SLU news

Fast-growing broadleaf trees gathered the forest sector

Published: 27 March 2023
Hybrid aspen towards the sky. Photo.

What potential do fast-growing broadleaf trees have and how does academia, industry and forest owners view the use of these tree species in forestry? These questions were raised when the National Commission for Fast-growing Broadleaf Trees in Sweden and Södra Skog recently co-organized a workshop focused on the climate benefits and social benefits of fast-growing broadleaves.

An increased use of broadleaf trees in Swedish forestry is seen by many as a possibility for greater biodiversity and a more sustainable land use in the forests, which can also make the forests more resilient to climate change. Stakeholders from all over the country, from small to large forest owners, forest companies and forest authorities as well as PhD students and researchers from academia presented and discussed ongoing development efforts and current research related to fast-growing broadleaf trees when they gathered at a recent stakeholder event in Blekinge.

Local broadleaves give global clothes

During the introduction at Södra's pulp mill in Mörrum, the participants learned more about the production of dissolving pulp from broadleaf trees and the major investment in the OnceMore® production process. In the process, a pulp combined of cellulose from recycled cotton fibers and cellulose from wood, is produced, which is then used for the clothing industry's textile materials. Currently, half of the textile pulp in the process comes from birch, and the rest from beech and aspen, but the wish is to use more and perhaps only birch in the dissolving pulp production.

“Södra wants to increase the production of dissolving pulp for textiles and the lack of raw material is currently the biggest challenge”, said Anders Ekstrand, expert on management of broadleaf forests at Södra and board member of the National Commission for Fast-growing Broadleaf Trees in Sweden. He also emphasized that the lack of raw material means that the import of birch, mainly from the Baltic countries, is large today and that the price on the imported birch is 40% higher compared to domestic birch.

The demand for birch seedlings is also bigger than the current supply, Anders Ekstrand pointed out, which affects forest owners' ability to increase the use of birch. An incentive that can contribute to more use of birch in forestry is the price, but the lack of sawmills for birch means that the forest owner must settle with lower prices, since pulpwood pays less than timber. The Covid-19 pandemic and the war in Ukraine were described as some of the reasons for the prevailing global shortage of raw material and for the fact that today there is a great demand for birch to be used for both firewood and pulpwood, which also means that less birch goes to sawmills with higher prices.

Anneli Adler, chair of the National Commission for Fast-growing Broadleaf Trees in Sweden, emphasized that the production of broadleaves in Sweden has potential from a global perspective.

“By producing cellulose for textile materials in Sweden and more locally, land can be freed from cotton production to food production in other countries”, Anneli Adler explained.

Regulations and management

During the conference excursion, the participants visited stands of improved hybrid aspen, birch and poplar. Among the participating smaller forest owners, better guidelines were requested on how to manage birch stands. The forest owners commented that today's attitude towards birch in forestry is completely new and requires new approaches, as many have previously been taught that birch is something that should be removed from our forests.

Per Hazell, forest management specialist at the Swedish Forest Agency, presented the latest guidelines for fast-growing broadleaf trees and how the establishment and regeneration of fast-growing broadleaves should be managed according to the Forestry Act and the Environmental Act. The latest news regarding forest certification and the extent to which non-native tree species may be used were also presented.

Researchers of the future

“How can we manage our fast-growing forests when we have so little scientific-based knowledge?” The question was raised by Jaime Luna when presenting his research project, in which he will investigate whether and how fast-growing broadleaf trees can contribute to increased biodiversity in the forest.

He is one of the PhD students affiliated with Trees For Me, the new centre of excellence focused on fast-growing broadleaf trees for sustainable forestry, materials and energy in Sweden.

Other examples of PhD students who presented to the participating forest stakeholders include Caroline Rapp, who in her Trees For Me research project will examine the extent to which private forest owners are willing to increase the use of fast-growing broadleaf trees and other deciduous trees, and the factors that influence such decisions. Ola Dosumu's research project focuses on developing site index and thinning strategies for planted birch in Sweden, and the hope is that this knowledge will increase the forestry sector's competence regarding planted birch stand management.