Intermediate disturbances are a key driver of long%term tree demography across old%growth temperate forests

Nagel, Thomas Andrew (author), Firm, Dejan (author), Rozman, Andrej (author)

Disentangling the relative influence of background versus disturbance related mortality on forest demography is crucial for understanding long%term dynamics and predicting the influence of global change on forests. Quantifying the rates and drivers of tree demography requires direct observations of tree populations over multiple decades, yet such studies are rare in old%growth forest, particularly in the temperate zone of Europe. We use multi%decade (1980%2020) monitoring of permanent plots, including observations of mode of mortality and disturbance events, to quantify rates and drivers of tree demography across a network of old%growth remnants in temperate mountain forests of Slovenia. Annual rates of mortality and recruitment varied markedly among sites and over time; census intervals that captured intermediate severity canopy disturbances caused subtle peaks in annual mortality (e.g., >2%/year), while rates of background mortality in non%disturbed intervals averaged about 1%/year. Roughly half of the trees died from modes of mortality associated with disturbance (i.e., uprooting or snapped%alive). Results of a Bayesian multilevel model indicate that beech (Fagus sylvatica) had a higher likelihood of disturbance related mortality compared to fir (Abies alba), which mainly died standing, and there was a notable increase in the odds of disturbance mortality with increasing diameter for all species. Annual recruitment rates were consistently low at sites (<0.5%) that lacked evidence of disturbance, but often exceeded 3% on sites with higher levels of past canopy mortality. Recruitment was dominated by beech on sites with more diffuse background mortality, while the less shade tolerant maple (Acer pseudoplatanus) recruited following known disturbance events. Our study highlights the important role of stand%scale, partial canopy disturbance for long%term forest demography. These results suggest that subtle climate%driven changes in the regime of intermediate severity disturbances could have an important influence on future forest dynamics and warrant attention.

• Language: English
• Keywords: demography, disturbance, forest dynamics, mode of mortality, moderate disturbance, mortality, permanent plots, recruitment, temperate forest
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: BF - Biotechnical Faculty
• Publication status: Published
• Publication version: Version of Record
• Submitted for review: 12.08.2021
• Article acceptance date: 04.10.2021
• Publication date: 12.11.2021
• Year: 2021
• Number of pages: Str. 16862-16873
• Numbering: Vol. 11, iss. 23
• PID: 20.500.12556/RUL-134606
• UDC: 630*2
• ISSN on article: 2045-7758
• DOI: 10.1002/ece3.8320
• COBISS.SI-ID: 83520515
• Publication date in RUL: 20.01.2022

Record is a part of a journal

• Title: Ecology and evolution
• Publisher: Wiley-Blackwell, Blackwell Publishing
• ISSN: 2045-7758
• COBISS.SI-ID: 518617625

Secondary language

• Language: Slovenian
• Keywords: demografija, motnje, dinamika gozdov, umrljivost, zmerna motnja, zmerni gozdovi, stalne raziskovalne ploskve

Projects

• Funder: ARRS - Slovenian Research Agency
• Project number: J4-1765
• Name: Razvoj gozdnih ekosistemov in klimatske spremembe: učinki ujm večjega obsega in segrevanja ozračja