Effects of thinning and canopy type on growth dynamics of Pinus sylvestris: Inter-annual variations and intra-annual interactions with microclimate

We assessed the effects of thinning (0, 20 and 30 % extraction of basal area) and canopy type (pine-beech vs. pine plots, beech accounting for 12 % of total basal area) on radial growth of dominant and codominant Scots pine at inter-annual scale and on microclimatic conditions, radial growth and xylogenesis 9 years after thinning at intra-annual scale. Thinning weakly affected pine growth, which was enhanced 3 years after harvesting. Over time, a gradual reduction in pine growth in mixed canopy relative to pure canopy occurred only in unthinned plots apparently due to beech expansion. Indeed, 9 years after thinning, a higher seasonal radial increment and a greater number of tracheids were produced under pine canopy in the unthinned plots, whereas no differences between canopy types were observed in the thinned plots. Radial increment and tracheid production were mainly affected by tree water status (air and soil humidity, throughfall). The differences of tree water status caused by treatments, and plausibly disparities in tree size and tree-to-tree competition, were the main drivers explaining the patterns observed for radial increment and xylogenesis. Our results suggest that the negative effects of beech competition on Scots pine growth in similar mixed forest may be controlled to some extent by thinning. © 2012 Springer-Verlag Berlin Heidelberg.We thank the GLOBIMED thematic network for making possible the collaboration between the ARAID-IPE and the ‘‘UPNA Ecology & Environment Research Group.’’ The ‘‘Departamento de Medio Ambiente’’ of the Government of Navarre for the experimental setting of silvicultural treatments and, in particular, Fernando Puertas, Carmen Traver and Ana Iriarte and the ‘‘Concejo’’ of Aspurz for permitting the access to the plots. The research has been carried out in the framework of the AGL2006-08288 project (‘‘Ministerio de Economı´ a y Competitividad’’ of the Spanish Government). I. Primicia was financially supported by the FPI program from the ‘‘Ministerio de Economıa y Competitividad’’ of the Spanish Government and the European Social Fund (ESF). J. J. Camarero thanks the support of ARAID. We also thank the two anonymous reviewers for their comments.Peer Reviewe

Mushroom productivity trends in relation to tree growth and climate across different European forest biomes

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Response to the interaction of thinning and pruning of pine species in Mediterranean mountains

Pruning allows knot-free timber to be obtained, thereby increasing the value of the highest-value wood products. However, the effect of pruning on growth is under discussion, and knowledge about the tree response to the simultaneous development of thinning and pruning is scarce. The objective of this study was to analyze the effect of the interaction of thinning and pruning on tree and stand level and the annual radial growth of two pine species native to Mediterranean mountains. We used long-term data of three trials installed in pine stands where several combinations of pruning and thinning were developed. Five inventories were carried out for each trial, and the mean dasometric features of the different treatments were compared using linear mixed models including a competition index. In addition, we collected cores from ten trees per plot in order to evaluate the annual response of trees to the thinning and pruning. We analyzed the annual radial growth using a semiparametric approach through a smooth penalized spline including rainfall and temperature covariates. Pruning did not show any effect on growth. However, larger diameter and increased annual radial growth were found in thinned plots, both with and without pruning, as compared to unthinned plots. Also, we found significant effects of climate on annual radial growth. We recommend the application of thinning and pruning in stands of Mediterranean mountains in order to get knot-free timber since growth reduction was not found in thinned stands. © 2014 Springer-Verlag Berlin Heidelberg