Regeneration processes on coarse woody debris in mixed forests: do tree germinants and seedlings have species‐specific responses when grown on coarse woody debris?

Abstract

1. Tree regeneration on coarse woody debris (CWD) is considered to be one the most ecologically valuable aspects of CWD in forest systems. However, most studies have focused solely on uncovering the differences in establishment and growth on CWD (regarded as a homogeneous substrate) in comparison to the forest floor. Our study concentrates on the underlying mechanisms of germinant and seedling colonization patterns and demographic responses relative to various properties of CWD. 2.We analyzed the effects of CWD properties (decay class, form, species and diameter) on: (i) germinant and seedling annual counts, (ii) annual germinant and seedling survival, and (iii) seedling growth and height. Our study comprised three species (beech, fir, and spruce) over 7-year span in two old-growth stands in the Western Carpathians, and employed generalized linear models and mixed models to test for differences between species.3. CWD properties affected regeneration at the germination stage. There were some demographic differences between species relative to CWD properties. Decay class had the most pronounced effect on beech, not only on its establishment but also survival and growth. Beech and spruce established and survived in higher densities on beech CWD, while their height growth was enhanced on conifer-derived CWD, particularly on spruce CWD.Stumps enhanced establishment of all species and survival of conifer seedlings. Synthesis:Our study shows that CWD properties do influence seedling establishment, growth, height distribution and survival. Moreover, there may be trade-offs between seedling growth and survival among tree species growing on different species of CWD. This highlights the need to include CWD heterogeneity as a factor that can affect the role of CWD in regeneration in forest ecosystems.

Ecological impacts of fungal wood decay types: A review of current knowledge and future research directions

“…Saproxylic communities consist not only of saprotrophic decomposers such as fungi, bacteria, protozoans, and invertebrates, but also autotrophic algae (including lichens), bryophytes, and vascular plants (Harmon et al, 1986;Stokland et al, 2012). The importance of deadwood as a site of regeneration of forest trees has been reported in boreal and subalpine (Harmon & Franklin, 1989;Hofgaard, 1993;Orman et al, 2016), temperate (Fukasawa, Komagata, & Kawakami, 2017;Harmon et al, 1986;Ota et al, 2012), and tropical forests (Sanchez et al, 2009;Santiago, 2000;Van der Meer et al, 1998). Focusing on ecological community networks associated with tree regeneration on deadwood is important for understanding forest dynamics which is another critical aspect of predicting the global carbon cycle.…”

Nutrition and mycorrhizae affect interspecific patterns of seedling growth on coarse wood and mineral soil substrates

“…, Marx and Walters , , Orman et al. ). For instance, evidence suggests that CWD from conifer species is a more favorable substrate for smaller‐seeded species seedling establishment and survival than CWD from angiosperm species (Cornett et al.…”

“…Limited evidence also suggests that CWD is not a generic substrate. Rather, the ability of CWD to support developing tree seedlings may differ among phyletic groups (e.g., conifers vs. angiosperms) or individual tree species (Cornett et al 2001, Marx and Walters 2006, 2008, Orman et al 2016. For instance, evidence suggests that CWD from conifer species is a more favorable substrate for smaller-seeded species seedling establishment and survival than CWD from angiosperm species (Cornett et al 2001, Bolton andD'Amato 2011).…”

Early emergence increases survival of tree seedlings in Central European temperate forests despite severe late frost

“…Beside emergence time, seed size and maternal or genetic effects may cause differences in seedling height (Kitajima & Fenner, ). Seedlings of the flush type phenology (i.e., shoot elongation and annual leaf production are completed at the time of emergence, such as in silver fir or Norway spruce) are usually much shorter than seedlings of the succeeding type phenology (Orman, Adamus, & Szewczyk, ). Seed size is decisive for the growth of seedlings of the flush type phenology, whereas emergence time is important for the growth of the succeeding type phenology (Seiwa, ).…”