Tag Archives: open-pollinated family.

853–861 U. Neimane, J. Katrevics, L. Sisenis, M. Purins, S. Luguza2 and A. Adamovics
Intra-annual dynamics of height growth of Norway spruce in Latvia
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Intra-annual dynamics of height growth of Norway spruce in Latvia

U. Neimane¹*, J. Katrevics¹, L. Sisenis², M. Purins¹, S. Luguza2 and A. Adamovics¹

¹Latvian State Forest Institute ‘Silava’, Rigas 111, LV 2169 Salaspils, Latvia
²Latvia University of Agriculture, Forest Faculty, Akademijas 11, LV 3001 Jelgava, Latvia
*Correspondence: una.neimane@silava.lv

Abstract:

 Norway spruce (Picea abies (L.) Karst.) is a tree species with the highest economic importance in northern Europe. Therefore, it is important to improve knowledge of the potential effects of climatic changes on the growth of this tree species. An essential part of the information is the tree’s intra-annual growth cycle. There are comprehensive studies describing the formation of radial increments of coniferous trees; however, information on height growth in hemiboreal forests is scarce. The aim of our study was to characterize the intra-annual height growth of Norway spruce in Latvia. The data was collected from two Norway spruce trials located in in former arable and forest land in the central part of Latvia, including 89 and 68 open-pollinated families (respectively) of plus-trees. Weekly height increment measurements of 20 trees per family were carried out during the 9th growing season. Growth intensity culminated in 10 ± 0.2 mm day-1, following similar trend, but resulting consistently in significantly different values between the trials; the higher growth intensity was observed in higher trees and families, which also showed higher frequency of lammas shoots, boosting their height superiority even further. Significant family effect on all coefficients of shoot elongation curves, described by Gompertz model, was found. Both tree height and height increment at family mean level was strongly correlated with the asymptote parameter (rfam = 0.93, P<0.01) and the growth rate parameter (rfam = -0.70, P<0.01).

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407–417 A. Jansons, U. Neimane, B. Dzerina and A. Adamovics
Influence of lammas shoots on height of young Scots pines in Latvia
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Influence of lammas shoots on height of young Scots pines in Latvia

A. Jansons*, U. Neimane, B. Dzerina and A. Adamovics

Latvian State Forest Institute ‘Silava’, Rigas 111, LV2169 Salaspils, Latvia
*Correspondence: aris.jansons@silava.lv

Abstract:

Scots pine is a commercially important tree species in northern Europe. Climate changes in combination with genetics cause differences in the tree growth rhythm, including the formation of lammas shoots. The aim of the study was to assess the relation between the occurrence of lammas shoots and the height of young Scots pines and its implications in tree breeding. Tree height was repeatedly measured, and the presence of lammas shoots was assessed at the end of the 4th through 8th growing seasons in two open-pollinated progeny trials (Daugmale and Norupe, both including the same 61 families) in the central part of Latvia. The proportion of trees with lammas shoots (max. 23%) decreased over the observation years. In both trials, at the age of 7 years, trees that had formed lammas shoot during at least one of the observed years were significantly (P < 0.001) higher than trees with no lammas shoots: 226 ± 3.5 cm vs 213 ± 3.3 cm in Norupe and 146 ± 3.9 cm vs 121 ± 1.9 cm in Daugmale, respectively. When only dominant trees (1,000 ha-1) were considered, the height superiority of trees with lammas shoots remained in Daugmale (trial with highest proportion of trees with lammas shoots), but not in Norupe. The earliest formed lammas shoots (assessed in the 4th growing season) had the strongest effect on the tree height. A correlation between the mean height and the proportion of trees with lammas shoots in the particular family was not found (P > 0.05).

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354-360 U. Neimane,, M. Zadina, L. Sisenis, B. Dzerina and A. Pobiarzens
Influence of lammas shoots on productivity of Norway spruce in Latvia
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Influence of lammas shoots on productivity of Norway spruce in Latvia

U. Neimane¹,*, M. Zadina¹, L. Sisenis², B. Dzerina¹ and A. Pobiarzens³

¹Latvian State Forest Institute ‘Silava’, Rigas 111, LV2169 Salaspils, Latvia
²Latvia University of Agriculture, Forest Faculty, Akademijas 11, LV3001 Jelgava ,Latvia
³Forest Competence Centre, Dzerbenes 27, LV1006 Riga, Latvia *Correspondence: una.neimane@silava.lv

Abstract:

The Norway spruce is widely spread in Eastern Europe and it is managed mainly for the production of sawlogs, though its logging residues are now increasingly used for the production of wood chips for bioenergy. The growth of the Norway spruce is and will be affected by climatic changes; one of the possible effects might be an increase in the frequency of trees with lammas shoots. Therefore, the aim of this study was to assess the influence of lammas shoots on the length of height increment of young Norway spruce in Latvia. Tree height and height increment was repeatedly measured and the presence of lammas shoots, bud flushing grades and frost injuries were assessed in two young (8–13 years) open-pollinated progeny tests in the central part of Latvia (56°46´N, 24°48´E). The mean portion of trees with lammas shoots in one experiment was 6% at the end of 8th growing season. In another experiment, it was 8.7%, 26.9% and 8.1% at the end of 10th, 11th and 13th growing seasons, respectively; 32.3% of trees had lammas shoots at least in one of three seasons. Faster growing and earlier flushing trees had a significantly higher frequency of lammas shoots. Lammas shoots increased the length of annual height increment by 10 to 14 cm, resulting in a 14–20% taller tree height at the age of 13 years. The reduction of height increment as a result of frost damages for very early flushing trees was less pronounced for trees with lammas shoots than without them.

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