Birch establishes anywhere! So, what is there to know about natural regeneration and direct seeding of birch?

Abstract

We tested three soil scarification approaches of varying intensity (intensive preparation exposing bare mineral soil, medium intensity with a mixture of organic material and mineral soil, and control without site preparation) on six clear-felled sites in two localities in northern and central Sweden between 2018 and 2021. The effect of soil scarification intensity and soil moisture on the occurrence of naturally regenerated birch seedlings was tested one, two and three years after soil scarification, and the density of direct-seeded birch seedlings one year after seeding. In addition, we tested the effect of the annual seed rain, and differences between the two birch species, on the density of direct-seeded seedlings. Soil scarification and its interaction with soil moisture had a significant positive effect on both the occurrence of naturally regenerated birch seedlings and the density of direct-seeded birch seedlings. There was no significant effect of neither annual natural seed rain nor species choice on direct-seeded seedling density. Time since soil scarification had a significant effect on the occurrence of naturally regenerated birch seedlings. In moist soils with high volumetric water content (≥ 28%), birch seeds germinate at high rates and seedlings survive without soil scarification. In mesic soils, birch seeds germinate with higher rates after soil scarification. In dry soils, birch seeds rarely germinate regardless of any disturbance of the humus layer.

Seed for the Future: Agricultural Advancement and Innovation for Sustainability Food Systems in Tanza, Cavite

“…The way the soil is prepared affects the growing circumstances that planted trees receive in an important manner. For example, in order to minimize the risk of seedling mortality during site preparation, the choice of soil scarification needs to be areaspecific (Lidman et al, 2023) [25] . Farmers have their own way to prepare soil, however, the method they used is somehow based on their own investigation and adaptation in modern farming.…”

Within-site adaptation: Growth and mortality of Norway spruce, Scots pine and Silver birch seedlings in different planting positions across a soil moisture gradient

“…One explanation could be that silver birch is a species that requires a lot of water and that the elevated position in the mound became drier than the hinge and depression. Birch often regenerates naturally on moist to wet parts on a clear-cut area and thrives in moist conditions (Lidman et al 2023).…”