No abstract

Aim of the study: To present a new spatiotemporal model for Pinus pinea L. annual cone production with validity for Spanish Northen Plateau and Central Range regions. The new model aims to deal with detected deficiencies in previous models: temporal shortage, overestimation of cone production on recent years, incompatibility with data from National Forest Inventory, difficulty for upscaling and ignorance of the inhibitory process due to resource depletion.Area of study: Spanish Northern Plateau and Central Range regions, covering an area where stone pine occupies more than 90,000 ha.Material and methods: Fitting data set include 190 plots and more than 1000 trees were cone production has been annually collected from 1996 to 2014. Models were fitted independently for each region, by means of zero-inflated log normal techniques. Validation of the models was carried out over the annual series of cone production at forest scale.Results: The spatial and temporal factors influencing cone production are similar in both regions, thus the main regional differences in cone yield are related with differences in the phenological timing, the intensity of the influent factors and forest intrinsic conditions. A significant inhibition of floral induction by resource depletion was detected and included into the model. Upscaling the model results in accurate prediction at forest scale.Research highlights:[1] The new model for annual cone production surpass the detected deficiencies of previous models, accurately predicting recent decay in cone production; [2] Regional differences in cone production are due to phenological and seasonal climatic differences rather than to between provenances genetic differences.

Cones of the Mediterranean stone pine (Pinus pinea L.) constitute one of the most relevant non-wood forest products collected in the Mediterranean forests, providing high value edible kernels. In the last years it has been observed a severe decline in the kernel-per-cone yield (kg of kernels obtained from a kg of fresh cones) through the whole area of the species. This decline has been associated with both ongoing climate change and the recent expansion over the Mediterranean Basin of the Western Conifer Seed Bug, Leptoglossus occidentalis Heideman, an exotic pest which predates seeds of conifer species. In the present work we aimed to confirm and quantify the impact of this recent decline on pine nut and kernel production, identify the main factors provoking this reduction, and give evidence over causality by a potential biotic agent. We analysed recent and historical series of pine nut and kernel production obtained in the four main regions where Pinus pinea occurs in Spain. Our results showed a significant drop in the final kernel-per-cone yield on three of the four regions analysed, reaching reductions over 50% in the most affected areas. We observed that this reduction is mainly associated with a significant and generalised drop in the kernel-per-nut yield (kg of kernels per kg of pine nuts in shell), triggered by an increment in the rate of damaged pine nuts and, to a lesser extent, a reduction in the number of pine nuts per cone. The prevalence of this reduction on kernel-per-cone yield over different years and provenances with contrasting climate reinforces the hypothesis of the implication of a biotic factor which can be aggravated on extreme drought years.

An extensive characterisation of Spanish laricio pine, Subsp. Salzmannii (Pinus nigra Arn. Subsp. Salzmannii) lumber has been carried out. The forest area for this species accounts for 352.954 Has and the average production for 310.000 m3/year (roundwood with bark). The study of technological characterisation of Pinus nigra Arn. Subsp. Salzmannii lumber is focussed only on three (Region 6 «Alto Maestrazgo», Region 7 «Sistema Ibérico Meridional» y Region 8 «Cordilleras Béticas») of the ten Regions of provenance that the species has in Spain due to the special interest of those forests and because they accounts for the 70,57 % of the total area and the 95 % of the total production of sawnwood. A test sample with 107 trees from 11 different sampling zones has been selected. 2886 boards, 500 disks and a very high number of small clear test samples, coming from 507 logs, has been prepared and tested. All the tests were carried out according to standards. Drying ability and quality have also been studied. This lumber seems to be highly resistant, with a high level of extractives and with a pronounced level of warp when drying. This lumber also seems to be very appropriated for structural purposes.

On a 776 boards sample of Pinus nigra 150 X 50 X 3.000 mm size, coming from felled trees in Jaen (Spain) a comparison of results is made using two different standards of visual strength grading, the German DIN 4074, usually employed within Europe, and the recent Spanish UNE 56544. Graded the same batch of timber by means of both standards, the yields and the physico-mechanical properties of every grade are calculated. The physico-mechanical properties of timber (density, bending strength and modulus of elasticity) are studied by testing according to the methodology included in the European standard EN 408, calculating the results according to the standard EN 384 and assigning the strength classes according to EN 338. The results lead to the conclusion that the use of the Spanish standard produces almost the same results than the use of the German standard, not only as far as the yields are concerned but also regarding the physico-mechanical properties of timber. In this way a second conclusion is reached, the Spanish standard follows criteria and produces results commonly accepted by the market.