The threat of ash dieback (Hymenoscyphus fraxineus), which is decimating European ash (Fraxinus excelsior) populations, has heightened the need for a cheap and simple method to propagate potentially tolerant trees. We tested the effects of mother plant age, mycorrhiza, rooting hormone, timing and substrate type on the rooting of ash cuttings in order to optimise current propagation techniques. Semi-hardwood and hardwood cuttings from two age classes of mother plant were subject to factorially combined treatments. These included different substrate types (peat-based and peat-free), rooting hormone concentrations (0–2% indole-3-butyric acid), and mycorrhizal inoculations. The most effective treatment was tested on cuttings from an intermediate age class of potentially ash dieback-tolerant trees. None of the cuttings from trees of an intermediate or older age rooted. Cuttings taken from 1–3-year-old plants rooted readily, especially when taken as semi-hardwood cuttings (91% rooted, whereas 54% of hardwood cuttings rooted). The use of higher rooting hormone concentrations improved rooting percentages in all cuttings from young plants by about 10%. There were no differences in rooting between peat-based and peat-free substrates. Finally, mycorrhizal inoculations had no effect on semi-hardwood cuttings, but inhibited the rooting of hardwood cuttings. A good protocol was obtained using semi-hardwood cuttings of young material, which could be used to propagate juvenile or rejuvenated disease-tolerant ash.

Our study, conducted in the mixed boreal forest of western Quebec, Canada, assessed the effectiveness of various site preparation treatments to promote black spruce (Picea mariana (Mill.) BSP) regeneration on wet sites invaded by speckled alder (Alnus incana subsp. rugosa (du roi) R.T. Clausen) following harvest. In 2019, four treatments were established: scalping, mulching, soil inversion, and an untreated control. Black spruce seedlings were planted in 2020. Measurements taken in 2021, at the end of the second growing season, revealed that the treatments doubled the growth and size of seedlings compared to the control group. While differences were small, seedlings in mulched plots showed significantly greater height growth and annual shoot elongation compared to those in inverted plots. The treatments also reduced competing species cover, while promoting the presence of grasses. Environmental conditions and soil properties did not vary significantly between treatments and the control group, except for pH and potassium in some cases. These results suggest that all three site preparation treatments tested are effective in establishing black spruce regeneration on wet sites invaded by speckled alder. Long-term monitoring is needed to assess the economic impact of treatments and better understand the role of alder in nitrogen availability on treated sites.

The primary objective of this study was to develop a universal, lightweight, and mobile system that seamlessly integrates the scanner with the construction of the horizontal spray boom at a forest nursery. This innovative approach holds tremendous potential for advancing the assessment and management of forest seedlings, providing valuable insights and streamlining nursery operations. Multichannel spectral devices mounted on irrigation booms can be used to significantly enhance the quality assessment of forest seedlings in container nurseries. Contrary to traditional and time-consuming approaches such as laboratory analysis or destructive sampling, an active canopy optical sensor operates independently of ambient light conditions and does not necessitate spectral reference readings. Mobile irrigation systems in nurseries are ideal for incorporating plant scanners owing to their exceptional repeatability, ensuring consistently high-quality results. In our study, we rigorously tested a set of four ACS 435 Holland Scientific active crop canopy sensor along with the Vega Plus C21 laser sensor, all strategically positioned on a sprinkler boom above the nursery production field from May to September 2022. The seamless integration of these devices with the GeoSCOUT X Holland Scientific data acquisition unit formed the foundation of our system. The primary objective of this study was to develop a universal, lightweight, and mobile system that seamlessly integrates the scanner with the construction of the horizontal spray boom at a forest nursery. This innovative approach holds tremendous potential for advancing the assessment and management of forest seedlings, providing valuable insights and streamlining nursery operations.

Intensively managed fast-growing tree plantations may affect plant diversity, and we have little knowledge on how it is affected by site origin in order to better orientate site selection for their establishment. The aim of this study was thus to determine the impact of site origin on plant diversity in intensively managed hybrid poplar plantations. We investigated vascular and non-vascular plant communities within fast growing hybrid poplar plantations (PEH) established on abandoned agricultural lands (AAL) with herbaceous or shrubby vegetation, and on previously forested lands, and compared them to adjoining non-afforested surrounding sites. Our results show that PEH plantations established on herbaceous and shrubby AALs had similar or higher plant diversity even though they contained no forest species after 15 years. When established on previously forested lands, PEH plantations favored the establishment of ruderal species compared to their non-reforested equivalents, but plant diversity and richness tended to decrease following plantation establishment. Thus, if site selection is made to preserve or increase plant diversity, abandoned agricultural lands should preferentially be chosen rather than previously forested sites to install intensively managed hybrid poplar plantations.