Tag Archives: growth intensity

xxx S. Šēnhofa, M. Zeps, L. Ķēniņa, U. Neimane, R. Kāpostiņš, A. Kārkliņa and Ā. Jansons
Intra–annual height growth of hybrid poplars in Latvia. Results from the year of establishment
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Intra–annual height growth of hybrid poplars in Latvia. Results from the year of establishment

S. Šēnhofa, M. Zeps, L. Ķēniņa*, U. Neimane, R. Kāpostiņš, A. Kārkliņa and Ā. Jansons

Latvia State Forest Research Institute Silava, Rigas street 111, LV–2169 Salaspils, Latvia
*Correspondence: laura.kenina@silava.lv

Abstract:

Fast growing hybrid poplars (Populus spp.) could be successfully used for bioenergy as well as wood production. Productivity of clones had been studied in Baltic States recently, however, little is known about the impact of weather conditions on poplar height growth, thus the potential effect of climate change. Therefore, the aim of this study was to characterize the intra–annual height growth of hybrid poplar clones in Latvia. Height increment of 12 hybrid poplar clones was measured on average with an 11–day interval in the first vegetation season in 2016. Annual shoot height was on average 81.0 ± 6.8 cm, significantly (p < 0.001) depending on the poplar clone. Use of long (0.5 m) instead of short (0.3 m) cuttings leaded to larger annual height increment during the year of establishment of the plantation. From June to September the mean growth intensity was 10 to 15 mm day-1. The trend of height growth intensity, described by Gompertz model, indicated that the poplar clones with largest height had relatively fast increase of the growth intensity from June to July. Changes of growth intensity was linked both with the temperature and sum of precipitation. This tendency was not so pronounced for clones with largest height increment, emphasizing the importance of the phenotypic plasticity in selection of clones for plantations.

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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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