An increased frequency of fire events on the Slovenian Karst is in line with future climate-change scenarios for drought-prone environments worldwide. It is therefore of the utmost importance to better understand tree-fire-climate interactions for predicting the impact of changing environment on tree functioning. To this purpose, we studied the post-fire effects on leaf development, leaf carbon isotope composition (%13C), radial growth patterns and the xylem and phloem anatomy in undamaged (H-trees) and fire-damaged trees (F-trees) of Q. pubescens with good re-sprouting ability in spring 2017, the growing season after a rangeland fire in August 2016. We found that the fully developed canopy of F-trees reached only half of the LAI values measured in H-trees. Throughout the season, F-trees were characterised by higher water potential and stomatal conductivity and achieved higher photosynthetic rates compared to unburnt H-trees. The foliage of F-trees had more negative %13C values than those of H-trees. This reflects that F-trees less frequently meet stomatal limitations due to reduced transpirational area and more favourable leaf-to-root ratio. In addition, the growth of leaves in F-trees relied more on the recent photosynthates than on reserves due to the fire disturbed starch accumulation in the previous season. Cambial production stopped 3 weeks later in F-trees, resulting in 60% and 22% wider xylem and phloem increments, respectively. A novel approach by including phloem...
COBISS.SI-ID: 5648294
In this work, the carbon exchange between the ecosystem and the atmosphere was determined using the eddy covariance micrometeorological method for the case of extensively used karst pasture. The estimated carbon flux was partitioned into gross primary production and ecosystem respiration. In parallel, we obtained LANDSAT and Proba-V satellite images of wider area in cosideration for a number of consecutive years and calculated several vegetation indices. We tried to predict the time course of carbon fluxes on the basis of these vegetation indices, taking into account different vapor pressure deficit periods and different types of eddy covariance-data aggregation (daily averages, midday averages). The results showed that air aridity was an important factor in determining the success of carbon flux prediction based on vegetation indices. In the period of adequate humidity for plant growth, the relatively simple NDVI index was appropriate, whereas in the drought period other, more specific indices were best.
COBISS.SI-ID: 5360038