How to use or limit the vegetative regeneration of birch
The approach to birch in agricultural practice has changed significantly in recent years, from an originally undesirable tree species, it has gradually become a welcome tree species with an amelioration effect.
Photo: Multiple sprouts from birch stumps; author Jiří Souček
High fertility from an early age, easy seed dispersal by the wind and rapid regrowth make birch a suitable tree species for natural and artificial regeneration in a wide range of habitats. As the proportion of birch in our forests increases, interest in its appropriate management will increase.
Birches can be regenerated not only through generative reproduction but also by vegetative propagation means using stump sprouts. The presence of sprouting capacity helps ensure the survival and regrowth of trees in the event of mechanical damage to the lower trunk or sudden changes in environmental conditions.
Stump sprouts grow from dormant buds located at the base of the trunk. Because these sprouts utilise the existing root system, their growth in the initial years tends to exceed that of birches grown from seed. However, the growth of stump sprouts in birch trees can have both positive and negative effects on forest stands.
The negative impact of birch stump sprouting is a crucial consideration when focusing on forest regeneration and initial silvicultural interventions. In mixed stands, birch often grows taller than the target tree species, which can hinder their development. This height advantage leads to shading and increased competition for light, water, nutrients, and space, ultimately slowing the growth of the target tree species.
Photo: Sprouting shoots attract game, and their chewing damage can greatly limit further growth; author Jiří Souček
When birch trees and target tree species grow close together in the crown area, the flexible branches of the birch can cause mechanical damage to the shoots of the target trees through a phenomenon known as whipping. Removing birch to support the growth of target tree species can lead to the formation of saplings, but repeated removals increase the costs of forest restoration and maintenance.
Birch saplings have the advantage of rapid growth and biomass production. In the Nordic countries, managing birch in the form of a low forest for energy-usable biomass is an alternative to traditional forest management practices.
While the biomass production of birch stands is typically lower than that of other fast-growing tree species, growing birch presents no risks associated with non-native species or their clones. Additionally, the costs of establishing birch stands are often significantly lower due to the species’ ability to regenerate naturally.
Photo: As marginal shoots grow, they can tilt due to competition and may overturn; author Jiří Souček
Interest in short-rotation managed young forests has been increasing in recent years. In addition to biomass production, this interest primarily aims to preserve biological diversity. However, there is a knowledge gap regarding birch stump regeneration and the factors affecting it in Central Europe.
Understanding the potential for birch stump regeneration, as well as its growth, biomass production, and disposal options, is valuable not just in forestry but also in other contexts where birch stump regeneration may limit public interest in maintaining areas without forests. This includes locations such as roadways, pipeline routes, and other sites. Selecting the appropriate technique and timing for disposal can help reduce the costs associated with maintaining these forest-free areas.
This interesting topic, which is not widely known, was studied by scientists at the Opočno Research Station, VÚLHM, v. v. i. They developed a certified methodology titled „Vegetativní obnova břízy – potenciál a možnosti jeho omezení“ (Vegetative Regeneration of Birch: Potential and Possibilities for Limitation). This methodology was created during the implementation of the project NAZV QK22020008 „Komplexní vyhodnocení plnění produkčních a mimoprodukčních funkcí lesa u porostů přípravných dřevin“, which focused on the comprehensive evaluation of the production and non-production functions of forests in stands of preparatory tree species.
Photo: In forest stands with sufficient canopy cover, young trees often die within one to two years after logging. Author Jiří Souček
This methodology summarises current knowledge on the vegetative regeneration of birch through stump sprouts and provides insights into the growth potential of cuttings. It includes detailed procedures for eliminating sprouts and addresses the associated risks during initial silvicultural interventions. The information presented will facilitate better decision-making regarding the use or removal of birch stump sprouts.
The methodology offers guidance on the factors that influence the growth potential of birch stump sprouts and the production of biomass suitable for energy use under different management options. Additionally, it outlines practical procedures that could restrict the growth potential of these sprouts.
The paper „Vegetativní obnova břízy – potenciál a možnosti jeho omezení“ (Vegetative Regeneration of Birch: Potential and Possibilities for Limitation) can be downloaded here.
Author: Ing. Jiří Souček, Ph.D., VÚLHM, v. v. i., Research Station (Výzkumná stanice) Opočno, e-mail: soucek@vulhmop.cz
Based on the original, prepared by Ing. Jan Řezáč, VÚLHM, v. v. i., e-mail: rezac@vulhm.cz
Introductory photo: Sprouts emerge from buds located above the soil surface, and thick bark in older ages restricts the growth of shoots. Author Jiří Souček