Ivanovs, J., Lazdins, A. and Lang, M. 2023. The influence of forest tree species composition on the forest height predicted from airborne laser scanning data – A case study in Latvia. Baltic Forestry 29(1): 2-11
Airborne laser scanning (ALS) is used to predict different forest inventory parameters; however, the ALS point cloud properties depend on various parameters such as the type of ALS scanner employed, flight altitude and scanning angle, forest stand structure, forest tree species composition, vegetation season, etc. This study used national coverage high-resolution ALS data with minimum point density of 4 points per square meter in combination with field data from the National Forest Inventory (NFI) to build forest stand height models for forest stands dominated by 6 most common tree species in Latvian mixed forest stands, viz. Pinus sylvestris L., Betula pendula Roth, Picea abies (L.) Karst., Populus tremula L., Alnus incana (L.) Moench and Alnus glutinosa (L.) Gaertn. for the various ALS scanners employed and at different growing seasons. The selected NFI plots are divided into modelling and validation datasets in a ratio of 3 : 1. The results show that for a universal forest stand height model, the RMSE value is 1.91 m and the MAE is 1.41 m. For the forest stand height models, which are stratified by scanner, individual tree species and seasons, the RMSE value is within the limits of 1.4 m for forest stands dominated by Scots pine in leaf-on canopy condition to 3.8 m for birch in leaf-off canopy condition.
Keywords: forest inventory, airborne laser scanning, phenology, large scale forest mapping
Güney, D., Bayraktar, A., Atar, F., Chavoshi, S.H. and Turna, İ. 2023. The effects of different rooting temperatures and phytohormones on the propagation of boxwood cuttings. Baltic Forestry 29(1): 12–19
Due to its wide range of utilization possibilities, boxwood has undergone severe damage, like all over the world, caused by the excessive forest use in Türkiye from the past to the present. Therefore, it is important to propagate it to ensure the continuity of the species. In this study, the effects of different rooting table temperatures and phytohormones on rooting were investigated in the propagation of Buxus sempervirens L. subsp. sempervirens by softwood cutting. First callus and root formation dates, rooting percentage, callus percentage, root length and the number of roots were determined on the cuttings. As a result, the highest rooting percentages were obtained as 100% in IBA 3,000, IBA 5,000, IAA 3,000, NAA 3,000 and NAA 5,000 ppm treatments in Greenhouse-1 medium and IBA 3,000 and IAA 3,000 ppm treatments in Greenhouse-2 medium. In terms of root length and the number of roots, the highest values were determined as 2.01 cm and 7.83, respectively, in IBA 3,000 ppm treatment in Greenhouse-2 medium. With the high success obtained, it has been concluded that the propagation of the species can be made by using softwood cutting and the genetic infrastructure of the species can be preserved and transferred to future generations.
Keywords: Buxus sempervirens, ornamental plant, cutting propagation, auxin
Ganbaatar, B., Ishiguri, F., Nezu, I., Ohshima, J., Yokota, S., Tumenjargal, B. and Sukhbaatar, G. 2023. Effects of radial growth rate on juvenile wood properties of Pinus sylvestris planted in Mongolia. Baltic Forestry 29(1): 33–40
The establishment of forest plantations in boreal zones in Mongolia is important for wood production as well as carbon dioxide fixation. The present study aims to elucidate the juvenile wood properties (basic density, modulus of elasticity [MOE], modulus of rupture [MOR], and compressive strength parallel to grain) of plantation-grown Pinus sylvestris to promote the establishment of plantations. In addition, the effect of the radial growth rate on wood properties was also evaluated using a linear mixed-effects model. In the juvenile wood phase, wood properties were increased from the pith to bark side based on the results of model selections. Up to the 20th annual ring from the pith, the estimated mean values of basic density, MOE, MOR, and compressive strength were 0.40 g/cm3, 5.35 GPa, 65.1 MPa, and 28.4 MPa, respectively. Variance component ratios of growth categories were low in wood properties, with the exception of basic density, suggesting that the radial growth rate did not affect wood properties in the juvenile wood phase in this species growing in Mongolia. Based on the results obtained in the present study, we have concluded that although basic density in the faster growth category yielded relatively lower values, appropriate radial growth promotion during the initial stage of growth in P. sylvestris trees planted in Mongolia exerted no negative impact on juvenile wood properties.
Keywords: annual ring width, basic density, compressive strength, modulus of elasticity, modulus of rupture
Zuševica, A., Lazdiņa, D., Štāls, T.A. and Dūmiņš, K. 2023. The effect of site preparation on vegetation restoration in young hemiboreal mixed stands. Baltic Forestry 29(1): 20–32
Tree logging significantly impacts environmental conditions, increases soil and air temperature, and changes the microclimate and soil hydrology. This contributes to the changes in bryophyte and vascular plant cover and species composition. Site preparation positively affects the growth of planted trees in young stands but also causes forest understorey disturbance. During site preparation in young stands by spot mounding and disc trenching methods, new microtopographies, e.g. soil tumps and hollows are made in young stands. Site preparation generally increases vascular plant diversity, but there is a lack of information about the vegetation differences between microtopography depending on different site preparation methods and soil types. The aim of this study was to investigate how the microtopography formed during site preparation by spot mounding or disc trenching affects bryophyte and vascular plant communities in hemiboreal young stands two to three years after tree logging. Spot mounding altered vegetation composition more than disc trenching. Bryophyte species cover decreased in prepared soil, but Ellenberg’s moisture value increased; therefore, site preparation before planting contributes to the conservation of typical forest bryophyte species in young stands. Hollows lead to better typical forest habitat species preservation, but soil tumps diversify environmental conditions by providing new patches for the development of grassland habitat species that are not typical in this ecosystem, but temporally provide new ecosystem services.
Keywords: bryophytes, spot mounding, disc trenching, vascular plants, plant growth forms, Ellenberg’s indicator values
Dinçer, D. 2023. Determination of optimal plant growth regulators for breaking seed dormancy and micropropagation of Sorbus aucuparia L. Baltic Forestry 29(1): 41–49
Sorbus aucuparia L. is an important forest tree used in the reforestation of high-altitude mountainous areas, which carries significant pharmaceutical, industrial, ornamental, food, and ecological properties. However, the seed propagation and micropropagation of mature trees of S. aucuparia L., presents various difficulties which are integral aspects for the repropagation and breeding of novel cultivars. In this study, we isolated the mature embryo-containing seeds of selected varieties of S. aucuparia L. from their seed coat and used them directly as explants in vitro to investigate and determine the optimal dose of cytokinin in breaking seed dormancy and micropropagation. 3 mg/L of benzyl adenine (BA) in addition to different concentrations and combinations of kinetin (0.5, 1, and 2 mg/L), indole-3-butyric acid (IBA) (0, 1, 0.5, and 1 mg/L), and 1-naphthalene acetic acid (NAA) (0, 1, 0.5, and 1 mg/L) were applied within a Murashige and Skoog (1962) (MS) medium at germination inhibition, shoot elongation, and shoot proliferation. In the MS mediums containing BA and kinetin, germination was achieved at the end of 1 week, and shoot proliferation was achieved at the end of 3 weeks. The most successful germination (96%), tallest shoot length (mean 5.1 cm), most shoot proliferation (mean 7.2 pieces), and number of nodes (mean 9.7 pieces) were identified in the MS containing 3 mg/L BA and 1 mg/L kinetin. Direct root formation with shoot elongation occurred in 25% of explants which germinated in the MS medium. For shoots propagated without roots in this medium, 62% of these achieved rooting at the highest dose of 1 mg/L indole-3-acetic acid (IAA) using a two-stage rooting method. Rooted shoots were successfully transferred to an ex vitro medium. These results provide a basis for breaking seed dormancy of selected Sorbus L. genotypes quicker, leading to more effective clonal production.
Keywords: Sorbus aucuparia L., rowanberry, tissue culture, seed dormancy, micropropagation, in vitro