Water and nutrient relationships for Pinus pinea modelling in Portugal: PINEA Project

Portugal is at the moment the country with the second largest area of stone pine (Pinus pinea), after Spain. It has 83,900 ha; the Iberian Peninsula accounts, approximately for 75% of stone pine distribution. Since 1995 this was the tree species with the highest rate of area increase in Portugal. Its recent large expansion t is mainly due to its adaptability to dry environments and the high value of its edible kernels, the “pine nuts”. Due to its favorable site and climate conditions Portugal has, on average, higher cone yields per unit  area than Spain. In addition, there is an increasing interest in Pinus pinea for afforestation in areas of Pinus pinaster highly affected by the pine wilt nematode.

Although there has been already empirical modelling work done  on Pinus pinea in relation to growth and cone yields, there is no process-based model calibrated or validated for this species. This is an important fact for two main reasons: (i) there is no way to predict  the likely effects of climate change on Pinus pinea productivity; (ii) although there is considerable interest in new plantings there is no tool to support decision-making on the selection of areas of interest for Pinus pinea.

The main objectives of the PINEA Project are:
(i) the calibration and validation of a process based model for Pinus pinea in Portugal. This model will allow estimation of the productivity of existing stone pine plantations in the context of climate change, considering different climate scenarios, and will provide a tool to support decision-making regarding new plantings;
(ii) evaluation of the effects of water and nutrient availability on Pinus pinea growth and cone yields;
(iii) to improve existing empirical modeling equations relating to growth and cone yield of Pinus pinea.

The PINEA Project is expected to carry out nine planned Tasks. The Project will use existing Pinus pinea data, including data from permanent sample plots, previous biomass trials, and an established fertilization trial. A new irrigation and fertilization trial, from which data will be collected, will be established. New data will also be collected in the existing permanent sample plots and fertilization trial. All these data will be validated and organized in databases. Following database development the data will be analyzed in different ways, bearing in mind that one of the major objectives is to develop a process based model calibrated for Pinus pinea.
 
A major challenge in relation to calibrating and validating a process-based model for Pinus pinea is that the one of the main products of interest is cone yield. This will require an innovative approach, to include carbohydrate allocation to cone/fruit biomass in a process-based model such as 3-PG. Data obtained from the irrigation and fertilization trial will be important in providing the information necessary to evaluate how Pinus pinea allocates carbon to the pine cones.

The fertilization and irrigation trial will provide an understanding about how water and nutrient availability influences cone yield, root biomass, leaf biomass and stem biomass. This experiment will  impose a range of conditions wider than the range likely to occur naturally. This allows the researchers to assess the responses of the trees to conditions that might not normally be encountered. This is called ‘filling the variable space’. It allows the factors that limit growth to be assessed without the, sometimes confounding, interactions that may result from water shortages. Irrigation to eliminate water stress in some treatments also allows the response functions of various processes to be determined (are they linear or non-linear?) and provides information essential for the parameterization and testing of process-based models, It would be important to impose irrigation treatments on this experiment whether or not widespread commercial irrigation of stone pine is likely in Portugal. The resulting model should allow evaluation of the potential growth and productivity of the pines in any area and it will be able to make predictions under different climate change scenarios.

The PINEA Project team includes the most active researchers in forest modelling in Portugal. The consultants for this project will provide strong scientific input that will contribute to the success of this research project. In tree physiology and process-based modelling Dr Joe Landsberg will be bring internationally recognized scientific knowledge. Equally in silviculture Dr Peter Savill has an extensive and impressive record of research work. Dr Rafael Calama is one of the current leading modelers working on Pinus pinea. Finally Maria Augusta Vacas de Carvalho is known in the Portuguese forestry sector of Portugal as one of the most knowledgeable people in the management of Portuguese Pinus pinea stands.

Disclaimer

PINEA Project is still only a project proposal waiting for financial support. We are thankful for all the email messages we have been receiving from many countries regarding Pinus pinea research and management. As PINEA Project is not yet running we might not be able to reply to all messages immediately. All the contacts we have been receiving show the great interest that there is in the Pinus pinea species. Thank you very much!