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Highlights• Scots pine transfer effect models for growth and survival, valid in both Sweden and Finland have been developed. • The models use high-resolution gridded climate data and can predict performance in future climatic conditions. • The models perform well both for unimproved and genetically improved material and can be used to develop deployment recommendations of contemporary forest regeneration material in Sweden and Finland. AbstractIn this study, we developed models of transfer effects for growth and survival of Scots pine (Pinus sylvestris L.) in Sweden and Finland using a general linear mixed-model approach. For model development, we used 378 provenance and progeny trials with a total of 276 unimproved genetic entries (provenances and stand seed check-lots) distributed over a wide variety of climatic conditions in both countries. In addition, we used 119 progeny trials with 3921 selected genetic entries (open-and control pollinated plus-tree families) for testing model performance. As explanatory variables, both climatic indices derived from high-resolution gridded climate datasets and geographical variables were used. For transfer, latitude (photoperiod) and, for describing the site, temperature sum were found to be main drivers for both survival and growth. In addition, interaction terms (between transfer in latitude and site altitude for survival, and transfer in latitude and temperature sum for growth) entail changed reaction patterns of the models depending on climatic conditions of the growing site. The new models behave in a way that corresponds well to previous studies and recommendations for both countries. The model performance was tested using selected plus-trees from open and control pollinated progeny tests. Results imply that the models are valid for both countries and perform well also for genetically improved material. These models are the first step in developing common deployment recommendations for genetically improved forest regeneration material in both Sweden and Finland.

We reviewed the genetic parameter estimates carried out from 1992 to 2006 for height increment in genetic tests of Norway spruce and Scots pine, to describe patterns of genetic variation, heritability, and genetic correlations. The material included seedling and clonal tests in Sweden, aged between 5 and 20 years. Multiple regression was used to explore relationships between parameter values and test environments. Results showed moderate narrow-sense heritabilities ( b h 2 : mean =0.29 in Norway spruce; mean =0.23 in Scots pine) that decreased with test site latitude for both species. In Norway spruce, b h 2 increased with better growth and decreased with tree age, while for Scots pine, b h 2 increased with tree age and southward transfer. The additive genetic coefficient of variation ( A V C ; mean 15%), in Norway spruce, decreased with growth as well as site latitude.in Scots pine (mean =8.5%) increased with southward transfer and more southerly test latitude. Additive and genotypic within-site genetic age-age correlations in Norway spruce were high, with mean r A and r G of 0.92 and 0.85, respectively. Corresponding across-sites estimates were on average lower. Genetic parameters were better expressed on favorable sites, at younger ages in Norway spruce and at older ages in Scots pine. The results imply that gain calculations should be based on different parameters in the two species. For maximizing genetic gain in the Swedish breeding program, testing times could be shorter for Norway spruce than for Scots pine. The investigation showed a large variation in parameter estimates from different field experiments, highlighting the importance of testing over multiple sites.

Field tests, each including 39 Á/83 Swedish plus-tree clones of silver birch (Betula pendula Roth) planted on 10 different sites in the southern part of Sweden, were evaluated at up to 10 years of age. The main conclusions can be summarized as follows. Growth traits were mostly under strong genetic influence, and showed substantial genetic variation and high potential genetic gain. Survival did not seem to be a trait of genetic importance. The genetic correlation between growth and growth cessation was weak, suggesting that it should be possible to find clones combining high growth and early autumn growth. Non-significant transfer effects for clones of different origin and weak G)/E interaction were found, indicating that southern Sweden can be treated as a single utilization zone and that few sites are needed for genetic tests. Strong genetic age )/age correlations were detected, suggesting that short test periods could be used.

Nitrogen (N) fertilization and soil scarification are common measures used in commercial forestry in the boreal zone. This study was performed to investigate how previous N fertilization in two N-limited Scots pine (Pinus sylvestris L.) stands affected the soil-solution chemistry after final felling and also to determine the effect of subsequent soil scarification. Nitrogen had been applied to study plots at different intervals, resulting in total applications of 0, 450, 900, or 1800 kg N·ha−1. Soil-solution samples were collected before and after whole-tree harvesting of the P. sylvestris stand, from undisturbed soil and also after harvesting from soil below furrows, tilts, and areas between furrows created by disc trenching. After harvesting, the K+ concentration was lower at higher N fertilization intensities. No overall effect on the N concentrations was detected. Electrical conductivity and the concentrations of Na+, K+, Mg2+, Ca2+, Cl−, NO3−–N, total N, and total C were all affected by soil scarification. The highest concentrations of these variables were found below tilts and the lowest concentrations below furrows. The experiment was repeated, at a lower monitoring intensity, at a site where the previous total N application amounted to 0 and 450 kg N·ha−1. Here the NO3−–N concentration responded to disc trenching in a similar way to that observed in the main experiment. The study shows that previous N fertilization of N-limited forest does not necessarily affect the soil-solution chemistry significantly after whole-tree harvesting.

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