Importance of conserving large and old trees to continuity of tree‐related microhabitats

Abstract

Protecting structural features, such as tree-related microhabitats (TreMs), is a cost-effective tool crucial for biodiversity conservation applicable to large forested landscapes. Although the development of TreMs is influenced by tree diameter, species, and vitality, the relationships between tree age and TreM profile remain poorly understood. Using a tree-ring-based approach and a large data set of 8038 trees, we modeled the effects of tree age, diameter, and site characteristics on TreM richness and occurrence across some of the most intact primary temperate forests in Europe, including mixed beech and spruce forests. We observed an overall increase in TreM richness on old and large trees in both forest types. The occurrence of specific TreM groups was variably related to tree age and diameter, but some TreM groups (e.g., epiphytes) had a stronger positive relationship with tree species and elevation. Although many TreM groups were positively associated with tree age and diameter, only two TreM groups in spruce stands reacted exclusively to tree age (insect galleries and exposed sapwood) without responding to diameter. Thus, the retention of trees for conservation purposes based on tree diameter appears to be a generally feasible approach with a rather low risk of underrepresentation of TreMs. Because greater tree age and diameter positively affected TreM development, placing a greater emphasis on conserving large trees and allowing them to reach older ages, for # These authors contributed equally to this work.

Spatial distribution of Tree-related Microhabitats in a primeval mountain forest: from natural patterns to landscape planning and forest management recommendations

“…We found no relationships between TreM numbers and slope inclination or elevation. A higher elevation may alter local rainfall and humidity, promoting tree cavity and epiphyte formation (Remm and Lõhmus, 2011; Kozák et al, 2023). Steep mountain slopes can be the cause of tree trunk damage due to rockfall (Šilhán, 2010), which leads to the development of reactive wood and asymmetrical root systems, and also the formation of root buttress cavities (Young and Perkocha, 1994).…”

Diversity of forest structures important for biodiversity is determined by the combined effects of productivity, stand age, and management

“…These were the only two structures for which the effect of management was positive, which was expected as pine and spruce are the most important commercial tree species in Sweden, and management specifically aims to promote their growth. However, the increased amount of large conifers in managed forests is likely of limited importance for biodiversity, since the trees are typically harvested before they reach a sufficiently old age to develop specific microhabitats that host specialized species (Paillet et al 2017 ; Kozák et al 2023 ), and since many species that inhabit living trees require longer time for colonization than the current rotation periods allow (Kuusinen and Siitonen 1998 ; Marmor et al 2011 ). The positive effect of management also decreased with productivity, thus changing the relationship between productivity and the amount of large conifers.…”

“…epiphytic lichens and bryophytes, insects, and cavity-dwelling birds (e.g. Paillet et al 2017 ; Kozák et al 2023 ). Thus, the amount and diversity of such structures can function as a proxy for forest biodiversity (Larrieu et al 2018 ; Hekkala et al 2023 ).…”

Distribution pattern of large old Ginkgo biloba in China under climate change scenarios

“…Many studies have demonstrated LOT's critical role in maintaining biodiversity, ecological balance, cultural heritage, and scientific research (Jim, 2017 ; Lindenmayer, 2017 ). They support a wide array of companion life forms such as lichen, moss, and fungus due to their structural complexity and sheer size, providing a diverse assortment of microhabitats to support many species, including rare and endangered ones (Kozák et al., 2023 ; Le Roux et al., 2014 ; Lindenmayer, 2017 ). In urban areas, preserving large trees can effectively conserve local biodiversity (Stagoll et al., 2012 ).…”