|
|
Dynamika růstu buku lesního (Fagus sylvatica L.) ve smíšeném lese a monokultuře ve Východních Karpatech
Vyčítalová, Hana
The study observes the difference in the growth dynamics of common beech (Fagus sylvatica L.) in monocultures and in stands with admixture of conifers like Norway spruce (Picea abies L.) and/or Silver fir (Abies alba Mill.) in the Eastern Carpathians. Point dendrometers and soil humidity sensors were used for measurement of tree growth and water availability that took place near the Râșca in the Suceava region. Out of the growing season, hemispherical ("fish-eye") images were also taken to evaluate canopy openness. Mixed models were used for the statistical evaluation of the data. Negative effect of increasing the percentage of conifers in the stand on growth and the maximum growth rate of beech was found insignifficant, which give an evidence of beeches strong competitive ability in habitats with favorable conditions. However, a negative effect of a higher admixture percentage of conifers on the availability of water in the soil was signifficant, probably due to higher interception, which indicates possible problems when growing beech with a high admixture of conifers in drought-prone locations. The growth rate was highest at the turn of June and July, which refers to the dependence of beech growth dynamics on the solar cycle and indicates that drought could have the strongest negative impact on growth in the period around the summer solstice. On the basis of the obtained results, beech silviculture could be recommended with only a small admixture of conifers, and the admixture of other deciduous trees should be preferred in order to reduce the interception of the stand
|
|
|
Long-term productivity of short rotation coppice under decreased soil water availability
Orság, Matěj ; Fischer, Milan ; Tripathi, Abishek ; Žalud, Zdeněk ; Trnka, Miroslav
Wood, in fact, is the unsung hero of the technological revolution that has brought us from a stone and bone culture to our present age (Perlin 1991). Given its high-energy content and versatile use, biomass in the form of wood has been used for energy purposes for millennia. The production and use of woody biomass resources has been expanding around the world. The main drivers of its use as a source of energy are diversification and mitigation of energy related greenhouse gas emissions through partial substitution for fossil fuels. An alternative to sourcing wood biomass from natural forests is short rotation woody coppice. Its productivity is largely dependent on the environment in terms of climatic conditions. Especially drought is the main constraint on woody biomass production and involves serious economic consequences. For that reason, our field experiment was designed to evaluate the impact of decreased soil water availability on productivity of a poplar based short rotation coppice plantation over multiple growing seasons during 2011–2014. Aboveground biomass productivity of treatments with and without throughfall exclusion was assessed within this study. Our results show a systematic decline in the productivity of the plots subjected to decreased soil water availability by 30% in 2011, 20% in 2012, 49% in 2013, and 51% in 2014 compared to control plot. Aboveground biomass productivity ranged from 8.8 to 9.9 t dry matter ha−1 year−1 for the control treatment and 4.5 to 8.0 t dry matter ha−1 year−1 for the treatment with throughfall exclusion.On average, the throughfall exclusion treatment exhibited 47% less productivity than control treatment had over the entire study period.
|
|
|
Water balance in short rotation poplar coppice and reference grass-plot in conditions of Czech-Moravian Highlands
Orság, Matěj ; Fischer, Milan ; Trnka, Miroslav ; Hlavinka, Petr ; Kučera, J. ; Balek, J. ; Žalud, Zdeněk
This text presents results of a study focusing on differences of water balance between two contrasting cultures - short rotation poplar coppice and grass plot in conditions of Czech-Moravian Highlands. Actual evapotranspiration (by Bowen ratio energy balance method), precipitation and soil moisture in two layers (0 – 0.45 m and 0.45 – 0.90 m) were measured on both plots during seasons 2008 – 2010. The seasonal water lost through evapotranspiration was higher for the grass (560.4 and 508 mm for grass and 523.8 and 351.8 mm for poplar during growing season 2009 and 2010 respectively), but generally the observed amounts of ETa are comparable for both cultures and within the range of values described in literature. Results of soil moisture measurements expressed as soil water availability [mm] were compared with simulations obtained from water balance model SoilClim. The model a little bit underestimated the amount of available water in the system, since based on water balance closure we suggest that there is a higher water income than was recorded from precipitation. This extra water found in observed systems may be supplied probably by lateral underground water inflow from the upper fields.
|
guest ::
