Towards Silviculture Guidelines to Produce Large-Sized Silver Birch (<i>Betula pendula</i> Roth) Logs in Western Europe

Forest health problems arising from climate change, pests and pathogens are a threat to the main timber tree species. As a result, silver birch (<i>Betula pendula</i> Roth) has become a precious asset for meeting oncoming forestry challenges in western Europe. However, silviculture guide...

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Main Authors: Héloïse Dubois, Hugues Claessens, Gauthier Ligot
Format: Article
Language:English
Published: MDPI AG 2021-05-01
Series:Forests
Subjects:
Online Access:https://www.mdpi.com/1999-4907/12/5/599
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spelling doaj-3636598bc40e427d89a0d9b05879873f2021-05-31T23:38:32ZengMDPI AGForests1999-49072021-05-011259959910.3390/f12050599Towards Silviculture Guidelines to Produce Large-Sized Silver Birch (<i>Betula pendula</i> Roth) Logs in Western EuropeHéloïse Dubois0Hugues Claessens1Gauthier Ligot2TERRA Teaching and Research Centre (Forest Is Life), Gembloux Agro-Bio Tech, University of Liege, Passage des Déportés 2, BE-5030 Gembloux, BelgiumTERRA Teaching and Research Centre (Forest Is Life), Gembloux Agro-Bio Tech, University of Liege, Passage des Déportés 2, BE-5030 Gembloux, BelgiumTERRA Teaching and Research Centre (Forest Is Life), Gembloux Agro-Bio Tech, University of Liege, Passage des Déportés 2, BE-5030 Gembloux, BelgiumForest health problems arising from climate change, pests and pathogens are a threat to the main timber tree species. As a result, silver birch (<i>Betula pendula</i> Roth) has become a precious asset for meeting oncoming forestry challenges in western Europe. However, silviculture guidelines to produce high-value birch logs in this region are lacking. Producing large-sized birch trunks requires crown release, i.e., removing crown competitors around selected target trees. These interventions are currently seldom carried out or else too late when the growth potential of the trees has already diminished. This study set out to ascertain the diameter at breast height (dbh) that could be reached by crown-released birch, determine dbh-associated crown diameters, and further characterize the gain obtained from early crown release on birch dbh growth. We measured 704 birch trees that had undergone crown release in 38 naturally regenerated pure birch stands in southern Belgium and in northeastern France. We then evaluated the variation in stem and crown diameter, and analyzed increments in response to the earliness of the interventions in three subsamples, also compared with control target birch. We found that trees with a dbh of 50 cm could be grown within 60 years. Based on crown diameter, to produce 40, 50 and 60 cm dbh trunk, the distance required between target birch trees at the end of the rotation was around 8, 10 and 12 m. With no intervention and in ordinary dense birch regenerations, the dbh increment was found to decline once the stand reached age 4–7 years. Starting crown release in stands aged 4–5 years can double the dbh increment of target trees and provide a continual gain that may last up to 20 years. When birch crowns are released after 9–12 years, it may already be too late for them to recover their best growth rate. Our contribution should help complete emerging guidelines in support of birch silviculture development.https://www.mdpi.com/1999-4907/12/5/599diameter at breast height growthcrown releasecrop tree silviculturecrown development
collection DOAJ
language English
format Article
sources DOAJ
author Héloïse Dubois
Hugues Claessens
Gauthier Ligot
spellingShingle Héloïse Dubois
Hugues Claessens
Gauthier Ligot
Towards Silviculture Guidelines to Produce Large-Sized Silver Birch (<i>Betula pendula</i> Roth) Logs in Western Europe
Forests
diameter at breast height growth
crown release
crop tree silviculture
crown development
author_facet Héloïse Dubois
Hugues Claessens
Gauthier Ligot
author_sort Héloïse Dubois
title Towards Silviculture Guidelines to Produce Large-Sized Silver Birch (<i>Betula pendula</i> Roth) Logs in Western Europe
title_short Towards Silviculture Guidelines to Produce Large-Sized Silver Birch (<i>Betula pendula</i> Roth) Logs in Western Europe
title_full Towards Silviculture Guidelines to Produce Large-Sized Silver Birch (<i>Betula pendula</i> Roth) Logs in Western Europe
title_fullStr Towards Silviculture Guidelines to Produce Large-Sized Silver Birch (<i>Betula pendula</i> Roth) Logs in Western Europe
title_full_unstemmed Towards Silviculture Guidelines to Produce Large-Sized Silver Birch (<i>Betula pendula</i> Roth) Logs in Western Europe
title_sort towards silviculture guidelines to produce large-sized silver birch (<i>betula pendula</i> roth) logs in western europe
publisher MDPI AG
series Forests
issn 1999-4907
publishDate 2021-05-01
description Forest health problems arising from climate change, pests and pathogens are a threat to the main timber tree species. As a result, silver birch (<i>Betula pendula</i> Roth) has become a precious asset for meeting oncoming forestry challenges in western Europe. However, silviculture guidelines to produce high-value birch logs in this region are lacking. Producing large-sized birch trunks requires crown release, i.e., removing crown competitors around selected target trees. These interventions are currently seldom carried out or else too late when the growth potential of the trees has already diminished. This study set out to ascertain the diameter at breast height (dbh) that could be reached by crown-released birch, determine dbh-associated crown diameters, and further characterize the gain obtained from early crown release on birch dbh growth. We measured 704 birch trees that had undergone crown release in 38 naturally regenerated pure birch stands in southern Belgium and in northeastern France. We then evaluated the variation in stem and crown diameter, and analyzed increments in response to the earliness of the interventions in three subsamples, also compared with control target birch. We found that trees with a dbh of 50 cm could be grown within 60 years. Based on crown diameter, to produce 40, 50 and 60 cm dbh trunk, the distance required between target birch trees at the end of the rotation was around 8, 10 and 12 m. With no intervention and in ordinary dense birch regenerations, the dbh increment was found to decline once the stand reached age 4–7 years. Starting crown release in stands aged 4–5 years can double the dbh increment of target trees and provide a continual gain that may last up to 20 years. When birch crowns are released after 9–12 years, it may already be too late for them to recover their best growth rate. Our contribution should help complete emerging guidelines in support of birch silviculture development.
topic diameter at breast height growth
crown release
crop tree silviculture
crown development
url https://www.mdpi.com/1999-4907/12/5/599
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