We develop our activity in the following research lines:
Material selection: Adaptation to the environment
There is a great variety of genetic material available for planting. Among the species tested to produce biomass, Populus spp. (poplars) has shown higher production and better adaptation to the site. The response of the different species and / or hybrids of the genus are not, however, homogeneous.
The analysis of the interaction with the environment identifies those clones of 'wide adaptation', not necessarily the most productive, that grow well in a wide range of soils and climates compared to the more 'site-specific', which require more particular conditions of soil and climate to maximize its production. Hybrids like 'Orion' or 'AF2' are postulated as site specific while 'I-214' or 'Monviso' are well suited to a wide variety of scenarios.
In general, euramerican hybrids improve their response with latitude and higher mean temperature, worsening their response in soils with high percentages of sand. The opposite is true for interamerican hybrids.
Knowing this interaction is essential to ensure sustainable production and facilitate clonal recommendation.
In addition, under certain stress conditions (salinity and drought), adapted autochthonous genotypes (Populus alba L.) have been identified with acceptable productive response.
Modeling: Predicting Production
The referred productive variability complicates biomass estimates through predictive models. In management systems oriented towards biomass production, in which the tree is harvested a certain number of times and sprouts again, the difference in the age of stems and roots is identified as a key factor that influences the allometry of the tree, and especially the year after resprouting.
It has been identified that the minimum sample size in these production models should be 50 trees. Including the variable of number of shoots per stool significantly improves the reliability of the model compared to considering only the diameter value. In the latter case, the variable would explain 87% of the variability.
General models have been developed (for the set of genotypes) as well as at the level of taxonomic group and individual genotype, the latter being the ones with which the greatest precision is achieved. General models or models by genetic proximity are not the most advisable since the similarities in terms of biomass allometry have not been explained in terms of genetic origin.
In addition, a management diagram has been implemented for the 1st rotation that facilitates management and decision-making, allowing the comparison of different situations, both with regard to planting density and in relation to the ideal time for cutting.
Currently, work is being done on the acquisition of parameters for the development of a specific model based on ecophysiological processes.
Plantation management: Improving sustainability
Management must seek to optimize production in a sustainable way. Exploring increasing diversity by including more than one species, minimizing water use or restricting fertilization are some of our interests.
The poplar-robinia mixed stands do not seem to improve production, although they do represent an advantage in terms of the management strategy of the main macronutrients.
On the other hand, determining the efficiency in the use of water of the materials under different scenarios of water regimes contributes to improving the choice of these when planting. The 'AF2' or 'Monviso' genotypes showed high efficiency and the highest productivity under conditions of water restriction.
Environmental services: Beyond wood
Forestry crops provide services of a very diverse nature. However, these services must be identified and quantified in order to consider their economic and social impact.
In short rotation plantations, the C accumulated in the aerial woody biomass was 7.74 Mg ha-1 year-1. The leaves contributed 2.56 Mg ha-1 year-1, and the root systems with 1 Mg ha-1 year-1, the latter remaining in the soil regardless of the use of woody biomass
The nutrients that return to the soil through leaf-litter in P. alba are around 65% for N, 70% for P and 35% for K, which represents a relevant contribution compared to agricultural crops that are developed in the same grounds.
And something else? Trees to solve environmental problems: Phytotechnologies
The cultivation of poplar, either in densities suitable for wood or for biomass production, are an effective tool to solve different environmental problems. The treatment of wastewater derived from the agri-food industry, and specifically those derived from beer production can be carried out by means of the soil-vegetation complex, at the same time that biomass is obtained without the need to apply clean water. This is an opportunity for the circular bioeconomy.
To this end, native poplar genotypes and productive hybrids are being characterized, as well as of willow genotypes that may represent a nature-based solution.