Phenological phases of trees on the intensive forest monitoring plots in Slovenia

Preučevanje razvojnih faz gozdnega drevja v dolgem časovnem nizu je vse pomembnejše orodje za ugotavljanje medsebojne odvisnosti vremenskih spremenljivk in z njimi povezanih bioloških odzivov. V naši raziskavi smo analizirali nastop fenofaz prvih listov in iglic ter splošnega rumenenja listja za listavce na 11 ploskvah intenzivnega monitoringa gozdnih ekosistemov v Sloveniji v letih od 2004 do 2011. Obravnavali smo fenofaze za dob (Quercus robur L.) na ploskvah Krakovski gozd in Murska šumabukev (Fagus sylvatica L.) na ploskvah Lontovž pod Kumom, Temenjak na Vinski gori, Borovec v Kočevski Reki, Fondek v Trnovskem gozdu, Gorica v Loškem Potokusmreko (Picea abies (L.) Karst.) na ploskvah Kladje na Pohorju in Krucmanove Konte na Pokljukirdeči bor (Pinus sylvestris L.) na ploskvi Brdo pri Kranjučrni bor (Pinus nigra Arnold) na ploskvi Gropajski Bori pri Sežani. V povprečju je fenofaza prvih iglic (BGS) smreke nastopila na 166 julijanski dan. Za rdeči bor je BGS nastopila na 128 julijanski dan, za črni bor pa 149. julijanski dan. Fenofaza prvih listov (BGS) je za bukev v povprečju nastopila na 128, za dob pa 117. julijanski dan. Splošno rumenenje listov (EGS) za bukevje v povprečju nastopilo na 297, za dob pa 308. julijanski dan. Dolžina vegetacijskega obdobja (LGS) doba je bila v povprečju 75 dni daljša kot za bukev. Ugotavljamo, da se je v obdobju od leta 2004 do 2011 nakazoval zgodnejši nastop fenofaze prvih iglic (BGS) smreke, rdečega bora ter črnega bora na vseh obravnavanih ploskvah. Zgodnejši nastop prvih listov (BGS) bukve in doba smo zaznali le na posameznih ploskvah, ne pa vseh. Kasnejši nastop splošnega rumenenja listov (EGS) za bukev smo zaznali le na dveh ploskvah (Borovec in Gorica), za dob pa smo ugotovili kasnejše pojavljanje EGS le na ploskvi Murska Šuma. Značilna je velika variabilnost dolžine vegetacijskega obdobja (LGS) za bukev in dob po letih. Daljšanje LGS za bukev je statistično značilno za tri ploskve (Fondek, Borovec in Gorica), za dob pa spremembe LGS v opazovanem obdobju niso bile statistično značilne.Study of developmental stages of forest trees in a long time series is of increasing importance for determination of interdependence between meteorological variables and the associated biological responses. In our study we analyzed the needle appearance and leaf unfolding of conifers and deciduous trees and the autumn colouring for broad-leaved tree species. We considered the phenological phases for oak (Quercus robur L.) in research plots Krakovski gozd and Murska šuma, beech (Fagus sylvatica L.) in research plots Lontovž, Temenjak, Borovec, Fondek, Goricaspruce (Picea abies (L.) Karst.) in research plots Kladje and Krucmanove KonteScotch pine (Pinus sylvestris L.) in the research plot Brdo, black pine (Pinus nigra Arnold) in the research plot Gropajski bori. On average, the needle appearance (BGS) of spruce started on the 166th Julian day. BGS of Scotch pine started on the 128th Julian Day, BGS of black pine on the 149th Julian day, respectively. The leaf unfolding (BGS) for beech started, on average, on the 128th Julian day and BGS for oak on the 117th Julian day, respectively. The autumn colouring(EGS) for beech, on average, started on the 297th Julian day, for oak on the 308th Julian day. It was assessed that BGS possibly commenced earlier for spruce, Scotch pine and black pine in all research plots during the 2004 to 2011 period. However, earlier BGS for beech and oak was noticed only in limited number of pots. Later EGS for beech could be confirmed in only two plots (Borovec in Gorica), whereas changes in EGS for oak were later only in plot Murska Šuma. There was a large variability of LGS for beech and oak over the years. Prolonged growing season (LGS) of beech was statistically significant for 3 plots (Fondek, Borovec in Gorica) during the 2004 to 2011 period. For oak prolonged LGS was not statistically significant during the observation period

Vpliv vremenskih spremenljivk in osutosti krošenj na fenološke faze dreves na ploskvah intenzivnega monitoringa gozdnih ekosistemov v Sloveniji

Data from the forest monitoring programme in Slovenia were used to assess the relationship between tree phenology, crown defoliation and meteorological conditions in Fagus sylvatica, Quercus robur and Picea abies forests in the 2004-2013 period. We hypothesized a species-specific response of first leaf unfolding, general leaf colouring, the length of the growing season to crown defoliation, air temperature, precipitation and soil water. In accordance with the hypothesis, we found a high sensitivity of first leaf unfolding to air temperature and precipitation for all species, exhibiting contrasting responses. We observed strong sensitivity of beech defoliation to precipitation and soil water conditions. Oak crown defoliation and next-year phenology were correlated, with higher crown defoliation contributing to earlier leaf unfolding, later autumn leaf colouring and longer growing season of oak in next year. Correlation between crown defoliation and phenology was found neither for beech nor spruce.V naši raziskavi smo na podlagi podatkov spremljanja stanja gozdnih ekosistemov v Sloveniji ugotavljali povezanost fenofaz dreves, osutosti krošenj dreves in vremenskih razmer v gozdovih bukve, doba in smreke v letih 2004-2013. Predpostavili smo, da je odziv fenofaz prvih listov in iglic, splošnega rumenenja listja in dolžine vegetacijskega obdobja na osutost krošenj, temperaturo zraka, padavine in vsebnost vode v tleh vrstno specifičen. Ugotovili smo veliko odzivnost nastopa fenofaze prvih listov in iglic na temperaturo zraka in padavine za vse obravnavane drevesne vrste, vendar so se odzivi razlikovali. Ugotovili smo tudi veliko odzivnost osutosti krošnje bukve na količino padavin in vsebnost vode v tleh. Osutost krošenj in fenofaze doba v sledečem letu so bile korelirane, pri čemer je večja osutost krošenj prispevala k zgodnejšemu nastopu fenofaze prvih listov, splošnega rumenenja listja in dolžine vegetacijskega obdobja za dob v sledečem letu. Nismo pa ugotovili povezanosti med osutostjo krošenj in fenofazami bukve ali smreke

Use of 3d process-based model to determine forests protecting against rockfall – case study Kamniška Bistrica

This case study of the Kamniška Bistrica forest management unit presents a 3D process-based model for determining forests protecting against rockfall. Modelling was performed using the ArcGIS 9.3.1 tool; the kinetic energy of rockfalls was calculated using the Conefall friction model. The finished map of protective forests was compared with the map of protective functions of forests, made by the Slovenia Forest Service. The protective function map covers 90% of forests classified in the 1st category forests by the modelled map. Taking into consideration the entire forest area in the forest management unit, the maps match in 48% of cases. The differences appear predominantly in higher altitudes where the protective function map includes dwarf pine sites, and in lower altitudes where the map does not consider the possibility that trees can perform their protective functions where the terrain becomes level. The aim of this article is to draw attention to the possibilities of using the models as tools for determining forests protecting against rockfalls.

Modelling Dominant Tree Heights of Fagus sylvatica L. Using Function-on-Scalar Regression Based on Forest Inventory Data

European beech (Fagus sylvatica L.) is an important tree species throughout Europe but shifts in its suitable habitats are expected in the future due to climate change. Finding provenances that are still economically viable and ecologically resilient is an ongoing field of research. We modelled the dominant tree heights of European beech as a trait reflecting growth performance dependent on provenance, climate and soil conditions. We derived dominant tree heights from national forest inventory (NFI) data from six European countries spanning over large ecological gradients. We performed function-on-scalar regression using hierarchical generalized additive models (HGAM) to model both the global effects shared among all provenances and the effects specific to a particular provenance. By comparing predictions for a reference period of 1981-2010 and 2071-2100 in a RCP 8.5 scenario, we showed that changes in growth performance can be expected in the future. Dominant tree heights decreased in Southern and Central Europe but increased in Northern Europe by more than 10 m. Changes in growth performance were always accompanied by a change in beech provenances, assuming assisted migration without dispersal limitations. Our results support the concept of assisted migration for the building of resilient future forests and emphasize the use of genetic data for future growth predictions