Analysis of adaptive capacity of Croatian Mediterranean forests to

climate change by using various indicators of tree and stand vitality

Ognjenović M. 1, Seletković I. 1, Timmermann V. 2, Potočić N. 1

1 Croatian Forest Research Institute, Cvjetno naselje 41, 10450 Jastrebarsko, Republic of Croatia

2Norwegian Institute of Bioeconomy Research P.O. Box 115, NO-1431 Ĺs, Norway

Project Background

Materials & Methods

Preliminary results

Further steps

• Mediterranean forests in Croatia account for 24% of total forest area.

• Important social and ecological functions (preservation of soil, air, water and

biodiversity; carbon sequestration; impact on microclimate conditions;

aesthetic and touristic function etc.).

• Several factors have been recognized to influence tree vitality, and the

reasons for the deterioration of tree condition can be found in specific

interactions of stress factors. More in-depth knowledge about the level of

stress and adaptive capacity of forests in Croatian Mediterranean is needed to

enable predictions of their future development

Research Aims

• Determine the spatio-temporal variability in condition of forest ecosystems

through the use of various indicators of tree and stand vitality

(increment, tree mineral nutrition, crown defoliation, and taking into account

soil characteristics, elevation, inclination, stand structure and floral composition,

exposition, soil erosion risks and climate influences)

• Explore interactions between indicators of forest ecosystem condition

• Determine the current adaptive capacity of Croatian Mediterranean forests to

climate change

Plots

• UNECE-ICP Forests large-scale

(Level I) plot network, 16x16 km grid

• National forest monitoring plot

network, 4x4 km grid

Defoliation data

• Crown defoliation assessed using the

approach established by ICP Forests

(Eichhorn et al., 2016)

• Time period: 2000 - 2016

• Plots were selected for analysis if

they were assessed at least 90% of the

time period

Sampling and Analysis of Needles

and Leaves

• We sampled 5 trees for each dominant

tree species on a specific ICP Forests

Level I plot, their defoliation

corresponding to the mean plot

defoliation

•Samples were collected by tree climbing

(double rope system), extension shears or

by the use of shotgun

• Samples were analysed following

methods described in ICP Forests Manual

(Rautio et al., 2016)

REFERENCES

Eichhorn, J., Roskams, P., Ferretti, M., Mues, V., Szepesi, A., Durrant, D., 2010 Visual Assessment of Crown Condition and Damaging Agents. Manual Part IV, In: Manual on Methods and Criteria for Harmonized Sampling,

Assessment, Monitoring and Analysis of the Effects of Air Pollution on Forests. UNECE ICP Forests Programme Coordinating Centre, Hamburg. ISBN: 978-3926301-1. <http://www.icp-forests.org/Manual.htm>.

GTOS (Global Terrestrial Observing System), 2008 TCO: Terrestrial Carbon Observations: Protocols for Vegetation Sampling and Data Submission, B.E. Law, T. Arkebauer, J. L. Campbell, J.Chen, O. Sun, M. Schwartz, C. van

Ingen, S. Verma (ed.), Rome

Stefan, K., Furst, A., Hacker, R. and Bartels, U., 1997 Forest Foliar Condition in Europe results of large-scale foliar chemistry surveys. EC-UN/ECE and FBVA.

Rautio P, Fürst A, Stefan K, Raitio H, Bartels U, 2010 Sampling and Analysis of Needles and Leaves.19 pp. Manual Part XII. In: Manual on methods and criteria for harmonized sampling, assessment, monitoring and

analysis of the effects of air pollution on forests, UNECE, ICP Forests Programme Co-ordinating Centre, Hamburg. ISBN: 978-3-926301-03-1. [http://www.icpforests.org/Manual.htm]

Rautio, P. and Fürst, A. 2013 Tree Foliage. Developments in Environmental Science, 12, 223-236.

ACKNOWLEDGMENTS

This publication was financed by the Ministry of Agriculture (Republic of Croatia), from the funds of the Beneficial Forest Functions Fee. The opinions expressed here do not necessarily reflect the views of the Ministry of Agriculture.

Overall defoliation trend of most frequent tree species (red line):

• Quercus cerris (Theil/Sen slope: 0.309, p= 0.08),

• Quercus pubescens (Theil/Sen slope = 0.391, p= 0.017)

• Pinus halepensis (Theil/Sen slope = 0.523, p = 0.016)

(Annual overall mean defoliation is represented by black lines. Points represent

annual plot defoliation means.)

High Ca in all species is expected due to predominantly Ca-rich soils. Mean foliar nutrient concentrations observed across all plots (black line)

compared to element concentration classes reported by Rautio and Fürst (2013).

Results of Kruskal-Wallis rank sum tests confirm

that overall mean defoliation varies by orientation.

(Size of the wedge indicates the proportion of plots in

our database according to orientation while the color

scale shows mean plot defoliation of the entire time

period for a certain orientation.)

• Continue assessment of crown condition on both monitoring networks

• Continue foliar sampling on ICP Forests Level I plots

• Soil, litter and woody debris sampling and measurement on ICP Forests Level I

plots

• Time series analysis on climate data (E-OBS gridded dataset)

• Stand structure measurements by adapting TCO protocol (GTSO, 2008) and

Croatian National Forest Inventory

• Tree Increment Coring of all trees on ICP Forests Level I plots