Speaker: Prof Dr Viacheslav Kharuk from the Sukachev Institute of Forests, RAN Siberian Branch, Krasnoyarsk Russia.
Title: Conifer decline and mortality in Siberia
Abstract: Conifer decline and mortality in the 21st century has been observed all over the boreal forests zone (e.g., Boyd et al., 2019), Europe (e.g., Hasenauer, & Seidl, 2017), and Russia (e.g., Kharuk et al., 2020). This report focused mostly on the causes of Siberian pine (Pinus sibirica Du Tour.) and fir (Abies sibirica Ledeb) decline and mortality in Siberia. In addition, a recent insect (Zeiraphera griseana) and fungi (Melampsora sp.) attacks on the Larix sibirica stands are considered.
1. Warming caused northward and uphill migration of the Siberian moth (Dendrolimus sibiricus Tschetv.) outbreaks range into the former pristine taiga.
2. Siberian fir mortality caused by the synergy of bark-beetles (Polygraphus proximus Blandford.) attacks and water stress.
3. Siberian pine and fir forest mortality preceded by trees growth index (GI) reduction caused by elevated air temperatures, acute droughts and following on insect attacks.
4. In mountains forest mortality observed mostly at low elevations, whereas within the areas with sufficient moisture availability (i.e., at elevations above ~1000 m) trees GI and forest area are increasing.
5. Consecutive years with elevated air temperature provoked immense insect (Zeiraphera griseana) outbreak within relatively dry larch habitat and fungi (Melampsora sp.) outbreak within moisture larch habitat.
6. With the projected drought increase, precipitation-sensitive Siberian pine and fir would retreat from its southern low elevation ranges and substitute by tolerant species (e.g., Betula spp, Larix sibirica, Pinus sylvestris).