Assessing temporal response to biomass removal: A framework for investigating evolving constraints on boreal stand development

2021 ◽  
Vol 497 ◽  
pp. 119518
Author(s):  
Robert L. Fleming ◽  
Dave M. Morris ◽  
Paul W. Hazlett
Silva Fennica ◽  
2021 ◽  
Vol 55 (3) ◽  
Author(s):  
Yrjö Nuutinen ◽  
Jari Miina ◽  
Timo Saksa ◽  
Dan Bergström ◽  
Johanna Routa

Young, dense forest in Finland and Sweden urgently need to receive first thinning. In such stands, conventional selective thinning methods make the harvester work time consuming and, thus, costly. To make small-sized trees economically competitive as raw material for bioenergy and biorefining, new harvesting technologies and/or thinning methods need to be developed. A potential solution is boom-corridor thinning (BCT), rendering effective cutting work. The aim of this study was to describe and compare the stand structure of two Scots pine stands ( L.) and one birch-dominated ( Roth with natural downy birch, Ehrh.) stand after BCT and selective thinning at the first thinning phase. Furthermore, simulations were conducted to predict the future stand development after the first thinning treatments. The density of the growing stock was 16–46% higher after BCT treatment than after selective thinning because BCT stands included more small and supressed trees with a dbh < 100 mm. However, the numbers of future crop trees with a dbh > 140 mm per hectare were at the same level in both treatments. The stem volume removal per hectare did not differ between treatments. However, simulation of stand development and intermediate thinning and clearcutting revealed that the total removal volume was 10–18% higher in BCT stands compared to selectively thinned ones. The saw log volumes harvested did, however, not differ between treatments. This study shows that BCT generates stands with higher biodiversity compared to conventional thinning as higher levels of biomass removal can be reached throughout stand rotations.Pinus sylvestrisBetula pendulaB. pubescens


Author(s):  
Colin P. R. McCarter ◽  
Stephen D. Sebestyen ◽  
Susan L. Eggert ◽  
Kristine M. Haynes ◽  
Randall K. Kolka ◽  
...  

2013 ◽  
Vol 164 (9) ◽  
pp. 262-270 ◽  
Author(s):  
Peter Ammann

Is young growth tending successful in the Swiss Plateau region? Analysis and implications (essay) The effect of the cost-intensive young growth tending used up to the present in the region of the Swiss Plateau is analysed using different approaches. It is evident that young growth tending is not only ineffective with respect to diameter growth but even hinders stand development. Negative effects on quality from young growth tending are also recognised. This is often due to premature interventions in the natural processes of self-differentiation and subsequent systematic errors in the thinning. Furthermore, the effect of tending measures on the tree species composition is often overestimated because in the first 10 to 20 years of stand development, it is primarily the rejuvenation strategy and the site which are decisive. As an alternative course of action, tending concepts are proposed which rely on biological rationalisation and future tree thinning, to achieve future trees which are as vigorous as possible. These are not only more effective, but are also significantly less expensive.


2021 ◽  
Author(s):  
Anna Kirschbaum ◽  
Oliver Bossdorf ◽  
J F Scheepens

Abstract Aims Plant populations in managed grasslands are subject to strong selection exerted by grazing, mowing and fertilization. Many previous studies showed that this can cause evolutionary changes in mean trait values, but little is known about the evolution of phenotypic plasticity in response to land use. In this study, we aimed to elucidate the relationships between phenotypic plasticity – specifically, regrowth ability after biomass removal – and the intensity of grassland management and levels of temporal variation therein. Methods We conducted an outdoor common garden experiment to test if plants from more intensively mown and grazed sites showed an increased ability to regrow after biomass removal. We used three common plant species from temperate European grasslands, with seed material from 58 – 68 populations along gradients of land-use intensity, ranging from extensive (only light grazing) to very intensive management (up to four cuts per year). Important findings In two out of three species, we found significant population differentiation in regrowth ability after clipping. While variation in regrowth ability was unrelated to the mean land-use intensity of populations of origin, we found a relationship with its temporal variation in P. lanceolata, where plants experiencing less variable environmental conditions over the last 11 years showed stronger regrowth in reproductive biomass after clipping. Therefore, while mean grazing and mowing intensity may not select for regrowth ability, the temporal stability of the environmental heterogeneity created by land use may have caused its evolution in some species.


2021 ◽  
Author(s):  
Krešimir Kavčić ◽  
Tena Radočaj ◽  
Luca Corlatti ◽  
Toni Safner ◽  
Ana Gračanin ◽  
...  

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