INTRA-ANNUAL HEIGHT GROWTH OF SILVER BIRCH (BETULA PENDULA) IN LATVIA

References: 17th International Multidisciplinary Scientific GeoConference SGEM 2017, www.sgemviennagreen.org, SGEM2017 Vienna GREEN Conference Proceedings, ISBN 978-619-7408-27-0 / ISSN 1314-2704, 27 - 29 November, 2017, Vol. 17, Issue 33, 593-600 pp; DOI: 10.5593/sgem2017H/33/S14.074

ABSTRACT

Silver birch is economically important tree species in Latvia. Currently most of clearcuts in stands of this tree species are regenerated naturally, however, there is an increasing demand of birch plants. Around 5 mil. plants are produced in Latvia annualy, exceeding the amounts in other countries in the region. With a goal to intensity the forest management, while propagating only the best genotypes and reducing initial spacing in order to ensure large radial increment, recently testing of vegetatively propagated plant material of this tree species had been started. Aim of our study was to characterize the development of height increment of vegetatively propagated silver birch during the first vegetation period after planting. Height increment of 15 clones (on average 10 trees per clone) and 53 seedlings was measured regularly – 12 times during the growing period, on average once per 10 days – in and experiment established on former agricultural land in central part of Latvia.
Initial height for vegetatively propagated birches was 76±3.0 cm (±CI), for seedlings 84±15.4, length of annual height increment 13±1.7 cm and 16±6.3 cm cm, respectively. Using initial height as covariate, no significant impact of type of planting material (vegetatively propagated vs. seedlings) was found. Clone (genotype) was a significant factor affecting total length of annual height increment. Clones with largest annual height increment had faster growth rate at the beginning of measurement period.

Keywords: growth intensity, height increment, microclonal propagation, clone