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Key message Non-selective thinning of a hybrid aspen coppice stands via corridor or cross-corridor cutting impacts residual trees differently depending on their competitive status. Suppressed residual trees' metabolic profile indicates increased stress level, especially after cross-corridor thinning.• Context Early thinning with regular corridor harvests is proposed for the management of post-harvest re-sprouted hybrid aspen (Populus tremula L. × P. tremuloides Michx.) coppice stands. The selection of remaining trees is not size-based and their physiological acclimation to the post-thinning conditions is unknown.• Aims To analyse differences in secondary metabolite profile between thinning treatments and trees competitive status.• Methods We used an HPLC-qTOF mass spectrometer to analyse the leaf extracts of dominant and suppressed trees from stands with different thinning intensities: un-thinned control with basal area of 15.4 ± 1.52 m 2 ha −1 , corridor thinning with basal area of 8.5 ± 0.46 m 2 ha −1 and cross-corridor thinning with basal area of 3.9 ± 0.34 m 2 ha −1 .• Results Competitive status and thinning treatment both had significant effects on the contents of compounds. Higher exposure to irradiance increased the contents of flavonoids and hydroxycinnamates. Corridor thinning treatments doubled the foliar contents of secondary metabolites and lowered macronutrient contents in competitively suppressed residual trees. Dominant residual trees were not affected in this respect.• Conclusion Forest management practice and competitive status can significantly modify the metabolite profile in tree leaves. After corridor thinning of a young aspen coppice stand, the small-sized residual trees may initially respond with increased allocation to leaf chemical defence rather than to productivity.

Hybrid aspen is one of the most promising tree species for short-rotation forestry in Northern Europe. After the clearcutting of hybrid aspen plantation, the next generation arises from root and stump sprouts. The economic feasibility of different management strategies of hybrid aspen coppice stands has not yet been comprehensively evaluated in Northern Europe. We compared the land expectation values (LEVs) of hybrid aspen coppice stands managed according to four scenarios: three early thinning methods (corridor, cross-corridor and single-tree) followed by conventional management and intensive bioenergy production (repeated harvests in 5-year rotations) over a 25-year period in hemiboreal Estonia. We considered the historic price volatility of aspen wood assortments under various discount rates (1–20%). We found that the 25-year rotation with different early thinning methods was more profitable than short bioenergy cycles in the case of low discount rates (<5%). The LEV of short coppice cycles for only bioenergy production became more profitable in comparison with those by thinning methods, when higher discount rates (>10%) were applied. Hybrid aspen coppice stands can be managed profitably, but more risks are taken when the management strategy focuses only on bioenergy production.

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Fast-growing Populus spp. are well-acknowledged to restore contaminated soils from heavy metals in industrial areas. Thus far, there is no knowledge about the phytoremediation capacity of Populusspp. plantations in hemiboreal conditions to restore industrially polluted areas. The objective of this study was to assess the soil contamination rate of heavy metals (As, Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb and Zn) and their uptake by trees in mature hybrid aspen (Populus tremula× Populus tremuloides Michx.) plantations at different industrial pollution (e.g. cement factory, thermal power plants, oil shale mining) levels and soil restoration methods. In total, 65 soil samples from the 0–10 cm topsoil layer, 39 wood samples and 39 bark samples were collected. Ingrowth cores were cut to separate wood developed to early and late ages. Soil pollution with heavy metals was determined in all studied plantations. Our study showed that tree growth was affected by soil pH and C:N ratio rather than the heavy metal concentration in the soil. Cd differs from other metals and accumulates less in wood and more in bark. A direct influence of wood age was confirmed; heavy metal (Cd, Cr, Cu, Fe, Mn, Ni and Zn) content in the old wood (formed 11–21 years ago) was higher than in young wood (formed during the last 10 years). The highest amounts of metals would be removed with felling on former agricultural soils with higher biomass, although wood on poorly growing stands in quarry spoil contained higher metal concentrations.