Journal of Forest Science - In Press
Simulated bark stripping reduces stem growth in young Norway spruce: Evidence from continuous dendrometer monitoringOriginal Paper
Zdeněk Vacek, Stanislav Vacek, Jan Cukor, Veronika Hammerová, Jakub Černý, Václav Šimůnek, Richard Ševčík, Kateřina Brynychová, Václav Trojan, Jan Budínský
Norway spruce [Picea abies (L.) Karst.] is Europe’s most important commercial tree species, whose stability, vitality, and production potential can be significantly compromised by cervids. Their populations in Europe have been growing over time. This study aimed to analyse the effect of simulated circumferential trunk damage – mimicking bark stripping by ungulates – on the diameter growth of young spruce trees through continuous measurements with point dendrometers at 15-minute intervals. Dendrometers were installed at two permanent research plots (PRPs) in the Lužické hory (Lusatian Mountains) and at another two PRPs in the Krušné hory (Ore Mountains) on spruce stands aged 16–21 years. At each PRP, 15 co-dominant trees were monitored; five served as undamaged control trees, while ten were experimentally damaged by removing bark over an area ranging from 5–90% of the trunk circumference. The most intense diameter growth occurred during an approximately 14-day period at the turn of May and June. The growth activity ceased on all PRPs during the second to third week of September. Even during the first growing season after the experimental damage, significantly lower diameter growth was observed in the evaluated trees when compared with undamaged control trees (P < 0.05). On PRP 2, undamaged trees achieved up to 87.8% higher growth than the damaged ones. Overall, the diameter growth of damaged trees was 37.9–43.2% lower than that of undamaged control ones, depending on the damage category, although no significant differences were found among the damage categories of 5–30%, 40–60%, and 70–90%, respectively. The results show that simulated bark damage can considerably reduce the diameter growth of young spruce trees as early as the first growing season, underscoring the importance of effective stand protection from harm caused by ungulates.
Morpho‑physiological traits and biomass scaling of the invasive Callery pear (Pyrus calleryana Decne.)Original Paper
Prabina Sharma, David R. Coyle, James F. Palmer, Nilesh Timilsina, Jessica Hartshorn
Accurately estimating aboveground biomass (AGB) of invasive plant species is essential for understanding their prevalence, ecological impacts, and informing management strategies. Pyrus calleryana (Callery pear) is established throughout the eastern United States, yet species‑specific biomass models and physiological trait data remain limited. We destructively sampled 40 single‑stem trees with diameter at breast height (DBH) ranging from 1.2 cm to 17.7 cm and height from 1.6 m to 10.3 m across six sites in South Carolina to quantify dry biomass, moisture content (MC), Carbon and Nitrogen ratios (C : N), and to develop allometric equations for predicting total AGB. The DBH-based log–linear model provided the strongest overall fit for total AGB (R2 = 0.91; bias = 0.41 kg), and hold-out validation indicated strong predictive performance for unobserved trees (Root Mean Square Error, i.e. RMSE = 5.59 kg; validation R2 = 0.967). Tissue traits differed significantly: leaves had the highest moisture content, whereas stems had the highest C : N ratio and AGB. These findings provide a practical, biologically interpretable DBH‑based equation and biomass data suitable for forest inventory applications and invasion monitoring. The study also establishes baseline physiological parameters for P. calleryana, supporting improved evaluation of its ecological footprint and management needs.