A New Method to Reconstruct Recent Tree and Stand Attributes of Temporary Research Plots: New Opportunity to Analyse Mixed Forest Stands

Abstract

In the last decades, studying effects of mixing tree species is increasingly important. In particular, under changing growing conditions and social requirements, investigations on mixed forest compared to mono-specific stands are of special interest, for example, stability, resilience or ecosystem services. Permanent forest research plots are a unique data source, providing the required information but being time-consuming and costly to establish. Moreover, large data sets of such plots are missing but needed for generalising any findings. Temporary research plots provide ad hoc information of its status quo and require less effort than permanent plots. Usually, such plots provide no information of the recent tree and stand characteristics. We demonstrate a new method developed under the scope of COST action FP 1206 EuMIXFOR (European Network on Mixed Forests) to estimate retrospective tree dynamics and stand characteristics. The results of validation reveal its usefulness for reconstructing 5-10 years. Thus, the method provides new potential in establishing larger networks across several countries, in particular, for studying underlying processes when comparing mono-specific with mixed forest stands.

Stand growth and structure of mixed-species and monospecific stands of Scots pine (Pinus sylvestris L.) and oak (Q. robur L., Quercus petraea (Matt.) Liebl.) analysed along a productivity gradient through Europe

“…For further evaluation, the annual ring widths on the cores were measured, the dendrometric time series cross-dated and synchronized, and arithmetic means of the annual ring widths from the cores in north and east directions calculated. For a more detailed description of the sampling and measuring procedure, see Heym et al (2017Heym et al ( , 2018 and Steckel et al (2019).…”

“…The evaluation for 2012, i.e. retrospectively for the last 5 years, is explained briefly in the next paragraph (see also Heym et al (2017Heym et al ( , 2018 for further details). Based on the reconstructed stand characteristics in 2012, the mean periodical stand basal area growth PAIBA and stem volume growth of the stand PAIV were calculated for 2012-2017 as PAIBA 2012-2017 = BA 2012 − BA 2017 + BA removal and PAIV 2012-2017 = V 2012 − V 2017 + V removal .…”

Drought Resistance of Norway Spruce (Picea abies [L.] Karst) and European Beech (Fagus sylvatica [L.]) in Mixed vs. Monospecific Stands and on Dry vs. Wet Sites. From Evidence at the Tree Level to Relevance at the Stand Level

“…Both a and b are regression parameters which were estimated from the exponentiated equation. The model assumes a constant bark width over time [53] and an allometric relationship between diameter and diameter increment [12]. Note that for extrapolation to the diameter over bark of the non-cored trees, we accounted for all the 379 tree core samples to provide more stable results for drought responses at the hectare scale.…”

“…Parameters b 0 and b 1 depend on the species-specific age at the plot level, species-specific quadratic mean height (h q ) (retrospective h q , which comes from the above mentioned yield tables) as well as quadratic mean diameter (d q ) (which comes from the reconstructed diameter) of the respective year. For a more detailed description of the diameter and height reconstruction, see Heym et al 2018 [53].…”

Assessing Differences in Competitive Effects Among Tree Species in Central British Columbia, Canada

“…Mixed-species forest stands are increasingly gaining attention as studies have highlighted their importance in providing higher levels of ecosystem services and functions [1]. Mixed-species stands may also be more productive and have a higher resistance to biotic and abiotic disturbances [2,3]. Interactions between tree species in such forests may be complex and dynamic due to changes to the environment and resource availability.…”