This study examines the spatial root development patterns of bareroot, containerized, and plug plus (plug+) saplings in hemiboreal forests of Latvia, focusing on the effects of two common soil preparation methods: mounding and disc trenching. In northern Europe, forest regeneration after clearcutting often involves planting, with soil preparation aimed at enhancing sapling survival and productivity. This study included four tree species: Pinus sylvestris, Picea abies, Betula pendula, and Alnus glutinosa. The results reveal that saplings planted in mounded sites developed more radially symmetrical root systems, while roots in trenched sites predominantly grew parallel to the furrow. This spatial root distribution was consistent across all forest types and did not show significant variation between stock types (containerized, bareroot, or plug+) or treatments (control or fertilized). Additionally, the number of main roots did not differ significantly between the soil preparation methods. These findings align with previous research and raise important questions regarding the impact of early root architecture on stand resilience at a mature stage, particularly in relation to windthrow, heavy snowfall, drought, and flooding resistance. The study underscores the need to consider root system development as a key factor in forest management practices aimed at ensuring long-term forest stability.

Short-rotation forest plantations on former agricultural land capture CO₂, provide bioeconomic materials, and mitigate climate change. This study aimed to enhance our understanding of the long-term effects of wood ash and wastewater sludge fertilization on various tree species (birch, hybrid aspen, grey alder, black alder, and hybrid alder) in short-rotation forestry plantations on abandoned agricultural land where tree growth measurements were taken over an 11-year period. After 11 years, the highest aboveground biomass (AGB) was observed for hybrid aspen clone No. 4 under wastewater sludge treatment (109.0 t ha⁻¹), birch under wood ash treatment (34.3 t ha⁻¹), black alder under wastewater sludge treatment (33.6 t ha⁻¹), grey alder under wastewater sludge treatment (40.9 t ha⁻¹), hybrid alder under control conditions (36.2 t ha⁻¹), and hybrid aspen clone No. 28 under wood ash treatment (37.2 t ha⁻¹). The average survival rate was 73% in control plots, 81% under wastewater sludge treatment, and 78% under wood ash treatment. Short-term positive impacts on tree growth were observed, effects that were not consistent over the long term. The impact of these treatments on tree growth varied between species, and the effects tended to diminish over time, which must be considered before fertilization.

Striving for climate neutrality and wider implementation of climate change mitigation measures including tree introduction in agricultural land, request for approaches and general allometric models for estimating carbon (C) stock in tree above-ground biomass (AGB) based on relatively easily obtainable remote sensing data is increasing. Here, we present estimates of individual trees’ crown diameters (CDs) for Betula pendula Roth (B. pendula) and Populus tremuloides Michx. × Populus tremula L. (P. tremuloides × P. tremula) in 11-year-old tree plantations (tree height ranged up to 12.8 and 18.1 m, respectively) in the hemiboreal region of Europe (in Latvia). Individual trees’ CDs were measured using a drone orthophoto map. Afterwards, linear equations were developed to predict individual trees’ stem diameters at breast height (DBHs) and, consequently, tree AGB (which was then converted to C stock) from remote-sensed tree CD data. RMSEs of the prediction models of tree stem DBH were in the ranges of 1.87–2.12 cm for B. pendula and 2.50–3.12 cm for P. tremuloides × P. tremula. This demonstrated approach is applicable to carry out, for instance, a self-assessment and approximate C stock in the AGB of selected tree species by land owners, managers, and other implementers of climate change mitigation measures.

Forests in Latvia are crucial, covering over half of the country’s territory and expanding continuously through afforestation and natural growth

Sand extraction drastically alters ecosystem structure and initiates conditions for primary succession development. Forest stands aged 9, 16, 19, and 28 years were surveyed to assess understory vegetation and epiphytic lichen communities in post-mining sand and gravel quarries in eastern Latvia. Community structure and functional traits were analyzed. Younger stands (9–19 years) exhibited the highest understory species diversity, dominated by hemicryptophytes, open-habitat grasses, and low-to-moderate ecological value lichens, while older stands (28 years) supported high-value epiphytic lichens and understory species typical of oligotrophic boreal forests. In 9-year-old stands, high-value epiphytic lichens comprised, on average, 5.7% (SE = 1.6) total lichen cover, while in 28-year-old stands it was 24.8% (SE = 1.9). Species with animal-mediated seed dispersal were more prevalent in younger stands, reflecting indications of animal presence based on vegetation composition and observed animal damage on trees. No invasive species were recorded, likely due to quarry isolation (≥1 km closest edge of the forest ecosystem) and proximity to mature forest margins. Our results highlight the multidimensionality of biodiversity by integrating two taxonomic groups and indicate high potential for passive natural regeneration toward Western Taiga 9010 habitat conditions under an oligotrophic environment.