Annals of Forest Science

In Spain, wildfires have increased during the last decades with Pinus halepensis forests being the most affected. Cone differentiation and the early flowering of this species in comparison to other native Spanish species, are traits considered as adaptations to postfire regeneration. The high recurrence of fires promotes a high increase in young and immature pine stands with low capability of regeneration. In this study, silvicultural treatments such as thinning and pruning were carried out 5 years after fire in eleven years old P. halepensis stands located in dry and semi-arid sites in SE Spain. The formation of male and female strobili, production of serotinous grey, mature brown and new green cones were recorded six years after treatments. Seed production and germination percentage were also tested. Results showed acceleration in cone and viable seed production in thinned plots, with some differences between sites being recorded. Serotinous cone production also increased as a result of this treatment.

Condensed tannins have been successfully used as substitutes for phenol in the production of resins for wood products. However, the enhancement of the properties of tannin-based resins with nontoxic and cost effective additives is of great interest. In the present work, the performance enhancement of tannin-based particleboards with cellulose nanofibers was investigated. In presence of 2 % of cellulose nanofibers, the viscosity of tannin-based adhesives and the internal bonding strength (IB) of the corresponding particleboards were increased from 350 to 5,462 mPa·s and from 0.85 to 0.98 MPa respectively. The modulus of elastic (MOE) and modulus of rupture (MOR) of the resins were also notably increased while thickness swelling (TS) of the panels was not affected. The addition of cellulose nanofibers to tannin adhesives is an effective method for the production of high performance particleboards. Tannin-based adhesive containing 2 % of cellulose nanofibers exhibits the best mechanical strength. The addition of cellulose nanofibers into tannin-based adhesives notably enhanced the mechanical properties of the wood particleboards produced. The formulation containing 2 % (w/w) of cellulose nanofibers exhibited the best mechanical strength.

The study presents novel model-based estimators for growing stock volume and its uncertainty estimation, combining a sparse sample of field plots, a sample of laser data, and wall-to-wall Landsat data. On the basis of our detailed simulation, we show that when the uncertainty of estimating mean growing stock volume on the basis of an intermediate ALS model is not accounted for, the estimated variance of the estimator can be biased by as much as a factor of three or more, depending on the sample size at the various stages of the design. This study concerns model-based inference for estimating growing stock volume in large-area forest inventories, combining wall-to-wall Landsat data, a sample of laser data, and a sparse subsample of field data. We develop and evaluate novel estimators and variance estimators for the population mean volume, taking into account the uncertainty in two model steps. Estimators and variance estimators were derived for two main methodological approaches and evaluated through Monte Carlo simulation. The first approach is known as two-stage least squares regression, where Landsat data were used to predict laser predictor variables, thus emulating the use of wall-to-wall laser data. In the second approach laser data were used to predict field-recorded volumes, which were subsequently used as response variables in modeling the relationship between Landsat and field data. ∙ The estimators and variance estimators are shown to be at least approximately unbiased. Under certain assumptions the two methods provide identical results with regard to estimators and similar results with regard to estimated variances. We show that ignoring the uncertainty due to one of the models leads to substantial underestimation of the variance, when two models are involved in the estimation procedure.

The recommendations accompanying pesticide derogations from the FSC are not efficient for the management of leaf-cutting ants and termites in certified forest plantations in Brazil compared with chemical control using insecticides. FSC recommendations ignore the biological and ecological features of pests and forest plantations in Brazil when they set global rules for forest certification.