Assessing selected microhabitat types on living trees in Oriental beech (Fagus orientalis L.) dominated forests in Iran

Abstract

& Key message On the selected sites in the investigated Oriental beech (Fagus orientalis L.) dominated forests in Iran with an extensive individual tree selection system, tree microhabitats (MH) are more influenced by tree level factors such as tree species and DBH than by plot level factors such as plot basal area or size and species diversity. & Context Despite the ecological importance of tree microhabitats for biodiversity, there is a lack of information about the occurrence of microhabitat features in Hyrcanian forests in Northern Iran. & Aims The aims of this study were to assess selected MH types on living trees in forests managed with an individual tree selection system and forests unmanaged since at least 30 years and to study the effect of tree and plot level factors on their occurrence. & Methods A total of 120 circular sample plots were used to collect tree level microhabitat information at six different sites in Oriental beech forests in Iran. Pairs of managed and recently unmanaged forests were located at six sites. Generalized linear mixed models were employed to analyze (i) the effect of management on microhabitat occurrence, and (ii) to explain the occurrence of microhabitats at tree level. & Results There was no significant difference in total number of assessed microhabitats per ha in forests managed with a lowintensity management regime with individual tree selection versus recently unmanaged forests (no management intervention for at least 30 years). Stem cavity with decay was by far the most frequent microhabitat type in managed (16.5 per ha) as well as in recently unmanaged forests (14.2 per ha). Hornbeam and oak trees have a higher probability to host microhabitats (bark loss, woodpecker cavity, and stem cavities) than the dominant oriental beech. Suppressed trees indicated by basal area of larger trees have a lower probability to show bark loss and conks of fungi. & Conclusion Models of microhabitat occurrence on trees have potential to support the development of management guidelines to foster biodiversity.

Factors influencing the rate of formation of tree‐related microhabitats and implications for biodiversity conservation and forest management

“…In accordance with many previous publications (Asbeck et al., 2019; Khanalizadeh et al., 2020; Kozak et al., 2018; Larrieu & Cabanettes, 2012; Larrieu, Cabanettes, Brin, et al., 2014; Paillet et al., 2019; Regnery et al., 2013; Vuidot et al., 2011), our results confirm that TreMs tend to accumulate on trees during their growth. However, the rate of TreM formation depends on DBH differently from what we expected.…”

“…In accordance with many previous publications (Asbeck et al, 2019;Khanalizadeh et al, 2020;Kozak et al, 2018;Larrieu, Cabanettes, Brin, et al, 2014;Paillet et al, 2019;Regnery et al, 2013;Vuidot et al, 2011) we observed an increase in hazard rate with DBH (Courbaud et al, 2017;Jahed et al, 2020). In this study, bark-loss, crowndeadwood, cracks and dendrotelm showed a decrease in hazard rate with DBH, which means that these TreMs usually form for the first time on a tree when it is still small.…”

The Use of Tree-Related Microhabitats as Forest Biodiversity Indicators and to Guide Integrated Forest Management

“…There are fewer studies on tree species such as Douglas fir (Pseudotsuga menziesii (Mirb.) Franco) or Oriental beech (Fagus orientalis Lipsky (Fo)) from outside Europe [52][53][54][55][56]. All these studies have in common that tree species is a determining factor of TreM abundance and richness.…”

Adaptive Forest Management under Climate Change: Some Adaption Criteria for Practical Purposes

“…This step takes into account the ecological interactions and the reciprocal influence exerted by both the biotic and abiotic components, such as type and modality of regeneration, humus quality, internal microclimate of the forest, periodicity in the availability of nutrients, etc. [41][42][43][44]; c. estimation of the development trends of the forest species composition and structure within the 'Ecological Forest Units'; d. comparison of the models identified through time within similar EFUs and through spatial variability between different EFUs; e. selection of the EFUs with the more stable and ecologically efficient chronological series of structure development. These series show the models available within the forest or forested area to which refer planning and management.…”