Sprout Regeneration of Shrub Willows after Cutting

Abstract

Shrub willow (Salix L. spp.) is a promising bioenergy resource crop due to its high growth rates and superb regenerative ability. Sprouting capacity is influenced by many factors, such as parent tree species and size, which are important limiting factors for stump survival or sprout growth. In this study, we aimed to quantify the survival and regeneration performance of sprouts (including sprout height, sprout diameter, sprout number, leaf morphological traits, leaf chlorophyll content, and ground part dry biomass) from the stumps of two Salix species from three diameter classes (10–15, 16–19, and 20–30 mm). An attempt was made to explore why the stump size affects the regeneration of willows by analyzing the carbon and nitrogen proportion of stumps. Stump survival did not differ between the two Salix species. However, the sprout regeneration of S. triandra was much better than that of S. suchowensis. An increase in stump diameter caused increases in the number of sprouts produced per stump, the mean height and basal diameter of sprouts per stump, the leaf chlorophyll content, and the biomass of sprouts per stump. By contrast, stump diameter did not significantly affect stump survival. The results indicate that the larger stumps store more carbon and nitrogen than small-sized stumps, which may be one of the reasons why the larger willow stumps have a stronger resprouting ability. This study provides essential information regarding the sprout regeneration of short-rotation coppice willow plantations after harvest.

Population Variability of Almond-Leaved Willow (Salix triandra L.) Based on the Leaf Morphometry: Isolation by Distance and Environment Explain Phenotypic Diversity

“…Almond-leaved willow research has been scarce, with generally little previously published data on the species [47][48][49][50]68]. Krüssmann [68] reported leaf length (LL) values in the range of 5 to 10 cm.…”

“…Growing in a wide variety of habitats, on a wide range of soil types and in various altitudes, almond-leaved willow is empirically adaptable, although previous research to support the observed population variability is unknown to us. To this date, this species has been a part of a research into Salix germplasm [47] and some research into leaf anatomy [48,49] and sprout regeneration [50] has been conducted. Most recently, the pollen grain morphology has been analysed and the species has been separated from the other species within the subgenus Salix, but remained morphologically similar to numerous species from subgenera Chamaetria and Vetrix [51].…”