Climate change and mixed forests: how do altered survival probabilities impact economically desirable species proportions of Norway spruce and European beech?

Ninety-five years of observed disturbance-based tree mortality modeled with climate-sensitive accelerated failure time models

“…Stand age, T, at the beginning and end of the observation interval together with the coded event (0/1) was the focus of the survival analysis. We selected stand age instead of other parameters (e.g., dbh, height) as time variable since age is often used in forest economic simulations and is therefore comparable with other models (Griess and Knoke 2013;Netherer et al 2015;Paul et al 2019;Brandl et al 2020). The nonparametric Kaplan-Meier estimator of the survival function } S(t) of T is defined as (Kaplan and Meier 1958): where } S(0) = 1 , d i is the trees that fail at t (i) and n i represents the total number of subjects at risk at t (i) .…”

“…In order to be more realistic, different species' growth characteristics, not only age, but also height should be taken into account as a reference. Tree or stand ages are important information for economic models and management decisions that include adjustments of the rotation cycles under climate change (Staupendahl and Möhring 2011;Möllmann and Möhring 2017) and economic-based species selection (Neuner and Knoke 2017;Paul et al 2019). To perform economic analyses, it is thus important to carry the variable tree or stand age in any study.…”

“…Here, our use of the term "risk" is limited to tree mortality. For comprehensive bio-economic analyses, the term "risk" needs to be broadened to represent the interplay of survival probabilities with tree growth, timber price fluctuations and harvesting costs (e.g., Möllmann and Möhring 2017;Neuner and Knoke 2017;Paul et al 2019). Our findings may, however, offer important insights to improve the representation of survival probabilities in such bio-economic studies to inform management decisions in face of great uncertainty.…”

European beech stem diameter grows better in mixed than in mono-specific stands at the edge of its distribution in mountain forests

“…However, there are also critical voices doubting the dominance of beech without humans due to an enhanced growth of beech since 1950 that can be primarily attributed to human influences like nitrogen fertilization or management effects (Scharnweber et al 2011(Scharnweber et al , 2019. Its dominance was reduced in the past for economic reasons, particularly in Central Europe, but its high mechanical stability against windthrow and comparatively high resistance and resilience to drought are leading to a comeback in view of climate change (Pretzsch et al 2020a;Paul et al 2019;Hanewinkel et al 2011). Presently beech forests cover about 12 × 10 6 ha in Europe (Brus et al 2012), and the area is steeply increasing due to a transition to close-to-nature forestry.…”

The Dynamics of Beech Roundwood Prices in Selected Central European Markets

“…Also reports from Slovakia, Austria, and Poland have indicated quantitative and volume increments for the European beech, as well as high regeneration levels in beech stands [50,51]. Taking into account climate change, which affects forest stability and productivity [52] and the revenues of forest owners [53], it should be noted that higher temperatures and lower precipitation levels will favor further beech expansion in central Europe, probably extending its horizontal and altitudinal ranges [54,55]. On the other hand, according to some climate scenarios, in southern Europe and in the southern region of Central Europe, beech growth is likely to slow down with some beech stands dying back due to their susceptibility to droughts at the beginning of the vegetative season [56][57][58][59].…”