Little is known about the interactions between the variables involved in the post-fire response of Mediterranean pine species to prescribed burning (PB). Thus, it is essential to develop an empirical model in order to assess the influence of tree and stand attributes, burn season, and fire severity on the probability of stem cambium damage occurring. Prescribed burnings were conducted in different seasons and areas covering a wide climatic and ecological range. Potential explanatory variables were measured. A random effects hurdle model framework was used to evaluate the temperature duration above 60 °C as a proxy for stem cambium damage at tree scale. The results showed significant differences in cambium damage between the PB seasons. Pinus nigra was more resistant than other pine species. Bark thickness was critical for protecting cambium. Volume of crown scorch, percentage of stem scorch, and maximum outer bark temperature were directly related to temperature duration above 60 °C in the cambium. Prescribed burning conducted under tree canopy in Mediterranean pine species generally results in a low level of cambium damage. Empirical models could help managers to predict the effects of PB and thus select the most suitable prescriptions.

Aim of study: To evaluate the effects of two different prescribed burning strategies on ectomycorrhizal (ECM) fungal species in Pinus cubensis-dominated natural forest. Area of study: Yateras Silvicultural Base Business Unit, Guantánamo, Cuba. Material and methods: In June 2015, six plots (20 × 50 m) were subjected to forward or back burning. Nine interval samplings (performed 1 week before and up to 120 days after prescribed burning) were undertaken to determine the total number of sporocarps and to evaluate the effect of fire on the soil. Main results: Eight ECM species were collected from the study plots. Suillus sp. and Amanita muscaria started fruiting 15 and 60 days after the fire, respectively. Boletus sp., Suillus brevipes, Suillus decipiens, Suillus sp., Amanita muscaria, Lactarius semisanguifluus, Scleroderma stellatum and Pisolithus arhizus were found before and after prescribed burning. Sporocarp numbers showed an increasing trend after fire and significantly recovered 75 days after forward or back burning and were significantly higher 120 days after forward burning compared to unburned plots. The ECM fungal community in the heading fire and the backfire plots did not differ significantly. However, non-metric multidimensional scaling confirmed that ECM composition differed over time. According to a Mantel test, the sampling time after prescribed burning accounted for 64% of the variation in ECM composition, followed by edaphic factors (26%) such as organic matter and Na. Research highlights: This preliminary study suggests that low-intensity prescribed burning does not have a negative effect on ECM fungal dynamics in humid tropical forests.

Aim of study: To assess the effect of prescribed underburning (PB) and tapping on resin yields in maritime pine stands. We hypothesized that PB reduces fire hazard, generates stress at the cambium level and potentially increases the number of resin canals and resin yield after tapping. Area of study: Northern Plateau of the Iberian Peninsula, central-eastern Spain. Material and methods: Six 50 m x 50 m plots were established in a Pinus pinaster Ait. stand, three of which were burned and tapped in 2018 and three controls plots (tapped only). Resin yield was monitored in 90 trees over four years (2018-2021). A Generalised Linear Mixed Model (GLMM) for repeated measures was used to analyse resin production. Average resin yield per tree was predicted by Treatment as a fixed between-subject factor (two levels: Tapping only vs PB+Tapping) and years as within-subject factor (four levels: 2018, 2019, 2020, 2021). Plot and tree were considered random factors. Main results: The GLMM revealed the significant effect of time (years after tapping), plot and tree. However, the potential effect of meteorology (time), site (plot) and the interaction between fire and individual trees (stress that potentially increases number of resin canals) did not generally have any effect on resin yield at stand level. The resin yield was maintained in burned and tapped plots relative to the tapped only control stand. Research highlights: Prescribed underburning before tapping in order to reduce fire hazard is compatible with tapping P. pinaster stands but does not increase the resin yield.