Articles containing the keyword 'rooting'

Cutting propagation of forest trees has recently been done in Finland mainly by the Foundation for Forest Tree Breeding. The aim has been to develop methods which could be used in forest nurseries for large scale production of rooted cuttings. Methods are being developed for tree species which seem to offer possibilities for economically profitable vegetative propagation. The most important tree species has been Norway spruce (Picea abies (L.) RH. Karst.), and also larches (Larix sp.), lodgepole pine (Pinus contorta), birches (Betula sp.), alders (Alnus sp.) and hybrid aspen (Populus tremula x P. tremuloides) are propagated. The sensitive rooting phase takes place in plastic greenhouses which have ventilation on the roof top, mist irrigation equipment and separate heating systems for the air and the ground. Methods used for cutting propagation of Norway spruce, lodgepole pine, larch species and broadleaved trees are described.

The PDF includes a summary in Finnish

• Niiranen, E-mail: jn@mm.unknown

Needle fascicles of Scots pine (Pinus sylvestris L.) were rooted in a standard Jacobsen’s germination apparatus. The apparatus was found to be suitable for rooting at least on laboratory scale. The best rooting substrate was living Sphangnum, which remained sufficiently moist in the germination containers throughout the experiments. In a comparison of various growth substrate treatments, the best result was obtained with a combination of IAA (100 mg/l) and thiamine (5 mg/l). The rooting percentage using these growth substances with Sphagnum as the rooting medium was in the first experiment 30 and in the second 48.

The PDF includes a summary in Finnish.

• Yli-Vakkuri, E-mail: py@mm.unknown
• Pelkonen, E-mail: pp@mm.unknown

A study of the in vitro rooting process in mature alder (Alnus glutinosa (L.) Gaertn.) shoots is described. Microcuttings from shoots cultured in vitro were transferred to a half-strength Woody Plant Medium containing 0 or 0.1 mg l^–1 indole-3-butyric acid (IBA) for 0 to 7 days. The presence of IBA in the medium increased the rooting percentage, number of roots, percentage of lateral roots, and length of the shoots. Histological studies were carried out with shoots treated with 0 or 0.1 mg l^–1 IBA for 7 days. According to these criteria, treatment with IBA for 2–3 days proved to be the most successful. In both treatments, substancial reactivation of cell division was observed at the base of the shoots after 1 day. Some cambial zone and adjacent phloem cells became dense cytoplasm, having nuclei with prominent nucleoli. The first cell divisions were also observed at this time. In the treatment with IBA (0.1 mg l^–1 for 7 days), meristemoids became individualized, consisting of densely staining cells, by day 3. Identifiable conical shaped root primordia with several cell layers were visible after 4–5 days. Roots with an organized tissue system emerged from the stem after 6 days in the IBA-treated shoots. Meristemoid formation was delayed until the fourth day and root emergence until the eight day in the control treatment (no IBA).

• San José, Instituto de Investigaciones Agrobiológicas de Galicia, CSIC, Avda de Vigo s/n, Apartado 122, 15780 Santiago de Compostela, Spain E-mail: sanjose@iiag.csic.es
• Romero, CIFP Politécnico de Santiago, Santiago de Compostela, Spain E-mail: lr@nn.es
• Janeiro, INLUDES, Diputación Provincial de Lugo, Lugo, Spain E-mail: lauravj68@hotmail.com

This work focuses on the combined occurrence of wind, snow loading and soil frost with implications for risks to forestry in Finland under the current and changing climatic conditions. For this purpose, we employ meteorological datasets, available for the period of 1971–2009 and global climate model (GCM) simulations for the current climate 1971–2000, and periods 2046–65 and 2081–2100 applying the A1B-climate change scenario. Based on our results, the wind and snow induced risks to Finnish forests are projected to increase in the future although the change in the occurrence of strong winds is small. This is because soil frost depths that support tree anchorage from late autumn to early spring in Finland are projected to nearly disappear in the southern and central parts of the country. Heavy snow loads > 30 kg m^–2 are becoming more common in southern and eastern Finland despite that the average cumulative 5-day snow loads decrease in these areas by 18 to 50%, respectively. As a result of the changes in the combined occurrence of wind, snow loading and soil frost, the risk of climatic conditions making conifers liable to uprooting are projected to increase in southern, central and eastern Finland. In the north, the risk of stem breakage is becoming more pronounced under snow loading > 20 kg m^–2. Despite some uncertainties related to this work, we assume that the findings can serve as valuable support for the risk assessment of wind and snow induced damages to Finnish forests and for forestry, in general.

• Gregow, Finnish Meteorological Institute, Helsinki, Finland E-mail: hilppa.gregow@fmi.fi
• Peltola, University of Eastern Finland, Faculty of Forest Sciences, Joensuu, Finland E-mail: heli.peltola@uef.fi
• Laapas, Finnish Meteorological Institute, Helsinki, Finland E-mail: ml@nn.fi
• Saku, Finnish Meteorological Institute, Helsinki, Finland E-mail: ss@nn.fi
• Venäläinen, Finnish Meteorological Institute, Helsinki, Finland E-mail: av@nn.fi

In order to understand the processes of snow and wind induced damage in a natural montane, secondary forest in northeastern China, we examined the impacts of site conditions on the snow and wind damage; analyzed if the dominant tree species differed in their susceptibilities to the damage; and established the relationships between the characteristics of tree and stand and the damage. The results indicated that in regard to the topography factors, slope steepness and soil depth played a relatively important role for the damage. Damage ratios of all types combined were positively related with the composition of dominant tree species. The stand density was also important in determining resistance to the damage, i.e., the densely populated stand exhibited less overall damage ratios; however, the dominant tree species were commonly damaged easily by the snow and wind. Four damage modes found (uprooting, stem breakage, canopy damage and bending) were closely related to the stem taper (p < 0.05), and they could be ranked in following order: bending (92.0 ) > uprooting (85.3) > stem breakage (80.1) > canopy damage (65.0). In regard to differences in tree species’ susceptibilities to the damage, Betula costata exhibited the most uprooting, bending and overall damage ratios; while Quercus mongolica showed the highest breakage (both stem breakage and canopy damage) ratio, and Fraxinus mandshurica exhibited the least damage ratio (overall). The major six tree species could also be divided into two groups according to the overall damage ratios, i.e., more susceptible ones (B. costata, Ulmus laciniata and Q. mongolica), and less susceptible ones (F. mandshurica, Acer mono and Juglans mandshurica) to the snow and wind damage.

• Zhu, Institute of Applied Ecology, Chinese Academy of Sciences, Wenhua Road 72, Shenyang 110016, China E-mail: zrms29@yahoo.com
• Li, Institute of Applied Ecology, Chinese Academy of Sciences, Wenhua Road 72, Shenyang 110016, China; Graduate School of Chinese Academy of Sciences, Yuquan Road 19-A, Beijing, 100039, China E-mail: xfl@nn.cn
• Liu, Institute of Applied Ecology, Chinese Academy of Sciences, Wenhua Road 72, Shenyang 110016, China; Graduate School of Chinese Academy of Sciences, Yuquan Road 19-A, Beijing, 100039, China E-mail: zgl@nn.cn
• Cao, Institute of Applied Ecology, Chinese Academy of Sciences, Wenhua Road 72, Shenyang 110016, China E-mail: wc@nn.cn
• Gonda, Faculty of Agriculture, Niigata University, Ikarashi 2-8050, Niigata, 950-2181, Japan E-mail: yg@nn.jp
• Matsuzaki, Faculty of Agriculture, Niigata University, Ikarashi 2-8050, Niigata, 950-2181, Japan E-mail: tm@nn.jp