Mikroklimatske razmere v sestojih in vrzelih dinarskih jelovobukovih gozdov Slovenije z vidika podnebnih sprememb
Dinarski jelovo-bukovi gozdovi so eden glavnih gozdnih vegetacijskih tipov v Sloveniji, v katerih so se v zadnjem obdobju zaradi naravnih ujm spremenile ekološke razmere. Namen raziskave je bila analiza izbranih spremenljivk mikroklime (temperatura zraka, relativna zračna vlaga) v strnjenih sestojih, v presvetljenih sestojih in v sestojnih vrzelih na treh raziskovalnih območjih (Trnovski gozd, Snežnik, Kočevski rog). Za strnjene sestoje je bila značilna visoka stopnja zastiranja tal s krošnjami dreves ( ~ 95 %). Sestojne vrzeli so nastale s posekom vseh dreves na krožni površini 0,4 ha, v presvetljenih sestojih pa je bila posekana približno polovica lesne zaloge gozdnega sestoja. Ukrepi so bili izvedeni leta 2012, meritve meteoroloških spremenljivk pa smo opravili prvo (2013) in drugo (2014) leto po sečnji. Primerjali smo, kako se mikroklimatske razmere v sestojih in vrzelih spreminjajo v vegetacijski sezoni (maj-oktober) in kakšne so razlike med dvema meteorološko razmeroma različnima poletjema v letih 2013 (več vročinskih valov, poletna suša) in 2014 (nestanovitno vreme z relativno veliko količino padavin). Izmerjene najvišje dnevne temperature zraka (Tmax) so bile izrazito višje v vrzelih kot v sestoju, v povprečju za 3,6 °C; najnižja relativna zračna vlaga (RVmin) pa je bila nižja, v povprečju za 15,0 odstotnih točk. Razlike v obeh spremenljivkah med sestoji in vrzelmi so bile največje v poletnih mesecih (junij-avgust) leta 2013 (Tmax: 4,9 °C; RVmin: -19,7 odstotnih točk), ki je bilo razmeroma vroče in sušno. Na podlagi meritev meteoroloških spremenljivk in zastora drevesnih krošenj (podatki LiDARskega snemanja) v presvetljenih sestojih smo ugotovili statistično značilno negativno linearno povezavo med zastorom drevesnih krošenj in Tmax ter pozitivno povezavo med zastorom krošenj in vrednostmi RVmin. Rezultate analiz smo prikazali v luči potencialnih vplivov podnebnih sprememb, katerim so dinarski jelovo-bukovi gozdovi zaradi kombinacije neugodnih dejavnikov npr. zmanjšana mehanska in biološka stabilnost sestojev zaradi velikopovršinskih motenj, poletne suše, vodoprepusten kraški teren ter pogosto plitva tla z majhno sposobnostjo zadrževanja vode - še posebej izpostavljeni.
Dinaric silver fir-beech forests in Slovenia represent one of the main forest vegetation types, where changes of ecological conditions occurred due to intense natural disturbances in the recent years. The aim of this research was to investigate microclimatic conditions (air temperature, relative humidity) in dense, mature forest stands, in thinned stands, and in canopy gaps, located within selected study sites (namely Trnovski gozd, Snežnik, Kočevski rog). Mature stands were characterized by dense overstory canopy cover ( ~ 95%). Artificial canopy gaps were created by cutting down all trees in circular areas of 0.4 ha, whereas in thinned stands approx. a half of the stand growing stock was removed. Silvicultural treatments were implemented in 2012 and field measurements of meteorological variables were conducted one (in 2013) and two (in 2014) years after the felling. We compared how the microclimate differed between stands and gaps during the growing season (May-October) and analysed these variations in relation to two meteorologically contrasting summers of the year 2013 (heath waves, summer drought) and the year 2014 (changeable weather with relatively high amount of rainfall). Measured maximal daily air temperatures (Tmax) were on average significantly higher in canopy gaps (on average for 3.6 °C) compared to below-canopy, while minimal relative humidity (RVmin) was lower (on average for 15.0 percentage points). The differences in these two variables were largest during the relatively hot and dry period of summer 2013 (Tmax: 4.9 °C; RVmin: -19.7 percentage points). Based on the measurements of meteorological variables and overstory canopy cover (LiDAR data) in thinned stands, we found statistically significant negative linear correlation between canopy cover and Tmax and positive correlation between canopy cover and RVmin. Results are discussed in the context of potential impacts of ongoing climate change, which are expected to strongly affect the Dinaric silver fir-beech forests in the future due to the combination of unfavourable factors, such as reduced mechanical and biological stability of forest stands as a consequence of large-scale disturbances, prolonged summer droughts, water-permeable karst terrain and associated shallow soils with low water storage capacity.
2019
2019-12-20 21:19:21
1060
dinarski jelovo-bukovi gozdovi, temperatura zraka, relativna zračna vlaga, sestojne vrzeli, zastor krošenj dreves, podnebne spremembe, Slovenija
Dinaric silver fir-beech forests, air temperature, relative humidity, canopy gaps, overstory canopy cover, climate change, Slovenia
r6
Janez
Kermavnar
70
Mitja
Ferlan
70
Aleksander
Marinšek
70
Klemen
Eler
70
Andrej
Kobler
70
Lado
Kutnar
70
UDK
4
630*56:630*53+630*111(045)=163.6
ISSN pri članku
9
0017-2723
COBISS_ID
3
5587622
OceCobissID
13
3736834
GV_2019_st_10_final_KermavnarJ.pdf
398250
Predstavitvena datoteka
2019-12-20 21:19:33