Non-native tree species in the viewpoint of climate change: chances and opportunities - Croatia as a case study

The management of tree species non-native to Republic of Croatia has a certain tradition within Croatian forest management practice; nowadays, their potential should be regarded and re-evaluated in the new frame of climate changes and growing society demands for forest products and services. This paper is a contribution to non-native tree species (NNTS) introduction and use in Croatia, aiming at providing state of the art of NNTS as well as overview of studies and examples of possible management opportunities. Because of the complexity of the matter and growing need to further investigate risks and challenges of NNTS in Croatia, authors have continued their research and will publish the results in a separate paper. Amount of the area occupied by NNTS forest cultures point to the conclusion that the use of these tree species in forest practice is not reached by far and the nursery production does not back up the need for NNTS use. Paper also provides a comprehensive overwiev of different aspects and benefits of the use of NNTS in Croatia. For example, increased wood production and non-wood forest products; production of high quality timber in short–time periods; use of fast-growing tree species for bioenergy production in higher proportion and enhancement of ecosystem services. Increase of stability and adaptive capacity of forest stands by the use of NNTS is highlighted as new silvicultural option for facing climate change. Their use in reforestation or conversion of degraded forest to more valuabe and more resistant/resilient stands offers new possibilities. Integrated and site-specific management is a strategy, which seems to be an appropriate approach for guidelines for the introduction and management of NNTS in Croatia. The use of high productive, resistant NNTS presents new silvicultural solution especially important in terms of site amelioration and enhancement of resistance and resilience of forest stands, which is the most important component of adaptive for
Gospodarenje alohtonim vrstama ima tradiciju u hrvatskome šumarstvu, ali njihov potencijal se treba ponovno razmotriti i ocijeniti u novonastalim okvirima klimatskih promjena te rastućim potrebama društva za šumskim proizvodima i uslugama. Unatoč činjenici da svaka država ima svoj popis introduciranih vrsta, uključujući i Hrvatsku, autori prihvaćaju definiciju COST Akcije FP1403 NNEXT te rad baziraju na šumskim vrstama drveća kojima se prirodni areal nalazi izvan granica Europe. Ovaj pregledni rad doprinos je saznanjima o introdukciji i aktivnoj uporabi alohtonih vrsta u zemlji, a obuhvaća dostupne znanstvene i stručne studije te primjere uspješne uporabe u gospodarenju šumama. Zbog složenosti ove problematike autori će objaviti pregled rizika i izazova uporabe alohtonih vrsta u zasebnome radu. Dostupni podaci o prisutnosti alohtonih vrsta na pokusnim objektima te u šumarskoj praksi ukazuju kako se u praksi koristi tek manji broj vrsta (Tablica 1), dok su stvarni potencijal i njihove koristi daleko veće. Analiza podataka ukazuje kako su najzastupljenije alohtone vrste u šumarskoj praksi: Robinia pseudoacacia L. (12003.88 ha), Pinus strobus L. (3218.69 ha), Juglans nigra L. (2376.66 ha), F. pennsylvanica Marshall. i Fraxinus americana L.(1099.77 ha), Pseudotsuga menziesii (Mirb.) Franco. (393,05 ha) i L Quercus rubra. (51,99 ha). Podaci o proizvodnji šumskoga reprodukcijskog materijala navedenih vrsta ukazuje da rasadnička proizvodnja nije usklađena s potencijalom njihove uporabe u praksi. U radu se daje i iscrpan pregled različitih gledišta i koristi uzgoja alohtonih vrsta u Hrvatskoj. Samo neke od njih su (Slika 1, Tablica 2): nove mogućnosti proizvodnje visoko kvalitetnog drveta u kraćim ophodnjama, kao i drveta za bioenergiju, novih drvnih proizvoda i tehnologija; socijane koristi (mali i srednji poduzetnici, privatni šumoposjednici); povećanje stabilnosti i adaptabilnosti šumskih sastojina, ali samo u slučajevima velikih šteta i male plastičnosti i otpornosti do