Potential of hybrid aspen (Populus tremuloides Michx. × Populus tremula L.) production in Latvia

Author(s):  
Mārtiņš Zeps
Holzforschung ◽  
2013 ◽  
Vol 67 (5) ◽  
pp. 505-510
Author(s):  
Inese Sable ◽  
Uldis Grinfelds ◽  
Martins Zeps ◽  
Ilze Irbe ◽  
Guna Noldt ◽  
...  

Abstract Micropropagated hybrid aspen clones (Populus tremuloides Michx.×Populus tremula L.) and a plus-tree (superior phenotypes selected) aspen (Populus tremula L.) were grown under similar conditions in the central part of Latvia. After cutting at the age of 12 years, 64 sample trees were examined. The dimensions of the vessels and the content of cellulose, lignin, extractives and ash were determined. The cell walls were characterised by UV microspectrophotometry (UMSP) in the UV range. The dimensions of fibres obtained by kraft pulping were determined such as length, width, and their shape factors. Coarseness measurements were performed, and strength properties of the handsheets were tested. One of the clones (no. 44) had a significantly higher stem volume of 208 dm3 and stem diameter of 17 cm at a height of 1.3 m. This clone had otherwise no notable differences to the other clones concerning the chemical composition, except a slightly higher lignin content (20.0% as compared with the mean value of 19.3% for other clones). Kraft cooking of hybrid aspen chips gave pulp yields in the range of 48.6–52.4%. Slightly higher strength properties (10–15%) were found for the handsheets prepared from a common aspen pulp (reference) as compared with those from hybrid aspen fibres.


2013 ◽  
Vol 198 (3) ◽  
pp. 788-800 ◽  
Author(s):  
Zhihong Sun ◽  
Ülo Niinemets ◽  
Katja Hüve ◽  
Bahtijor Rasulov ◽  
Steffen M. Noe

2008 ◽  
Vol 29 (1) ◽  
pp. 53-66 ◽  
Author(s):  
E. Haikio ◽  
V. Freiwald ◽  
R. Julkunen-Tiitto ◽  
E. Beuker ◽  
T. Holopainen ◽  
...  

Silva Fennica ◽  
2001 ◽  
Vol 35 (1) ◽  
Author(s):  
Qibin Yu ◽  
P. Tigerstedt ◽  
Matti Haapanen

2007 ◽  
Vol 37 (11) ◽  
pp. 2326-2336 ◽  
Author(s):  
Elina Häikiö ◽  
Vera Freiwald ◽  
Tarja Silfver ◽  
Egbert Beuker ◽  
Toini Holopainen ◽  
...  

Impacts of elevated tropospheric ozone and soil nitrogen amendment on two native European aspen ( Populus tremula L.) and eight hybrid aspen (P. tremula L. × Populus tremuloides Michx.) clones were studied in a free-air ozone exposure system. Potted saplings were exposed to ambient (ca. 20 ppb) or 1.5× ambient ozone and two levels of soil nitrogen (39 and 78 kg N·ha–1·year–1 in the first year, 60 and 140 kg N·ha–1·year–1 in the second year for low-nitrogen and high-nitrogen treatments, respectively) over two growing seasons. The plants were measured for photosynthesis, chlorophyll fluorescence, and biomass accumulation. Ozone decreased leaf-level net photosynthesis (Asat) in particular early in the growing season and maximum quantum yield of photosystem II (Fv/Fm) at the end of the growing season. Nitrogen amendment increased the growth of all plant parts and mitigated the adverse ozone effects. There were significant differences in ozone responses among the clones, and we were able to cluster the clones into sensitivity groups based on their growth responses. The most ozone-tolerant genotypes were hybrid aspen clones, indicating that populations that have already experienced selection for ozone-tolerant genotypes should be used to cross-breed with ozone-sensitive populations to achieve tolerance of a climate with increasing tropospheric ozone concentrations.


Author(s):  
Skaidrīte Būmane ◽  
Liena Poiša ◽  
Aleksandrs Adamovičs ◽  
Rasma Platače ◽  
Edgars Čubars

For solid fuels ash melting temperature is recommended to be higher than 1000°C, so that it can be used in automated furnaces; therefore-promising energy crops are investigated as renewable energy source. This paper presents the results of tests on melting temperature of different energy crop ashes.The field trial was carried out in the study farm of the Latvia University of Agriculture "Pēterlauki" (56°53'N, 23°71'E) in the sod calcareous soils characterized by pH KCl 6.7, P 52 mg kg-1, K 128 mg kg-1, organic matter content from 21 to 25 g kg-1 in the soil. Energy crops analysed: reed canary grass (Phalaris arundinacea L.), birch (Betula pendula Roth.), osier (Salix spp.), grey alder (Alnus incana (L.) Moench), poplar (Populus tremula L.), hybrid aspen (Populus tremuloides x Populus tremula). Results indicate that the ash melting temperature (D, St, Ht, Ft) for the wood energy crops were higher than for the studied grass energy crops and their mixture. Ash melting temperature in all phases over 1200°C was observed for such poplar and hybrid aspen mixture proportions: 3 parts of wood and 1 part of reed canary grass, or 1 part of wood and 1 part of reed canary grass.


2009 ◽  
Vol 35 (6) ◽  
pp. 664-678 ◽  
Author(s):  
E. Häikiö ◽  
M. Makkonen ◽  
R. Julkunen-Tiitto ◽  
J. Sitte ◽  
V. Freiwald ◽  
...  

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