Drivers of tree growth, productivity and regeneration in traditional coppices

Ing. Marek Mejstřík

Disertační práce

Abstract:

Traditional coppices and coppice-with-standards were widely used throughout Europe and Asia for centuries but were largely abandoned in the second half of the 19th century, particularly in central and northwestern Europe. In the last decades, there has been renewed interest in traditional coppicing, mainly for nature conservation and rapid woody biomass production. However, there is little empirical knowledge regarding the main drivers affecting tree growth, biomass production, and natural regeneration in coppices, especially in the context of changing environmental conditions. This thesis seeks to fill this knowledge gap by investigating the interactions between tree growth, forest structure and climatic factors in newly restored coppices and coppice-with-standards in the Czech Republic. Specifically, we aimed to (1) to quantify the effects of stand density, standards, and tree species composition on sprout growth and biomass production; (2) to assess the contributions of seed and sprout regeneration to above-ground biomass (AGB) productivity and species diversity in early-stage forest development; and (3) to evaluate the growth responses of vegetative sprouts, seed regeneration, and standard trees to climatic factors, particularly drought. The research was conducted in two experimental forest plots, where a high, oak-dominated forest was transformed into coppice and coppice-with-standards. Trees were cut at varying intensities, leaving different densities of standing residual trees (standards) while allowing the stumps to resprout. Over time, we monitored the growth of all sprouting stumps, standards, and measured seed regeneration. Main Findings of the thesis: (1) Total sprout biomass decreased significantly with increasing density of standards for Quercus petraea and Carpinus betulus, while Acer campestre and Tilia cordata were not affected. The stand-level biomass productivity increased linearly with the density of sprouting stumps. A significant shift in species composition was observed due to differential resprouting success and sprout growth after tree cutting, resulting in a large decline of Quercus in favor of Carpinus and Tilia, which, as very good resprouters, benefited substantially from coppice establishment (Section 5.1). (2) Sprout regeneration contributed the majority of above-ground biomass and species diversity in early-stage forest development. Seed regeneration was significantly suppressed by residual trees, but despite low abundance, it introduced new species, enriching species pool and enhancing overall species diversity. This highlights the crucial but differential role of sprout and seed regeneration in post-disturbance forest dynamics (Section 5.2). (3) Quercus, the predominant species at our study sites, consistently exhibits faster growth and maintains higher productivity in sprouts compared to seed regeneration, regardless of climatic conditions. While responses to relative air humidity and temperature showed no significant differences among regeneration types for Quercus, Tilia, or Carpinus, variations in precipitation response were observed in Quercus at different sites. Tilia and Carpinus exhibited no significant response to rising temperatures, unlike Quercus, which experienced a notable decrease in tree ring width (Section 5.3). The findings of this thesis underscore the complex interactions between climate, forest structure, and tree growth in traditional coppice systems. The results suggest coppice restoration may enhance woody biomass production which is likely to be sustained under climate change as well as support woody plant diversity. Therefore, coppicing is a good forest management option particularly in warmer areas of Central Europe, which are most affected by increasing water limitation.

Keywords

forest regeneration, traditional coppice, coppice with standards, forest structure, tree growth, above-ground biomass

Jazyk práce: angličtina

Datum vytvoření / odevzdání či podání práce: 2. 10. 2024

Obhajoba závěrečné práce

• Vedoucí: doc. Ing. Radim Matula, Ph.D.

Česká zemědělská univerzita v Praze

Fakulta lesnická a dřevařská

Doktorský studijní program / obor:
Lesní inženýrství / Biologie lesa