. The growth results and production capacity in central European countries are lower compared to Southern Europe. Experiments on paulownia cultivation are still relatively young, mainly consisting of replicating the cultivation of hybrids developed in Asia or Southern Europe. However, agronomic procedures are being developed and reactions to local climatic conditions are being studied. It is likely that, in the next few years, the profitability of growing paulownia in these regions will become apparent.
... Of Asian origin, Paulownia is a fast-growing deciduous tree, with at least nine subspecies [1]. In Europe, in the last decade, is growing interest on Paulownia as regards tree cultivation and agro-forestry plantations for industrial use [2]. Paulownia was also introduced in North America, Australia and Japan [3], and is cultivated worldwide in more than 40 countries [4]. ...
Article
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The aim of this research is the characterization of physical and mechanical properties of Paulownia sawn wood from three plantation sites in Europe, namely Spain, Bulgaria and Serbia. As a fast-growing wood species, Paulownia has a significant positive forecast for the European markets and a wide range of possible applications that still need to be explored. For this purpose, Paulownia tomentosa(Tunb.) x elongata(S.Y. Hu) wood species was investigated. Sorption behaviour, Brinell hardness, 3-point bending strength, flexural modulus of elasticity, tensile strength, compressive strength and screw withdrawal resistance were examined in detail. The samples from Spain have the higher average bulk density (266 kg/m3), 3-point flexural strength (~40 N/mm2), 3-point flexural modulus of elasticity (~4900 N/mm2), compressive strength (~23 N/mm2), tensile strength (~44 N/mm2) and screw withdrawal resistance (~56 N/mm). The plantation wood from Bulgaria has the highest average of annual ring width (46 mm). Paulownia wood has potential in lightweight applications and can replace successfully expensive tropical species as Balsa.
... Milde vintre og høje sommertemperaturer vurderes generelt afgørende for dyrkningssucces. Observationer fra England og Irland har også indikeret, at for lave sommertemperaturer kan vaere årsag til manglende trivsel og tilvaekst (Jensen, 2016). Vanding i etableringsårene 2016-2017 er vist i Polske forsøg med Shan Tong hybrid planter at fremme både etablering og tilvaekst vaesentligt (Langowski et al., 2019). ...
... Within these systems, the objective is to utilize the same land in multiple ways, obtain food and feed products simultaneously or consecutively, increase the yield from the land, improve the socioeconomic conditions, control illegal logging, and reduce erosion (Turna et al., 2014). These systems are applied as agrisilviculture (agriculture + forestry), silvopastoral (forestry + livestock), agrosilvopastoral (agrisilviculture + silvopastoral), and the production of multipurpose trees (King, 1979;Jensen, 2016). Among these, the leaves of these multipurpose trees are used as fresh and green grass for ruminants during seasonal transitions and when roughage production is insufficient. ...
Article
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ABSTRACT The study aimed to evaluate the potential use of dried or ensiled paulownia (Paulownia spp.) leaves as roughage source for ruminants. Paulownia tree leaves were collected from one-year-old hybrid (C-125, CAR, and TF-33 clones) trees. Dried paulownia leaves of the clones were different in dry matter (DM), crude ash (CA), crude protein (CP), ether extract (EE), crude fiber (CF), and nitrogen-free extract (NfE) and similar in neutral detergent fiber (NDF), acid detergent fiber (ADF), and acid detergent lignin (ADL); however, these values (except EE and ADL) of ensiled leaves were significantly different among the clones. Mean CP, CA, and condensed tannin contents in dried leaves were 15.36, 9.21, and 1.75%, respectively; NDF, ADF, and ADL contents were 38.35, 35.49, and 12.08%, respectively. Mean total volatile fatty acids, in vitro organic matter digestibility (IVOMD), and metabolizable energy (ME) value in dried leaves were 95.26 mmol/L, 76.34%, and 10.77 MJ/kg, respectively, whereas, CO2 and CH4 production were 54.66 and 29.78 mmol/L, respectively. Buffering capacity and water-soluble carbohydrates varied among the pre-ensiled paulownia leaves, although their means were 395.66 mEq/kg DM and 86.63 g/kg DM, respectively. In ensiled leaves, the pH, lactic acid ratio, and acetic acid ratio were 4.98, 11.23, and 2.56%, respectively, and butyric acid was not detected in any of the silages. Mean values of IVOMD and ME in ensiled leaves were 72.30% and 9.93 MJ/kg, respectively. Dried paulownia leaves are a high-quality alternative forage and the ensiled form is of medium quality. Therefore, paulownia leaves could be used as an alternative roughage source for ruminants.
... Paulownia, in particular P. tomentosa, has been planted as an ornamental tree in NW Europe since the early 1800's, but has not been considered as a possible commercial species in the region until the last few years. The results of the studies, based on the data gathered from the existing sites, presented by Jensen [3], indicate that Paulownia species and the hybrids could grow successfully as a commercial agroforestry crop in north-western Europe. Paulownia can be propagated by seeds, roots or stem cuttings. ...
... Paulownia, in particular P. tomentosa, has been planted as an ornamental tree in NW Europe since the early 1800`s but has not been considered as a possible commercial species in the region until the last few years. The results of studies, based on data gathered from existing sites, presented by Jensen (2016), indicates that Paulownia species and the hybrids could grow successfully as a commercial agroforestry crop in north-western Europe. Paulownia can be propagated by seeds, roots or stem cuttings. ...
Conference Paper
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The field experiment was carried out in 2016 on sandy soil in the forest nursery Białe-Błota (Bydgoszcz Forest Division, Poland). The effect of sprinkler irrigation on the growth Paulownia Shan Tong trees was investigated. The experiment was established as one factorial. The variability factor was the irrigation: S-sprinkler irrigation and C- without irrigation (control). The process included the controls of growth parameters: tree height, trunk diameter, number and surface of leaves. It was found that the sprinkled seedlings of Paulownia Shan Tong were significantly higher than those growing in the non-irrigated plots. The sprinkler irrigation applied in the experiment resulted in an increase in the number of leaves of the Paulownia and their surface area, which resulted in an increase in biomass yield. By analysing the results of the study on trunk diameter, leaf number and surface, it may be stated that irrigation watering significantly influenced the tested parameters. Irrigation significantly increased the height of Paulownia trees. The positive effect of the usage of sprinkler irrigation may indicate the possibility of effective application of this method in the field cultivation of Paulownia Shan Tong.
Article
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Short-rotation plantations for wood biomass production are systems in which different, fast-growing forest species are grown in intensive agricultural technologies to achieve high biomass yields. The genus paulownia comprises very fast-growing tree species, mainly used in biomass production for energy purposes, but not only. The biomass produced by this plant is used in its entirety; as heating material, industrial, ecological and decorative wood, protection of soil erosion, phytoremediation of polluted soils, air purification, animal feed, pharmaceutical industry, melifer, etc. Among the most promising applications are the production of biopolymers and bioethanol derived from cellulose. The proper cultivation and use of paulownia species contribute to maintaining ecological balance and nature conservation. The main objective of the paper was to carry out a careful and detailed analysis of the specific scientific literature describing their main characteristics and practical applicability to the different species of the genus Paulownia. The paper also examines the importance of cultivating paulownia species under conditions of economic viability while ensuring the maintenance of biodiversity and the protection of ecosystems.
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Paulownia is a very adaptable, fast growing and multi-purpose agroforestry tree species. Paulownia and its hybrids become much more interesting globally in the last few decades, because of many uses including timber (for construction, doors, furniture, kitchens, boats etc.), intercropping (with wheat, maize, grass or other crops), CO2 and dust absorption etc. Additionally, Paulownia leaves are used for animal feed in some countries of the World, as well. According to that, this paper is dealing with the evaluation of nutritive value of Paulownia hybrid tree leaves. For determining the nutritive value of Paulownia containing dry matter (DM) 286.4 g/kg forage, crude protein 177.5 g/kg DM; neutral detergent fibre (NDF) 415.2 g/kg DM; acid detergent fibre (ADF) 372.6 g/kg DM; acid detergent lignin (ADL) 94.7 g/kg DM. In terms of the crude protein contents, this trial reported that the leaves of investigated Paulownia spp. hybrid could be used as forage for the ruminant nutrition.
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The results of two experiments to investigate the survival, early growth and chemical characteristics of six Spanish and three Moroccan genotypes of Paulownia, grown from container produced and bare root plants, respectively, are described. Both trials were planted in Northern Ireland (NI) and after three growing seasons the overall mean survival and height of the Spanish and Moroccan genotypes were 70.8% and 32.2% and 1.1 m and 2.2 m, respectively. Chemical characteristics, except for nitrogen and ash content, were similar to those reported for other biomass crops such as willow and miscanthus (Miscanthus × giganteus). Genotypes that performed well were PWST-33 (P. fortunei) from Spain and P. fortunei from Morocco. Biomass yields varied significantly (P <0.05) and were considerably lower than those reported for other fast growing species grown as energy crops. The results suggest that the potential of Paulownia as an energy crop in NI is limited due to its low performance in biomass production. The main constraints to further planting of Paulownia in this region are the edaphic and climatic conditions that pertain, which appear not to be conducive to growth of this tree species.
Technical Report
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This report (updated in August 2016) is an output from work-package 1 which aims to understand the context and extent of agroforestry in Europe. In an earlier report, den Herder et al (2015) reviewed literature sources to provide a preliminary estimate of the extent of agroforestry in Europe. That report (which collected only limited data from some countries) estimated that agroforestry extends to at least 10.6 million hectares in Europe. By contrast the CORINE land cover survey gives an “agroforestry” classification to 3.3 million ha in Europe. This is substantially less than the value reported by den Herder et al (2015) and is the result of CORINE having a very narrow definition of agroforestry. It is apparent that a more harmonized and uniform pan-European estimate is needed. In this report, the agroforestry areas of Europe were primarily mapped using LUCAS Land Use and Land Cover data. The Copernicus Land Monitoring Survey (high resolution maps with tree cover density) was also used to estimate tree cover on agricultural land in seven countries (Austria, Switzerland, Estonia, Latvia, Lithuania, Sweden and Norway). Both sets of results were compared with a review of the literature and statistical inventories. Using the LUCAS database the total area under agroforestry in the EU27 is estimated to be 15.4 million ha which is equivalent to 3.6% of the territorial area or 8.8% of the utilised agricultural area. This is a larger estimate than the 10.6 million ha reported in the literature review. Livestock agroforestry is, by far, the dominant type of agroforestry in Europe accounting for 15.1 million ha. The area of silvoarable systems is estimated to be 358 thousand ha. The above totals include the grazing and intercropping of permanent crops (e.g. fruit trees and olives) (1.05 million ha) comprising 0.85 million ha of grazed systems and 0.22 million ha of intercropped systems. A hot spot analysis revealed that a high abundance of areas under agroforestry can be found in south, central and north-east Portugal, south-west, central and parts of north Spain, south of France, Sardinia, south Italy, central and north-east Greece, central and west Bulgaria, and an area in northern Romania. LUCAS data were also used to estimate the extent of single trees and green linear elements such as hedgerows. Agroforestry involving single trees covers almost 300 thousand hectares corresponding to around 0.02% of the territorial area in the EU, with high values in France, Spain, the UK, and Italy. Agroforestry involving hedgerows cover about 1.78 million hectares representing around 0.42% of the territorial area in the EU, with large values in France, the UK, and Italy. The higher estimate for the agroforestry area using the LUCAS data (15.4 million ha) than the literature review (10.6 million ha) can be partly explained by the inclusion of Bulgaria (+0.87 million ha) and higher estimates for Spain (+1.74 million ha), France (+1.05 million ha), Romania (+0.71 million ha), Italy (+0.44 million ha), the UK (+0.39 million ha), and Sweden (+0.37 million ha); there were lower estimates for Greece (-0.67 million ha) and Portugal (-0.48 million ha). When the LUCAS estimates were compared with national inventories, the LUCAS-based estimate of 5.58 million ha of agroforestry in Spain was within 10% of a national inventory value of 6.14 million ha. However the LUCAS estimate for Portugal (1.17 million ha) was 22% lower than an estimate based on national inventories. Although there may still be some systematic errors, because the LUCAS data were collected and analysed in a uniform manner, it provides a method to compare agroforestry areas between countries and regions. It can highlight where agroforestry is currently practiced and where there are opportunities. Considering the fact that agroforestry covers about 9% of the utilised agricultural area of the EU, agroforestry deserves a more prominent place on policy agendas.
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A greenhouse experiment was done with vegetatively propagated trees to examine the influence of swine lagoon effluent on the growth and foliar nutrient content of the fast-growing hardwood species Paulownia elongata. Application of swine lagoon effluent promoted plant growth and was as beneficial as a complete chemical fertilizer applied at a similar nitrogen loading rate. Foliar concentrations of nitrogen were high, typically between 3.5% and 4.5%, when swine lagoon effluent was applied at a nitrogen loading rate equivalent to 205 or 409 kg/ha. Zinc and copper concentrations were also relatively high when plants received these swine lagoon effluent treatments (45 to 55 ppm and 17 to 23 ppm, respectively). Sufficient variation among P. elongata clones was revealed for growth parameters and foliar nutrient concentrations to anticipate a benefit from the selection of genotypes that are the most efficient for remediation of animal waste, i.e., high biomass production and foliar nutrient accumulation. The data show that P. elongata has potential for use as a swine waste utilization species.
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The work reports about the establishment and the development after two years of a Paulownia tree plantation in a large and homogeneous agricultural area, representative as a test site for climate, soil and land use characters of the countryside of Oristano, central Sardinia, Italy. The first results showed that the role assigned to Paulownia trees can be a beneficial system leading to a low carbon and high biomass productive agriculture in short time.
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