Abstract
The economic importance of fast-growing tree species like silver birch (Betula pendula Roth.) is increasing due to growing demand for timber. Tree breeding provides the opportunity to increase the timber supply and thus ensure the most efficient use of forest land. Application of the results of a breeding program—the planting of young stands—is costly, and information on (potential) early income for the landowner from this investment is scarce. Therefore, the aim of this study was to characterize the gain from the use of improved silver birch material at the first commercial thinning. Material was collected from an open-pollinated progeny trial of 524 silver birch plus-trees at the age of 14 years in the central part of Latvia. Incomes from the first thinning were calculated at low and high timber prices. Heritability of growth traits (assessed as diameter at breast height) and timber value at first thinning were similar. Both timber market fluctuations and genetics had a notable impact on economic outcome: the internal rate of return for the selected best-performing families was 9.4% and 8.3% in the case of high and low timber prices, respectively; on average, for all families in the trial the figures were 8.1% and 6.7%, respectively. Results indicate profitability for investments in planting of improved regeneration material, even at a young age, in hemiboreal forests.
Highlights
The economic importance of fast-growing pioneer tree species is increasing due to the growing demand for timber both for solid wood products and chemical processing [1,2]
Silver birch (Betula pendula Roth), with its high productivity on agricultural land, is suitable for such purposes and less affected by biotic factors than conifers [3]. It has been included in tree breeding programs to select the most productive genotypes [4]
The studied trial of silver birch was located in the central part of Latvia (56◦ 440 N, 24◦ 49” E)
Summary
The economic importance of fast-growing pioneer tree species is increasing due to the growing demand for timber both for solid wood products and chemical processing [1,2]. Silver birch (Betula pendula Roth), with its high productivity on agricultural land, is suitable for such purposes and less affected by biotic factors (browsing, insect and fungus damages) than conifers [3]. It has been included in tree breeding programs to select the most productive genotypes [4]. In northern Europe, the internal rate of return for improved Norway spruce was 5.3%, but for Scots pine from a third round of seed orchards was 7% [7,8] Such rates were notably higher than in stands regenerated from unimproved material [9]. The values were estimated (calculated) based on the genetic gain, not actual harvests, and did not include information on silver birch
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