A recruitment model for beech–oak pure and mixed stands in Belgium

Abstract

We present a recruitment model for pure and mixed beech and oak stands in Belgium, the first empirical model for this forest type in this geographical area. Data from the Wallonia National Forest Inventory were used to fit the model. We adopted a zero-inflated formulation where model parameters governing species’ behaviour were simultaneously fitted. Plot random effects specific to each species were included, the simultaneous fit allowing them to correlate. Model predictions proved accurate and corresponded to current ecological knowledge about the regeneration dynamics of this kind of mixture. While our model could potentially be used to complement the existing beech and oak growth models for this region of Europe, our results also show that beech recruits tend to dominate regardless of the oak share in the overstorey composition and the stand stocking. This confirms that the beech–oak mixture may not be stable under the conditions of the study area and current management aimed at promoting continuous forest cover.

Chances and Limitations of Mixed Oak Regeneration under Continuous Canopy Cover—Evidence from Long-Term Observations

“…In particular, the decreasing survival probabilities indicated the need for silvicultural assistance in the given stand situations (see Figure 2). Accordingly, the participation of oak in a mixture with beech was not stable throughout the regeneration period and confirmed the results of some studies [18,19,39,49], which can also be found in the early silvicultural principles for oak management [18,25,50]. Differences between experimental sites and forest stand types were clearly recognizable and should be considered in pre-commercial thinnings.…”

“…These observations were also made for even younger oak regenerations [34,53]. Accordingly, oak requires the support of the silvicultural regulation of woody competitors for successful establishment in many sites [18,49,54].…”

Beech and hornbeam dominate oak 20 years after the creation of storm-induced gaps

“…Several studies have shown the impact of surrounding stand composition (Petritan et al, 2012;Annighöfer et al, 2015;Manso et al, 2020) or of distance from the gap edge on the density of oak and beech saplings in canopy gaps (Van Couwenberghe et al, 2010;Tinya et al, 2020). To date, very few studies (Tinya et al, 2020) have quantified these patterns for hornbeam.…”

Effects of Skidding Operations after Tree Harvesting and Soil Scarification by Felled Trees on Initial Seedling Emergence of Spanish Black Pine (Pinus nigra Arn. ssp. salzmannii)

“…However, a preliminary check of the data showed that there were many more zero counts than would be expected at random from a Poisson distribution. This is known as "zero inflation" and it is a common issue in regeneration data [30,31]. Ignoring this excess of zeros would lead to biased parameter estimates and standard errors.…”