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Growth of retained Scots pines and their influence on the new stand

Jakobsson, Rikard (2005). Growth of retained Scots pines and their influence on the new stand. Diss. (sammanfattning/summary) Umeå : Sveriges lantbruksuniv., Acta Universitatis Agriculturae Sueciae, 1652-6880 ; 2005:34
ISBN 91-576-7033-1
[Doctoral thesis]

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In the 1990s, management practice in forestry changed from a main focus on timber production into a deeper concern also for biological diversity and aesthetics. Two features of the changing priorities were retention of old trees on final harvest areas and increasing edge zones due to smaller-sized clear-cuts. The overall purposes of this thesis were to establish the growth of retained Scots pines (Pinus sylvestris L.) and quantify the effect of their competition on the new stand, and to establish the effect of edge zones on the production in adjacent young and old stands. Four separate studies were carried out to (i) establish the growth of Scots pines after liberation and their effect on the production in the new stand on a specific site, (ii) model the volume of the new stand as dependent on distance to a retained tree under different site conditions, (iii) model the thinning response of totally liberated Scots pines under different site conditions and establish the variation in basal area growth, (iv) establish the tree growth and composition of field vegetation in edge zones between adjacent old and young Scots pine stands. Data on tree growth (six cores per tree) and volume of surrounding stand was gathered from 104 totally liberated retained Scots pines and from edges of four borders between young and old stands. The effect on the production in the new stand was estimated as a reduction with 2-4 % per ha over one rotation with 10 evenly dispersed Scots pines per ha. During the same period the retained Scots pines had grown with more than that. Retained trees increased their growth in basal area after liberation independently of age. The response in basal area growth culminated 5-7 years after initial growth increase on a level of 2.5 above that before liberation and lasted for more than 20 years. Growth was expressed as function of diameter, age and height level in the tree. The coefficient of variation in residuals in basal area growth was estimated as 41 % composed of random variation within trees, between trees and between stands to approximately equal shares. Age and diameter explained 34 % of the variation in basal area growth. Retained trees increased their growth in the lower trunk the most after liberation resulting in deterioration in stem form, though less than expected. Over time, the stem form improved. Of field vegetation lichens (Cladonia sp.) and heather (Calluna vulgaris L.) were more common close to the retained trees than further away. The spatial extent of the effect of an edge on production in old and young Scots pine stands was 5 m. In the young stands the volume in the 5 m zone closest to the edge was 10 % of that beyond 5 m. The equivalent zone in the old stand had a 57 % higher basal area than further away. The vegetation cover in the edge zones differed from that in the stands with increased lichen and decreased blueberry (Vaccinium myrtillus L.), lingonberry (V. vitis-idaea L.) and bryophytes.

Authors/Creators:Jakobsson, Rikard
Title:Growth of retained Scots pines and their influence on the new stand
Series Name/Journal:Acta Universitatis Agriculturae Sueciae
Year of publishing :March 2005
Number of Pages:33
ALLI. Jakobsson, R. and Elfving, B. 2004. Development of an 80-year-old mixed stand with retained Pinus sylvestris in Northern Sweden. Forest Ecology and Management 194, 249-258. II. Jakobsson, R. and Elfving, B. Effects of retained trees on the production of Scots pine stands in Sweden. Manuscript. III. Jakobsson, R. and Elfving, B. Retained pines growth pattern and growth variation as measured on increment cores from standing trees. Manuscript. IV. Jakobsson, R. and Nilsson, M. Effect of border zones on volume production in Scots pine stands. Manuscript.
Place of Publication:Umeå
ISBN for printed version:91-576-7033-1
Publication Type:Doctoral thesis
Full Text Status:Public
Agris subject categories.:K Forestry > K10 Forestry production
Subjects:Not in use, please see Agris categories
Agrovoc terms:pinus sylvestris, forest stands, growth, yields, plant competition, thinning, plant response
Keywords:Pinus, retention, remnant, growth variation, yield, competition, liberation, thinning response
Permanent URL:
ID Code:782
Department:(S) > Institutionen för skogsskötsel
Deposited By: Rikard Jakobsson
Deposited On:22 Mar 2005 00:00
Metadata Last Modified:02 Dec 2014 10:07

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